Two New Acylated Flavonol Glycosides from the Roots of Otostegia limbata

Two new acylated flavonol glycosides, 5‐hydroxy‐2‐(4‐hydroxyphenyl)‐4‐oxo‐7‐[(α‐L‐rhamnopyranosyl)oxy]‐4H‐chromen‐3‐yl β‐D‐glucopyranosyl‐(1→2)‐[β‐D‐glucopyranosyl‐(1→4)]‐[6‐O‐[(2E)‐3‐(4‐hydroxyphenyl)prop‐2‐enoyl]‐β‐D‐glucopyranosyl‐(1→3)]‐α‐L‐rhamnopyranoside (1) and 5‐hydroxy‐2‐(4‐hydroxyphenyl)‐4‐oxo‐7‐[(α‐L‐rhamnopyranosyl)oxy]‐4H‐chromen‐3‐yl [6‐O‐[(2E)‐3‐(4‐hydroxyphenyl)prop‐2‐enoyl]‐β‐D‐glucopyranosyl‐(1→2)]‐[β‐D‐glucopyranosyl‐(1→4)]‐[6‐O‐[(2E)‐3‐(4‐hydroxyphenyl)prop‐2‐enoyl]‐β‐D‐glucopyranosyl‐(1→3)]‐α‐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.