Polyphenolic enriched extract of Cassia glauca Lamk, improves streptozotocin-induced type-1 diabetes linked with partial insulin resistance in rats

Ethnopharmacological relevance Traditionally Cassia glauca (CG) has been used to treat diabetes. Aim of the study The study was undertaken to evaluate anti-diabetic and antioxidant activity of polyphenolic enriched extract of CG in standardized streptozotocin (STZ)-induced diabetic rats. Materials and methods The effect of ethanol (CGE) and water (CGW) extracts of CG (200 and 400 mg/kg) treatment were evaluated in STZ (50 mg/kg, iv) induced diabetic rats. On 10^th day, oral glucose tolerance test and degree of insulin resistance was calculated. On 13^th day, insulin tolerance test was performed to know the peripheral utilization of glucose. On 15^th day, blood glucose, lipid profiles and endogenous antioxidant levels were estimated. In addition, the effects on oral glucose/sucrose tolerance test in normal rats. Further, HPLC fingerprinting profile of CGE and simultaneous quantification of biomarkers were carried out. Results Supplementation with CGE and CGW significantly reduced STZ-induced deleterious effects and improved glucose tolerance, and insulin tolerance. In addition, supplementation also decreased oxidative stress by improving endogenous antioxidant levels. Furthermore, administration significantly improves sucrose tolerance suggesting that extract possess inhibition of α-glucosidase enzyme. Further, HPLC studies revealed that CGE contains three bioactive polyphenolic compounds viz., rutin (0.10±0.01 mg/g), luteolin-7-glucoside (0.06±0.01 mg/g) and isorhoifolin (0.7±0.05 mg/g). Conclusion Observed beneficial outcome of CG might be attributed to the presence of polyphenolic compounds and mediated by interacting with multiple targets of diabetes and oxidative stress. Taken together, this study provided the scientific evidence for the traditional use of CG.