Euphorbiae humifusae wind is a traditional medicinal plant generally used in Oriental medicine therapy. Previous studies have shown that E. humifusae exhibits anti-proliferative and antioxidant activities. However, the mechanism responsible for the anticancer effects of E. humifusae not clearly understood. In the present study, we investigated the anti-proliferative effects by the water extract of E. humifusae (WEEH) in Hep3B human hepatocarcinoma cells. It was found that WEEH could inhibit the cell growth in a dose-dependent manner as measured by MTT assay, which was associated with morphological change and apoptosis induction. Furthermore, WEEH treatment decreased the level of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthease (iNOS) expression without significant changes in the expression of COX-1, which was correlated with a decrease in prostaglandin E₂ (PGE₂) and NaNO₂ synthesis. These findings suggest that WEEH may be a potential chemopreventive and chemotherapeutic agent for the control of human cancer cells. (Cancer Prev Res 13, 130-136, 2008)

Keywords: Euphorbiae humifusae, Hep3B, COX-2, iNOS