Bio

Dr. Solomon Derese

Senior Lecturer

Department of Chemistry, University of Nairobi.

Web Champion Chemistry.

 

 

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Publications


2017

Muthaura, CN, Keriko JM, Mutai C, Yenesew A, Heydenreich M, Atilaw Y, Gathirwa JW, Irungu BN, Derese S.  2017.  Antiplasmodial, Cytotoxicity and Phytochemical Constituents of Four Maytenus Species Used in Traditional Medicine in Kenya. The Natural Products Journal. 7(2):144-152.
Derese, S, Guantai EM, Yaouba S, Kuete V.  2017.  Mangifera indica L. (Anacardiaceae). Medicinal Spices and Vegetables from Africa. , London: Elsevier Academic Press

2016

Omosa, LK, Midiwo JO, Mbaveng AT, Tankeo SB, Seukep JA, Voukeng IK, Dzotam JK, Isemeki J, Derese S, Omolle RA, Efferth T, Kuete V.  2016.  Antibacterial activities and structure–activity relationships of a panel of 48 compounds from Kenyan plants against multidrug resistant phenotypes. SpringerPlus. 5(1):1-15.
Marco, M, Deyou T, Gruhonjic A, Holleran JP, Duffy S, Heydenreich M, Fitzpatric PA, Landberg G, Koch A, Derese S, Pelletier J, Avery VM, Erdélyi Máté, Yenesew A.  2016.  Pterocarpans and Isoflavones from the Root Bark of Millettia micans and of Millettia dura. Advances in Drug Discovery and Development. :1-8. Abstract

Pterocarpans and Isoflavones from the Root Bark of Millettia micans and of
Millettia dura
Makungu Marco1, Tsegaye Deyou1,2, Amra Gruhonjic2,5, John P. Holleran3, Sandra Duffy3,
Matthias Heydenreich4, Paul A. Fitzpatrick5, Göran Landberg5, Andreas Koch4, Solomon
Derese1, Jerry Pelletier6, Vicky M. Avery3, Máté Erdélyi2,7,* and Abiy Yenesew1,*
1Department of Chemistry, University of Nairobi, P. O. Box 30197-00100, Nairobi, Kenya; 2Department of
Chemistry and Molecular Biology, University of Gothenburg, SE-40530, Gothenburg, Sweden; 3Discovery
Biology, Eskitis Institute for drug discovery, Griffith University, Nathan Qld 4111 Australia; 4Institut für Chemie,
Universität Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam, Germany; 5Sahlgrenska Cancer
Centre, University of Gothenburg, SE-405 30 Gothenburg, Sweden; 6Department of Biochemistry, McGill
University, Montreal, QC, H3G 1Y6, Canada and 7Swedish NMR Center, University of Gothenburg, P.O. Box
465, SE-40530, Gothenburg, Sweden
Abstract: From the CH2Cl2/CH3OH (1:1) extract of the root bark of Millettia micans, a new pterocarpan,
(6aR,11aR)-7,8,9-trimethoxy-3-hydroxypterocarpan (1), named micanspterocarpan, was isolated. Similar
investigation of the CH2Cl2/CH3OH (1:1) extract of the root bark of Millettia dura gave a further new pterocarpan,
3-O-prenylmaackiain (2) along with six known isoflavones (3-8) and a chalcone (9). All purified
compounds were identified by NMR and MS, and the absolute configuration of 1 was established by quantum
chemical CD calculation. The isolated constituents, calopogonium isoflavone B (3) and isoerythrin A-4'-
(3-methylbut-2-enyl) ether (4) showed marginal activities against the 3D7 and the Dd2 strains of Plasmodium
falciparum (70-90% inhibition at 40

2015

IN Chege, Okalebo FA, A Nkatha Guantai, S Karanja, Derese S.  2015.  Management of type 2 diabetes mellitus by traditional medicine practitioners in Kenya-key informant interviews. The Pan African Medical Journa. 22(90):1-12. Abstract

Abstract
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.

CN, M, Keriko JM, Mutai C, A Y, Gathirwa JW, Irungu BN, Nyangacha R, Mungai GM, s. D.  2015.  Antiplasmodial potential of traditional phytotherapy of some remedies used in treatment of malaria in Meru-Tharaka Nithi County of Kenya. J Ethnopharmacol.. 175(3):15-23. Abstract

J Ethnopharmacol. 2015 Dec 4;175:315-23. doi: 10.1016/j.jep.2015.09.017. Epub 2015 Sep 25.
Antiplasmodial potential of traditional phytotherapy of some remedies used in treatment of malaria in Meru-Tharaka Nithi County of Kenya.
Muthaura CN1, Keriko JM2, Mutai C3, Yenesew A4, Gathirwa JW5, Irungu BN5, Nyangacha R5, Mungai GM6, Derese S4.
Author information
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE:
Medicinal plants play a major role in many communities across the world, in the treatment and prevention of disease and the promotion of general health. The aim of the study was to escalate documentation from an earlier study of medicinal plants, traditionally used to combat malaria by the Ameru community of Imenti Forest area and Gatunga in Eastern Region of Kenya, and validate their ethnopharmacological claims by evaluating their antiplasmodial efficacies.
MATERIALS AND METHODS:
The study was carried out in Meru County at Imenti Forest Game Reserve and in Tharaka Nithi County at Gatunga. Traditional health practitioners (THP) were interviewed with a standard questionnaire to obtain information on medicinal plants traditionally used for management of malaria. Group interviews were also held among THPs and members of the community. The antiplasmodial activities of the crude extracts against chloroquine sensitive (D6) and resistant (W2) Plasmodium falciparum were determined using the semi-automated micro-dilution technique that measures the ability of the extracts to inhibit the incorporation of (G-3H) hypoxanthine into the malaria parasite.
RESULTS:
Ninety nine (99) species in eighty one (81) genera and forty five (45) families were documented and evaluated for in vitro antiplasmodial activity. Compositae, Fabaceae, Meliceae, Rubiaceae, Rutaceae and Verbenaceae had the highest number of species mentioned in treatment of malaria in Meru/Tharaka Nithi study area. Twenty four (24.2%) species showed antiplasmodial efficacy of IC50≤5µg/ml and were considered to have potential for isolation of antimalarial compounds. Eight plant (8) species with moderate antiplasmodial activity namely; Cordia africana, Commiphora africana, Elaeodendron buchananii, Gomphocarpus semilunatus, Tarena graveolens, Plectranthus igniarius, Acacia senegal and Ziziphus abyssinica were documented from this region for the first time for the treatment of malaria. The antiplasmodial activity of MeOH root bark extract of Maytenus obtusifolia was very promising (IC50<1.9µg/ml) and this is the first report on traditional use of M. obtusifolia for treatment of malaria and antimalarial activity.
CONCLUSIONS:
The results seem to indicate that ethnopharmacological inquiry used in search for new herbal remedies as predictive and could be used as the basis for search of new active principles. Eight plant (8) species are documented from this region for the first time for the treatment of malaria. This is the first report on traditional use of M. obtusifolia for treatment of malaria and evaluation of its antiplasmodial activity.

T, D, I G, F P, A G, Mumo M, Holleran J, Duffy S, Fitzpatrick PA, Heydenreich M, G L, S D, Avery V, Rissanen K, Erdélyi M, A Y.  2015.  Rotenoids, Flavonoids, and Chalcones from the Root Bark of Millettia usaramensis.. J Nat Prod. 78(12):2932-9. Abstract

J Nat Prod. 2015 Dec 24;78(12):2932-9. doi: 10.1021/acs.jnatprod.5b00581. Epub 2015 Dec 14.
Rotenoids, Flavonoids, and Chalcones from the Root Bark of Millettia usaramensis.
Deyou T1, Gumula I1, Pang F2, Gruhonjic A, Mumo M1, Holleran J3, Duffy S3, Fitzpatrick PA, Heydenreich M4, Landberg G, Derese S1, Avery V3, Rissanen K2, Erdélyi M, Yenesew A1.
Author information
Abstract
Five new compounds, 4-O-geranylisoliquiritigenin (1), 12-dihydrousararotenoid B (2), 12-dihydrousararotenoid C (3), 4'-O-geranyl-7-hydroxyflavanone (4), and 4'-O-geranyl-7-hydroxydihydroflavanol (5), along with 12 known natural products (6-17) were isolated from the CH2Cl2/MeOH (1:1) extract of the root bark of Millettia usaramensis ssp. usaramensis by chromatographic separation. The purified metabolites were identified by NMR spectroscopic and mass spectrometric analyses, whereas their absolute configurations were established on the basis of chiroptical data and in some cases also by X-ray crystallography. The crude extract was moderately active (IC50 = 11.63 μg/mL) against the ER-negative MDB-MB-231 human breast cancer cell line, and accordingly compounds 6, 8, 9, 10, 12, and 16 also showed moderate to low cytotoxic activities (IC50 25.7-207.2 μM). The new natural product 1 exhibited antiplasmodial activity with IC50 values of 3.7 and 5.3 μM against the chloroquine-sensitive 3D7 and the chloroquine-resistant Dd2 Plasmodium falciparum strains, respectively, and was also cytotoxic to the HEK293 cell line.

Irene Njeri Chege, Faith Apolot Okalebo, ANGSKSD.  2015.  Herbal Product Processing Practices of Traditional Medicine Practitioners in Kenya-Key Informant Interviews. Journal of Health, Medicine and Nursing. 16:11-23. Abstract24799-27406-1-pb_1.pdf

Herbal Product Processing Practices of Traditional Medicine Practitioners in Kenya-Key Informant Interviews
Irene Njeri Chege, Faith Apolot Okalebo, Anastasia Nkatha Guantai, Simon Karanja, Solomon Derese
Journal of Health, Medicine and Nursing, 2015, 16, 11-23

Abstract
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

Muthaura CN, Keriko JM, MYGJWIBNNMGMDCAR.  2015.  Antiplasmodial potential of traditional antimalarial phytotherapy remedies used by the Kwale community of the Kenyan coast. Journal of ethnopharmacology. 170:148-157. Abstract

Antiplasmodial potential of traditional antimalarial phytotherapy remedies used by the Kwale community of the Kenyan Coast.

Muthaura CN, Keriko JM, Mutai C, Yenesew A, Gathirwa JW, Irungu BN, Nyangacha R, Mungai GM, Derese S
Kenya Medical Research Institute, P.O. Box 54840, 00200 Nairobi, Kenya. Electronic address: cmuthaura@yahoo.com.
Journal of Ethnopharmacology [2015, 170:148-157]

ETHNOPHARMACOLOGICAL RELEVANCE: In Kenya, 22 million people are at risk of malaria, 70% of them are in rural areas and most of these people use traditional plant based medicines to treat malaria. The aim of the study was to escalate documentation, from an earlier study of medicinal plants, traditionally used to treat malaria by the Digo community of Kwale County, taking cognizance of their pharmacological information by evaluating their antiplasmodial efficacies.

MATERIALS AND METHODS: The study was carried out in Kwale County at Shimba Hills Game Reserve and adjoining part of Kinango. Traditional health practitioners (THP) were interviewed with a standard questionnaire to obtain information on medicinal plants traditionally used for management of malaria. Group interviews were also held among THPs and members of the community. The plant samples collected were tested for antiplasmodial activity against chloroquine sensitive (D6) and resistant (W2) Plasmodium falciparum using the ability of extracts, prepared from the plant species, to inhibit the incorporation of [G-3H] hypoxanthine into the malaria parasites.

RESULTS: Fifty seven (57) species in forty eight (48) genera and thirty (30) families were documented and evaluated for in vitro antiplasmodial activity. Apocynaceae, Euphorbiaceae, and Rubiaceae families had each about 12% of the plant species reported as antimalarial remedy and represented the species that are most commonly used. Twelve species (21.1%) showed antiplasmodial efficacy of IC50<5µg/ml and these were Boscia salicifolia, Cissampelos mucronata, Clerodendrum myricoides, Commiphora schimperi, Flueggea virosa, Maytenus undata, Maytenus senegalensis, Maytenus putterlickioides, Vernonia amygdalina, Warburgia stuhlmannii, Zanthoxylum chalybeum and Tabernaemontana pachysiphon.

CONCLUSIONS: These results seem to indicate that ethnopharmacological inquiry used in search for new herbal remedies as predictive and could form the basis of an ethnopharmacopoeia and search for new active principles. This is the first report on traditional use of T. pachysiphon for malaria and its antiplasmodial activity.

2014

Lois Muiva-Mutisya, Bernard Macharia, MHAKHASDLOAMK.  2014.  6α-Hydroxy-α-toxicarol and (+)-tephrodin with antiplasmodial activities from Tephrosia species. Phytochemistry Letters. 10:179-183. Abstract

6α-Hydroxy-α-toxicarol and (+)-tephrodin with antiplasmodial activities from Tephrosia species

Lois Muiva-Mutisyaa, Bernard Machariaa, Matthias Heydenreichb, Andreas Kochb, Hoseah M. Akalac, Solomon Deresea, Leonidah K. Omosaa, Amir O. Yusufa, Edwin Kamauc, Abiy Yenesew
Phytochemistry Letters, Volume 10, December 2014, Pages 179–183

Abstract
The CH2Cl2/MeOH (1:1) extract of the roots of Tephrosia villosa showed good antiplasmodial activity against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum with IC50 values of 3.1 ± 0.4 and 1.3 ± 0.3 μg/mL, respectively. Chromatographic separation of the extract yielded a new rotenoid, 6α-hydroxy-α-toxicarol, along with five known rotenoids, (rotenone, deguelin, sumatrol, 12a-hydroxy-α-toxicarol and villosinol). Similar treatment of the extract of the stem of Tephrosia purpurea (IC50 = 4.1 ± 0.4 and 1.9 ± 0.2 μg/mL against D6 and W2 strains of P. falciparum, respectively) yielded a new flavone having a unique substituent at C-7/C-8 [trivial name (+)-tephrodin], along with the known flavonoids tachrosin, obovatin methyl ether and derrone. The relative configuration and the most stable conformation in (+)-tephrodin was determined by NMR and theoretical energy calculations. The rotenoids and flavones tested showed good to moderate antiplasmodial activities (IC50 = 9 − 23 μМ). Whereas the cytotoxicity of rotenoids is known, the flavones (+)-tephrodin and tachrosin did not show significant cytotoxicity (IC50 > 100 μМ) against mammalian African monkey kidney (vero) and human larynx carcinoma (HEp2) cell lines.

Derese, S.  2014.  4′-Prenyloxyderrone from the stem bark of Millettia oblata ssp. teitensis and the antiplasmodial activities of isoflavones from some Millettia species. Phytochemistry Letters. 8:69-72. Abstract

4′-Prenyloxyderrone from the stem bark of Millettia oblata ssp. teitensis and the antiplasmodial activities of isoflavones from some Millettia species

Solomon Derese, Leonard Barasa, Hoseah M. Akala, Amir O. Yusuf, Edwin Kamau, Matthias Heydenreich, Abiy Yenesew

The CH2Cl2/MeOH (1:1) extract of the stem bark of Millettia oblata ssp. teitensis showed antiplasmodial activity (IC50 = 10–12 μg/mL) against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum. Chromatographic separation of the extract led to the isolation of a new isoflavone, 4′-prenyloxyderrone (1), together with known isoflavones (8-O-methylretusin, durmillone, maximaisoflavone B, maximaisoflavone H and maximaisoflavone J), a rotenoid (tephrosin) and a triterpene (lupeol). Similar investigation of Millettia leucantha resulted in the identification of the isoflavones afrormosin and wistin, and the flavone chrysin. The identification of these compounds was based on their spectroscopic data. Five of the isoflavones isolated from these plants as well as 11 previously reported compounds from Millettia dura were tested and showed good to moderate antiplasmodial activities (IC50 = 13–53 μM), with the new compound, 4′-prenyloxyderrone, being the most active (IC50 = 13–15 μM).

2013

Derese, S.  2013.  Antiplasmodial activity of compounds from the surface exudates of Senecio roseiflorus. Natural product communications. 8(2):175-6. Abstract

Antiplasmodial activity of compounds from the surface exudates of Senecio roseiflorus.

Leonidah Omosa Kerubo, Jacob Ogweno Midiwo, Solomon Derese, Moses K Langat, Hosea M Akala, Norman C Waters, Martin Peter, Matthias
Natural Products Communications: 2013; 8(2):175-6.

From the surface exudates of Senecio roseiflorus fourteen known methylated flavonoids and one phenol were isolated and characterized. The structures of these compounds were determined on the basis of their spectroscopic analysis. The surface exudate and the flavonoids isolated showed moderate to good antiplasmodial activity with 5,4'-dihydroxy-7-dimethoxyflavanone having the highest activity against chloroquine-sensitive (D6) and resistant (W2) strains of Plasmodium falciparum, with IC50 values of 3.2 +/- 0.8 and 4.4 +/- 0.01 microg/mL respectively.

2012

SOLOMON, DRDERESE.  2012.  Four isoflavanones from the stem bark of Platycelphium voense. Phytochemistry Letters. 5(1):150–154.: Elsevier AbstractScienceDirect

From the stem bark of Platycelphium voënse (Leguminosae) four new isoflavanones were isolated and characterized as (S)-5,7-dihydroxy-2′,4′-dimethoxy-3′-(3″-methylbut-2″-enyl)-isoflavanone (trivial name platyisoflavanone A), (±)-5,7,2′-trihydroxy-4′-methoxy-3′-(3″-methylbut-2″-enyl)-isoflavanone (platyisoflavanone B), 5,7-dihydroxy-4′-methoxy-2″-(2‴-hydroxyisopropyl)-dihydrofurano-[4″,5″:3′,2′]-isoflavanone (platyisoflavanone C) and 5,7,2′,3″-tetrahydroxy-2″,2″-dimethyldihydropyrano-[5″,6″:3′,4′]-isoflavanone (platyisoflavanone D). In addition, the known isoflavanones, sophoraisoflavanone A and glyasperin F; the isoflavone, formononetin; two flavones, kumatakenin and isokaempferide; as well as two triterpenes, betulin and β-amyrin were identified. The structures were elucidated on the basis of spectroscopic evidence. Platyisoflavanone A showed antibacterial activity against Mycobacterium tuberculosis in the microplate alamar blue assay (MABA) with MIC = 23.7 μM, but also showed cytotoxicity (IC50 = 21.1 μM) in the vero cell test.

SOLOMON, DRDERESE.  2012.  Antiplasmodial Quinones from Pentas longiflora and Pentas lanceolata. Planta Medica. 78:31–35.: Thieme AbstractWebsite

Milkyas Endale, John Patrick Alao, Hoseah M. Akala, Nelson K. Rono, Fredrick L. Eyase, Solomon Derese,
Albert Ndakala, Martin Mbugua, Douglas S.Walsh, Per Sunnerhagen, Mate Erdelyi, Abiy Yenesew

Planta Med 2012; 78: 31–35

The dichloromethane/methanol (1 :1) extracts of the roots of Pentas longiflora and Pentas lanceolata showed low micromolar (IC50 = 0.9–3 μg/mL) in vitro antiplasmodial activity against chloroquineresistant (W2) and chloroquine-sensitive (D6) strains of Plasmodium falciparum. Chromatographic separation of the extract of Pentas longiflora led to the isolation of the pyranonaphthoquinones pentalongin (1) and psychorubrin (2) with IC50 values below 1 μg/mL and the naphthalene derivative mollugin (3), which showed marginal activity. Similar treatment of Pentas lanceolata led to the isolation of eight anthraquinones (4–11, IC50 = 5–31 μg/mL) of which one is new (5,6-dihydroxydamnacanthol, 11), while three – nordamnacanthal (7), lucidin-ω-methyl ether (9), and damnacanthol (10) – are reported here for the first time from the genus Pentas. The compounds were identified by NMR and mass spectroscopic techniques.

2011

Yenesew, A, Gumuia I, Heydenreich M, Derese S, Okalebo FA, Ndiege IO, Erdelyi M.  2011.  Bioactivity of 'Flemingin A' and other Natural Products from the leaves of Flemingia grahamiana. yenesew.pdfWebsite
SOLOMON, DRDERESE.  2011.  Investigation of some medicinal plants traditionally used for treatment of malaria in Kenya as potential sources of antimalarial drugs.. Experimental Parasitology. 127(2):609–626.: Elsevier AbstractScienceDirect

Malaria is a major public health problem in many tropical and subtropical countries and the burden of this disease is getting worse, mainly due to the increasing resistance of Plasmodium falciparum against the widely available antimalarial drugs. There is an urgent need for discovery of new antimalarial agents. Herbal medicines for the treatment of various diseases including malaria are an important part of the cultural diversity and traditions of which Kenya′s biodiversity has been an integral part. Two major antimalarial drugs widely used today came originally from indigenous medical systems, that is quinine and artemisinin, from Peruvian and Chinese ancestral treatments, respectively. Thus ethnopharmacology is a very important resource in which new therapies may be discovered. The present review is an analysis of ethnopharmacological publications on antimalarial therapies from some Kenyan medicinal plants.

2010

SOLOMON, DRDERESE.  2010.  Antimicrobial and antiparasitic abietane diterpenoids from the roots of Clerodendrum eriophyllum.. Natural Products Communication. 5(6):853-858.: Elsevier AbstractWebsite

Machumi F, Samoylenko V, Yenesew A, Derese S, Midiwo JO, Wiggers FT, Jacob MR, Tekwani BL, Khan SI, Walker LA, Muhammad I.; Nat Prod Commun. 2010 5(6), pp. 853-8.

Chromatographic separation of the roots of a Kenyan medicinal plant, Clerodendrum eriophyllum, led to the isolation of ten abietane diterpenoids (1-10), one of which (1) was isolated for the first time from a natural source. Using spectroscopic data, the structure of 1 was determined to be 12-hydroxy-8,12-abietadiene-3,11,14-trione. Circular dichroism (CD) spectra showed that the stereochemistry of compounds 1, 3, and 6-8 belongs to the normal series of abietane diterpenes, which confirmed the absolute stereochemistry of the isolated compounds. Compounds 1-10 were evaluated for their in vitro antiplasmodial, antileishmanial, antifungal and antibacterial activities. Compounds 3 and 7 exhibited potent antifungal activity (IC50/MIC 0.58/1.25 and 0.96/2.5 microg/mL, respectively) against C. neoformans, whereas 3, 6 and 7 showed strong antibacterial activity against Staphylococcus aureus and methicillin-resistant S. aureus with IC50/MIC values between 1.33-1.75/2.5-5 and 0.96-1.56/2.5 microg/mL, respectively. In addition, compounds 3 and 9 exhibited potent antileishmanial activity (IC50 0.08 and 0.20 microg/mL, respectively) against L. donovani, while 3 and 7 displayed weak antimalarial activity against Plasmodium falciparum, but 9 was inactive.

SOLOMON, DRDERESE.  2010.  neo-Clerodane diterpenoids from the leaf exudate of Dodonaea angustifolia.. Phytochemistry Letters. 3(4):217-220.: Elsevier AbstractWebsite

Leonidah K. Omosa, Jacob O. Midiwo, Solomon Derese, Abiy Yenesew, Martin G. Peter, Matthias Heydenreich.

Phytochemical investigation of the leaf surface exudate of Dodonaea angustifolia L.f. yielded two new neo-clerodane diterpenes, neo-clerodan-3,13-dien-16,15:18,19-diolide (mkapwanin) and 15-methoxy-neo-clerodan-3,13-dien-16,15:18,19-diolide (15-methoxymkapwanin). In addition, ten known compounds were identified. The structures were determined on the basis of spectroscopic evidence. This additional chemical information could contribute towards solving the taxonomical controversy that exists between Dodonaea angustifolia and Dodonaea viscosa Jacq., which are morphologically similar.

2009

Martin, PG, Yenesew A, Heydenreich M, Guchu SM, lrungu B, Derese S, Midiwo JO.  2009.  Flavonoids and isoflavonoids of Erythrina burttii. isoflavanoes_...0001.pdfWebsite
SOLOMON, DRDERESE.  2009.  Antiplasmodial β-hydroxydihydrochalcone from seedpods of Tephrosiaelata. Phytochemistry Letters. 2(3):99-102.: Elsevier AbstractWebsite

Muiva, L.M. Yenesew, A., Solomon Derese, Heydenreich, M., Peter, M.G., Akala, H.M., F. Eyase, Waters, N.C., Mutai, C., Keriko, J.M., Walsh, D. Phytochemistry Letters, 2009, pp. 99-102.

From the seedpods of Tephrosia elata, a new β-hydroxydihydrochalcone named (S)-elatadihydrochalcone was isolated. In addition, the known flavonoids obovatachalcone, obovatin, obovatin methyl ether and deguelin were identified. The structures were determined on the basis of spectroscopic evidence. The crude extract and the flavonoids obtained from the seedpods of this plant showed antiplasmodial activities. The literature NMR data on β-hydroxydihydrochalcones is reviewed and the identity of some of the compounds assigned β-hydroxydihydrochalcone skeleton is questioned.

2006

SOLOMON, DRDERESE.  2006.  Two unusual rotenoid derivatives, 7a-O-methyl-12a-hydroxydeguelol and spiro-13-homo-13-oxaelliptone, from the seeds of Derris trifoliata.. Phytochemistry. 67:988-91.: Elsevier AbstractWebsite

Abiy Yenesew; John T Kiplagat; Solomon Derese; Jacob O Midiwo; Jacques M Kabaru; Matthias Heydenreich; Martin G Peter

The crude methanol extract of the seeds of Derris trifoliata showed potent and dose dependent larvicidal activity against the 2nd instar larvae of Aedes aegypti. From this extract two unusual rotenoid derivatives, a rotenoloid (named 7a-O-methyl-12a-hydroxydeguelol) and a spirohomooxarotenoid (named spiro-13-homo-13-oxaelliptone), were isolated and characterised. In addition a rare natural chromanone (6,7-dimethoxy-4-chromanone) and the known rotenoids rotenone, tephrosin and dehydrodeguelin were identified. The structures were assigned on the basis of spectroscopic evidence. The larvicidal activity of the crude extract is mainly due to rotenone.

SOLOMON, DRDERESE.  2006.  Antiplasmodial activities of flavonoids from Erythrina sacleuxii.. Planta Medica. 72(2):187-9.: Elsevier AbstractWebsite

Andrew .W. Andayi, A. Yenesew, Solomon Derese, Jacob O. Midiwo, Peter M. Gitu, Ogoche I. Jondiko, Norman Waters, Pamela Liyala, Hosea Akala, Matthias Heydenreich, Martin G Peter. (2006): Planta medica, 72 (2), pp. 187-189.

The acetone extracts of the root bark and stem bark of Erythrina sacleuxii showed antiplasmodial activities against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum. Chromatographic separation of the acetone extract of the root bark afforded a new isoflavone, 7-hydroxy-4'-methoxy-3'-prenylisoflavone (trivial name 5-deoxy-3'-prenylbiochanin A) along with known isoflavonoids as the antiplasmodial principles. Flavonoids and isoflavonoids isolated from the stem bark of E. sacleuxii were also tested and showed antiplasmodial activities. The structures were determined on the basis of spectroscopic evidence.

2005

Derese, S.  2005.  Screening of Plant Extracts for Searching Antiplasmodial Activity. 11th NAPRECA Symposium. :136-144., Madagascar: NAPRECA Abstractscreening_of_plant_extracts_for_searching_antiplasmodial_activity.pdf

The aim objective of this study consists in isolating the active molecules from plants used in traditional medicine to treat malaria and its symptoms.
197 plants were collected following to the ethnobotanic investigations. Plants were dried, powdered and macerated in a hydroalcoholic solution. Resulting extracts have been assessed for in vitro & in vivo antimalarial and toxicity activities.
For the plants collected in Madagascar: 15 extracts (i.e. 16%) prepared from 91 medicinal plants (of which 57 are antimalarial) present an interesting antiplasmodial activity with a value of IC50 less than 10 μg/mL, their cytotoxicity are weak with a value of IC50 evaluated at more than 50 μg/mL. Two of these extracts have an ED50 lower than 100 mg/kg.
With regard to the Congolese plants: five out of twenty six (i.e. 19%) collected plants would be interesting.

Key words:
Malaria, Screening, Plants, Madagascar, Africa

SOLOMON, DRDERESE.  2005.  Antimicrobial flavonoids from the stem bark of Erythrina burttii.. Fitoterapia. 76(5):469-72.: Elsevier AbstractWebsite

Antimicrobial flavonoids from the stem bark of Erythrina burttii.

Yenesew A, Derese S, Midiwo JO, Bii CC, Heydenreich M, Peter MG.

Abstract

The chloroform extract of the stem bark of Erythrina burttii showed antifungal and antibacterial activities using the disk diffusion method. Flavonoids were identified as the active principles. Activities were observed against fungi and Gram(+) bacteria, but the Gram(-) bacteria Escherichia coli was resistant.

SOLOMON, DRDERESE.  2005.  7a-O-Methyldeguelol, a modified rotenoid with an open ring-C, from the roots of Derris trifoliata.. Phytochemistry. 66:653-657.: Elsevier AbstractWebsite

Phytochemistry. 2005 Mar;66(6):653-7.

7a-O-methyldeguelol, a modified rotenoid with an open ring-C, from the roots of Derris trifoliata.

Yenesew A, Mushibe EK, Induli M, Derese S, Midiwo JO, Kabaru JM, Heydenreich M, Koch A, Peter MG.

From the acetone extract of the roots of Derris trifoliata an isoflavonoid derivative, named 7a-O-methyldeguelol, a modified rotenoid with an open ring-C, representing a new sub-class of isoflavonoids (the sub-class is here named as rotenoloid), was isolated and characterised. In addition, the known rotenoids, rotenone, deguelin and alpha-toxicarol, were identified. The structures were determined on the basis of spectroscopic evidence. Rotenone and deguelin were identified as the larvicidal principles of the acetone extract of the roots of Derris trifoliata.

2004

SOLOMON, DRDERESE.  2004.  Anti-plasmodial flavonoids from the stem bark of Erythrina abyssinica.. Phytochemistry. 65(22):3029-32.: Elsevier AbstractWebsite

Phytochemistry. 2004 Nov;65(22):3029-32.

Anti-plasmodial flavonoids from the stem bark of Erythrina abyssinica.

Yenesew A, Induli M, Derese S, Midiwo JO, Heydenreich M, Peter MG, Akala H, Wangui J, Liyala P, Waters NC.

The ethyl acetate extract of the stem bark of Erythrina abyssinica showed anti-plasmodial activity against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum with IC(50) values of 7.9+/-1.1 and 5.3+/-0.7 microg/ml, respectively. From this extract, a new chalcone, 2',3,4,4'-tetrahydroxy-5-prenylchalcone (trivial name 5-prenylbutein) and a new flavanone, 4',7-dihydroxy-3'-methoxy-5'-prenylflavanone (trivial name, 5-deoxyabyssinin II) along with known flavonoids have been isolated as the anti-plasmodial principles. The structures were determined on the basis of spectroscopic evidence.

2003

SOLOMON, DRDERESE.  2003.  Anti-plasmodial activities and X-ray crystal structures of rotenoids from Millettia usaramensis subspecies usaramensis .. Chemical Sciences Journal Vol. 2012: CSJ-56. : Elsevier Abstract

The dichloromethane extract of the stem bark of Millettia usaramensis subspecies usaramensis showed anti-plasmodial activity against the chloroquine sensitive (D6) and chloroquine resistant (W2) strains of Plasmodium falciparum. Chromatographic separation of the extract led to the identification of a new rotenoid, (6aR,12aS)-2,3-methylenedioxy-9-methoxy-8-(3,3-dimethylallyl)-12a-hydroxyrotenoid (trivial name, usararotenoid C) along with known flavonoids (usararotenoid A, 12a-epimillettosin, 6a,12a-dehydromillettone, barbigerone and 4′-O-geranylisoliquiritigenin) as the anti-plasmodial principles. The structures were determined by spectroscopic analyses. CD and X-ray analyses established absolute configurations.

SOLOMON, DRDERESE.  2003.  Effect of Rotenoids from the seeds of Millettia dura on Larvae of Aedes aegypti.. Chemical Sciences Journal Vol. 2012: CSJ-56. : Elsevier Abstract

A crude chloroform extract of seeds of Millettia dura Dunn (Leguminosae) showed high activity (LC50 = 3.5 microg ml(-1) at 24 h) against second-instar larvae of the mosquito, Aedes aegypti L (Diptera: Culicidae). The rotenoids, deguelin and tephrosin, isolated from the seeds of this plant also showed potent activities, with LC50 values of 1.6 and 1.4 microg ml(-1) at 24 h, respectively. The related rotenoids millettone and millettosin were inactive at 20 microg ml(-1). Saturation at the B/C ring junction and the presence of methoxy groups at C-2 and/or C-3 in deguelin and tephrosin appear to be important for the observed larvicidal activity.

SOLOMON, DRDERESE.  2003.  Flavonoids and isoflavonoids with anti-plasmodial activities from the roots of Erythrina abyssinica.. Chemical Sciences Journal Vol. 2012: CSJ-56. : Elsevier Abstract

From the root bark of Erythrina abyssinica a new pterocarpene [3-hydroxy-9-methoxy-10-(3,3-dimethylallyl)pterocarpene] and a new isoflav-3-ene [7,4'-dihydroxy-2',5'-dimethoxyisoflav-3-ene] were isolated. In addition, the known compounds erycristagallin, licoagrochalcone A, octacosyl ferulate and triacontyl 4-hydroxycinnamate were identified. The structures were determined on the basis of spectroscopic evidence. The crude extract and the flavonoids and isoflavonoids obtained from the roots of this plant showed antiplasmodial activities.

SOLOMON, DRDERESE.  2003.  Two prenylated flavonoids from the stem bark of Erythrina burttii.. Phytochemistry. 63(4):445-8.: Elsevier AbstractWebsite

Phytochemistry. 2003 Jun;63(4):445-8.

Two prenylated flavonoids from the stem bark of Erythrina burttii.

Yenesew A, Irungu B, Derese S, Midiwo JO, Heydenreich M, Peter MG.

From the stem bark of Erythrina burttii, a new isoflavone, 5,2',4'-trihydroxy-7-methoxy-6-(3-methylbut-2-enyl)isoflavone (trivial name, 7-O-methylluteone) and a new flavanone, 5,7-dihydroxy-4'-methoxy-3'-(3-methylbutadienyl)-5'-(3-methylbut-2-enyl)flavanone (trivial name, burttinonedehydrate) along with three known isoflavonoids (8-prenylluteone, 3-O-methylcalopocarpin and genistein) were isolated. The structures were determined on the basis of spectroscopic evidence.

SOLOMON, DRDERESE.  2003.  A new isoflavones from the stem bark of Millettia dura.. Bull. Chem. Soc. Ethiop.. 17(1):113-115.: Elsevier AbstractWebsite

Solomon Derese, Abiy Yenesew, J.O. Midiwo, Matthias Heydenreich and Martin G. Peter. Bull. Chem. Soc. Ethiop., 2003, 17(1), pp. 113-115.

A new isoflavone (7,3’-dimethoxy-4’,5’-methylenedioxyisoflavone) and three known isoflavones [isoerythrinin A 4’-(3-methylbut-2-enyl) ether, isojamaicin and nordurlettone] were isolated from the stem bark of Millettia dura (Leguminosae). The structures were determined by spectroscopic methods.

KEY WORDS: Millettia dura, Leguminosae, Isoflavone, 7,3’-Dimethoxy-4’,5’-

methylenedioxyisoflavone, Isoerythrinin A 4’-(3-methylbut-2-enyl) ether, Isojamaicin,

Nordurlettone_

2002

SOLOMON, DRDERESE.  2002.  Bioactive Compounds from Some Kenyan Ethno-medicinal Plants: Myrsinaceae, Polygonaceae and Psiadia punctulata.. Chemical Sciences Journal Vol. 2012: CSJ-56. : Elsevier Abstract

There are several described medicinal plants in Kenya from a flora of approximately 10,000 members. Strong cross-medical information from the 42 ethnic groups points to the high potential of some of these species. The Myrsinaceae are well established ethno-anthelmintics and anti-bacterials. They are harbingers of long alkyl side chain benzoquinones which clearly have a protective function from their histochemical disposition. The main benzoquinone in the sub-family Myrsinodae is embelin while for the Maesodae it is maesaquinone together with its 5-acetyl derivative; the distribution of these benzoquinones by their alkyl side chain length or the presence/absence of a 6-methyl group is in accord with morphological sub-family de-limitation. The benzoquinones showed anti-feedant, anti-microbial, phytotoxic, acaricidal, insecticidal and nematicidal activity. Many other benzoquinones of medium and minor concentration were also isolated and characterised. Some plants belonging to the Polygonaceae which are widely used as ethno-anthelmintics have been studied. The common anthelmintic anthraquinones were obtained from all five Rumex species while the naphthalenic acetogenin derivative, nepodin was more selectively distributed. The leaf of Polygonum senegalense is up to 17% surface exudate; about thirteen non polar flavonoid derivatives (chalcones, dihydrochalcones, flavanones and a flavone) have been isolated from it. From the internal aerial tissues of this plant, the major flavonoids were common flavonoids, quercetin, kaempferol, luteolin and their glycosides. The only unique compound isolated from this plant was 2′-glucosyl-6′-hydroxy-4′-methoxydihydrochalcone whose aglycone, uvangolatin is part of the exudate mixture. Other leaf exudate plants studied include the stomach-ache medicine, Psiadia punctulata (Compositae) from which novel methylated flavonoids, kaurene and trachyloban diterpenes have been found.

2000

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