Cytotoxic cis-fused bicyclic sesquiterpenoids from Jatropha neopauciflora.

Analysis of polar fractions of the bark extract of Jatropha neopauciflora provided two uncommon cis-fused bicyclic sesquiterpenoids, which were characterized as (1R,2R,5S,6S,7S,10S)*-5-epi-eudesm-4(15)-ene-1alpha,2beta,6alpha-triol (1) and (1R,2R,5S,6S,7R,10S)*-ax-4(15)-ene-1alpha,2beta,7beta-triol (2). Their absolute configuration and biogenesis were derived by correlations with congeners of known absolute configurations. Biological investigation of less polar fractions of the bark extract led to the isolation of moderately cytotoxic triterpenes, calenduladiol (3) and (3beta,16beta)-16-hydroxylup-20(29)-en-3-yl (E)-3-(4-hydroxyphenyl)prop-2-enoate (4).