Belamcandaquinones A and B, novel dimeric 1,4-benzoquinone derivatives possessing cyclooxygenase inhibitory activity

Abstract Belamcandaquinone A ( 1 ), a new dimeric 1,4-benzoquinone derivative, has been isolated as specific cyclooxygenase inhibitor (IC 50 8.33 μM) from the seed of Belamcanda chinensis together with belamcandaquinone B ( 2 ), an inactive congener, and their structures elucidated on the basis of spectroscopic data and chemical degradation.