Xanthine oxidase inhibitory activity of constituents of Cinnamomum cassia twigs.

A methanol extract of the twigs of Cinnamomum cassia was found to inhibit xanthine oxidase. Purification of the methanol extract afforded three new phenolic glycosides, cinnacasolide A-C (11-13), together with 10 known compounds (1-10). The structures of the three new compounds were determined by interpretation of spectroscopic data. Cinnamaldehyde derivatives 1-5 and 7 were significant inhibitors of xanthine oxidase, with IC(50) values ranging from 7.8 to 36.3 µg/mL. The results indicate that the acyl group of these cinnamaldehyde derivatives plays an important role in the inhibition of xanthine oxidase.