Isointricatinol, a new antioxidant homoisoflavonoid from the roots of Caesalpinia digyna Rottler

A new homoisoflavonoid, isointricatinol (1), together with eight known homoisoflavonoids, three flavonoids, bergenin and 11-O-galloylbergenin were isolated from the EtOAc fraction of MeOH extract of Caesalpinia digyna roots and evaluated for the antioxidant activity against DPPH and ABTS free radicals. The structure of 1 was elucidated by various spectroscopic techniques and found to be a Z-isomer of 7,8-dihydroxy-3-(4'-methoxybenzyl)chroman-4-one. Compound 1 was found to exhibit mild to moderate free radical scavenging effect against DPPH (IC(50), 85.50 µM) and ABTS (IC(50), 44.13 µM) radicals.