Effect of Aglycon and Glycoside Flavonoid-Enriched Extracts Obtained from Buxus sempervirens L. on Glucose and Lipid Metabolism in Diabetic Rats

Background: Buxus sempervirens L. is a medicinal plant with several beneficial effects on health and is widely used in Moroccan folklore as an antidiabetic plant. Objective: The aim of this study was to evaluate the antidiabetic effect of both aglycone and glycoside flavonoid enriched extracts of this plant in the experimental diabetic state. Methods: In the current work, the effect of aglycone and glycoside flavonoid-enriched extracts from the leaves of Buxus sempervirens L. (AFBS and GFBS) (10 mg/kg) on blood glucose levels has been evaluated in normal and streptozotocin (STZ) diabetic rats. Moreover, the histopathological changes in the liver and pancreas have been assessed in STZ diabetic rats. The ability of AFBS and GFBS to improve glucose tolerance in normal rats was also evaluated. Results: In normal rats, both a single and repeated administration of AFBS and GFBS (10 mg/kg) showed no significant effects on blood glucose levels. However, both single and repeated oral administration of the two fractions showed a significant blood glucose lowering effect (p<0.0001) in STZ rats. In addition, histopathological analysis has demonstrated the beneficial impact of AFBS and GFBS on the pancreas and liver. Whereas, the oral glucose tolerance test demonstrated no significant ability of these extracts to improve the increase in blood glucose levels in normal and diabetic treated rats. In the current study, no significant changes in body weight in normal and STZ rats have been shown. In addition, the antioxidant activity of both AFBS and GFBS revealed the antioxidant effect of both extracts. Furthermore, both flavonoid-enriched fractions had no significant effect on blood lipid levels. Conclusion: In conclusion, AFBS and GFBS exhibited an interesting antidiabetic effect on streptozotocin rats and GFBS which seems to be more effective than AFBS.