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

The resistance of Plasinodium spp. to currently used drugs has become a ser ious problem and efforts are being directed in obtaining new drugs with dif ferent structural features. One option favoured is the search for new plant derived antimalarial drugs. Bark and leaves of 20 extracts from 14 South A frican plant species were tested for in vitro antiplasmodial activity by me ans of the flow cytometric test. The most active extract of each species gi ving more than 70% inhibition at 50 mug/ml was selected for determination o f IC50 values. Two extracts had IC50 values below 2 mug/ml, another seven h ad 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 a ctive extracts at 50 mug/ml were determined with the monkey kidney cell tox icity test and the ID50 values ranged between 35 and 100 mug/ml. (C) 2001 E lsevier Science Ireland Ltd. All rights reserved.