Abstract
A new triterpene glycoside (I) named acetyl shengmanol xyloside, mp 280-281°, [α]27D-23.7°, which was isolated from the underground part of Gimicifga japonica, yielded an amorphous aglycone (XII) on enzymatic hydrolysis. The peracetate of I afforded mainly 25-O-methylcimigenol (IV) along with cimigenol (V) and isodahurinol (VI) on acidic hydrolysis, while I gave cimigol xyloside (III), mp 297-299°, on alkaline treatment. The degradation of I with meta-periodate-cyclohexylamine gave an aldehyde-carboxylic acid, methyl ester of which has structure (IX). From chemical and spectral evidence, the structure of acetyl shengmanol (XII) was proposed to be (23R, 24S)-24, 25-epoxy-3β, 15ξ-dihydroxy-23-acetoxy-9, 19-cyclolanost-16-one. I is so unstable that it is readily convertible to cimigol xyloside (III) on alkaline treatment and to cimigenol (V) during acid hydrolysis. XII seems to be a precursor of cimigenol and cimigol in C. japonica. The mechanism of transformation of XII to V and VII was discussed.
