PHYTOCHEMICAL AND ANTIVENOM STUDIES ON THE STEM BARK OF ALBIZIA CHEVALIERI HAMS (MIMOSACEAE) ON NAJA NIGRICOLLIS BROADLEY ENVENOMATED MICE

PHYTOCHEMICAL AND ANTIVENOM STUDIES ON THE STEM BARK OF ALBIZIA CHEVALIERI HAMS (MIMOSACEAE) ON NAJA NIGRICOLLIS BROADLEY ENVENOMATED MICE

Abstract:

Albizia chevalieri Hams (Mimosaceae), mostly found in the Northern Sahel Savannah region of Nigeria as well as in Nigér and Senegal is a tree of the acacia type with a long list of folklore therapeutic claims which include its use as purgative, taenicidal, cough remedy, dysentery, cancer, diabetes mellitus, tuberculosis and snake bite remedy. The stem bark was collected, dried and powdered. The powder was firstly extracted with hexane, and subsequently with methanol. The methanolic extract was then fractionated into ethyl acetate (EtOAc) and n-butanol soluble parts. Chromatographic separation of the EtOAc and hexane fractions led to the isolation of four pure compounds—β-sitosterol (EAC1) and three pentacyclic triterpenoids (Friedelin, Friedelinol and Lupeol, labelled as HXC1, HXC2, and HXC3 respectively), which were characterized using spectroscopic techniques (HREIMS, NMR, IR and UV). Two of the four isolated compounds (HXC1 and EAC1), were investigated for antivenom activity, including the extract and fractions in experimental albino mice using standard methods. The results showed that the isolated compound, EAC1 offered the highest protection to the animals by prolonging time of death of animal in the treated group at a dose dependant concentration of 8mgkg-1 with a minimum survival rate of 60%, followed by compound HXC1 which recorded 20% survival rate at same doses; compared to the group administered with the minimum lethal dose (MLD) of venom only, where 80% of the animals died within an average time of 17minutes. The fractions of n-butanol and hexane recoded antivenom activity at 200 mgkg-1 while those of methanol and EtOAc recorded no activity. Gross histopathological changes in liver and kidney tissues of envenomated mice treated with two of the isolated compounds were observed to be less obvious than seen in the tissues of envenomated mice treated with the candidate plant extracts and fractions. This study went to show the likely antivenom potentials in the isolated compounds evaluated as well as those of the fractions of n-butanol and hexane, which is being reported for the first viii time in the plant A. chevalieri. The results obtained also provided scientific basis for the use of A. chevalieri in folklore medicine in the treatment of snake bites.

PHYTOCHEMICAL AND ANTIVENOM STUDIES ON THE STEM BARK OF ALBIZIA CHEVALIERI HAMS (MIMOSACEAE) ON NAJA NIGRICOLLIS BROADLEY ENVENOMATED MICE