A bioactive prodelphinidin from Mangifera indica leaf extract.

A new trimeric proanthocyanidin, epigallocatechin-3-O-gallat-(4beta-->8)-epigallocatechin-(4beta-->8)-catechin (1), was isolated together with three known flavan-3-ols, catechin (2), epicatechin (3), and epigallocatechin (4), and three dimeric proanthocyanidins, 5-7, from the air-dried leaves of Mangifera indica. Their chemical structures were determined on the basis of 1D- and 2D-NMR spectra (HSQC, HMBC) of their peracetylated derivatives, MALDI-TOF-mass spectra, and by acid-catalyzed degradation with phloroglucinol. The isolated compounds 1-7 were in vitro tested for their inhibitory activities against COX-1 and COX-2. Compound 1 was found to have a potent inhibitory effect on COX-2, while compounds 1 and 5-7 exhibited moderate inhibition against COX-1.