Effects of morin on snake venom phospholipase A2 (PLA2).

Flavonoids are potent anti-inflammatory compounds isolated from several plant extracts, and have been used experimentally against inflammatory processes. In this work, a PLA2 isolated from the Crotalus durissus cascavella venom and rat paw oedema were used as a model to study the effect of flavonoids on PLA2. We observed that a treatment of PLA2 with morin induces several modifications in the aromatic amino acids, with accompanying changes in its amino acid composition. In addition, results from circular dichroism spectroscopy and UV scanning revealed important structural modifications. Concomitantly, a considerable decrease in the enzymatic and antibacterial activities was observed, even though anti-inflammatory and neurotoxic activities were not affected. These apparent controversial results may be an indication that PLA2 possess a second pharmacological site which does not affect or depend on the enzymatic activity.