Bioactive friedolanostanes and 11(10-->8)-abeolanostanes from the bark of Garcinia speciosa.

A new friedolanostane, 7, and three triterpenes, 8, 9a, and 10, possessing the new 11(10-->8)-abeolanostane carbon skeleton were isolated from the bark of Garcinia speciosa. Structures were elucidated by spectroscopic and spectrometric studies and the structure of 8 by X-ray crystallographic analysis, thus forcing structure revision of a triterpene from the same source previously assumed to be a friedolanostane. These and several friedo- and lanostanes earlier isolated from the same source were evaluated for cytotoxicity against three human cell lines. Most were moderately active, with three friedolanostanes effective in inducing apoptosis in the MCF-7 cell line.