A new flavonol, morin-3-O-alpha-rhamnopyranoside (1), along with four known flavonols, kaempferol 3-O-alpha-rhamnopyranoside (2), kaempferol 3-O-beta-glucopyranoside (3), quercetin 3-O-alpha-rhamnopyranoside (4) and (+)-catechin (5), were isolated from the methanolic extract of Muehlenbeckia