In vitro cytotoxicity of tanshinones from Salvia miltiorrhiza

The cytotoxicity-guided fractionation of the roots of Salvia miltiorrhiza B. (Labiatae) extracts led to the isolation of eighteen active principles 1 similar to 18, responsible for the cytotoxicity against five cultured human tumor cell lines, i,e., A549 (nonsmall cell lung), SK-OV-3 (ovary), SK-MEL-2 (melanoma), XF498 (central nerve system) and HCT-15 (colon), using the SRB (sulfrhodamine-B) method in vitro. All active compounds 1 similar to 18 including two novel components 5 and 11 were comprised of tanshinone pigments, unusual diterpenes exclusively found in this species. The proliferation of each examined tumor cell line was significantly inhibited (ICS, values ranged from O.2 to 8.1 mu g/ml) during the continuous exposure of tumor cells to 1 similar to 18 for 48 hours, respectively.