Cytotoxic Screening of some Tanzania Medicinal plants

Abstract

Twenty plants that are used in traditional medicine in Iringa, Tanzania, were tested for in vitro cytotoxic activity on human bladder carcinoma (RT-4), colon adenocarcinoma (HT29), and skin carcinoma (A431) cell lines. At 100 μg/ml Albizia harveyi, Albizia anthelmintica, Dalbergia nitidula, Euphorbia grantii and Rauvolfia caffra reduced cell proliferation to 50% or more of the three cell lines. Albizia harveyi showed a significant cytotoxic activity on the RT-4 cell line (percentage survival 23%) at 10μg/ml. It showed a weak cytotoxic activity on the HT-29 cell line. Dalbergia nitidula showed a weak cytotoxic activity with percentage death of the RT-4 and HT-29 cell lines of 39 and 34%, respectively, at the 10 μg/ml level. These results show that 19 (95%) of the plant extracts tested are non-toxic. One plant (5%), Albizia harveyi showed cytotoxic activity on one of the cell lines used, which was in agreement with the accepted detection level of biological activity by chance. Bioassay guided fractionation of the plant extracts to identify active compound(s) is suggested.