[Studies on chemical constitutes of green alga Chaetomorpha basiretorsa and their bioactivity]

To study the chemical constituents of Chaetomorpha basiretorsa and screen for bioactive leading compounds.

Compounds were isolated by normal phase silica gel and Sephadex LH-20 gel column chromatography, reverse phase MPLC and reverse phase HPLC. Their structures were elucidated by spectroscopic methods including MS, IR and 1D, 2D NMR. Cytotoxicity of the compounds was screened by using standard MTT method. The purified compounds' inhibition against proliferation of dog vascular smooth muscle cells was also screened by MTT assay.

Five compounds were isolated from C. basiretorsa and their structures were identified as euphol (I), loloilide (II), 4-cumylphenol (III), zeaxanthin (IV) and lactucaxanthin (V).

All these compounds were obtained from this genus for the first time. Compound (III), 4-cumylphenol, was a new nature product. All compounds were inactive (IC50 > 10 microg x mL(-1)) in cytotoxicity screening. In inhibition against proliferation of dog vascular smooth muscle cells test, the cell survival ratio to compound I was (0.32 +/- 0.056)% which indicate its potential anti-atherosclerotic bioactivity.