Bioactive chemical constituents of Duboscia macrocarpa Bocq., and X-ray diffraction study of 11 beta, 12 beta-epoxyfriedours-14-en-3 alpha-ol

摘要

A new gamma-lactone triterpenoid, Evodoulolide (1) and a new triterpenoid Duboscic acid B (2), along with five known compounds, maslinic acid (3), arboreic acid (4), (E)-3-(4-hydroxyphenyl)-N-[2-(4-hydroxyphenyl) ethyl] prop-2-enamide (5), (E)-heptacos-19-enoic acid (6) and 11 beta,12 beta-epoxyfriedours-14-en-3 alpha-ol (7) were isolated from the trunk wood of Duboscia macrocarpa. Their structures were elucidated from extensive D-1- and D-2-NMR and MS and by comparison of their spectra with published data. Compounds 1, 3, 5 and 6 exhibited significant alpha-glucosidase inhibitory activity. Compound 5 was found to be a potent inhibitor (IC50 = 5.1 +/- 0.1 mu M) of alpha-glucosidase as compared to acarbose (IC50 = 625.0 +/- 1 mu M) used as standard drug. These compounds did not show anti-glycation activity using the BSA-MG glycation model or inhibition against the a-chymotrypsin enzyme. The chemotaxonomic connotation of the isolated secondary metabolites is also herein described. The single-crystal X-ray and absolute configuration diffraction analysis of 11 alpha, 12 alpha-epoxyfriedours-14-en-3-ol (7) is also described here for the first time.