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1981
W PROFMWANGIJULIUS, N PROFGUANTAIA. "C.K. Maitai, A.N. Guantai and J.W. Mwangi (1981). Self-medication in management of minor health problem in Kenya. E.A. Medical J. 58: 593-600.". In: E.A. Medical J. 58: 593-600. A.N. GUANTAI and C.K. MAITA; 1981. Abstract
he distribution of cathinone and d-norpseudoephedrine in Catha edit/is plants from 2 different geographical localities has been investigated. There was no difference in the chemical constituents of Catha material from 2 locali-ties. D-norpseudoephedrine was present in all parts of the plant examined except the root but cathinone was only detected in the young shoots and bran-chlets. It is concluded that the psychostinaulant effect following chewing of young Catha shoots is due to both cathinone and d-norpseudoephedrine with the cathinone being more important since it is 7-10 times more potent than d-norpseudoephedrine.
N PROFGUANTAIA. "SELF MEDICATION IN MANAGEMENT OF MINOR HEALTH PROBLEMS IN KENYA.". In: THE EAST AFRICAN MEDICAL JOURNAL. C.K. Maitai, AN Guantai, Mwangi; 1981. Abstract
A survey of proprietary pharmaceutical products used inslf-medication, in Kenya, has been undertaken. Out of 472 products covered in the survey, 32% were those used for gastrointestinal disorders and 18% for respiratory disorders. The significance and limitations of self-medication as they relate to management of minor health problems are discussed.
N PROFGUANTAIA. "ESTABLISHMENT OF A BIOBANK AND PHARMACOGENETICS DATABASE OF AFRICAN POPULATIONS.". In: THE EAST AFRICAN MEDICAL JOURNAL. A Matimba, M Oluka, B Ebeshi, J Sayi, Bolaji, J Del Favero , C Van Broeckhoven, AN Guanta; 1981.
N PROFGUANTAIA. "Evaluation of the potential of the marine sponges of the Zanzibar Island to yield antimalarial and antimicrobial active compounds.". In: THE EAST AFRICAN MEDICAL JOURNAL. S.A.SAID, M.J.MOSHF, R.S.O. NOND(Y, 1; 1981.
N PROFGUANTAIA. "Maitai C.K Guantai A.N, and Mwangi J.W, Self Medication in management of Minor Health Problems in Kenya. East African Medical Journal 58 (8) 593 1981.". In: East African Medical Journal 58 (8) 593 1981. A.N. GUANTAI and C.K. MAITA; 1981. Abstract

he distribution of cathinone and d-norpseudoephedrine in Catha edit/is plants from 2 different geographical localities has been investigated. There was no difference in the chemical constituents of Catha material from 2 locali-ties. D-norpseudoephedrine was present in all parts of the plant examined except the root but cathinone was only detected in the young shoots and bran-chlets. It is concluded that the psychostinaulant effect following chewing of young Catha shoots is due to both cathinone and d-norpseudoephedrine with the cathinone being more important since it is 7-10 times more potent than d-norpseudoephedrine.

N PROFGUANTAIA. "Mwangi J.W., Guantai A.N. and Muriuki G. Eucalyptus Citriodora - Essential oil contents and chemical varieties in Kenya. E.Afric. Agr. For J. 46, 89 1981.". In: E.Afric. Agr. For J. 46, 89 1981. A.N. GUANTAI and C.K. MAITA; 1981. Abstract

he distribution of cathinone and d-norpseudoephedrine in Catha edit/is plants from 2 different geographical localities has been investigated. There was no difference in the chemical constituents of Catha material from 2 locali-ties. D-norpseudoephedrine was present in all parts of the plant examined except the root but cathinone was only detected in the young shoots and bran-chlets. It is concluded that the psychostinaulant effect following chewing of young Catha shoots is due to both cathinone and d-norpseudoephedrine with the cathinone being more important since it is 7-10 times more potent than d-norpseudoephedrine.

N PROFGUANTAIA. "PHARMACOGENETICS OF DRUG METABOLIZING ENZYMES IN THE LUO, KIKUYU AND MAASAI ETHINIC POPULATIONS OF KENYA.". In: THE EAST AFRICAN MEDICAL JOURNAL. MN Oluka, A Matimba,AN Guantai, C Masirembwa, BH Estambale; 1981. Abstract

ere is great heterogeneity in the way individuals and populations respond to medications in terms of both host toxicity and efficacy. It is now well recognized that genetic differences in drug metabolism and disposition as well in drug target receptors could have an even greater influence on the efficacy and toxicity of medications. A Wide range of drug metabolizing enzymes (DME) are subject to genetic polymorphism. The genotype-phenotype relationship is particularly important for drugs with narrow therapeutic index where slight changes in plasma levels can result in serious toxicity or lack of efficacy. While Caucasian and oriental populations have benefited from the intense interest in the field of pharmacogenomics, there still exists a wide gap in this knowledge on African populations. Hence, the main objective of this study was to investigate the occurrence and frequency of allelic variants of polymorphic DME in three major ethnic populations in Kenya.

1982
N PROFGUANTAIA. "DISTRIBUTION OF CATHINONE AND D-NORPSEUDOEPHEDRINE IN CATHA EDULIS.". In: EAST AFRICAN MEDICAL JOURNA. A.N. GUANTAI and C.K. MAITA; 1982. Abstract
he distribution of cathinone and d-norpseudoephedrine in Catha edit/is plants from 2 different geographical localities has been investigated. There was no difference in the chemical constituents of Catha material from 2 locali-ties. D-norpseudoephedrine was present in all parts of the plant examined except the root but cathinone was only detected in the young shoots and bran-chlets. It is concluded that the psychostinaulant effect following chewing of young Catha shoots is due to both cathinone and d-norpseudoephedrine with the cathinone being more important since it is 7-10 times more potent than d-norpseudoephedrine.
K PROFMAITAICHARLES, N PROFGUANTAIA. "Guantai AN, Maitai CK.Relative distribution of cathinone and D-norpseudoephedrine in Catha edulis (Miraa) growing in Kenya.East Afr Med J. 1982 Jun;59(6):394-8.". In: East Afr Med J. 1982 Jun;59(6):394-8. A. N. GUANTAI, J. W. MWANG1, G1CHURU MURIUKI and K. A. M. KURIA; 1982. Abstract
Cathinone, a potent psychostimulant isolated from young shoots of Catha edulis was given to four human volunteers. Examination of urine collected from the volunteers at predetermined intervals showed the presence of unchanged cathinone, d-norpseudoephedrine, and two unidentified basic substances. The observed biotransformation of cathinone to the less potent psychostimulant, d-norpseudoephedrine involves reduction of a ketone group to alcohol, a common metabolic pathway in humans.
N PROFGUANTAIA. "Relative distribution of cathinone and D-norpseudoephedrine in Catha edulis (Miraa) growing in Kenya. East Afr Med J. 1982 Jun;59(6):394-8.". In: East Afr Med J. 1982 Jun;59(6):394-8. A. N. GUANTAI, J. W. MWANG1, G1CHURU MURIUKI and K. A. M. KURIA; 1982. Abstract
Cathinone, a potent psychostimulant isolated from young shoots of Catha edulis was given to four human volunteers. Examination of urine collected from the volunteers at predetermined intervals showed the presence of unchanged cathinone, d-norpseudoephedrine, and two unidentified basic substances. The observed biotransformation of cathinone to the less potent psychostimulant, d-norpseudoephedrine involves reduction of a ketone group to alcohol, a common metabolic pathway in humans.
N PROFGUANTAIA. "Relative distribution of cathinone and D-norpseudoephedrine in Catha edulis (Miraa) growing in Kenya. East Afr Med J. 1982 Jun;59(6):394-8.". In: East Afr Med J. 1982 Jun;59(6):394-8. A. N. GUANTAI, J. W. MWANG1, G1CHURU MURIUKI and K. A. M. KURIA; 1982. Abstract
Cathinone, a potent psychostimulant isolated from young shoots of Catha edulis was given to four human volunteers. Examination of urine collected from the volunteers at predetermined intervals showed the presence of unchanged cathinone, d-norpseudoephedrine, and two unidentified basic substances. The observed biotransformation of cathinone to the less potent psychostimulant, d-norpseudoephedrine involves reduction of a ketone group to alcohol, a common metabolic pathway in humans.
1983
K PROFMAITAICHARLES, N PROFGUANTAIA. "Guantai AN, Maitai CK. Metabolism of cathinone to d-norpseudoephedrine in humans.J Pharm Sci. 1983 Oct;72(10):1217-8.". In: J Pharm Sci. 1983 Oct;72(10):1217-8. A. N. GUANTAI, J. W. MWANG1, G1CHURU MURIUKI and K. A. M. KURIA; 1983. Abstract
Cathinone, a potent psychostimulant isolated from young shoots of Catha edulis was given to four human volunteers. Examination of urine collected from the volunteers at predetermined intervals showed the presence of unchanged cathinone, d-norpseudoephedrine, and two unidentified basic substances. The observed biotransformation of cathinone to the less potent psychostimulant, d-norpseudoephedrine involves reduction of a ketone group to alcohol, a common metabolic pathway in humans.
N PROFGUANTAIA. "Metabolism of cathinone to d-norpseudoephedrine in humans. J Pharm Sci. 1983 Oct;72(10):1217-8.". In: J Pharm Sci. 1983 Oct;72(10):1217-8. A. N. GUANTAI, J. W. MWANG1, G1CHURU MURIUKI and K. A. M. KURIA; 1983. Abstract
Cathinone, a potent psychostimulant isolated from young shoots of Catha edulis was given to four human volunteers. Examination of urine collected from the volunteers at predetermined intervals showed the presence of unchanged cathinone, d-norpseudoephedrine, and two unidentified basic substances. The observed biotransformation of cathinone to the less potent psychostimulant, d-norpseudoephedrine involves reduction of a ketone group to alcohol, a common metabolic pathway in humans.
1985
W PROFMWANGIJULIUS, N PROFGUANTAIA. "J.W. Mwangi, A.N. Guantai and Gichuru Muriuki (1985) Eucalyptus citriodora .". In: E. Africa Agric. For. J. 46: 89-96. A. N. GUANTAI, J. W. MWANG1, G1CHURU MURIUKI and K. A. M. KURIA; 1985.
1986
N PROFGUANTAIA. "Mwangi J.W. Guantai A.N., Muriuki G.m Essential oil of Plectrathus marrubiodes Benth. Kenya J. Sci. Technnol (A 63 1986.". In: Kenya J. Sci. Technnol (A 63 1986. A. N. GUANTAI, J. W. MWANG1, G1CHURU MURIUKI and K. A. M. KURIA; 1986.
1987
N PROFGUANTAIA. "EFFECTS OF THE ACTIVE CONSTITUENTS OF CATHA EDULIS ON THE NEUROMUSCULAR JUNCTION.". In: Pergarnon Journals Ltd. A. N. GUANTAI, J. W. MWANG1, G1CHURU MURIUKI and K. A. M. KURIA; 1987.
N PROFGUANTAIA. "Effects of the active constituents of Catha edulis on the neuromuscular junction.Guantai AN, Mwangi JW, Muriuki G, Kuria KA. Neuropharmacology. 1987 May;26(5):401-5.". In: Neuropharmacology. 1987 May;26(5):401-5. Ivan Addae-Mensah,t Rahab Munenge and Anastasia N. Guantai; 1987. Abstract
(-)-Cathinone and d-norpseudoephedrine (DNE) in the dose range 0.2-1.2 mg/ml produced a reduction in contractions of skeletal muscle, evoked by direct and indirect electrical stimulation and antagonised the facilitatory action of physostigmine on the neuromuscular junction; but failed to antagonise a partial blockade induced by d-tubocurarine (dTb) as occurs with norepinephrine or epinephrine. The local anaesthetic actions of (-)-cathinone and DNE were found to be almost equivalent to that of lignocaine. These results indicate that (-)-cathinone and DNE may have a direct blocking action on the neuromuscular junction, which is independent of cholinergic and adrenergic transmission.
1988
W PROFMWANGIJULIUS, N PROFGUANTAIA. "J.W. Mwangi, G. Muriuki, A.N. Guantai and W. Lwande (1988). Volatile constituents of Ocimum fischeri Guerke. Kenya J. Sci. B.9: 119-121.". In: Kenya J. Sci. B.9: 119-121. Ivan Addae-Mensah,t Rahab Munenge and Anastasia N. Guantai; 1988. Abstract

Cardiovascular activities of nitidine chloride from Zanthoxylunt chalybeum have been compared with those of 9-methoxychelerythrine. Whereas nitidinc chloride was found to show significant hypotensive activity in rabbits, 9-methoxychelerythrine chloride showed no hypotensive activity. The effect of nitidine chloride on isolated rabbit heart was also compared with those of adrenaline and acetylcholine. 9-Methoxychelerythrine, which has hitherto been regarded as an artefact formed by recrystallization of chelerythrine base from methanol, has been shown in this work to be a true natural constituent of Zanthoxylum chalybeum. Keywords: 9-inethoxychelerythrine; nitidine chloride; cardiovascular properties; hypotensive effect; Zanthoxylum chalybeum.

N PROFGUANTAIA. "Mwangi J.W. Guantai A.N., Muriuki G., Kwande W.Constituents of the essential oil of ocimum fischeri guerke. Kenya J. Sci series (B) 9:119-121 1988.". In: Kenya J. Sci series (B) 9:119-121 1988. Ivan Addae-Mensah,t Rahab Munenge and Anastasia N. Guantai; 1988. Abstract

Cardiovascular activities of nitidine chloride from Zanthoxylunt chalybeum have been compared with those of 9-methoxychelerythrine. Whereas nitidinc chloride was found to show significant hypotensive activity in rabbits, 9-methoxychelerythrine chloride showed no hypotensive activity. The effect of nitidine chloride on isolated rabbit heart was also compared with those of adrenaline and acetylcholine. 9-Methoxychelerythrine, which has hitherto been regarded as an artefact formed by recrystallization of chelerythrine base from methanol, has been shown in this work to be a true natural constituent of Zanthoxylum chalybeum. Keywords: 9-inethoxychelerythrine; nitidine chloride; cardiovascular properties; hypotensive effect; Zanthoxylum chalybeum.

1989
N PROFGUANTAIA. "Comparative Examination of Two Zanthoxylum Benzophenanthridine Alkaloids for Cardiovascular Effects in Rabbits.". In: EAST AND CENTRAL AFRICAN JOURNAL OF PHARMACEUTICAL SCIENCES - VOL. 1. Ivan Addae-Mensah,t Rahab Munenge and Anastasia N. Guantai; 1989. Abstract

Cardiovascular activities of nitidine chloride from Zanthoxylunt chalybeum have been compared with those of 9-methoxychelerythrine. Whereas nitidinc chloride was found to show significant hypotensive activity in rabbits, 9-methoxychelerythrine chloride showed no hypotensive activity. The effect of nitidine chloride on isolated rabbit heart was also compared with those of adrenaline and acetylcholine. 9-Methoxychelerythrine, which has hitherto been regarded as an artefact formed by recrystallization of chelerythrine base from methanol, has been shown in this work to be a true natural constituent of Zanthoxylum chalybeum. Keywords: 9-inethoxychelerythrine; nitidine chloride; cardiovascular properties; hypotensive effect; Zanthoxylum chalybeum.

1993
N PROFGUANTAIA. "A Retrospective Study of Childhood Poisoning in Kenya.". In: EAST AND CENTRAL AFRICAN JOURNAL OF PHARMACEUTICAL SCIENCES - VOL. 1. CHARLES K. MAITAI*, ISAAC 0. KIBWAGE, ANASTASIA N. GUANTAI, JAMES N. OMBEGA AND FRANCIS A. NDEM0; 1993. Abstract

A literature survey revealed lack of adequate information on poisoning in Kenya, thus providing the impetus for the present work. In this, study, a 3 year retrospective survey of human poisoning in 19 Kenyan District, Provincial hospitals and Kenyatta National Hospital (KNH), representing approximately 40% of such public hospitals in the country, was carried out. Cases of poisoning were identified by diagnosis codes entered on hospital records at the time of discharge. A total of 1904 cases of poisoning were recorded and the information analyzed with particular focus on childhood poisoning. Distribution pattern with respect to poisoning agents, age and sex is presented. Children aged 0-5 years account for 29.78% while those aged 6-14 years account for 10.24% of cases of poisoning recorded. In the age group 0-5 years, Kerosine, drugs and organophosphates account for 41.09, 23.81 and 15.17% of poisoning cases respectively. It is concluded that any preventive measures targeted at children must focus on the 3 classes of poisons which together account for approximately 80% of all classes of poisoning in children.

1998
N PROFGUANTAIA. "Chloroquine Drug Interactions Part I: Interaction with drugs acting at the neuromuscular junction.". In: EAST AND CENTRAL AFRICAN JOURNAL OF PHARMACEUTICAL SCIENCES, VOL. I. ANASTASIA N. GUANTAI , IVAN ADDAE-MENSAH, DAVID K. NJOROGE; 1998. Abstract

Chloroquine is extensively used in the management of malaria in Kenya. It is widely available for self medication. Often it is used concurrently with other drugs. In the present paper, possible drug interactions with Chloroquine have been investigated. Isolated rat phrenic nerve diaphragm preparation was used to study the effect of Chloroquine alone and in combination with several drugs on neuromuscular impulse transmission. Chloroquine in the dose range 0.025 - 0.3 vg/m1 organ bath concentration induced a dose-dependent neuromuscular junction (NMJ) transmission blockade. The drug significantly potentiated the NMJ transmissionblockade induced by commonly used agents gallamine, succinylcholine and lignocaine. It antagonised the NMJ facilitatory action of physostigmine, calcium chloride and barium chloride. Chloraquine could. be interfering with ion conductance processes. It is suggested that Chloroquine should be used with caution in conditions characterised by muscle contractile disorders or during treatment with drugs that cause decreased skeletal muscle activity. Key Words: Chloroquine, interactions, neuromuscular junction.

N PROFGUANTAIA. "Guantai A.N., Addae-Mensah I.,. Njoroge D.K.. Chloroquine Drug Interactions. Part I Interaction with drugs on the neuromuscular junction. The East and /central African Journal of Pharmaceutical Sciences Vol. 1 (3)-50-53 Dec. 1998.". In: The East and /central African Journal of Pharmaceutical Sciences Vol. 1 (3)-50-53 Dec. 1998. F.A. OKALEBO*, H.A. RABAHI, A.N. GUANTAII, C.K. MALTA', I.0. K1BWAGE, J.W. MWANGI AND W. MASENGO; 1998. Abstract

The in vitro antimalarial activity of the root extract in partly supports the ethnobotanical use of the plant to manage malaria. Clematis brachiata Thunberg (Ranunculaceae) is used in Kenya for the management of headaches, malaria and other febrile illnesses, abdominal disorders, yaws and for skin disorders. Old stems and leaves are chewed for the management of toothaches and sore throats. Extracts of the plant were subjected to tests for antimalarial, antibacterial and antifungal activity. The toxicity of the extracts was assessed using the brine shrimp lethality bioassay. The root extract gave the highest in vitro antimalarial activity against the inulitidrug resistant strain, Plasmodium falciparum VI/S (IC50=39.24 jig/nil). The stem and leaf extracts had insignificant antiplasmodial activity. The leaf, stein and root extracts had no bacterial or fungal inhibitory effects even at very high concentrations of 10 mg/ml. The Lll50 values of the stem and leaf methanol extracts against the brine shrimp larvae was 365.60 and 66.5 jig/ml, respectively. Key Words: Clematis brachiata, Ranuneulaceae, antimalarial, antibacterial, antifungal, brine shrimp.

N PROFGUANTAIA. "Maitai C.K., Kibwage I.O., Guantai A.N., Ombega J.O and Ndemo F.A. A retrospective study of childhood poisoning in Kenya 1991-93 E.C.A.J. PSc. 1.7-10. 1998.". In: E.C.A.J. PSc. 1.7-10. 1998. F.A. OKALEBO*, H.A. RABAHI, A.N. GUANTAII, C.K. MALTA', I.0. K1BWAGE, J.W. MWANGI AND W. MASENGO; 1998. Abstract

The in vitro antimalarial activity of the root extract in partly supports the ethnobotanical use of the plant to manage malaria. Clematis brachiata Thunberg (Ranunculaceae) is used in Kenya for the management of headaches, malaria and other febrile illnesses, abdominal disorders, yaws and for skin disorders. Old stems and leaves are chewed for the management of toothaches and sore throats. Extracts of the plant were subjected to tests for antimalarial, antibacterial and antifungal activity. The toxicity of the extracts was assessed using the brine shrimp lethality bioassay. The root extract gave the highest in vitro antimalarial activity against the inulitidrug resistant strain, Plasmodium falciparum VI/S (IC50=39.24 jig/nil). The stem and leaf extracts had insignificant antiplasmodial activity. The leaf, stein and root extracts had no bacterial or fungal inhibitory effects even at very high concentrations of 10 mg/ml. The Lll50 values of the stem and leaf methanol extracts against the brine shrimp larvae was 365.60 and 66.5 jig/ml, respectively. Key Words: Clematis brachiata, Ranuneulaceae, antimalarial, antibacterial, antifungal, brine shrimp.

2000
N PROFGUANTAIA. "Guantai A.N and Addae-Mensah I.Chloroquine Drug Interactions Part 1I. Interactions with diuretics. East and Central African Journal of Pharmaceutical Sciences Vol (3. No.3, 31-35 (2000).". In: East and Central African Journal of Pharmaceutical Sciences Vol (3. No.3, 31-35 (2000). F.A. OKALEBO*, H.A. RABAHI, A.N. GUANTAII, C.K. MALTA', I.0. K1BWAGE, J.W. MWANGI AND W. MASENGO; 2000. Abstract

The in vitro antimalarial activity of the root extract in partly supports the ethnobotanical use of the plant to manage malaria. Clematis brachiata Thunberg (Ranunculaceae) is used in Kenya for the management of headaches, malaria and other febrile illnesses, abdominal disorders, yaws and for skin disorders. Old stems and leaves are chewed for the management of toothaches and sore throats. Extracts of the plant were subjected to tests for antimalarial, antibacterial and antifungal activity. The toxicity of the extracts was assessed using the brine shrimp lethality bioassay. The root extract gave the highest in vitro antimalarial activity against the inulitidrug resistant strain, Plasmodium falciparum VI/S (IC50=39.24 jig/nil). The stem and leaf extracts had insignificant antiplasmodial activity. The leaf, stein and root extracts had no bacterial or fungal inhibitory effects even at very high concentrations of 10 mg/ml. The Lll50 values of the stem and leaf methanol extracts against the brine shrimp larvae was 365.60 and 66.5 jig/ml, respectively. Key Words: Clematis brachiata, Ranuneulaceae, antimalarial, antibacterial, antifungal, brine shrimp.

2002
N PROFGUANTAIA, N PROFGUANTAIA. "The Antimalarial and Antimicrobial Activity and Brine Shrimp Toxicity of Clematis Brachiata Extracts.". In: East and Central African Journal of Pharmaceutical Sciences Vol. 5. F.A. OKALEBO*, H.A. RABAHI, A.N. GUANTAII, C.K. MALTA', I.0. K1BWAGE, J.W. MWANGI AND W. MASENGO; 2002. Abstract

The in vitro antimalarial activity of the root extract in partly supports the ethnobotanical use of the plant to manage malaria. Clematis brachiata Thunberg (Ranunculaceae) is used in Kenya for the management of headaches, malaria and other febrile illnesses, abdominal disorders, yaws and for skin disorders. Old stems and leaves are chewed for the management of toothaches and sore throats. Extracts of the plant were subjected to tests for antimalarial, antibacterial and antifungal activity. The toxicity of the extracts was assessed using the brine shrimp lethality bioassay. The root extract gave the highest in vitro antimalarial activity against the inulitidrug resistant strain, Plasmodium falciparum VI/S (IC50=39.24 jig/nil). The stem and leaf extracts had insignificant antiplasmodial activity. The leaf, stein and root extracts had no bacterial or fungal inhibitory effects even at very high concentrations of 10 mg/ml. The Lll50 values of the stem and leaf methanol extracts against the brine shrimp larvae was 365.60 and 66.5 jig/ml, respectively. Key Words: Clematis brachiata, Ranuneulaceae, antimalarial, antibacterial, antifungal, brine shrimp.

N PROFGUANTAIA. "Kamau F,N. I.O.Kibwage, Muriuki G, Guantai A.N., Hoog martens J, Roets E, Govaerts, C; Chepkwony. H. and Busson R.Estrogenic and Anti-inflamatory activity of a steroidal. Idoxyl, The East and Central Journal of Pharmaceutical Sciences Vol. 5 (3) 44-48 Dec.". In: The East and Central Journal of Pharmaceutical Sciences Vol. 5 (3) 44-48 Dec 2002. F. N. KAMAU., 1.0. KIBWAGE, A. N. GUANTAI, G. MURIUKI R. MUNENGE; 2002. Abstract

The anti-inflammatory and antidiarrhoeal activities of 3(1-Hydroxy-16. 17-seco-16- nor-5-androsten-15-(2-indoxyliden)-17-oic acid (I) are reported. After intraperitoneal administration, compound (I) gave an ED50 of 9.5 mg/kg using the carrageenan induced rat paw oedema anti-inflammatory assay method. Indomethacin had an ED50 of 5.8 mg/kg in this assay. Compound (I) and indomethacin caused comparable and dose-dependent varying degrees of delay in diarrhoea and also significantly reduced net colonic water flux into the colon of rats induced by castor oil. Key words: Steroidal Indoxyl, Anti-Inflammatory, Antidiarrhoeal.

2003
N PROFGUANTAIA. "Anti-infiammatory and Anti-Diarrimeai Activities of a Steroidal indoxy.". In: East and Central African Journal of Pharmaceutical Sciences 6. F. N. KAMAU., 1.0. KIBWAGE, A. N. GUANTAI, G. MURIUKI R. MUNENGE; 2003. Abstract

The anti-inflammatory and antidiarrhoeal activities of 3(1-Hydroxy-16. 17-seco-16- nor-5-androsten-15-(2-indoxyliden)-17-oic acid (I) are reported. After intraperitoneal administration, compound (I) gave an ED50 of 9.5 mg/kg using the carrageenan induced rat paw oedema anti-inflammatory assay method. Indomethacin had an ED50 of 5.8 mg/kg in this assay. Compound (I) and indomethacin caused comparable and dose-dependent varying degrees of delay in diarrhoea and also significantly reduced net colonic water flux into the colon of rats induced by castor oil. Key words: Steroidal Indoxyl, Anti-Inflammatory, Antidiarrhoeal.

N PROFGUANTAIA. "Kamau F.N., Kibwage I.O, Guantai A.N. Muriuki G., Munenge, R.Anti-inflammatory and Anti-diarrhoea activities of a steroidal indoxyl: E. C. African Journal of Pharmaceutical Sciences Vol. 6 (2) pp 26.". In: African Journal of Pharmaceutical Sciences Vol. 6 (2) pp 26 . O Wesongah*l, GA Murilla, AN Guantai, RE Mdachi I, WM Karanja and TE Maitho; 2003. Abstract

hloramphenicol is a broad-spectrum antibiotic widely used in human and veterinary medicine due to its low cost and ready availability. However its use has been associated with serious adverse effects, (bone marrow suppression, hemolytic anaemia and aplastic anaemia) that may or may not be dose related. Consequently chloramphenicol is currently banned for use in food producing animals and restricted to non-food producing animals and management of life threatening infections in humans in absence of alternative therapy. Exposure to chloramphenicol can occur after regular consumption of animal foods from treated animals. Therefore the pharmacokinetic of chloramphenicol should be determined using a highly sensitive and specific assay method that can detect residue levels at the lowest concentration possible. Previous methods were limited due to low sensitivity (10 ng/m1-50Ong/mi). Therefore the aim of this study was to determine pharmacokinetics of chloramphenicol and potential residue levels in food producing animals using a published highly sensitive detection method; Chloramphenicol enzyme-linked immunosorbent assay, with a detection limit of 0.1 ng/ml. Methods: Eight male red Maasai sheep aged 9 to 12 months and weighing between 21kg to 25 kg, were weaned and allowed to acclimatize for three weeks. Pre-treatment blood samples (10m1) was collected from each animal and then 25mg/kg chloramphenicol sodium succinate administered by deep intramuscular injection. Post treatment blood samples were collected at 5, 10, 15 and 30minutes, I, 2, 4, 6 8, 12, 24 and 32 hour intervals then twice a day (week 1), once daily (week 2) thrice daily (week 3) twice daily (week 4). Phannacokinetic parameters were measured using chloramphenicol ELISA method. Data was analyzed by fitting four, parameter logistics regression curve of calibration standards and sample chloramphenicol concentration calculated from optical densities using ELISA data Eiaquik program (MC. Eisler, 1995). Samples were analyzed in duplicate. Results from these assays were compared with those from published data with respect to elimination half life, species variation, and minimum retention time. Results: Chlorarnphenicol elimination half life (36.4+3.66 h) obtained in the present study was significantly (P<0.05) longer than that of 5.75+1.25 h reported in similar species using colorimetric method. The method was able to detect the drug 7 days post administration. The area under the curve of 124,487.8 ng.h/m1 observed in sheep in the present study was significant higher than that of 31.220+3.25 rig.himl reported in literature in goats using similar treatment route and dose but different assay method. Conclusion: Chloramphenicol pharmacokinetic parameters are significantly influenced by animal species and analytical assay methods used in their determination and care must be taken when reporting the residue levels in food producing animals.

2006
Kamau FN, Kibwage IO, Muriuki G, Guantai, A N, Chepkwony H, Hoogmartens J, Roets E, Busson R. "Steroidal Indoxyls: Evaluation of Pk, values and anti-inflammatory activity.". 2006. Abstract

Three steroidal indoxyls, 3-oxo-16,17-seco-16;.nor-l,4-androstadien-15-(7'-methoxy-2-indoxyliden)17-oic acid, 1-(2'-indoxyliden)-2-nor-l,2-secocholestan-3~ oic acid and 1-(5'- chloro-2-indoxyliden)-2-nor-l,2-secocholestan-3-oic acid were synthesized and screened for anti-inflammatory activity. Their pK. values were also determined using a solubility method. The first compound, 3-oxo-16,17- seco-16-nor-l ,4-androstadien-15-(7' -methoxy-2-indoxyliden) 17 -oic acid, had an EDso value of 15.3 mg/kg and a pK. of 7.09. The cholestane derivative, 1-(2'-indoxyliden)-2-nor-l,2-secocholestan-3-oic acid, and its chloro analogue 1-(5'-chloro-2-indoxyliden)-2-nor-l,2-secocholestan-3-oic acid had EDso values of 16.2 and 22.8 mg/kg, while their pK. values were 6.56 and 7.07, respectively, suggesting that these compounds are relatively weak acids.

2007
N PROFGUANTAIA. "Antimalarial activity of some plants traditionally used in Meru district of Kenya.Muthaura CN, Rukunga GM, Chhabra SC, Omar SA, Guantai AN, Gathirwa JW, Tolo FM, Mwitari PG, Keter LK, Kirira PG, Kimani CW, Mungai GM, Njagi EN.Phytother Res. 2007 Sep;21(9).". In: Phytother Res. 2007 Sep;21(9):860-7. FA Okalebol , L Wiesner, AN Guantai, K Chibale, P Smith; 2007. Abstract

Ten plant extracts commonly used by the Meru community of Kenya were evaluated for the in vitro antiplasmodial, in vivo antimalarial, cytotoxicity and animal toxicity activities. The water and methanol extracts of Ludwigia erecta and the methanol extracts of Fuerstia africana and Schkuhria pinnata exhibited high antiplasmodial activity (IC(50) < 5 microg/mL) against chloroquine sensitive (D6) and resistant (W2) Plasmodium falciparum clones. The cytotoxicity of these highly active extracts on Vero E6 cells were in the range 161.5-4650.0 microg/mL with a selectivity index (SI) of 124.2-3530.7. In vivo studies of these extracts showed less activity with chemosuppression of parasitaemia in Plasmodium berghei infected mice of 49.64-65.28%. The methanol extract of Clerodendrum eriophyllum with a lower in vitro activity (IC(50) 9.51-10.56 microg/mL) exhibited the highest chemosuppression of 90.13%. The methanol and water extracts of Pittosporum viridiflorum were toxic to mice but at a lower dose prolonged survival of P. berghei infected mice (p < 0.05) with no overt signs of toxicity. However, the extracts were cytotoxic (SI, 0.96-2.51) on Vero E6 cells. These results suggest that there is potential to isolate active non-toxic antimalarial principles from these plants.

N PROFGUANTAIA. "Antimalarial activity of some plants traditionally used in treatment of malaria in Kwale district of Kenya.Muthaura CN, Rukunga GM, Chhabra SC, Omar SA, Guantai AN, Gathirwa JW, Tolo FM, Mwitari PG, Keter LK, Kirira PG, Kimani CW, Mungai GM, Njagi EN.J Et.". In: J Ethnopharmacol. 2007 Jul 25;112(3):545-51. Epub 2007 May 5. FA Okalebol , L Wiesner, AN Guantai, K Chibale, P Smith; 2007. Abstract

Methanolic and water extracts of five medicinal plant species used for treatment of malaria in traditional/cultural health systems of Kwale people in Kenya were tested for antimalarial activity against Plasmodium falciparum and Plasmodium berghei, respectively and for their cytotoxic effects. The most active extracts (IC(50)<10 microg/ml) screened against chloroquine (CQ) sensitive (D6) and resistant (W2) P. falciparum clones, were the water and methanol extracts of Maytenus undata (Thunb.) Blakelock (Celasteraceae), methanol extracts of Flueggea virosa (Willd.) Voigt (Euphorbiaceae), Maytenus putterlickioides (Loes.) Excell and Mendoca (Celastraceae), and Warburgia stuhlmannii Engl. (Canellaceae). These extracts showed various cytotoxic levels on Vero E6 cells with the water extract of M. undata exhibiting least cytotoxicity. At least one of the extracts of the plant species exhibited a high chemo suppression of parasitaemia >70% in a murine model of P. berghei infected mice. These results indicate that there is potential for isolation of a lead compound from the extracts of the five plants. W. stuhlmannii and M. putterlickioides have not been reported before for antiplasmodial activity.

N PROFGUANTAIA. "A competitive enzyme-linked immunosorbent assay for determination of chloramphenicol.Wesongah JO, Murilla GA, Guantai AN, Elliot C, Fodey T, Cannavan A.J Vet Pharmacol Ther. 2007 Feb;30(1):68-73.". In: J Vet Pharmacol Ther. 2007 Feb;30(1):68-73. FA Okalebol , L Wiesner, AN Guantai, K Chibale, P Smith; 2007. Abstract

Chloramphenicol is a broad-spectrum antibiotic shown to have specific activity against a wide variety of organisms that are causative agents of several disease conditions in domestic animals. Chloramphenicol has been banned for use in food-producing animals for its serious adverse toxic effects in humans. Due to the harmful effects of chloramphenicol residues livestock products should be free of any traces of these residues. Several analytical methods are available for chloramphenicol analysis but sensitive methods are required in order to ensure that no traces of chloramphenicol residues are present in edible animal products. In order to prevent the illegal use of chloramphenicol, regulatory control of its residues in food of animal origin is essential. A competitive enzyme-linked immunosorbent assay for chloramphenicol has been locally developed and optimized for the detection of chloramphenicol in sheep serum. In the assay, chloramphenicol in the test samples and that in chloramphenicol-horseradish peroxidase conjugate compete for antibodies raised against the drug in camels and immobilized on a microtitre plate. Tetramethylbenzidine-hydrogen peroxide (TMB/H(2)O(2)) is used as chromogen-substrate system. The assay has a detection limit of 0.1 ng/mL of serum with a high specificity for chloramphenicol. Cross-reactivity with florfenicol, thiamphenicol, penicillin, tetracyclines and sulfamethazine was not observed. The assay was able to detect chloramphenicol concentrations in normal sheep serum for at least 1 week after intramuscular injection with the drug at a dose of 25 mg/kg body weight (b.w.). The assay can be used as a screening tool for chloramphenicol use in animals.

N PROFGUANTAIA, N PROFGUANTAIA, N PROFGUANTAIA. "A competitive enzyme-linked immunosorbent assay for determination of chloramplienicol.". In: j. VET PHARMACO. THERAP. J. 0. WESONGAH* G. A. MUMMA* A. N. GUANTAI C. ELLIOT T FODEY1 & A. CANNA VAN; 2007. Abstract

Chloramphenicol is a broad-spectrum antibioi ic shown to have specific activity against a wide variety of organisms that are causative agents of several disease conditions in domestic animals. Chloramphenicol has been banned for use in food-producing animals for its serious adverse toxic effects in humans. Due to the harmful effects of chloramphenicol residues livestock products should be free of any traces of these residues. Several analytical methods are available for chloramphenicol analysis hut sensitive methods are required in order to ensure that no traces of chloramphenicol residues are present in edible animal products. In order to prevent the illegal use of chloramphenicol, regulatory control of its residues in food of animal origin is essential. A competitive enzyme-linked immunosorbent assay for chloramphenicol has been locally developed and optimized for the detection of chloramphenicol in sheep serum. fn the assay, chloramphenicol in the test samples and that. in chloramphenicol-horseradish peroxidase conjugate compete for antibodies raised against the drug in camels and immobilized on a microtitre plate. Tetramethylbenzidine-hydrogen peroxide (Th413/11202) is used as chromogen-substrate system. The assay has a detection limit of 0.1 ng/ml, of serum with a high specificity for chloramphenicol. Cross-reactivity with florfenicol, thiamphenicol, penicillin, tetracyclines and sulfa-methazine was not observed. The assay was able to detect chloramphenicol concentrations in normal sheep serum for at least 1 week after intramuscular Injection with the drug at a dose of 25 mg/kg body weight (b.w.). The assay can be used as a screening tool for chloramphenicol use in animals. Paper received 27 July 2006; accepted for publication 29 September 2006 1.0. Wesongaii, Kenya Agricultural Research Institute-Trypanosmniasis Research Centre

Gathirwa JW;, Rukunga GM;, Njagi ENM;, Omar SA;, Guantai AN;, Muthaura CN;, Mwitari PG;, Kimani CW;, Kirira PG;, Tolo FM;, Ndunda TN;, Ndiege IO. "In vitro anti-plasmodial and in vivo anti-malarial activity of some plants traditionally used for the treatment of malaria by the Meru community in Kenya.". 2007. Abstract

Extracts of seven medicinal plant species used for treatment of malaria in traditional/cultural health systems of the Ameru people in Kenya were tested in vitro and in vivo against Plasmodium falciparum (D6 and W2 strains) and P. berghei, respectively. Of the plants tested, 28.57% were highly active (IC50 <10 μg/ml) and 42.86% moderately active (IC50 10–50 μg/ml), while 28.57% had weak activity of 50–125 μg/ml in vitro. The water and methanol extracts of Boscia salicifolia Oliv. and Artemisia afra Jacq. (ex-Willd.) were the most active against both the chloroquine (CQ)-sensitive (D6) and the CQ-resistant (W2) P. falciparum strains. Artemisia afra and Rhus natalensis Bernh. (ex-Krauss) exhibited the highest parasite clearance and chemo-suppression (>70%) in vivo (in mice). The plants with high in vitro anti-plasmodial (low IC50 values) and high anti-malarial activity (high chemo-suppression) in vivo are potential sources of novel anti-malarial drugs.

N PROFGUANTAIA. "SE OF ELISA METHOD TO DETERMINE CHLORAMPHENICOL KINETICS IN RED MASAAI SHEEP AFTER INTRAMUSCULAR INJECTION.". In: j. VET PHARMACO. THERAP. O Wesongah*l, GA Murilla, AN Guantai, RE Mdachi I, WM Karanja and TE Maitho; 2007. Abstract

hloramphenicol is a broad-spectrum antibiotic widely used in human and veterinary medicine due to its low cost and ready availability. However its use has been associated with serious adverse effects, (bone marrow suppression, hemolytic anaemia and aplastic anaemia) that may or may not be dose related. Consequently chloramphenicol is currently banned for use in food producing animals and restricted to non-food producing animals and management of life threatening infections in humans in absence of alternative therapy. Exposure to chloramphenicol can occur after regular consumption of animal foods from treated animals. Therefore the pharmacokinetic of chloramphenicol should be determined using a highly sensitive and specific assay method that can detect residue levels at the lowest concentration possible. Previous methods were limited due to low sensitivity (10 ng/m1-50Ong/mi). Therefore the aim of this study was to determine pharmacokinetics of chloramphenicol and potential residue levels in food producing animals using a published highly sensitive detection method; Chloramphenicol enzyme-linked immunosorbent assay, with a detection limit of 0.1 ng/ml. Methods: Eight male red Maasai sheep aged 9 to 12 months and weighing between 21kg to 25 kg, were weaned and allowed to acclimatize for three weeks. Pre-treatment blood samples (10m1) was collected from each animal and then 25mg/kg chloramphenicol sodium succinate administered by deep intramuscular injection. Post treatment blood samples were collected at 5, 10, 15 and 30minutes, I, 2, 4, 6 8, 12, 24 and 32 hour intervals then twice a day (week 1), once daily (week 2) thrice daily (week 3) twice daily (week 4). Phannacokinetic parameters were measured using chloramphenicol ELISA method. Data was analyzed by fitting four, parameter logistics regression curve of calibration standards and sample chloramphenicol concentration calculated from optical densities using ELISA data Eiaquik program (MC. Eisler, 1995). Samples were analyzed in duplicate. Results from these assays were compared with those from published data with respect to elimination half life, species variation, and minimum retention time. Results: Chlorarnphenicol elimination half life (36.4+3.66 h) obtained in the present study was significantly (P<0.05) longer than that of 5.75+1.25 h reported in similar species using colorimetric method. The method was able to detect the drug 7 days post administration. The area under the curve of 124,487.8 ng.h/m1 observed in sheep in the present study was significant higher than that of 31.220+3.25 rig.himl reported in literature in goats using similar treatment route and dose but different assay method. Conclusion: Chloramphenicol pharmacokinetic parameters are significantly influenced by animal species and analytical assay methods used in their determination and care must be taken when reporting the residue levels in food producing animals.

2008
N PROFGUANTAIA. "Establishment of a biobank and pharmacogenetics database of African populations.Matimba A, Oluka MN, Ebeshi BU, Sayi J, Bolaji OO, Guantai AN, Masimirembwa CM.Eur J Hum Genet. 2008 Jul;16(7):780-3. Epub 2008 Apr 2.". In: Eur J Hum Genet. 2008 Jul;16(7):780-3. Epub 2008 Apr 2. FA Okalebol , L Wiesner, AN Guantai, K Chibale, P Smith; 2008. Abstract

The natural product curcumin has a wide range of useful biological effects. However its use in humans is limited due to its short half-life, rapid metabolism and poor oral bioavailability. It is metabolized by sequential reduction of carbon-carbon double two carbonyl groups. To overcome these limitations, a hydrazide derivative of curcumin was synthesized to improve its water solubility and reduce its rate of metabolism. The objective of study was, therefore, to develop a method for the analysis of hydrazinocureumin in murinc blood. This method will be eventually used to evaluate the pharmokinetic profile of hydrazinocurcumin in mice. Method: LC/MS/MS was selected as the analytic method because its high sensitivity allowed for sampling of small volumes of blood from mice. The optimal chromatographic and mass spectrometry conditions were determined by trial arid error. The column performance was monitored by measuring retention time, peak symmetry factor. A calibration curve was generated by using standard solutions with concentrations ranging from 0.78 - 10 rig/ml. The method was validated by determining the recovery, limit of detection, accuracy, linearity and intraday precision. The optimal method for extracting hydrazinocurcumin from biological fluids was determined by spiking human blood and plasma and extraction was done by solvent extraction from a spotted filter paper and liquid-liquid extraction. Instrumentation: The samples were assayed using an Agilent LC/MS/MS 3200Q Trap system (1100 series, USA) in the positive ionization mode. HPLC separation was done using an Agilent 1200 system (Agilent Technologies, Japan) interfaced with the MS/MS system. Ionization was done by electron spray ionization with a collision energy was 33eV. Chromatograms were integrated using Analyst version 1.4 software. Weighted linear regression was used to generate calibration curves from standard solutions. Results: The optimal conditions for HPLC separation was a mobile phase of 0.1% formic acid in acetonitrile: acetonitrile (1:1) with an isocratic flow rate of 0.3m1/minute and run time of 2 minutes. The analytical column was a 50 by 2.0 mm Pheromex C18 column with a particle size of 5 microns. The injection volume was 1 Out The hydrazinocurcumin formed molecular ion at M+H+ m/z 365.2 and two metastable ions at m/z 351 and m/z. 349.2. The transition monitored was m/z 365.2 to 349.2 at unit resolution and a dwelling time of 150 milliseconds. The retention time was 1.11 minutes. The optimal method of extraction was liquid-liquid extraction using 250 ul of ethyl acetate from 10 ul of whole blood in 50 ul of buffer at pH 10. The filter paper method of extraction was found to give erratic results. The calibration curve was linear over the concentration range of 10n/m1 to 0.5 ng/ml of hydrazinocurmin in whole human blood. Conclusion: The precision, accuracy, recovery and applicability were found to be adequate for pharmacokinetic studies in mice.

N PROFGUANTAIA. "The in vitro anti-plasmodial and in vivo anti-malarial efficacy of combinations of some medicinal plants used traditionally for treatment of malaria by the Meru community in Kenya.Gathirwa JW, Rukunga GM, Njagi EN, Omar SA, Mwitari PG, Guantai AN, Tolo FM.". In: J Ethnopharmacol. 2008 Jan 17;115(2):223-31. Epub 2007 Sep 29. FA Okalebol , L Wiesner, AN Guantai, K Chibale, P Smith; 2008. Abstract

The use of herbal drugs as combinations has existed for centuries in several cultural systems. However, the safety and efficacy of such combinations have not been validated. In this study, the toxicity, anti-plasmodial and antimalarial efficacy of several herbal drug combinations were investigated. Lannea schweinfurthii, Turraea robusta and Sclerocarya birrea, used by traditional health practitioners in Meru community, were tested for in vitro anti-plasmodial and in vivo anti-malarial activity singly against Plasmodium falciparum and Plasmodium berghei, respectively. Methanolic extract of Turraea robusta was the most active against Plasmodium falciparum D6 strain. Aqueous extracts of Lannea schweinfurthii had the highest anti-plamodial activity followed by Turraea robusta and Sclerocarya birrea. D6 was more sensitive to the plant extracts than W2 strain. Lannea schweinfurthii extracts had the highest anti-malarial activity in mice followed by Turraea robusta and Sclerocarya birrea with the methanol extracts being more active than aqueous ones. Combinations of aqueous extracts of the three plants and two others (Boscia salicifolia and Rhus natalensis) previously shown to exhibit anti-plasmodial and anti-malarial activity singly were tested in mice. Marked synergy and additive interactions were observed when combinations of the drugs were assayed in vitro. Different combinations of Turraea robusta and Lannea schweinfurthii exhibited good in vitro synergistic interactions. Combinations of Boscia salicifolia and Sclerocarya birrea; Rhus natalensis and Turraea robusta; Rhus natalensis and Boscia salicifolia; Turraea robusta and Sclerocarya birrea; and Lannea schweinfurthii and Boscia salicifolia exhibited high malaria parasite suppression (chemo-suppression >90%) in vivo when tested in mice. The findings are a preliminary demonstration of the usefulness of combining several plants in herbal drugs, as a normal practice of traditional health practitioners.

2009
N PROFGUANTAIA, N PROFGUANTAIA. "DEVELOPMEMENT OF A HPLC-MS/MS METHOD FOR THE ANALYSIS OF HYDROZINOCURCUMIN IN PLASMA.". In: 12 East and Central African Journal of Pharmaceutical Sciences. FA Okalebol , L Wiesner, AN Guantai, K Chibale, P Smith; 2009. Abstract

The natural product curcumin has a wide range of useful biological effects. However its use in humans is limited due to its short half-life, rapid metabolism and poor oral bioavailability. It is metabolized by sequential reduction of carbon-carbon double two carbonyl groups. To overcome these limitations, a hydrazide derivative of curcumin was synthesized to improve its water solubility and reduce its rate of metabolism. The objective of study was, therefore, to develop a method for the analysis of hydrazinocureumin in murinc blood. This method will be eventually used to evaluate the pharmokinetic profile of hydrazinocurcumin in mice. Method: LC/MS/MS was selected as the analytic method because its high sensitivity allowed for sampling of small volumes of blood from mice. The optimal chromatographic and mass spectrometry conditions were determined by trial arid error. The column performance was monitored by measuring retention time, peak symmetry factor. A calibration curve was generated by using standard solutions with concentrations ranging from 0.78 - 10 rig/ml. The method was validated by determining the recovery, limit of detection, accuracy, linearity and intraday precision. The optimal method for extracting hydrazinocurcumin from biological fluids was determined by spiking human blood and plasma and extraction was done by solvent extraction from a spotted filter paper and liquid-liquid extraction. Instrumentation: The samples were assayed using an Agilent LC/MS/MS 3200Q Trap system (1100 series, USA) in the positive ionization mode. HPLC separation was done using an Agilent 1200 system (Agilent Technologies, Japan) interfaced with the MS/MS system. Ionization was done by electron spray ionization with a collision energy was 33eV. Chromatograms were integrated using Analyst version 1.4 software. Weighted linear regression was used to generate calibration curves from standard solutions. Results: The optimal conditions for HPLC separation was a mobile phase of 0.1% formic acid in acetonitrile: acetonitrile (1:1) with an isocratic flow rate of 0.3m1/minute and run time of 2 minutes. The analytical column was a 50 by 2.0 mm Pheromex C18 column with a particle size of 5 microns. The injection volume was 1 Out The hydrazinocurcumin formed molecular ion at M+H+ m/z 365.2 and two metastable ions at m/z 351 and m/z. 349.2. The transition monitored was m/z 365.2 to 349.2 at unit resolution and a dwelling time of 150 milliseconds. The retention time was 1.11 minutes. The optimal method of extraction was liquid-liquid extraction using 250 ul of ethyl acetate from 10 ul of whole blood in 50 ul of buffer at pH 10. The filter paper method of extraction was found to give erratic results. The calibration curve was linear over the concentration range of 10n/m1 to 0.5 ng/ml of hydrazinocurmin in whole human blood. Conclusion: The precision, accuracy, recovery and applicability were found to be adequate for pharmacokinetic studies in mice.

2010
N PROFGUANTAIA. "Comparative tolerability and efficacy of stavudine 30 mg versus stavudine 40 mg in patients on combination antiretroviral therapy in Kenya.". In: ournal of AIDS and HIV Research Vol. 2(2) pp. 024-031. Monicah Wanjiru Karara, Faith Apolot Okalebo, Margaret Ng; 2010. Abstract

Stavudine- containing regimens are currently the most widely used first-line anti-HIV treatment option in Kenya. This study compared the efficacy and tolerability of stavudine at two dose levels in patients attending a HIV Comprehensive Care Centre in Kenya. Data were collected retrospectively from the records of 810 adult patients. Fewer stavudine related adverse effects were seen in patients 60 kg treated with 30 mg stavudine compared to those who received 40 mg (4.2 vs 16.7%, p <0.001). Patients < 60 kg were more likely to experience drug toxicity than those 60 kg when given 30 mg stavudine (12.8 vs 4.2%, p < 0.001). Occurrence of any adverse drug reaction was significantly associated with severe immunosuppression (HR =1.45, Cl: 0.86 - 2.45, p < 0.001), co-morbidities (HR = 2.16, Cl: 1.06 - 4.38, p < 0.001) and treatment with isoniazid (HR = 2.07, Cl: 1.09 - 3.96, p < 0.001). The onset of drug related toxicities was principally in the first year of commencing therapy. Similar immunologic outcomes were demonstrated across all the treatment groups with median CD4 cell counts after 12 months of treatment more than doubling for patients in all the study cohorts. The findings support the use of combination antiretroviral therapy regimens containing low dose stavudine in Kenya. Key words: Low -dose stavudine, combination antiretroviral therapy, HIV, stavudine tolerability.

N PROFGUANTAIA, N PROFGUANTAIA, N PROFGUANTAIA, N PROFGUANTAIA. "Validation of a competitive chloramiphenicol enzyme linked immunosorbent assay for determination of residues in Ovine tissues.". In: 12 East and Central African Journal of Pharmaceutical Sciences. G. A MURILLA, J.O WESONGA, T. FODDEY, S. CROOKS, A.N GUANTAI, W,M KARANJA, T.E MAITHO; 2010.
2011
Kibwage IO, Okalebo FA, Guantai AN, Karume DW, K. M, Maitai CK. "Pharmacological screening of extracts of Clematis brachiata THUNBERG (RANUNCULACEAE).". 2011.
2012
Nwaka S, Ochem A, Besson D, Ramirez B, Fakorede F, Botros S, Inyang U, Mgone C, Adae-Mensah I, Konde V, Nyasse B, Okole B, Guantai A, Loots G, Atadja P, Ndumbe P, Sanou I, Olesen O, Ridley R, Ilunga T. "Analysis of pan-African Centres of excellence in health innovation highlights opportunities and challenges for local innovation and financing in the continent." 12. 2012;11(12):2-15.analysis_of_pan-african_centres_of_excellence_in_health_innovation_highlights_opportunities_and_challenges_for_local_innovation_and_in.pdf
Tarkang PA, Guantai AN;, Tsabang N;, Agbor GA;, Okalebo FA;, Rukunga GM;. "Indigenous Knowledge and folk use of a polyherbal antimalarial by the Bayang Community, South West Region of Cameroon.". 2012. Abstract

Nefang is a polyherbal preparation constituted of the leavesof six plants and the bark of one of these,used traditionally for the treatment of malaria by the Bayang community, South West Region of Cameroon. Since no ethnopharmacological survey has been carried out on this preparation, this study aims at obtaining indigenous and folkloric information on the optimal methods for harvesting of constituent plants, preparation and administration of Nefang in the treatment of malaria. The study design was an exploratory survey.Semi-structured questionnaires were administered randomly to 20 respondents after obtaining their informed consent with the assistance of a medical practitioner. Review of literature of constituent plants was also undertaken. This study revealed that the respondents had a good knowledge of malaria and its causes. Various compositions for the preparation by decoction was obtained and administration was ascertained to be by oral route or by enema. The brief scientific review also validated the pharmacological actions of the constituent plants. The diverse indigenous knowledge and folk use of this preparation in the treatment of malaria are a pre-requisite for theoptimization of its compositionfor efficacy and pharmacological screening

2013
2014
Tarkang PA, Okalebo FA, Ayong LS, Agbor GA, Guantai AN. "Anti-malarial activity of a polyherbal product (Nefang) during early and established Plasmodium infection in rodent models." Malaria Journal. 2014;13:DOI: 10.1186/1475-2875-13-456. Abstract2014_-_antimalarial_activity_of_polyherbal_nefang.pdf

Background: The emerging resistance of Plasmodium species to currently available anti-malarials remains a public health concern, hence the need for new effective, safe and affordable drugs. Natural products remain a reliable source of drugs. Nefang is a polyherbal anti-malarial of the Cameroonian folklore medicine with demonstrated in vitro antiplasmodial and antioxidant activities. It is composed of Mangifera indica (bark and leaf), Psidium guajava, Carica papaya, Cymbopogon citratus, Citrus sinensis, Ocimum gratissimum (leaves). This study aimed at investigating the suppressive, prophylactic and curative activities of Nefang in Plasmodium infected rodent models.

Methods: Systemic acute oral toxicity of Nefang aqueous and ethanol extracts was assessed in mice up to a
dose of 5,000 mgkg−1 body weight. BALB/c mice and Wistar rats were inoculated with Plasmodium chabaudi
chabaudi and Plasmodium berghei, respectively, and treated with Nefang, the Mangifera indica bark/Psidium
guajava combination and a Psidium guajava leaf aqueous extracts (75, 150, 300 and 600 mgkg−1 bwt). Their
schizonticidal activity was then evaluated using the Peter’s 4-day suppressive test). The prophylactic and curative (Rane’s Test) activity of Nefang was also evaluated by determining the parasitaemia, survival time, body weight and temperature in pre-treated rodents.

Results: Acute oral toxicity of the extract did not cause any observed adverse effects. Percent suppressions of
parasitaemia at 600 mgkg−1 bwt were as follows (P. berghei/P. chabaudi): Nefang – 82.9/86.3, Mangifera indica bark/Psidium guajava leaf combination extract – 79.5/81.2 and Psidium guajava leaf – 58.9/67.4. Nefang exhibited a prophylactic activity of 79.5% and its chemotherapeutic effects ranged from 61.2 – 86.1% with maximum effect observed at the highest experimental dose.

Conclusion: These results indicate that Nefang has excellent in vivo anti-malarial activities against P. berghei
and P. chabaudi, upholding earlier in vitro antiplasmodial activities against multi-drug resistant P. falciparum
parasites as well as its traditional use. Hence, Nefang represents a promising source of new anti-malarial
agents.

Keywords: Medicinal Plants, Nefang, Acute toxicity, Malaria, In vivo antiplasmodial activity, Suppressive
activity, Prophylactic activity, Curative activity, Combination phytotherapy

Oluka MN, Matimba A, Okalebo FA, Osanjo GO, Guantai AN, Masimirembwa CM. "Characterization of inter-ethnic genetic variability of CYP2D6, CYP2C19, CYP2B6, NAT2 and GSTs in the Bantu and Nilotic populations of Kenya and implications for the chemotherapy of infectious diseases." African Journal of Pharmacology and Therapeutics. 2014;3(2):38-46. Abstract2014_-_characterisation_of_interethnic_genetic_variability_of_cyp2d6cyp2c19--.pdf

Background: Drug metabolism genes are variable in populations. African populations are highly genetically
differentiated. Analysis of drug metabolism genes offers opportunities to enhance drug efficacy and reduce toxicity.

Objectives: We characterized SNPs of CYP2D6, CYP2C19, CYP2B6, NAT2 and GST genes in Kenyans.

Methodology: Genotyping of CYP2C19 (*2, *3); CYP2B6 (*6); CYP2D6 (*2,*4, *17, *29); NAT2 (*5, *6, *7, *14); GSTM1 and GSTT1 by PCR-RFLP.

Results: CYP2D6*4 was higher in Eastern Nilotes (9%) compared to Western Nilotes (2.5%) and Bantus (1.7%) (P = 0.002). CYP2D6*17 was higher in Bantus (34%) compared to Nilotes (18 – 23%) (P = 0.003). GSTM1del was higher in Western Nilotes and Bantus (29% -31%) compared to Eastern Nilotes (16%) (P = 0.009). GSTT1del was higher in Eastern Nilotes (41%) compared to Bantus and Western Nilotes (22 - 26%) (P = 0.005). CYP2C19*3 was undetected in Bantus but was >1.0% in Nilotes ((P <0.01). CYP2C19*2 (10 – 18%), CYP2B6*6 (35 – 37%), NAT2*5 (30 – 42%), NAT2*6 (20 – 27%), NAT2*7 (2 – 6%), NAT2*14 (8-14%) were similar in Kenyans. Kenyan frequencies were comparable to other Africans but different from caucasians and Asians.

Discussion: Variability was evident for CYP2D6*4, CYP2D6*17, GSTM1del and GSTT1del. Findings provide a
framework for Pharmacogenomic optimization of therapeutic outcomes.

Key Words: Pharmacogenomics, Drug metabolism, inter-ethnic variability, Kenyans

Tarkang PA, Franzoi KD, Lee S, Lee E, Vivarelli D, Freitas-Junior L, Liuzzi M, Nolé T, Ayong LS, Agbor GA, Okalebo FA, Guantai AN. "In Vitro Antiplasmodial Activities and Synergistic Combinations of Differential Solvent Extracts of the Polyherbal Product, Nefang." BioMed Research International. 2014;Article ID 835013:DOI: /10.1155/2014/835013. Abstract2014_-_in_vitro_antiplasmodial_activities.pdf

Nefang, a polyherbal product composed of Mangifera indica (bark and leaf), Psidium guajava, Carica papaya, Cymbopogon citratus, Citrus sinensis, and Ocimum gratissimum (leaves), is a potential therapy against P. falciparum malaria. In vitro antiplasmodial activities of its constituent solvent extractswere analyzed onCQ-sensitive (3D7) andmultidrug resistant (Dd2) P. falciparum strains. The interactions involving the differential solvent extracts were further analyzed using a variable potency ratio drug combination approach. Effective concentration 50 (EC50) values were determined by nonlinear regression curve-fitting of the dose-response data and used in calculating the fractional inhibitory concentration 50 (FIC50) and combination indices (CI) for each pair. The derived EC50 values (3D7/Dd2,

Ebeshi BU, Bolaji OO, Oluka MN, Edebi VN, Soyinka JO, Guantai AN. "Simple Reversed-Phase High Performance Liquid Chromatographic Estimation of the Antiretroviral Agent Efavirenz from Human Plasma." British Journal of Pharmaceutical Research. 2014;4(1):145-157. Abstract2014_-_simple_reversed-phase_high_performance.pdf

Aims: Sequel to the resurgence of TB co-infection in HIV/AIDS patients in sub-Saharan Africa, efavirenz has become an important component of the highly active antiretroviral treatment (HAART). The objective of this study therefore is to provide a simple reversedphase high performance liquid chromatographic (HPLC) method for the determination of efavirenz in human plasma.

Study Design: Method development and experimental study.
Place and Duration of Study: School of Pharmacy, University of Nairobi, Nairobi, Kenya, between October 2009 and September 2010.

Methodology: A 500μl drug-free plasma sample was each placed in six different centrifuge tubes (2ml) and varying aliquots of the stock solution (100μg/ml) of efavirenz were spiked and vortexed for 60sec to give concentrations of 0.5, 1.0, 2.0, 4.0, 8.0 and 16μg/ml for calibration standards and 2.0, 4.0, 8.0 and 16.0μg/ml for quality control samples. The off-column sample pretreatment was carried out by protein precipitation
using ice-cold acetonitrile. The samples were chromatographed in a phenomenex (C18) 5μm particle size column with 250x4.6mm I.D and UV detection at 254nm using a mobile phase, which was made up of a mixture of solutions A and B. Both consisted of acetonitrile, 25mM ammonium acetate buffer and glacial acetic acid in proportions of 90:10:0.1 and 10:90:0.1(v/v), respectively. The analytical technique was validated for precision, accuracy and analyte recovery.

Results: The calibration plot for efavirenz was found to be linear over the concentration range of 0.5 to 16.0μg/ml with the regression line equation obtained as y=26842x–409.4 and the regression coefficient (R2=0.999), which allows for accurate reading of the concentrations of the test samples. The RSD (%) in intraday and interday assays ranged from 0.44 to 0.78%. Accuracy ranged from 92 to 110% and the recovery was >97%.

Conclusion: This new HPLC method is simple, reproducible and cost-effective and can be used for therapeutic drug monitoring of efavirenz in HIV/AIDS patients on HAART as demonstrated in this study.

2015
Kivai JM, Guantai AN, Mwanda WO, Maitho TE. "Abandonment of treatment and loss to follow up: a potential cause of treatment failure in patients with AIDS-related Kaposi’s sarcoma." African Journal of Pharmacology and Therapeutics. 2015;4(4):156-160. Abstract2015_-_abandonment_of_treatment_and_ltfu_aids_karposis.pdf

Background: Management of patients with cancer is complex, multi-disciplinary, longitudinal and costly. Abandonment of treatment by patients and loss to follow up is a common scenario, especially in resource poor countries and severely compromises health outcomes.

Objective: To assess the commitment to drug treatment protocol of patients with Acquired Immunodeficiency Syndrome (AIDS)-Related Kaposi’s Sarcoma at Kenyatta National Hospital, Kenya, over a 10 week period .

Methods: The study design was prospective, observational, cross-sectional period prevalence study on patients infected with human immunodeficiency virus (HIV) with Kaposi’s sarcoma. Patients with histological diagnosis of Kaposi’s sarcoma were sequentially enrolled into the study as they attended either the Haematology or Radiotherapy clinic or during their admission in the wards. The choice of the treatment protocol was left at the discretion of the attending physician. A pretested data collection form was used to collect demographic and clinical information about the patients, including treatments prescribed and completion of follow up.

Results: A total of 74 patients were enrolled into the study, 42 (56.8%) males and 32 (43.2%) females. The age ranged between 13 years to 55 years. Their treatment protocols included: Vincristine only, Vincristine plus Bleomycin, Vincristine plus Bleomycin plus Doxorubicin, Radiotherapy plus Vincristine and Radiotherapy only. Few of the patients were not assigned any antitumor treatment. Antiemetic and other conventional medicines were also prescribed when necessary. Fifty four (73%) of the patients abandoned treatment, five (6.8%) died, 15(20.3%) continued to attend clinic over the 10 week period. There was no significant association between sex and outcome (p=0.661).

Discussion: The results of this study demonstrate that abandonment of treatment is a major problem among patients on treatment for cancer in Kenyatta National Hospital in Kenya. Abandonment of treatment heavily contributes to poor clinical outcome hence complicating the burden of cancer in the country. It is therefore important to develop and establish follow-up systems to improve adherence to treatment for the cancer patients at Kenyatta National Hospital.

Key words: Abandonment of treatment, Loss to follow up, AIDS-Related Kaposi’s Sarcoma

Oluka MN, Okalebo FA, Guantai AN, McClelland S, Graham SM. "Cytochrome P450 2B6 genetic variants are associated with plasma nevirapine levels and clinical response in HIV-1 infected Kenyan women: a prospective cohort study." AIDS Research and Therapy. 2015;12(10):DOI 10.1186/s12981-015-0052-0. Abstract2015_-_cytochrome_p450_genetic_variants_nevirapine.pdfWebsite

Background: Polymorphisms in cytochrome P450 2B6 (CYP2B6) affect the steady state plasma concentration of nevirapine. CYP2B6 516G>T and 983T>C are common in African populations, but data on their influence on plasma nevirapine concentration and clinical response in African women are limited. We investigated the impact of CYP 516G>T and 983T>C on plasma nevirapine concentration and clinical outcomes in a prospective cohort study of HIV-infected Kenyan women.
Methods: Study subjects were 66 HIV-1-seropositive women taking nevirapine-based antiretroviral therapy. Plasma collected at week 12 was analyzed for nevirapine concentration by high performance liquid chromatography. Baseline samples were genotyped for CYP2B6 516G>T and 983T>C single nucleotide polymorphisms by real-time polymerase chain reaction. CD4 cell count, plasma viral load, and genotypic drug resistance in plasma and genital secretions were assessed at baseline and during follow up. We evaluated the effect of each genotype on plasma nevirapine concentration at week 12 and on change in CD4 cell count at months 3, 6 and 12. Associations between plasma nevirapine concentration and clinical outcomes were analyzed by logistic or linear regression.
Results: Women with CYP2B6 516TT genotype (n=9) had higher mean nevirapine plasma levels (14.33 μg/mL) compared to those with heterozygous 516GT (9.18 μg/mL; n=25) and wild- type 516GG (7.95 μg/mL; n=32) genotypes (P=0.01). Women heterozygous for the CYP2B6 983TC genotype (n=13) had higher mean nevirapine plasma levels (12.94 μg/mL), compared to women with the homozygous 983TT (8.35 μg/mL; n=53) genotype (P=0.007). In Generalized Estimating Equation analysis, plasma nevirapine levels predicted greater change in CD4 cell count after ART initiation (adjusted beta 119.4 cells/μL, 95% CI, 27.3–211.5 cells/μL, P=0.01). The CYP2B6 983TT genotype also predicted greater change in CD4 cell count (adjusted beta 68.6 cells/μL, 95% CI, 3.9–133.4 cells/μL, P=0.04). We found no associations between CYP2B6 genotypes and virologic response or toxicity.
Conclusions: CYP2B6 516G>T and CYP2B6 983T>C genotypes were strongly associated with plasma nevirapine concentration, which predicted immunologic response in women on nevirapine-based antiretroviral therapy. These data support continued work on the potential utility of human genetic testing to inform nevirapine dosage optimization for individual patients.
Keywords: CYP2B6, Pharmacogenetics, Nevirapine, HIV infection, Antiretroviral therapy, Women

Chege IN, Okalebo FA, Guantai AN, Karanja S, Derese S. "Herbal Product Processing Practices of Traditional Medicine Practitioners in Kenya- Key Informant Interviews." Journal of Health, Medicine and Nursing. 2015;16:11-23. Abstract2015_-_herbal_product_processing_practices.pdf

Introduction: Herbalists in Kenya use self-taught processing practices which are inadequate. The objective of
this study was to conduct an assessment of selected practices used by herbalists during drug processing and to identify knowledge gaps.

Method: Four long practicing traditional medicinal practitioners were identified using purposive sampling. An
interview guide and field visits were used to gather data. Data analysis was done using content thematic
approach.

Results: Sources of herbal knowledge were varied with the use of internet being a key finding. Regulatory
compliance presented various challenges to the herbalists. The wild and cultivation of herbs were identified as key medicinal sources although the protection of biodiversity was a key concern of the herbalists. The facilities, area of practice and general hygiene were inadequate. Positive and negative practices were identified in processing of the herbal medicines.

Conclusions: Secrecy by the herbalists has resulted in limited in innovation. More training of herbalists is
required to improve on the quality of their drugs. It is however encouraging that they have adopted some
modern methods in their practice.

Keywords: Herbalists, processing practices, herbal drugs

Ambetsa MO, Makori JO, Osanjo GO, Oluka M, Maitai CK, Guantai AN, McClelland S, Okalebo FA. "Incidence and Risk Factors of Renal Dysfunction in Patients on Nevirapine-Based Regimens at a Referral Hospital in Kenya." African Journal of Pharmacology and Therapeutics. 2015;4(2):48-58. Abstract2015_-_incidence_of_risk_factors_of_renal_dysfunction--nevirapine.pdf

Introduction: Nevirapine-based regimens are the most commonly used ART in Kenya. There is little literature on the renal toxicity of NNRTIS in Kenyan settings. Some studies in Asia have demonstrated an association of NNRTIs and renal toxicity. Given that NNRTIs may cause renal toxicity, clinical studies on their contribution to the same are required.

Objectives: To evaluate the incidence and risk factors for renal dysfunction in HIV adult patients on Nevirapine based regimens.

Methodology: The design was a descriptive (right censored arm) hospital based retrospective cohort study carried out at a national referral hospital. Ethical approval was obtained. The study population was patients on Nevirapine based regimens seen between May and August, 2014. Convenient sampling was used to recruit 241 patients. Estimated glomerular filtration rate (eGFR) was calculated using the Modification of Diet in Renal Disease (MDRD) formula. Patients with eGFR < 50ml/min/1.73m2 were considered to have renal dysfunction. Data obtained by the patient interviews and abstraction of patient files and was analyzed using STATA software. Ordered Logistic regression was used to identify covariates that determine the severity of renal dysfunction.

Results: The incidence of renal dysfunction was 4.3% (95% C.I, 1.68-6.94).Five (2.1%) patients had a low eGFR at baseline, while ten (8.3%) patients had elevated serum creatinine (above 120μg/l). None of the patients developed severe renal dysfunction. Seventy (32%) and ten (4.6%) had mild and moderate renal dysfunction respectively. The females had a higher risk of developing renal dysfunction (adjusted O.R 0.48 (95% C.I 0.24-1.04; p=0.04). Alcohol consumption was a significant predictor of renal dysfunction (adjusted O.R 1.84 (95% C.I 1.01-3.29; p=0.04). All fifteen patients with a BMI of over 18.5 had elevated eGFR of below 50ml/min/1.73m.2Patients who had been initiated on stavudine based regimens had the highest incidence of renal dysfunction.

Conclusion: Routine eGFR calculations should be done at each clinical visit. Early detection of risk factors and systematic screening should be advocated for improved patient care.

Key Words: Body Mass Index, Renal dysfunction, Stavudine, Nevirapine

Chege IN, Okalebo FA, Guantai AN, Karanja S, Derese S. "Management of Type 2 Diabetes Mellitus by Traditional Medicine Practitioners in Kenya- Key Informant Interviews." Pan African Medical Journal. 2015;22(90):doi:10.11604/pamj.2015.22.90.6485. Abstract2015_-_management_of_type_2_diabetes_mellitus.pdf

Introduction: Worldwide, plant based medicines are increasing in popularity due to perceptions of safety and efficacy. Herbalists in Kenya are widely consulted for the management of many diseases including Type 2 Diabetes Mellitus (T2DM). This study investigated the level of knowledge of the herbalists in management of T2DM.

Methods: Purposive sampling was used to identify 4 herbalists working in the urban areas who actively manage T2DM. Key informant interviews were used to gather data about the management of T2DM. It was analyzed using a content thematic approach.

Results: Diverse management methods which included both pharmacological and non- pharmacological were noted. Glycemic control was assessed with the help of a glucometer. In addition, presenting signs and symptoms were key in diagnosing T2DM. The herbalists used various herbs, minerals and animals as medicinal sources. The drugs were dispensed as decoctions with excipients being added appropriately.
Adverse effects were recorded. The herbalists acknowledged that patients use both herbal and allopathic medicine together. A level of record keeping was observed but patient follow-up was poor. The cost of the herbal drugs was perceived to be excessive.

Conclusion: Some similarities exist in the management of T2DM between allopathic and traditional medicine practitioners. Training of herbalists is required to improve the quality of care given to patients.

Malele CN, Lang’at-Thoruwa CC, Guantai AN, Chhabra SC. "A new pterocarpan from the leaves of Abrus precatorius L." Academic journals. 2015;9(27):749-754,. Abstract2015_-_new_pterocarpan_from_abrus_precatorius.pdf

A pterocarpan, 2,3,4,8-tetramethoxy-6a,11a-dihydro-6H-benzo[4,5]furo[3,2-c]chromene-7,9-diol
(compound 1) was isolated from the dichloromethane extract of the leaves of Abrus precatorius L. The
structure of the compound was elucidated by detailed spectroscopic analysis such as 1H NMR, 13C NMR,
distortionless enhancement by polarisation transfer (DEPT), heteronuclear multiple-quantum correlation
(HMQC) and heteronuclear multiple-bond correlation (HMBC). The crude extracts displayed brine shrimp
lethality and in vitro antimalarial activity. The methanolic crude extract demonstrated an A/B ratio of 9.7
signifying that it is more toxic against Plasmodium falciparum than brine shrimp.

Makori J, Ambetsa M, Sinei KA, Osanjo GO, Guantai AN, McClelland S, Oluka MN, Okalebo FA. "Patterns and Risk Factors for Alanine Aminotransferase Elevation among HIV Patients on Nevirapine Regimens." African Journal of Pharmacology and Therapeutics. 2015;4(2):59-66. Abstract2015_-_patterns_and_risk_factors_for_alanine_aminotrasferase_elevation--nevirapine.pdf

Background: Elevated levels of serum transaminases are often detected in HIV patients. This has often been
attributed to hepatic effects of antiretroviral drugs.

Objective: To determine the pattern and risk factors for alanine aminotransferase elevation in HIV patients positive on nevirapine based regimens.

Methodology: We conducted a retrospective cohort study of HIV infected patients on nevirapine containing regimens who attended the Kenyatta National Hospital comprehensive care clinic between May and August 2014. We sampled participants by convenient sampling method. Generalized linear regression was performed to establish patterns and predictors for hepatotoxicity (grade 1-4) which were the primary outcomes of interest. Predictor variables that were included in the analysis include; demographic information, baseline ALT and CD4 levels, ART regimens, comorbidities and treatment duration.

Results: Risk factors for ALT elevation differed by gender. Predictor variables that were significantly associated with ALT elevation in both sexes included; elevated baseline ALT level [β=10.14 (95%CI 7.34- 12.96); P<0.001], [β=13.52 (95%CI 9.36 –17.68); P < 0.001] and renal disease [β=5.44 (95%CI 2.62 – 8.25); P <0.001], [β=11.52 (95%CI 3.46 – 19.60); P = 0.005] in females and males respectively. Ethnicity had a protective effect in both sexes; [β-6.61(95%CI- 9.28, -3.93); P< 0.001] in males and [β-1.20 (95% CI-2.39, -0.01); P= 0.048] in females. Among the different ethnic groups, Nilotes and Cushites had lower ALT levels compared to Bantus. Other factors that were significant included; smoking (P=0.001), concurrent illnesses (P=0.045), previous adverse drug reactions (P=0.040) in females and a longer duration of anti-retroviral therapy [β 1.81(95%CI 0.89 – 2.73); P < 0.001] in males. Poor adherence had a protective effect [β -1.62(95%CI -3.20, -0.04); P=0.045] among females, whereas initiation on AZT+3TC+NVP had a significant protective effect [β-7.80 (95%CI -13.96, -1.63); P=0.013] in males.

Conclusion: Creatinine and transaminase testing should be done routinely to deal with delayed hepatotoxicity in patients with abnormal ALT baseline levels.

Key words: Alanine aminotransferase, hepatotoxicity, nevirapine.

Tarkang PA, Okalebo FA, Siminyu JD, Ngugi WN, Mwaura AM, Mugweru J, Agbor GA, Guantai AN. "Pharmacological evidence for the folk use of Nefang: antipyretic, anti-inflammatory and antinociceptive activities of its constituent plants." BMC Complementary and Alternative Medicine. 2015;15:174. Abstract2015_-_pharmacological_evidence_for_the_folk_use_of_nefang.pdf

Background: Nefang is a polyherbal anti-malarial composed of Mangifera indica (MiB and MiL; bark and leaf),
Psidium guajava (Pg), Carica papaya (Cp), Cymbopogon citratus (Cc), Citrus sinensis (Cs) and Ocimum gratissimum (Og) (leaves). Previous studies have demonstrated its in vitro and in vivo antiplasmodial activities, antioxidant properties and safety profile. This study aimed at evaluating the antipyretic, anti-inflammatory and antinociceptive activities of the constituent plants of Nefang which are relevant to the symptomatic treatment of malaria fever.
Methods: Antipyretic activities were determined by the D-Amphetamine induced pyrexia and Brewer’s Yeast induced hyperpyrexia methods. Anti-inflammatory activities were investigated using the carrageenan-induced rat paw edema method. Antinociceptive activities were determined by mechanical nociception in the tail pressure and thermal nociception in the radiant heat tail flick and hot plate methods. Data was analysed using the one way ANOVA followed by Neuman-Keuls multiple comparison test.
Results: Best percentage inhibition of induced pyrexia (amphetamine/brewer’s yeast; p < 0.05) was exhibited by Cc (95/97) followed by Og (85/94), MiL (90/89), MiB (88/84) and Cs (82/89). Cc and Og exhibited comparable activities to paracetamol (100/95). Anti-inflammatory studies revealed paw edema inhibition (%) as follows (p < 0.05): Indomethacin (47), MiL (40), Cp (30), MiB (28) and Og (22), suggesting best activity by MiL. Antinociceptive studies revealed significant (p < 0.01) pain inhibition (%) as follows: Paracetamol (97), Og (113), MiL (108), Pg (84) and MiB (88). Og and MiL exhibited the best activities.
Conclusion: The results obtained suggest that the constituent plants possess biologically active compounds with antipyretic, anti-inflammatory and antinociceptive activities. These activities are essential in the symptomatic treatment of malaria fever, thereby justifying the folk use of Nefang. This would be useful in its subsequent development for clinical application.
Keywords: Medicinal plants, Nefang, Pharmacological effects, Antipyretic, Anti-inflammatory, Antinociceptive
activities

Chege IN, Okalebo FA, Guantai AN, Karanja S. "A Quality Control of Hypoglycemic Herbal Preparations in Nairobi, Kenya." Journal of Pharmacognosy and Phytochemistry. 2015;3(4):16-21. Abstract2015_-_a_quality_control_of_hypoglycemic_herbal_preparations.pdf

Introduction:
Methods used by Kenyan herbalists to identify plants and preserve herbal drugs are unclear.
Objective:
To assess the accuracy of plant identification, microbial and heavy metal contamination in hypoglycemic herbal preparations.
Method:
Four herbalists were identified by purposeful sampling and key informant interviews were carried out. Ethnobotanical walks were used to collect herbs and a botanist checked the accuracy of scientific names. Herbalists were asked to submit formulations. Microbial contamination was evaluated using selective and non-selective cultural media. Levels of heavy metals were evaluated by atomic absorption.
Analysis:
Content thematic approach was used to analyze key informant interviews. Degree of agreement between the names assigned by the herbalists and botanists was measured using percentage.
Results:
Plant identification relied heavily on macroscopic qualities aided by the plant’s geographical location. Both indigenous and botanical names were used. Naming errors using botanical names were recorded. Three formulations were submitted and one of them recorded contamination by Candida albicans,
Escherichia coli and Klebsiella pneumoniae. Heavy metal contamination was not detected.
Conclusion:
Plant identification by herbalists by use of botanical names may be inaccurate. Herbalist should be trained on good manufacturing practices.

2016
Wesongah JO, Guantai AN. "Isolation and Characterization of Antichloramphenicol Antibodies using SDS Page." African Journal of Pharmacology and Therapeutics. 2016;5(3):174-180. Abstract2016_-_isolation_and_characterization_of_antichloramphenicol_antibodies.pdf

Background: Antichloramphenicol antibodies can be produced in small or large animals depending on the requirement of the researcher. Previously most researchers have raised antibodies in small animals such as rabbits due to their easy availability and handling. In the present study antichloramphenicol antibodies were produced in large animals because large volumes of serum was needed for various studies.

Objective: The objective of the present study was to isolate and characterize antichloramphenicol antibodies produced in camels, donkeys and goats for development of a CAP Enzyme Linked Immunosorbent Assay.

Methods: The methods employed were SDS-PAGE electrophoresis which involved the analysis of crude and purified goat, camel and donkey antichloramphenicol antibodies. Purification of the antichloramphenicol antibodies was carried out by precipitation using ammonium sulphate. Immunization of experimental animals was carried out using standard immunological methods.

Results: The results indicated that the crude anti-CAP antibody produced in camels, goats and donkeys showed 7 protein bands of molecular sizes 11.7, 40, 61.6, 134.3, 145, 169.5 and 182 kda. However the protein band of molecular weight 11.7 kda was not observed in the purified antibody from the 3 animal species. The protein bands of the camel appeared smaller and were more distinct as compared to those of donkeys and goats.

Conclusion: From this study it was concluded that purified camel antibodies are smaller and more specific followed closely by goat antibodies and donkey antibodies.

Keywords: anti-chloramphenicol (CAP) antibodies, camels, goats and donkeys

Yarmoshuk AN, Guantai AN, Mwangu M, Cole DC, Zarowsky C. "Mapping International University Partnerships Identi fi ed by East African Universities as Strengthening Their Medicine, Nursing, and Public Health Programs." Annals of Global Health. 2016;82(5):665-677. Abstract2016_-_mapping_international_university_partnerships.pdf

Background: International university partnerships are recommended for increasing the capacity of sub-Saharan African universities. Many publications describe individual partnerships and projects, and tools are available for guiding collaborations, but systematic mappings of the basic, common characteristics of partnerships are scarce.

Objective: To document and categorize the international interuniversity partnerships deemed significant to building the capacity of medicine, nursing, and public health programs of 4 East African universities.

Methods: Two universities in Kenya and 2 in Tanzania were purposefully selected. Key informant interviews, conducted with 42 senior representatives of the 4 universities, identified partnerships they considered significant for increasing the capacity of their institutions' medicine, nursing, and public health programs in education, research, or service. Interviews were transcribed and analyzed. Partners were classified by country of origin and corresponding international groupings, duration, programs, and academic health science components.

Findings: One hundred twenty-nine university-to-university partnerships from 23 countries were identified. Each university reported between 25 and 36 international university partners. Seventy-four percent of partnerships were with universities in high-income countries, 15% in low- and middle-income countries, and 11% with consortia. Seventy percent included medicine, 37% nursing, and 45% public health; 15% included all 3 programs. Ninety-two percent included an education component, 47% research, and 24% service; 12% included all 3 components.

Conclusions: This study confirms the rapid growth of inter-university cross-border health partnerships this century. It also finds, however, that there is a pool of established international partnerships from numerous countries at each university. Most partnerships that seek to strengthen universities in East Africa should likely ensure they have a significant education component. Universities should make more systematic information about past and existing partnerships available publicly.

Yarmoshuk AN, Gauntai A, Mwangu M, Cole D, Zarowsky C. "Resilient and responsive Global Health partnerships of East African universities in a changing world.". In: Fourth Global Symposium on Health Systems Research.; 2016.resilient_and_responsive_global_health_partnerships_of_east_african.pdf
2017
Nyamu DG, Guantai AN, Osanjo GO, Mwatha E, Gitonga I, Kanyiri ML. "Predictors of Adequate Ambulatory Anticoagulation Services among Adult Patients in a Tertiary Teaching and Referral Hospital in Kenya." African Journal of Pharmacology and Therapeutics. 2017;6(1):20-26. Abstract2017_-_predictors_of_adequate_ambulatory_anticoagulation_services.pdf

Background: Local anticoagulation services are inadequate and substantially underutilized despite compelling evidence showing that their appropriate use significantly reduces the risk of thromboembolic complications.
Objectives: To determine the predictors of adequate ambulatory anticoagulation services in Kenyatta National Hospital.
Methodology: A cross sectional study between December 2014 and April 2015 among 102 adult outpatients on anticoagulation using consecutive sampling was done. Information abstracted into a predesigned data collection tool included participants’ sociodemographic characteristics, regular sources of supply of anticoagulant, clinic pre-appointment reminders, indications of treatment and international normalized ratio tests. Data were analyzed using IBM Statistical Package for Social Sciences version 21.0 and logistic regression was used to determine independent predictors of adequate anticoagulation, which was defined as international normalized ratio ranging 2 - 3.
Results: Females were majority (76.5 %) and only 27.5 % of patients had adequate anticoagulation control. The indication of warfarin for heart valve surgery (p=0.014) and deep venous thrombosis (p=0.021) were associated with adequate anticoagulation. Age above 60 years was associated with poor anticoagulation (p=0.006). Logistic regression revealed that the independent predictor of adequate anticoagulation was warfarin use due to heart valve surgery (OR=3.1; 95% CI: 1.2 – 7.9, p=0.017).
Conclusions: Ambulatory anticoagulation control in the hospital is poor. Further investigation is required to find out the reasons behind adequate anticoagulation in heart valve surgery patients.
Key Words: Ambulatory anticoagulation, anticoagulant, outpatient, international normalized ratio tests.

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