九子参苷A的结构

从石竹科植物九子参(Silene rubicunda Franch.)根中得到一个糖链上带双乙酰基的新三萜八糖苷──九子参苷A(rubicunoside A, 1)。以化学降解反应、酶解和波谱分析, 得到15个衍生物, 其结构最后确定为皂树酸-3-O-β-D-吡喃半乳糖-(1→2)-β-D-吡喃木糖-(1→3)]-β-D-吡喃葡萄糖醛酸-28-O-β-D-吡喃木糖-(1→3)-β-D-吡喃木糖-(1→4)-α-L-吡喃鼠李糖-(1→4)-2'-O-乙酰基-β-D-吡喃鸡纳糖-(1→2)]-3'-O-乙酰基]-β-D-吡喃夫糖苷{3-O-β-D-galactopyranosyl-(1→2)-→β-D-xylopyranosyl-(1→3)]-β-D-glucuronopyranosyl quillaic acid 28-O-β-D-xylopyranosyl-(1→3)-β-D-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl-(→4)-2'-OAc-→β-D-quinovopyranosyl-(1→2)]-3'-OAc]-β-D-fucopyranoside, 1}。同时发现甘草酸酶的两个新酶解特性。。

The structure of rubicunoside A

A new acetylated triterpenoid saponin, rubicunoside A (1), was isolated from the roots of Silene rubicunda Franch. It was characterized on the basis of extensive chemical, enzymic, and spectral methods as 3-O-β-D-galactopyranosyl-(1→2)-β-D-xylopyranosyl-(1→3)]-β -D-glucuronopyranosyl quillaic acid 28-O-β-D-xylopyranosyl-(1→3)-β -D-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→4)-2'-OAc-β -D-quinovopyranosyl-(1→2)]-3'-OAc]-β-D-fucopyranoside (1). During the enzymic cleavage with glycyrrhizinic acid hydrolase, we unexpectedly found two new characteristics of the hydrolase. It can selectively hydrolyzed not only 28-O-monoprosapogenins, but also the acetyl group in the sugar moieties of the prosapogenins. The enzymic cleavage method with glycyrrhizinic acid hydrolase providing selectivly 3-oligosaccharides and 28-O0glucosides and partial methanolysis providing selectively 28-oligosaccharides from 3,28-O-bisglucosides were effective for the structure elucidation.