The fruits of Virola sebifera contain in the seed (2R, 3S)-3-(3,4-dimethoxybenzyl)-2-(3,4-methylenedioxybenzyl)-butyrolactone, and in the pericarp (2R, 3R)-3-(3,4-dimethoxybenzyl)-2-(3,4-methylenedioxybenzyl)-butyrolactone, (2R, 3R)-2,3-di-(3, 4-dimethoxybenzyl)-butyrolactone and (2R, 3R)-2,3-di-(3,4-methylenedioxybenzyl) butyrolactone; A new biflavonoid, semecarpuflavanone, has been isolated from the nut shells of Semecarpus anacardium. Its structure has been assigned on the basis of chemical and spectroscopic evidence.