Evaluation of the cytotoxic activity of extracts from medicinal plants used for the treatment of malaria in Kagera and Lindi regions, Tanzania

Abstract

A number of medicinal plants used for treatment of malaria in Tanzania have been documented, but information on their safety and efficacy is still based on traditional knowledge accumulated over years and not on pre-clinical and clinical evaluation. The present study aimed to assess the cytotoxic activity of extracts of selected plant species used for treatment of malaria in Tanzania. Ethanol extracts were evaluated for cytoxicity by using MTT assay on LLC-MK2 cells and by brine shrimp lethality assay. Forty five (93.75%) out of 48 crude extracts assessed using LLC-MK2 cells were non-cytotoxic while three extracts (6.25%) were cytotoxic with CC 50 <30 μg/mL (cut-off point). In the brine shrimp assay 30 (65.2%) out of 46 extracts tested were non-toxic while 16 extracts (34.8%) were toxic (LC 50 <100 μg/mL). Antiaris toxicaria stem bark extract was the most cytotoxic to mammalian cells. This study demonstrates that, most of the antimalarial plants tested were non-toxic. These observations corroborate with traditional healers' claims that the herbal medicines used in their areas are safe. However, further studies using different toxicity models are suggested to further confirm their claims.