Abstract

Objective: To evaluate the antioxidant and α-glucosidase inhibitory activities of luteolin and luteolin 7-O-glucoside isolated from Scabiosa arenaria Forssk. Methods: Antioxidant activity was measured by the 2,2-diphenyl-1-picrylhydrazyl free radical scavenging assay. The α-glucosidase inhibition was determined by colorimetric assay using the enzyme from Aspergillus niger, and the p-nitrophenyl glucopyranoside (pNPG) as substrate. Results: The two compounds showed remarkable inhibition of α-glucosidase (IC50 = 0.009 2 mg/mL and 0.014 mg/mL, respectively) and they appeared to be even more potent than acarbose. A kinetic binding study indicated that the two compounds used a mechanism of noncompetition to inhibit α-glucosidase. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay further showed that the aglycone form (luteolin) possessed the best antioxidant activity. Conclusions: The results showed that the two flavonoids had biological activities with high potential for food and pharmacological uses.

Authors and Affiliations