Sweet cucurbitane glycosides from fruits of Siraitia siamensis (chi-zi luo-han-guo), a Chinese folk medicine.

Abstract

Cucurbitane-type triterpenes are known as bitter principles of cucurbitaceous plants, while some of the glycosides of triterpenes of this type are sweet tasting; bryodul-coside1* from roots of Bryonia dioica Jacq., mogrosides IV (1) and V (2)2 ~4) from fruits of Siraitia grosvenori Swingle ( = Momordica grosvenori Swingle; Chinese name of the fruit, luo-han-guo) and glycosides from rhizomes of Hemsleya carnosiflora C. Y. Wu et Z. L. Chen sp. nov.15) and H. panacis-scandens C. Y. Wuet Z. L. Chen.6) In our series of studies on Chinese cucurbitaceous plants, the present paper describes the characterization of sweet glycosides from fruits of Siraitia siamensis Craib. (Chinese name, chi-zi lou-han-guo) which grows in Xi-shuang-bana, South-Yunnan, China and is closely related to S. grosvenori. Dried and powdered fruits were extracted with petroleum ether to remove the lipophilic materials and then extracted with methanol. The sweet methanolic extract was separated by chromatography on a highly porous polymer, then on silica gel and finally by highperformance liquid chromatography (HPLC)on a reverse-