Antioxidant and cytotoxic activities of Hypericum sp. on brine shrimps and human cancer cell lines.

Ten different samples of five Hypericum sp. were tested on brine shrimps, human colon carcinoma and human hepatoma cell lines for their cytotoxic activities. H. triquetrifolium Turra. (Rafina) showed the highest activity (LC50 = 22 mg/mL) on brine shrimps, while the extracts of the other nine samples showed significant to moderate activities (LC50 from 37 to 107 mg/mL). H. empetrifolium Wild. (Parnon) showed the highest activity in human colon carcinoma and human hepatoma cell lines, with LC50 values 29 and 25.1 mg/mL, respectively, while the LC50 values of the other samples were more than 45 mg/mL. It is very interesting to observe that most Hypericum samples showed good antioxidant activity in vitro. Copyright 2002 John Wiley & Sons, Ltd.