Evaluation of Andira inermis stem bark extract for hypoglycaemic and antioxidant effects’

Background The aqueous methanolic extract of Andira inermis(A. inermis) stem bark was screened for phytochemical constituents, antioxidant activity, acute oral toxicity, and preliminary prophylactic normoglycaemic test and effect on Oral Glucose Tolerance in albino rats. Methods Andira inermis was double macerated and extracted with 80% methanol. Phytochemical analysis and acute toxicity were performed using standard methods. The extract was screened for in vitro antioxidant activity using Ferric Reducing/Antioxidant Power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging spectrophotometric assays. Prophylactic control of glucose was evaluated in normoglycaemic and glucose-challenged albino rats. Graded test doses (100–400 mg/kg body weight) of the extract were used in the investigation. The effects observed were compared with that of glibenclamide (0.2 mg/kg) and distilled water control groups. Results The stem bark extract of A. inermis was found to contain saponins, terpenes, tannins, steroids, flavanoids, anthraquinones, carbohydrates and alkaloids. The extract was found to have a significant in vitro antioxidant activity in both methods. The oral acute toxicity study showed the extract had LD 50 greater than 5000 mg/kg. The extract significantly ( p ≤ 0.05) reduced blood glucose levels in normoglycaemic animal model (the control group seen to have − 5.6(− 8.7%) poor glucose handling; and the glibenclamide& extract treatment group (100 mg/kg) to positively reduce blood glucose 14.8(26.8%) & 16.4(25.9%) respectively). The glucose challenged test, from the 1st hour, showed − 57.4(− 89.4%),-26.8(− 33.8%),-23.8(− 26.3%),-12.8(− 13.9%) and − 9.8(− 10.4%) for the vehicle control, glibenclamide (positive control), and the 100, 200 & 400 mg/kg extract treatment groups respectively. The extract showed mild hypoglycemic effect in the results recorded, up to the 4th hour. Conclusion The results of this study elucidated that the aqueous methanolic extract of Andira inermis stem bark possessed potent antioxidant phyto-constituents with potential hypoglycaemic effects that could be explored for therapeutic use worldwide following isolation and characterization of the bioactive principles. And the results also authenticate the folklore use of the plant.