A New Flavonol Triglycoside from Eustoma giandiflorum

摘要

A new flavonol triglycoside, kaempferol 3-O-alpha-L-rhamnopyranosyl (1 -> 6)-(3-O-E-p-coumaroyl)-beta-D-galactopyranoside-7-O-alpha-L-rhamnopyranoside (1: Eustograndifloside A) was isolated from the flower of Eustoma grandiflorum in addition to eight known flavonols (2: kaempferol 3-O-alpha-L-rhamnopyranosyl (1 -> 6)-(4-O-E-p-coumaroyl)-beta-d-galactopyranoside-7-0-alpha-L-rharrinopyranoside, 3: kaempferol 3-O-beta-robinobioside-7-O-alpha-L-rhamnopyranoside, 4: isorhamne-tin 3-O-alpha-L.-rhamnopyranosyl (1 -> 2) [alpha-L-rhamnopyranosyl (1 -> 6)]-(4-O-E-p-coumaroyl)-beta-D-galactopyranoside-7-0-alpha-L-rhamnopyranoside, 5: kaempferol 3-O-alpha-L-rhamnopyranosyl (1 -> 2) [alpha-L-rhamnopyranosyl (l -> 6)]-(4-0-E-p-coumaroyl)-beta-D-galactopyranoside-7-O-alpha-L-rhamnopyranoside, 6: kaempferol 3-O-beta-robinobioside, 7: quercetin 3-O-beta-robinobioside, 8: isorhamnetin 3-O-beta-robinobioside, and 9: kaempferol 7-O-alpha-L-rhamnopyranoside) and two known secoiridoid glycosides (10: swertiamarin and 11: sweroside). The structure elucidation of these compounds was accomplished through analyses of spectroscopic, including 1D and 2D NMR, and ESIMS data.