Browsing by Author "Devkota, Krishna P."

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    In Vitro Cytotoxicity of Some Medicinal Plants Used in Traditional Medicine in Tanzania
    (2011) Kisangau, Daniel P.; Lyaruu, Herbert V. M.; Hosea, Ken M.; Joseph, C. C.; Bruno, L. N.; Devkota, Krishna P.; Bogner, T.; Sewald, Norbert
    Plants used in traditional medicine in Tanzania were screened for their cytotoxicity using the brine shrimp and CellTiter-BlueTM cell viability assays. Dichloromethane extracts of Capparis erythrocarpos, Cussonia arborea, Dracaena steudneri, Lannea schimperi, Pseudospondias microcarpa, Rauvolfia vomitoria, Sapium ellipticum and Zehneria scabra exhibited various cytotoxic activities against brine shrimp larvae. Only semi-purified fractions of C. erythrocarpos, C. arborea, D. steudneri, Lannea schimperi and S. ellipticum and one pure compound Lup-20(29)-en-3-one (1) from S.ellipticum were tested against K562 Leukaemia cell line using the CellTiter-BlueTM cell viability assay method. In the brine shrimp lethality assay, P. microcarpa was the most toxic plant with an LC50 value of 1.9 μg/ml (95%CI, 1.6-2.2 μg/ml) , while Z. scabra was the least toxic plant with LC50 value of 179.4 μg/ml (95%CI, 156.1-213.9 μg/ml). In the CellTiter-BlueTM cell viability assay, the mean % cell vitality growth for the fractions of each of the five plant species C. arborea, C. erythrocarpos, D. steudneri, L. schimperi and S. ellipticum were 43.1%, 67.2%, 82.1%, 52.3% and 87.6% respectively, with P<0.0001 and 95% confidence intervals (CI) of 54.746-81.082 μg/ml. The IC50 concentration for compound Lup-20(29)-en-3-one (1) was 1.747x10-6 μM with 95% confidence intervals (CI) of 3.019x10-7 to 1.011x10-4 μM. Results indicate that most of the extracts tested were relatively non-toxic hence supporting the inherent use of these plants in traditional medicine.
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    Screening of Traditionally Used Tanzanian Medicinal Plants for Antifungal Activity
    (2009) Kisangau, Daniel P.; Hosea, Ken M.; Lyaruua, Herbert V. M.; Joseph, Cosam C.; Mbwambo, Zakaria H.; Masimba, Pax J.; Gwandu, Catherine B.; Bruno, L. N.; Devkota, Krishna P.; Sewald, Norbert
    Fungal infections represent a significant cause of morbidity and mortality especially in immunocompromised patients in the world today. Dichloromethane (DM) and aqueous (W) extracts of nine plants used traditionally for the treatment of fungal infections in Bukoba rural district in Tanzania were screened for antifungal activity against Candida albicans, Cryptococcus neoformans, and Aspergillus niger using agar well and disk diffusion methods. Dichloromethane extracts of Capparis erythrocarpos [CE] Isert (Capparaceae), Cussonia arborea [CA] Hochst. Ex A. Rich (Araliaceae), Dracaena steudneri [DS] Engl. (Dracaenaceae), Lannea schimperi [LS] (A. Rich) Engl. (Anacardiaceae), Rauvolfia vomitoria [RV] Afz (Apocynaceae), and Sapium ellipticum [SE] (Krauss) Pax (Euphorbiaceae) showed activity against all three fungi. Extracts of Rumex usambarensis [RU] (Dammer) Dammer (Polygonaceae) and Zehneria scabra [ZS] (L.f.) Sond. (Cucurbitaceae) had an activity limited to only one or two of the test organisms. Rhoicissus tridentata [RT] (L.f.) Wild & Drum (Vitaceae) was the only plant without activity. Fractions of the active extracts CE, CA, DS, LS, and SE exhibited higher antifungal activity against one or more of the three fungi. Four compounds isolated from S. ellipticum also exhibited antifungal activity against one or more of the three fungi. The minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs), determined using the microplate assay method, ranged between 0.4 and 50.0 μg/mL for crude extracts, 1.6 and 50.0 μg/mL for semi-purified fractions, and 0.12 and 1.0 μg/mL for pure compounds, as compared to 0.016–1.5 μg/mL for fluconazole. We confirm the potential of traditionally used plants as a source of new drugs for treatment of fungal infections.