New antiulcer quassinoids from Eurycoma longifolia

Abstract A bioassay study of Pasak bumi (Eurycoma longifolia) led to the isolation of four quassinoids, pasakbumin-A ( 1 ), -B ( 2 ), -C ( 4 ), and -D ( 7 ). Both pasakbumin-A (= eurycomanone) 1 and pasakbumin-B 2 exhibited potent antiulcer activity. This prompted us to test some modified quassinoids to reveal that ailanthone ( 8 ), the main quassinoid of Ailanthus altissima , and its α-epoxide ( 9 ) have potent activity and less toxicity. Thus, quassinoids which are generally recognised as antitumor compounds were revealed to have antiulcer activity.