Acemosin- a cytotoxic 20-norsteroid from Asparagus racemosus.

A novel cytotoxic 20-norsteroid with twenty-six carbon atoms named acemosin (1) was isolated and structural characterized together with two known compounds, asparacosin A (2) and stigmasterol (3) from the roots of Asparagus racemosus. Their structures were elucidated by a combination of 2D NMR, HR-MS and X-ray crystallographic analyses. Acemosin (1) possesses an unprecedented carbon skeleton, where the methyl group at C-20 is absent. Acemosin shows moderate cytotoxicity against HepG2 cancer cell line with its IC50 value of 87.3 μg/mL.