In vitro cytotoxic effects of Senecio stabianus Lacaita (Asteraceae) on human cancer cell lines.

This study is aimed to evaluate the in vitro cytotoxicity of Senecio stabianus Lacaita (Asteraceae) against renal adenocarcinoma ACHN, hormone-dependent prostate carcinoma LNCaP, amelanotic melanoma C32 and human breast adenocarcinoma MCF-7 cell lines. The n-hexane extract showed an interesting activity with IC(50) values of 62.7 and 71.1 microg mL(-1) against C32 and LNCaP, respectively. Two compounds identified in the n-hexane extract, linalool and beta-caryophyllene, were found to be active against C32 cells (IC(50) values of 23.2 and 20.1 microg mL(-1), respectively). Among tested constituents, the highest activity was found when alpha-humulene was applied to LNCaP cells (IC(50) of 11.2 microg mL(-1)). In order to complete the phytochemical study on S. stabianus, which has not been investigated previously, the most characteristic secondary metabolites of Senecio genus, pyrrolizidine alkaloids (PAs), were analysed. Here we report the isolation, structural elucidation and identification of nine PAs.