Biological activity and polyphenol content in selected herbal tea blends used in diabetes

Abstract

This study aimed to evaluate the antioxidant properties, α -glucosidase inhibitory activity, and the total content of polyphenols and flavonoids in the selected anti-diabetic herbal blends (1-6), used traditionally in diabetes. The strongest antioxidant activity (DPPH and CUPRAC) was observed in extracts from blends 1 and 6 (IC50 < 70 μg/mL, IC0.5 < 110 μg/mL, respectively). Extracts from these blends also contained most of the polyphenolic compounds (> 40 mg GAE/g), had a high content of flavonoids (6 n 10.96 mg QE/g, 1 ñ 7.51 mg QE/g) and the highest α-glucosidase inhibiting capacity (for 1 > 90%, for 6 > 90% and 5.55%, while for acarbose 1.76% and 0.93% at the 100 μg/mL and 10 μg/mL, respectively). The antioxidant activity of 1 and 6 correlated with the content of polyphenols and α-glucosidase inhibitory properties and indicates the existence of this mechanism in supporting the treatment of type 2 diabetes and diabetic complications by the above preparations.