Blood glucose lowering activity of five Nigerian medicinal plants in alloxan-induced diabetic wistar albino rats

Abstract

The blood glucose lowering effects of the aqueous leaf extracts of Cassia alata, Acalypha torta and Breynia nivosa, and aqueous root extracts of Daniellia oliveri and Nauclea latifolia traditionally employed in Nigeria in the management of diabetes mellitus were compared in alloxan-induced diabetic Wistar rats. The same dose, 100.0 mg/kg body wt. of each extract was used. Alloxan (150.0 mg/kg body wt.), extracts, and the reference drug, glibenclamide (20.0 mg/70kg body wt.) were solubilized in normal saline and administered intraperitoneally. Investigation into the mechanisms of action of the most potent extract was carried out by determining it’s effects on lipid-peroxidation, superoxide dismutase (SOD), catalase and glucokinase. The extracts caused significant (p< 0.01) reductions in the blood glucose concentrations of the diabetic animals, thereby validating their antidiabetic properties. The order of potency was Nauclea latifolia (79.9%) > Acalypha torta (66.5%) > Breynia nivosa (50.4%) > Cassia alata (39.2%) > Daniellia oliveri (31.9%). The most active extract, Nauclea latifolia, was more potent than glibenclamide. N. latifolia extract decreased malonylaldehyde concentration and superoxide dismutase activity, although these effects were not statistically significant, whereas significant reduction in catalase activity was noted. Alteration of body’s oxidantantioxidant balance may be enhancing the antidiabetic activity of Nauclea latifolia root. Glucokinase activity was also significantly (p<0.05) elevated.

Keywords: Antidiabetic activity, Cassia alata, Breynia nivosa, Acalypha torta, Nauclea latifolia, Daniellia oliveri, Lipid-peroxidation, Superoxide dismutase, Catalase, Glucokinase