Abstract
Abstract
In addition to the three acetylated flavonol glycosides, quercetin 3-O-[(2,3,4-triacetyl-α-rhamnopyranosyl)-(1→6)]-β-galactopyranoside, quercetin 3-O-[(2,3,4-triacetyl-α-rhamnopyranosyl)-(1→6)]-3-acetyl-β-galactopyranoside, and quercetin 3-O-[(2,3,4- triacetyl-α-rhamnopyranosyl)-(1→6)]-4-acetyl-β-galactopyranoside, which have recently been isolated from CENTAURIUM SPICATUM (L.) Fritsch (Gentianaceae), a new pentaacetylated flavonoid glycoside was isolated from the same plant. Structure elucidation, especially the localization of the acetyl groups, and complete
1
H- and
13
C-NMR assignments, was carried out using one- and two-dimensional NMR methods, including
1
H- and
13
C-NMR, DEPT-135 and DEPT-90, and gradient-assisted experiments such as DQF-COSY, TOCSY, HSQC and HMBC. The structure of the new flavonoid glycoside was established as quercetin 3-O-[(2,3,4-triacetyl-α-rhamnopyranosyl)-(1→6)]-3,4-diacetyl-β-galactopyranoside. The anticomplement and antioxidant activities of these compounds were evaluated. The triacetylated flavonoid glycoside showed the highest activity in the two assays.