Structure Elucidation of Six Acylated Iridoid Glucosides from Jasminum hemsleyi.

Abstract

Six new iridoid glucosides, jashemslosides A-D (2-5), 6'-O-trans-p-coumaroylloganin (6) and 6'-O-cis-p-coumaroylloganin (7), were isolated from the leaves of Jasminum hemsleyi, together with the known glycosides, loganin, 7-dehydrologanin, jasminoside, 10-hydroxyoleoside dimethyl ester and lariciresinol-4-O-β-D-glucoside. The structures of the new glucosides 2-7, which contain a menthiafolic acid unit or p-coumaroyl group in addition to the loganin moiety, were elucidated by spectroscopic and chemical studies. Chirospecific HPLC analysis of the monoterpenic acid derivatives prepared from 2 and 3 revealed that each of the new compounds was a mixture of two inseparable diastereoisomers.