A bioactive flavan-3-ol from the stem bark of Neocarya macrophylla

Abstract

Antisnake venom activity of the ethylacetate and n-butanol soluble fractions of the methanol stem bark extract of Neocarya macrophylla were evaluated against Naja nigricollis venom. There was maximum protection to mice against venom-induced action after administration of the pre-incubated mixture of the venom and the fractions compared with the venom only. The fractions were also able to significantly inhibit phospholipase A2 enzyme activity. Based on the above findings, the ethylacetate fraction was subjected to purification using column chromatography and gel filtration; the procedures led to the isolation of a flavan-3-ol, catechin. The structure of the compound was identified based on chemical test, NMR analysis (1D- & 2D-NMR) and comparison with existing data in the literature. The catechin have demonstrated significant (p<0.05) antisnake venom activity in vitro with 100% survival rate; it was also found to be 42.0% effective in combating the hydrolytic action of N. nigricollis PLA2 enzyme. Catechin significantly (p<0.05) reduced the nociceptive response induced by formalin in both phases and there was remarkable inhibition of formalin-induced inflammation at the 1st, 2nd and 3rd hours, though the effect was not statistically significant compared to the control. The compound, catechin could serve as a lead in the development of novel antisnake venoms, analgesics and anti-inflammatory agents.