Two New Acylated Flavonol Glycosides from the Roots of Otostegia limbata

Two new acylated flavonol glycosides, 5-hydroxy-2-(4-hydroxyphenyl)-4-oxo-7-[(alpha-L-rhamnophyranosyl)oxy]-4H-chromen-3-yl beta-D-glucopyranosyl-(1 -> 2)-[beta-D-glucopyranosyl-(1 -> 4)]-[6-O-[(2E)-3-(4-hydroxyphenyl)prop-2-enoyl]beta-D-glucopyranosyl-(1 -> 3)]-alpha-L-rhamnopyranoside (1) and 5-hydroxy-2-(4-hydroxyphenyl)4-oxo-7-[(alpha-L-rhamnopyranosyl)oxy]-4H-chromen-3-yl[6-O-[(2E)-3-(4-hydroxyphenyl)prop-2-enoyl]-beta-D-glucopyranosyl-(1 -> 2)]-[beta-D-glucopyranosyl-(1 -> 4)]-[6-O-[(2E)-3-(4-hydroxypheny)prop-2-enoyl]-beta-D-glucopyranosyl-(1 -> 3)]alpha-L-rhamnopyranoside (2), were isolated from the roots of Otostegia limbata, along with two known flavones, cirsimaritin and 3'-O-methyleupatorin. Their structures were elucidated on the basis of spectroscopic evidences and chemical methods.