Monoamine Oxidase Inhibitors from Cinchonae Cortex

Abstract

Three strong alkaloidal monoamine oxidase (MAO) inhibitors, quinine (1), cinchonicinol ([15,3 ‘/?,4’/?]-3-(3-ethenyl-4-piperidinyl)-l-{4-quinolinyi)-l-propanol) (2) and cinchonaminone ([3 ‘/?,4’5]-2-[2-(3-ethenyl-4-piperidinyl>-acety 1]–1 //-indole-3-ethanol) (3), were isolated from Cinchonae Cortex (Cinchona succirubra PAV. Rubiaceae). The structures of 2 and 3 were elucidated on the bases of spectral data and chemical evidence, and 3 is a new alkaloid. The inhibitory effects on MAO of 1,2,3 and related alkaloids were assayed. The type of inhibition by 1 with respect to benzylamine as a substrate was competitive. © 1989, The Pharmaceutical Society of Japan. All rights reserved.