A new flavonol triglycoside from Eustoma grandiflorum

Abstract

A new flavonol triglycoside, kaempferol 3-O-α-L-rhamnopyranosyl (1→6)-(3-O-E-p-coumaroyl)-α-D-galactopyranoside-7-O-α-L-rhamnopyranoside (1: Eustograndifloside A) was isolated from the flower of Eustoma grandiflorum in addition to eight known flavonols (2: kaempferol 3-O-α-L-rhamnopyranosyl (1→6)-(4-O-E-p-coumaroyl)-β-D-galactopyranoside-7-O-α-L-rhamnopyranoside, 3: kaempferol 3-O-β-robinobioside-7-O-α-L-rhamnopyranoside, 4: isorhamne-Tin 3-O-β-L-rhamnopyranosyl (1→2) [-α-L-rhamnopyranosyl (1→6)]-(4-O-E-p-coumaroyl)-α-D-galactopyranoside-7-O-α-L-rhamnopyranoside, 5: kaempferol 3-O-β-L-rhamnopyranosyl (1→2) [-α-L-rhamnopyranosyl (1→6)]-(4-O-E-p-coumaroyl)-α-D-galactopyranoside-7-O-α-L-rhamnopyranoside, 6: kaempferol 3-O-α-robinobioside, 7: quercetin 3-O-β-robinobioside, 8: isorhamnetin 3-O-β-robinobioside, and 9: kaempferol 7-O-α-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.