Glucuronide triterpene saponins from Bersama engleriana

Five 3-O-glucuronide triterpene saponins (1-5) were isolated from the stem bark of Bersama engleriana Gurke along with two known saponins, polyscias saponin C and aralia saponin 15, and one major C-glycoside xanthone, mangiferin. The structures of the saponins were established mainly by means of spectroscopic methods (one- and two-dimensional NMR spectroscopy as well as FAB-, HRESI-mass spectrometry) as 3-O-[beta-D-glucopyranosyl-(1 -> 2)-beta-D-glucuronopyranosyl]-28-O-[beta-D-glucopyranosyl]-betulinic acid (1), 3-O-[beta-D-glucopyranosyl-(1 -> 2)-[beta-D-galactopyranosyl-(1 -> 3)]-beta-D-glucuronopyranosyl]-oleanolic acid (2), 3-O-[beta-D-glucopyranosyl-(1 -> 3)-beta-D-glucuronopyranosyl]-28-O-[beta-D-xylopyranosyl-(1 -> 6)-beta-D-glucopyranosyl]-oleanolic acid (3), 3-O-[beta-D-galactopyranosyl-(1 -> 3)-beta-D-glucuronopyranosyl]-28-O-[beta-D-glucopyranosyl-(1 -> 4)-beta-D-glucopyranosyl]-oleanolic acid (4), and 3-O-[beta-D-glucopyranosyl-(1 -> 3)-beta-D-galactopyranosyl-(1 -> 3)-beta-D-glucuronopyranosyl]-28-O-[beta-D-xylopyranosyl-(1 -> 6)-beta-D-glucopyranosyl]-oleanolic acid (5). (c) 2006 Elsevier Ltd. All rights reserved.