Cytotoxic Diterpenoids from Scoparia dulcis

A new scopadulane-type diterpenoid (1) and one known labdane-type diterpenoid (2) have been isolated from the whole plants of a traditional medicinal plant, Scoparia dulcis. Their structures were established mainly by spectroscopic methods, and the absolute configuration of compound 1 has been determined by quantum chemical calculation of the electronic circular dichroism (ECD) spectrum and comparison with the experimental one. The cytotoxicity of 1 and 2 against two breast cancer cell lines (MCF-7 and MDA-MB231) and a cervical cancer cell line (Hela) were tested, and only compound 2 displayed inhibitory activities against these cells with IC50 values ranging from 8.1 to 45.2 .M, while compound 1 were inactive. In addition, compound 2 also showed in vitro anti-tumor activity against MCF-7, MDA-MB231, and Hela cells in a concentration-dependent manner.