A new chalcone from Pongamia pinnata and its antioxidant properties.

The root bark of Pongamia pinnata Pierre [syn P. glabra (family: Fabaceae)] afforded a new chalcone (karanjapin) and two known flavonoids, a pyranoflavonoid (karanjachromene) and a furanoflavonoid (karanjin) The structure of karanjapin has been established from extensive 2D NMR spectral studies as beta,2'-dihydroxy-a,4'-dimethoxy-3,4-methylenedioxychalcone. Karanjapin and karanjachromene were found to possess significant antioxidant activity. This may play an important role in the pathogenesis of several diseases.