Antisnake venom activity and isolation of quercetin from the leaf of Neocarya macrophylla (Sabine) Prance ex F. White (Malpighiales: Chrysobalanaceae)

Snake envenomation is a major cause of death and disability in many developing countries. Neocarya macrophylla (Sabine) Prance ex F. White (Malpighiales: Chrysobalanaceae) have been reportedly used in traditional medicine to treat snake envenomation. Bioassay-guided isolation of antivenom principles was carried out on the leaf of N. macrophylla against Naja nigricollis venom. The methanol extract of N. macrophylla leaf and its ethylacetate and n-butanol fraction significantly (P < 0.05) protected mice against venom-induced lethality with 100% survival rate and there was remarkable inhibition of the poisonous effects of PLA2 enzyme by the extracts and the fractions. Encouraged by this result, the ethylacetate soluble fraction was subjected to purification using vacuum liquid chromatography and gel filtration which led to the isolation of quercetin as the bioactive principle. The identity of the compound was determined on the basis of chemical tests, and by comparison of its 1H-NMR data with literature, this is the first report of isolation of this compound from the leaf of the plant. However, the results of the study suggests that the leaf of N. macrophylla possess significant antisnake venom activity which provide the scientific basis for its use in traditional treatment of snakebites.