1983 Volume 31 Issue 6 Pages 1998-2005
From pericarps of Sapindus mukurossi (Japanese name : Enmei-hi), saponins of hederagenin (1), 2-7, 9, 11 and 12 were isolated along with sapindosides A (10) and B (8), both of which have already been isolated from this crude drug. Saponins 7 and 9 were identified as α-L-arabinopyranosyl (1→3)-α-L-rhamnopyranosyl (1→2)-α-L-arabinopyranoside and α-L-arabinofuranosyl (1→3)-α-L-rhamnopyranosyl (1→2)-α-L-arabinopyranoside of 1, respectively, both of which were recently isolated from Lecaniodiscus cupanoides by Sandberg et al. New saponins named mukurozi-saponins E1 (11) and G (12) were proved to be the mono-acetate of 8 and the di-acetate of 7, respectively. By means of mass and 13C nuclear magnetic resonance (NMR) spectroscopy, the locations of the acetyl groups of 11 and 12 were established to be at the 4-hydroxyl group of the xylosyl unit of 8 and at the 3, 4-hydroxyl groups of the terminal arabinosyl unit of 7, respectively. The other new saponins, named mukurozi-saponins X (6), Y1 (5) and Y2 (4), were revealed to be β-sophorosyl esters of 10, 8 and 7, respectively, by comparison of the mass and 13C NMR spectra with those of the β-sophorosyl ester of 1 (13), which was synthesized from 1 as a reference compound for the study of the anomalous glycosylation shifts. Studies on the structures of the remaining saponins, 2 and 3, are in progress. The water solubilities of the monodesmosides, 7-9, which cause remarkable enhancement of the absorption of sodium ampicillin from rat intestine and rectum, were greatly increased by the bisdesmosides, 4-6.
