Studies on the Constituents of Aceraceae Plants. VII. : Diarylheptanoids from Acer griseum and Acer triflorum

A diarylheptanoid glycoside, named aceroside IX (1), C30H40O12, [α]D -63.5°, was isolated from the stem bark of Acer griseum and A. triflorum. Another diarylheptanoid glycoside, named aceroside X (2), C25H31O8, mp 121°, [α]21D -29.7°, and catechin were isolated from the stem bark of A. griseum and detected by thin layer chromatography in the case of A. triflorum. On acid hydrolysis 1 yielded a new diarylheptanoid, acerogenin G (3), C19H22O3, which was identified as a ketonic derivative of (-)-centrolobol (5), and sugars, glucose and apiose. On partial hydrolysis, 1 gave aceroside X (2) and apiose. The sugar moiety of aceroside IX is bound to the phenolic hydroxyl at C-4" of acerogenin G (3) from the results of mass spectral analysis of 3 and its monomethyl ether (6), the latter of which was formed on methylation of 1 followed by acid hydrolysis. Acerosides (1) and X (2) were determined to be the 4"-O-β-D-apiofuranosyl-(1→6)-β-D-glucopyranoside and the 4"-O-β-D-glucopyranoside of acerogenin G, respectively, on the basis of carbon-13 nuclear magnetic resonancence spectral analyses in comparison with the spectrum of aceroside VIII (7).