In vitro antiplasmodial activity and cytotoxicity of ethnobotanically selected South African plants

The resistance of Plasinodium spp. to currently used drugs has become a serious problem and efforts are being directed in obtaining new drugs with different structural features. One option favoured is the search for new plant derived antimalarial drugs. Bark and leaves of 20 extracts from 14 South African plant species were tested for in vitro antiplasmodial activity by means of the flow cytometric test. The most active extract of each species giving more than 70% inhibition at 50 mug/ml was selected for determination of IC50 values. Two extracts had IC50 values below 2 mug/ml, another seven had IC50 values between 2 and 5 mug/ml while one had an IC50 of 10.1 mug/ml. Chloroquine had an IC50 of 0.043 mug/ml. Cytotoxicities of the five most active extracts at 50 mug/ml were determined with the monkey kidney cell toxicity test and the ID50 values ranged between 35 and 100 mug/ml. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.