Monoamine oxidase inhibitory flavonoids from the root bark of Cudrania tricuspidata

Abstract

Two new benzylated flavonoids, 5,7,4′-trihydroxy-6-p- hydroxybenzylflavanone (1) and 5,7,4′-trihydroxy-6,8-di-p- hydroxybenzylflavanone (2) together with six known flavonoids, kaempferol (3), artocarpesin (4), cycloartocarpesin (5), cudraflavone D (6), gericudranin E (7), and leachianone G (8) have been isolated from the root bark of Cudrania tricuspidata. The structures of 1 and 2 were characterized based on spectroscopic data including 1D- and 2D-NMR. All the isolates were evaluated for their inhibitory effects of monoamine oxidase (MAO). Among them, kaempferol (3), artocarpesin (4), and cudraflavone D (6) showed moderate inhibitory effects with IC50 values of 82.3, 30.8, and 71.8 μM, respectively.