Effect of Pterocarpus santalinoides Leaf Extract on Oral Glucose Tolerance Test in Normal and Alloxan-Induced Diabetic Rats doi.org/10.26538/tjnpr/v4i6.4

Abstract

Hypoglycemic effect of Pterocarpus santalinoides has been scientifically reported but without any clue to its mechanism of action. To elucidate its mode of hypoglycemic activity, the effect of the plant on postprandial hyperglycemia was investigated. Dried, pulverized leaves (500 g) of P. santalinoides was macerated in 80% methanol (1.5 L), filtered and concentrated to dryness.
Preliminary phytochemistry of the extract was done and its acute toxicity was evaluated following the up-and-down method. The effect of varying doses (50, 100 and 200 mg kg-1, peros) of the extract on oral glucose tolerance test was assessed in normal and alloxan (160 mg kg-1,i.p.)-induced diabetic rats. The positive and negative control groups received glibenclamide (2mg kg-1) and distilled water (5 mL kg-1), respectively. Glycosides, alkaloids, flavonoids,saponins tannins and terpenes were found to be present in the extract. Its acute toxicity test recorded neither death nor sign of toxicity in the rats even at the maximum oral dose of 5000 mg
kg-1. In normal rats, 50, 100 and 200 mg kg-1 of the extract exhibited significant (p < 0.05) hypoglycemic activity by lowering blood glucose levels to 70.00±2.85, 69.33±3.29 and 68.17±3.34 mg dL-1, respectively, 180 min post-glucose load (2 g kg-1). In diabetic rats, the
extract (100 and 200 mg kg-1) significantly (p < 0.05) lowered blood glucose levels of treated rats when compared with the negative control group. The results show that Pterocarpus santalinoides leaf extract significantly lowers blood glucose levels in rats, via enhanced glucose utilization.