[Bioactive sterols from red alga Acanthophora spicifera boergesen]

To study the chemical constituents of the red alga Acanthophora spicifera boergesen aiming at searching for bioactive leading compounds.

Compounds were isolated by various chromatographic techniques including column chromatography over normal phase silica gel and Sephadex LH-20 gel and reverse phase HPLC as well as recrystallization. Their structures were determined by spectroscopic methods including IR, MS, 1D and 2D NMR techniques. MTT method was used for testing cytotoxicity of compounds against human cancer cell lines HCT-8, Bel-7402, BGC-823, A549 and HELA. Their inhibition against proliferation of dog vascular smooth muscle cells was also screened by MTT assay.

Six sterols were isolated from the ethanolic extract of the red alga Acanthophora spicifera. Their structures were identified as 6-hydroxycholest-4-ene-3-one (1), cholest-4-ene-3, 6-dione (2), cholest-5-ene-3 beta-ol (3), 5 alpha-cholestane-3, 6-dione (4), beta-sitosterol (5) and saringosterol (6).

Compounds 1-3 and 5 were obtained from this genus for the first time. Compounds 1, 2 and 4 showed moderate cytotoxic activity against human cancer cell lines.