Extract of Bauhinia vahlii shows antihyperglycemic activity, reverses oxidative stress, and protects against liver damage in streptozotocin-induced diabetic rats

Abstract

The polar fraction of the <i>Bauhinia vahlii</i> leaves (defatted ethanolic extract [DEE]) exhibited both <i>in vitro</i> antioxidant activity in 2,2-diphenyl-1-picrylhydrazyl scavenging assay and strong α-glucosidase inhibition while the nonpolar fraction (<i>n</i>-hexane extract) failed to show any activity in both assays. DEE was further investigated in streptozotocin-induced diabetic rat model where oral administration of DEE at 2 doses (150 and 300 mg/kg) for 4 weeks resulted in significant reduction in fasting blood glucose and glycated hemoglobin and reversal of oxidative stress signs as indicated by measurement of hepatic reduced glutathione, nitric oxide, and malondialdehyde levels. In addition, histopathological examination and measurement of serum aspartate transaminase and alanine transaminase levels showed that DEE protected the liver from signs of pathogenesis observed in diabetic untreated rats. Phytochemical analysis of DEE showed high flavonoid content with quercitrin as the major constituent (62.9 ± 0.18 mg/mg). <b>Abbreviations used:</b> ALT: Alanine transaminase, AST: Aspartate transaminase, DEE: Defatted ethanol extract, DPPH: 2,2-diphenyl-1-picrylhydrazyl, FBG: Fasting blood glucose, GAE: Gallic acid equivalent, GSH: Reduced glutathione, Hb1Ac: Glycated hemoglobin, HE: Hexane extract MDA: Malondialdehyde, QE: Quercetin equivalent, STZ: Streptozotocin, TAC: Total antioxidant capacity.