AbstractCnidium monnieri(L.) Cusson is a Chinese medicine which is used widely by traditional medicine doctors. Osthol is a major bio‐activity compound of the herb. In this study, osthol was isolated fromC. monnieriand itsin vitroandin vivoantitumor effects studied. The results of thein vitrostudy showed: that osthol inhibited the growth of HeLa, in a time‐ and concentration‐dependent manner, with IC50values of 77.96 and 64.94 µmfor 24 and 48 h, respectively; that osthol had lower cytotoxic effects in primary cultured normal cervical fibroblasts; and that increased DNA fragmentation and activated PARP in HeLa after treatment with osthol which could induce apoptosis. The results of thein vivomodel showed that the survival days of the P‐388 D1 tumor‐bearing CDF1mice were prolonged (ILS% = 37) after osthol (30 mg/kg) was given once a day for 9 days. Based on these results, it is suggested that osthol could inhibit P‐388 D1 cellsin vivoand induce apoptosis in HeLa cellsin vitro, and that osthol is good lead compound for developing antitumor drugs. However,C. formosanumYabe of Taiwan's endemic plants contained little osthol, with no imperatorin, and its major components were different from that ofC. monnieri. Therefore, it is suggested thatC. formosanumalso may possess economic worth. Copyright © 2006 John Wiley & Sons, Ltd.
