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Manani RO, Abuga KO, Chepkwony HK. "Pharmaceutical Equivalence of Clarithromycin Oral Dosage Forms Marketed in Nairobi County, Kenya." Scientia Pharmaceutica. 2017;85(2):20. Abstract

Clarithromycin is a broad-spectrum semi-synthetic macrolide indicated for treatment of pneumonias, Helicobacter pylori, and chlamydial and skin infections. The object of this study was to evaluate the pharmaceutical equivalence of 14 generic clarithromycin products marketed in Nairobi County, Kenya, to the innovator products, using in vitro dissolution profiles and similarity factors (f2). Further, dissolution profiles of four innovator formulations manufactured in different sites were compared. Fourteen clarithromycin tablets/capsules and four suspensions were subjected to assay and comparative dissolution runs at pH 1.2, 4.5 and 6.8, for 60 and 90 min, respectively. All products complied with pharmacopoeial assay specifications. However, significant differences were observed in their dissolution profiles. The non-compliance rates for tablets/capsules were 50% at pH 1.2, 33% at pH 4.5 and 50% at pH 6.8, while none of the four suspensions were compliant. Overall, only four (25%) products complied with the specifications for similarity factor. The results obtained indicate that a significant percentage of generic clarithromycin products are pharmaceutically non-equivalent to the innovator products, and that assay and single-point dissolution tests are insufficient demonstration of equivalence between the generic and innovator products.

Mubiu JK, Ndwigah SN, Abuga KO, Ongarora DSB. "Antimicrobial activity of extracts and phytosterols from the root bark of Lonchocarpus eriocalyx." East Cent. Afr. J. Pharm. Sci. . 2017;20:13-16. Abstract

The root bark of Lonchocarpus eriocalyx was dried, powdered and extracted using chloroform, methanol and hot water. The extracts exhibited antibacterial activity against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus and antifungal activity against Saccharomyces cerevisiae. The decoction (100mg/ml) was more active than the chloroform and methanol extracts against the four microorganisms. Chromatographic fractionation of the chloroform extract using normal phase silica yielded the phytosterols lupeol and lupenone. At 100 mg/ml, the compounds were active against all the four microorganisms, with lupeol being more active than lupenone. This is the first report of the isolation of lupenone from Lonchocarpus eriocalyx.

Muema SM, Abuga KO, Yenesew A, Thoithi GN. "Phytochemical and Anthelmintic Study of the Root Bark of Teclea Trichocarpa, Engl. (Rutaceae)." East Cent. Afr. J. Pharm.. 2014;17(2):44-47. Abstract

The root bark of Teclea trichocarpa exhibited anthelmintic activity against egg hatching and larval development of sheep nematodes (Strongyloides). Three compounds, namely lupeol, melicopicine and 6-methoxytecleanthine were isolated from the dichloromethane-methanol (50:50) extract of the plant. Melicopicine and 6-methoxytecleanthine exhibited mild anthelmintic activity. The present study lends scientific credence to the traditional use of Teclea trichocarpa in the treatment of human helminth infections.

Mukungu NA, Abuga KO, Okalebo FO, Ingwela RT, Mwangi JW. "Medicinal plants used for management of malaria among the Luhya community of Kakamega East sub-County, Kenya." Journal of ethnopharmacology. 2016;194 :98-107. Abstract

Background

Malaria remains a major health problem worldwide especially in sub-Saharan Africa. In Kenya, 80% of the population is at risk of contracting the disease. Pregnant mothers and children under five years are the most affected by this disease. Antimalarial drug resistance poses a major threat in the fight against malaria necessitating continuous search for new antimalarial drugs. Due to inadequate and inaccessible health facilities, majority of people living in rural communities heavily depend on traditional medicine which involves the use of medicinal plants for the management of malaria. Most of these indigenous knowledge is undocumented and risks being lost yet such information could be useful in the search of new antimalarial agents.

Aim of study

An ethnobotanical survey was carried out among the Luhya community of Kakamega East sub-County, a malaria epidemic region, with the aim of documenting the plants used in the management of malaria.

Materials and methods

Semi-structured questionnaires were used to collect information from 21 informants who included traditional medicine practitioners and other caregivers who had experience in use of plants in management of malaria. These were drawn from 4 villages located in Kakamega East sub-county, within Kakamega County based on their differences in topography. Information recorded included plant names, parts used, mode of preparation and administration and the sources of plant materials. A literature search was conducted using PubMed and google scholar to identify the reported traditional uses of these plants and studied antiplasmodial activities.

Results

In this study, 57% of the informants were aged above 50 years and a total of 61% had either no formal education or had only attained primary school education. A total of 42 plant species belonging to 24 families were identified. Most plants used in the management of malaria in this community belonged to Lamiaceae (18%), Leguminosae (9%) and Compositae (9%) plant families. Plants mostly used included Melia azedarach L, Aloe spp, Ajuga integrifolia Buch. Ham, Vernonia amygdalina Del., Rotheca myricoides (Hochst.) Steane and Mabb, Fuerstia africana T.C.E.Fr., Zanthoxylum gilletii (De Wild.) P.G.Waterman and Leucas calostachys Oliv. Rumex steudelii Hochst.ex A. Rich and Phyllanthus sepialis Müll. Arg are reported for the first time in the management of malaria. Although Clerodendrum johnstonii Oliv. ( Jeruto et al., 2011) and Physalis peruviana L.(Ramadan et al., 2015) are reported in other studies for management of malaria, no studies have been carried out to demonstrate their antiplasmodial activity.
The plant parts mostly used were the leaves (36%) and stem barks (26%). Majority of these plants were prepared as decoctions by boiling and allowed to cool before administration (66%) while infusions accounted for 28% of the preparations. The literature mined supports the use of these plants for the management of malaria since most of them have demonstrated in-vitro and in-vivo antiplasmodial activities.

Conclusion

Most of the reported plant species in this study have been investigated for antiplasmodial activity and are in agreement with the ethnomedical use. Two (2) plants are reported for the first time in the management of malaria. There is need for documentation and preservation of the rich ethnomedical knowledge within this community given that most of the practitioners are advanced in age and less educated. There is also the danger of over-exploitation of plant species as most of them are obtained from the wild, mainly Kakamega forest. Therefore, there is need for determining the economically and medicinally important plants in this community and planning for their preservation.

Mukungu NA, Okalebo FA, Abuga KO, Oyugi JO, Ochola L, Tanabe M, Ohta M, Mwangi JW. "Identification of antimalarial compounds from Leucas calostachys, using High Performance Liquid Chromatography and Electrospray Ionization Mass Spectrometry." East Cent. Afr. J. Pharm. Sci. . 2021;24(3):92-102. Abstract

Leucas calostachys is widely used in traditional medicine in Kenya for management of various ailments including malaria. Bio-assay guided fractionation of Leucas calostachys extracts was carried out using in-vitro antiplasmodial and β-hematin inhibition assays with semi-preparative high performance liquid chromatography (HPLC). The active methanol fraction was subjected to liquid chromatography tandem mass spectrometry to identify constituent compounds. A total of twenty compounds consisting of eight flavonoids and 12 phenylethanoids were identified from this fraction. The flavonoids included, isorhamnetin, luteolin-7-O-glucoside, luteolin-4′-O-glucoside, luteolin diglucoside, apigenin-O-glucoside, genistein-O-glucoside, chrysoeriol-7-O-glucoside, and chrysoeriol-7-O-glucuronide. Seven of the phenylethanoids were identified as acteoside, isoactoeside, hydroxyacteoside, forthsoside B, samioside, alyssonoside and leucoseptoside A. The antimalarial activity of Leucas calostachys could be linked to presence of flavonoids and phenylethanoids.

Mukungu NA, Abuga KO, Mungai NN, Karumi EW. "Isolation and structural elucidation of compounds from the non-alkaloidal extract of Nicandra physaloides and the antimicrobial activity of withanicandrin." East Cent. Afr. J. Pharm. . 2013;16(2):49-53. Abstract

The aerial parts of Nicandra physaloides plant collected from Kenyatta National Hospital grounds were dried and subjected to acid-base extraction and partitioned to obtain alkaloidal and non-alkaloidal extracts. The non-alkaloidal extract yielded three compounds; withanicandrin, β-sitosterol and stigmasterol after column chromatography. Withanicandrin exhibited antifungal activity against Saccharomyces cerevisiae and Candida albicans but lacked antibacterial activity.

Mwangi S, Abuga K, Mungai N, Mwangi J. "A High Performance Liquid Chromatography Method for the Determination of Artemisinin in Artemisia annua L. Leaf Extracts." East Cent. Afr. J. Pharm. Sci. . 2020;23(2):48-53. Abstract

A simple, sensitive, accurate and precise high performance liquid chromatography (HPLC) method for determination of artemisinin in crude plant material was developed and validated. Optimal separation of artemisinin from matrix components in the plant extracts was achieved using a Waters XTerra® RP18 , 5 m, 250 × 4.6 mm column, maintained at 40 °C, a mobile phase consisting of 0.05 M potassium phosphate buffer, pH 6.0 - acetonitrile (60:40) containing 5 mM hexane sulfonate in isocratic flow. The mobile phase flow rate was 1.0 ml/min while elution was monitored at 216 nm. The method satisfied the International Conference on Harmonization (ICH) validation criteria for linearity, accuracy, precision and sensitivity. The developed method is applicable in routine quality control of Artemisia annua crude extracts.

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