Triterpene saponins from Alternanthera repens

Four new triterpene saponins were isolated from the methanol extract of the aerial parts of Alternanthera repens. Their structures have been elucidate d using a combination of 1D and 2D NMR techniques as 2 alpha,3 beta-dihydro xyurs-12,20(30)-dien-28 oic acid 3-O-{O-beta-D-glucopyranosyl-(1 --> 2)-O-a lpha-L-arabinopyranosyl-(1 --> 2)-O-[beta-D-xylopyranosyl-(1 --> 3)]beta-D- glucopyranoside}; 2 alpha,3 beta-dihydroxyurs-12,20(30)-dien-28 oic acid 3- O-{O-beta-D-quinovopyranosyl-(1 --> 2)-O-alpha-L-arabinopyranosyl-(1 --> 2) -O-[beta-D-xylopyranosyl-(1 --> 3)]beta-D-glucopyranoside}; 2 alpha,3 beta- dihydroxyurs-12,20(30)-dien-28 oic acid 3-O-{O-alpha-L-arabinopyranosyl-(1 --> 2)-O-[beta-D-xylopyranosyl-(1 --> 3)]beta-D-glucopyranoside}; 2 alpha,3 beta-dihydroxyurs-12,20(30)-dien-28 oic acid 3-O-{O-beta-D-xylopyranosyl-( 1 --> 3)-beta-D-glucopyranoside}.(C) 1999 Elsevier Science Ltd. All rights reserved.