[Study on the steroid constituents of soft coral Lobophytum microspiculatum]

The soft coral Lobophytum microspiculatum collected from Xisa Islands of the South China Sea was immersed in and extracted with ethyl alcohol and the extract was concentrated, and then partitioned between ethyl acetate and water. The portion soluble in ethyl acetate was subjected to column chromatography over Sillca H, eluted with a step gradient of EtOAc and petroleum ether. The sterols were obtained from 20% EtOAc-petroleum ether eluent portion. By means of GC/MS method, the sterols were identified to be: cholesta-26-methyl-ol; ergosta-8, 22-dien-3 beta-ol, 24-methyl; ergosta-5, 22-dien-3 beta-ol, 23, 24-dimethyl; cholesta-5,22(23)-dien-3 beta-ol, 22,24-dimethyl; cholesterol; ergosta-5,22-dien-3 beta-ol, 24-methyl; ergosta-5,22-dien-3 beta-ol, 22,24-dimethyl, 24-methyl-cholesterol; ergosta-7-en-3 beta-ol, 24-methyl; nor-ergosta-7-en-3 beta-ol and gorgosterol. Among them cholest-5,22(23)-3 beta-ol, 22,24-dimethyl (4) is a new compound which was found at the first time from the nature. This finding gave a further prove for the biogenesis path way of gorgosterol.