Isolation of a new cytotoxic polyhydroxysterol from the South China Sea soft coral Sinularia sp.

Abstract

A new polyhydroxysterol, (22E)-24-methylenecholestane-22-ene-3β,5α,6β-triol (1), together with four known analogues (2–5) were isolated from the South China Sea soft coral Sinularia sp. Their structures were elucidated by spectroscopic analyses and comparison with previously reported data. All these compounds exhibited cytotoxic effect against both HepG2 and HeLa cell lines with IC₅₀ values ranging from 8.36 to 37.30 μM. Preliminary structure–activity relationship study identified that the presence of double bonds in the side chains of these polyhydroxysterols significantly reduced the biological effect obtained.

Keywords:

• Soft coral
• Sinularia sp.
• sterols
• cytotoxicity

Funding

This work was financially supported by the National Natural Science Foundation of China [grant number 21315046], [grant number 21172094], [grant number 41376155], [grant number 21372100], [grant number 31201028], [grant number U1301131]; the National High Technology Research and Development Program (‘863’ Program) of China [grant number 2013AA092902]; the Science and Technology Program of Guangzhou, China [grant number 2013000000163].