Inhibitory activity of monoamine oxidase by coumarins from Peucedanum japonicum

Four coumarins were isolated from chloroform extract of the root of Peuceda num japonicum and identified as praeruptorin A (1), xanthotoxin (2), psoral en (3) and bergapten (4) on the basis of spectroscopic methods. The inhibit ory activities of these coumarins on monoamine oxidase prepared by mouse br ain were tested. The IC, values of them were shown to be 27.4 mu M (1), 40. 7 mu M (2), 35.8 mu M (3), and 13.8 mu M (4), in vitro.