Cytotoxic activity of some Tanzanian medicinal plants

Thirty-three aqueous methanolic extracts obtained from thirty plant species, belonging to seventeen families were screened for cytotoxic activity against HeLa (Human cervical carcinoma) cells. The ability of the extracts (10 g/ml and 1 g/ml) to inhibit proliferation of HeLa cells was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) dye reduction assay. Extracts from roots of Agathisanthemum bojeri, Synaptolepis kirkii and Zanha africana and the leaf extract of Physalis peruviana at a concentration of 10 µg/ml inhibited cell proliferation by 58.3 %, 68.1 %, 75.7 % and 91.8 %, respectively. The remaining 29 extracts exhibited no pronounced cytotoxic activity at the tested concentrations. It is worth investigating the four extracts, which showed pronounced cytotoxic activity so as to isolate and identify the compounds responsible for cytotoxic activity. Keywords: cytotoxic plants, Tanzanian medicinal plants, Agathisanthemum bojeri, Synaptolepis kirkii, Zanha africana, Physalis peruviana The East and Central African Journal of Pharmaceutical Sciences Vol. 8(2) 2005: 35-3

Biological Activities of Essential Oils from Plants Growing in Tanzania

Essential oils from eleven plant species belonging to the Asteraceae, Lamiaceae, Lauraceae and Myrothamnaceae families growing in Tanzania were screened for mosquito larvicidal and anti-candida activities, and were subjected to the brine shrimp lethality test. In the larvicidal and brine shrimp tests, the organisms were exposed to varying oil concentrations for 24 h, after which mortality was assessed. The anticandida activity was determined using the bioautography agar overlay method. All oils showed larvicidal activity with two Ocimum suave oil samples being the most active with LC50 values of 169.8 and 151.3 ppm. The same Ocimum suave oils also exhibited the highest brine shrimp mortality (LC50 4.0 and 12.6 ppm). Most of the oils showed anti-candida activity, with oils from Ocimum species being the most active compared to the others. Thus, Ocimum suave oils merit further investigation towards the development of safe and biodegradable larvicides. Furthermore, oils from Ocimum basilicum and Ocimum kilimandscharicum could offer useful alternatives for combating candidiasis, a common opportunistic infection in HIV/AIDS patients.Keywords: Ocimum species, larvicides, brine shrimp, Candida albicansEast and Central African Journal of Pharmaceutical Sciences Vol. 13 (2010) 85-9