Bioactive Ergost-5-ene-3β/,7α-diol Derivatives from Pseudobersama mossambicensis

Abstract
Bioactivity-directed fractionation of the methyl ethyl ketone extract of Pseudobersama mossambicensis resulted in the isolation of ergosta-5,24(28)-diene-3 beta,7 alpha-diol [1], 24,28-epoxyergost-5-ene-3 beta,7 alpha-diol [2], and ergost-5-ene-3 beta,7 alpha,24,28-tetraol [3]. All three sterols showed selective activity towards DNA repair-deficient yeast mutants. The sterol 1 also showed cytotoxicity towards wild-type P-388 murine leukemia cells. The isolation, structural elucidation, and biological activities of these sterols are reported. The sterol 3 is most probably an artifact formed from 2 during the isolation process.