Saponins of pericarps of Chinese Sapindus delavayi (Pyi-shiau-tzu), a source of natural surfactants.

Abstract

From pericarps of Sapindus delavayi (Chinese name : Pyi-shiau-tzu, Japanese name : Hishoushi)collected in Yunnan, China, several monodesmosides, 2-4 and 8-10 were isolated, all of which have already been isolated from pericarps of S. mukurossi (Japanese name : Enmeihi). Besides these known saponins, Sapenins 11 (a new saponin named hishoushi-saponin A), 13 and 14 (a new saponin named hishoushi-saponin Ee) were isolated from Pyi-shiau-tzu and their structures were elucidated to be as follows : 11, oleanolic acid 3-O-α-L-arabinopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranoside; 13, oleanolic acid 3-0-β-D-xylopyranesyl-(1→3)-x-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranoside (identica with the prosapogenin of the saponins from Clematis chinensis); 14, an acetate of sapindoside B (3) in which the acetyl group is located at the 3-hydroxyl group of the terminal xylosyl unit. It was found that the content of acylated saponins such as 14 in Pyi-shiau-tzu is higher than that in Enmeihi. Two diacetylated saponins, 15 and 16, were isolated from Pyi-shiau-tzu not in an impure state and their structures were deduced by nuclear magnetic reonance spectrometry. It is noteworthy that in contrast to Enmeihi, no bisdesmoside was detected in Pyi-shiau-tzu.