Anti-venom potentials of Friedelin isolated from hexane extract fraction of <i>Albizia chevalieri</i> Hams (Mimosaceae)

Abstract

Albizia chevalieri Hams (Mimosaceae), mostly found in the Northern Sahel Savannah regions of Nigeria as well as in Nigér Republic and Senegal is a tree of the acacia type with a long list of folklore therapeutic claims, which include its plant parts use as purgative, taenicidal, cough remedy, dysentery, cancer, diabetes mellitus, tuberculosis and snake bite remedy. In this report, an attempt has been made to evaluate the bioactive molecules in the plant that are anti-venom agents. Consequently, the stem bark was exhaustively extracted with hexane and subsequently with methanol. The methanolic extract was fractionated into ethyl acetate (EA) and n-butanol (NB) soluble parts after which the hexane extract were subjected to silica gel gravity column chromatography for the isolation of pure bioactive molecules. The major compound isolated, HXC₁ (friedelin), determined using   spectrometric analysis of ¹HR-ESIMS,  ¹³HNMR, CNMR and IR spectra was investigated for anti-venom activity, including the extract fractions in experimental albino mice using standard methods. The extent of cobra venom  (Naja nigricollis venom) induced lethal activity (minimum lethal dose of 5mgkg^-1 or MLD) in the positive control group (venom-only) was compared with the mortality rate in the treatment group so as to evaluate the likely inhibitive/prophylaxis potentials of HXC₁ and those of the extract fractions in the animals within 24 hours. The results showed that the isolated compound, HXC₁ offered the highest protection by prolonging time of death of   HXC₁  envenomated animal treated group at a dose dependant amount of 4mgkg^-1 and 8mgkg^-1 with a minimum  survival rate of 20%, as compared to the positive control and plant extracts treated groups where about 80% of the animals died within an average time of 17 minutes. This study went to show the likely anti-venom potentials in the isolated compound as well as those of NB and hexane extracts of Albizia chevalieri, which is being reported for the first time.

Keywords: Albizia chevalieri, Friedelin, Naja nigricollis, Anti-venom agent, Hexane-Extract Fraction, LD .