Chemical investigation on the root bark of Bombax malabarica

摘要

Ten compounds were isolated from the root bark of Bombax malabarica, including two new compounds, born-bamalin (1) and 3,4,5-trimethoxypheno1-1[beta-xylopyranosyl-(1 -> 2)]beta-glucopyranoside (3), and shorealactone (4), a rare dehydroascorbic acid fused 1-epsilon-viniferin. Compound 1 is an unusual bissesquiterpene, containing a 1,4-dioxene ring formed by fusing isohemigossypol with ent-cadinen-2-one. Their structures were elucidated by extensive spectroscopic analysis. This chemical reinvestigation is of value for chemotaxonomy of the Bombax genus, in particular the finding of the unusual 1 and rare 4. Among the isolates, shorealactone (4), bepicatechin 5-O-beta-D-xyloside (5), and 2-C-U3-D-apiosyl-(1 -> 6)1- beta-D-glucosyl)-1,3,6-trihydroxy-7-methoxyxanthone (6) displayed some inhibition against alpha-glucosidase with IC50 values of 224, 345, and 285 mu M, respectively.