Studies on the constituents of orchidaceous plants. III. Isolation of non-conventional side chain sterols from Nervilia purpurea SCHLECHTER and structure determination of nervisterol.

From the neutral fraction of the ether extract of Nervilia purpurea SCHLECHTER (Orchidaceae), unusual side chain sterols (5a, 6a, and 7a), previously reported as the constituents of marine invertebrates, were isolated along with 24-epibrassicasterol, 24ξ-methylcholesterol, ergosterol, and stigmasterol. A new non-conventional side chain sterol, named nervisterol (8a), was also isolated and its structure was elucidated.