In vitro antiplasmodial activities and cytotoxicity of water extracts of Piper rostratum Roxb., Sida rhombiforia Linn. and Tiliacora triandra (Colebr.) Diels
This study aims to evaluate the in vitro antiplasmodial activity and cytotoxicity of Piper rostratum Roxb., Sida rhombiforia Linn. and Tiliacora triandra (Colebr.) Diels., herbs traditional used to treat malaria in Thailand. The water extracts of these Thai medicinal plants were tested for their antiplasmodial activity by assessing their ability to inhibit the uptake of [3H] hypoxanthine into the multidrug-resistant strain Plasmodium falciparum K1. The antiplasmodial activity was expressed by the concentration that inhibited 50% of parasite growth (IC50). Cytotoxicity of the extracts was determined on Vero cells, and the Cytotoxicity Index (CI=IC50 on Vero cells/IC50 on Plasmodium falciparum) was calculated to evaluate the safety of tested extracts. Tiliacora triandra (Colebr.) Diels. was the only one of three plants that showed the in vitro antiplasmodial activity (IC50=43.43±0.90µg/ml) with good Cytotoxicity Index (CI=5.92) whereas Piper rostratum Roxb. and Sida rhombifora Linn. did not show this activity. Further study is needed to evaluate an in vivo antiplasmodial activity of Tiliacora triandra (Colebr.) Diels. extract.
Acknowledgement: This study was supported by The Annual Government Statement of Expenditure for Thammasat University.