Triterpenoid saponins and sapogenins from Vaccaria segetalis

Four new triterpenoid saponins, vaccarosides E, F, G and H were isolated from the seeds of Vaccaria segetalis and were respectively defined to be 3-O-beta-D-galactopyranosyl-(1 --> 2)-beta-D-glucuronopyranosyl] quillaic acid 28-O-beta-D-xylopyranosyl-( 1 --> 4) -alpha-L-rhamnopyranosyl-( 1 --> 2)-[alpha-L-arabinofuranosyl-(1 --> 3)1-beta-D-4-O-acetylfucopyranoside; 3-O-[beta-D-galactopyranosyl-(1 --> 2)-beta-D-glucuronopyranosyl] 3 beta,4 alpha, 16 alpha-trihydroxy-23-norolean-12-en-28-oic acid 28-O-beta-D-xylopyranosyl-( 1 --> 4) -alpha-L-rhamnopyranosyl-( I --> 2)-[alpha-L-arabinofuranosyl-(1 --> 3)]-beta-D-4-O-acetylfucopyranoside; 3-O-[beta-D-galactopyranosyl-(1 --> 2)-beta-D-glucuronopyranosyl] gypsogenin 28-O-beta-D-xylopyranosyl-(1 --> 4)-alpha-L-rhamnopyranosyl-(1 --> 2)-[alpha-L-arabinofuranosyl(1 (1 --> 3)]-beta-D-4-O-acetylfucopyranoside; and 3-O-[beta-D-galactopyranosyl-(1 --> 2)-beta-D-glucuronopyranosyl] 3 beta,4 alpha-dihydroxy-23-norolean-12-en-28-oic acid 28-O-beta-D-xylopyranosyl-(1 --> 4)-alpha-L-rhamnopyranosyl-(1 --> 2)-[alpha-L-arabinofuranosyl-( 1 --> 3)1-beta-D-4-O-acetylfucopyranoside. Their structures were established on-the basis of extensive NMR (DEPT, COSY, HOHAHA, HETCOR, HMBC AND NOESY), FAB-MS and ESI-MS studies as well as chemical strategies and enzymatic degradation. The new aglycones of two-of the saponins have been designated as segetalic acid and vaccaric acid, respectively. (C) 1998 Elsevier Science Ltd. All rights reserved.