Bioassay Guided Isolation and Evaluation of the Antidiabetic Principles of Combretum dolichopetalum Root.

Aims: The present study was aimed at investigating the antidiabetic potentials of Combretum dolichopetalum root in alloxan-induced animals with the hope of isolating its antidiabetic principles. Study Design: Sixty four Wistar albino rats of either sexes were randomly segregated into 16 groups (n=4). Also, thirty two albino mice were segregated into 8 groups. These received various doses of the plant sample, vehicle or glibenclamide for the antidiabetic study. Place and Duration of Study: This study was done in the laboratory of the Department of Pharmaceutical and Medicinal Chemistry, University of Nigeria, Nsukka between March and October, 2013. Methodology: The root of C. dolichopetalum was extracted with methanol (ME) and fractionated successively with various solvents (n-hexane, chloroform, ethylacetate, methanol and water) to afford the respective fractions: HF, CF, EF, MF and AF. CF was further fractionated to afford six sub-fractions: C1-C6. Acute toxicity study was done using ME. Antidiabetic activity of various doses (p.o.) of ME (100, 200, 400 and 600 mg/kg body weight), its fractions (200 and 400 mg/kg) and sub-fractions (200 mg/kg), glibenclamide (0.2 mg/kg) and vehicle (control) were investigated in alloxan-induced (i.p.) diabetic animals for 9 h. Phytochemical analysis was also carried on ME and fractions. Results: The extract was considered safe with LD50 greater than 5000 mg/kg. ME (400 mg/kg), CF (400 mg/kg) and C3 (200 mg/kg) produced maximum reduction (36.78%, 72.43% and 83.17% respectively) in fasting blood glucose of animals after 9 h which were significantly (P < .01, P < .001) different from the control and better than glibenclamide (48.18%). Phytochemical analysis showed alkaloids, flavonoids, terpens and steroids as the likely antidiabetic agent(s). Conclusion: The root of C. dolichopetalum possesses potent antidiabetic activity which increases as the extract is purified. The antidiabetic effect of the plant may likely be due to the presence of alkaloids, flavonoids, terpens or steroids.