Carbonic anhydrase inhibitors from the pericarps of Punica granatum L.

Seven highly active inhibitors against carbonic anhydrase (CA, EC 4.2.1.1), punicalin (2), punicalagin (3), granatin B (5), gallagyldilactone (7), casuarinin (8), pedunculagin (9) and tellimagrandin I (10), and four weakly active inhibitors, gallic acid (1), granatin A (4), corilagin (6) and ellagic acid (11), were isolated from the pericarps of Punica granatum L. (Punicaceae). They are ellagitannins. The type of inhibition by 3 and 7 using p-nitrophenyl acetate as a substrate, is noncompetitive. The structure-activity relationship of inhibitory effects on CA is discussed.