Bioactive steroids from the brown Alga Sargassum carpophyllum

By activity-guided fractionation, two new sterols, 3 g ,28 ξ -dihydroxy-24-ethylcholesta-5,23 Z -dien ( 1 ) and 2a-oxa-2-oxo-5 f -hydroxy-3,4-dinor-24-ethylcholesta-24(28)-ene ( 2 ), together with five known steroids, fucosterol ( 3 ), 24-ethylcholesta-4,24(28)-dien-3,6-dione ( 4 ), 24 ξ -hydroperoxy-24-vinylcholesterol ( 5 ), 24-ketocholesterol ( 6 ), 24 R ,28 R - and 24 S , 28 S -epoxy-24-ethylcholesterol ( 7 ), were isolated from the brown alga Sargassum carpophyllum as active compounds causing morphological abnormality of Pyricularia oryzae mycelia. Compounds 1 , 3 , 4 , 5 and 7 also exhibited cytotoxic activity against various cancer cell lines. The IC 50 values for 1 and 5 against HL-60 were 7.8 and 8.5 w g/ml, 3 and 4 against P-388 were 0.7 and 0.8 w g/ml, whereas 7 against MCF-7, HCT-8, 1A9, HOS and PC-3 were 4.0, 8.8, 10.0, 10.0 and 7.2 w g/ml, respectively.

Keywords:

• Brown Alga
• Sargassum Carpophyllum
• Steroids
• Pyricularia Oryzae