The antioxidant and antidiabetic activities of vanadium-binding protein (VBP) and trifuhalol A, alone or combined, were investigated. Both VBP and trifuhalol A showed potent radical scavenging activity (RSA) on 2,2'-azinobis (3-ethylbenzothiazoline)-6-sulfonic acid (ABTS), hydrogen peroxide, and ferric-reducing antioxidant power. Their combination at a concentration of 100 μg/ml VBP and 40 μg/ml trifuhalol A exhibited more than 99% RSA against ABTS. Additionally, VBP and trifuhalol A, alone or combined, displayed potential antidiabetic activities against Saccharomyces cerevisiae α-glucosidase. The highest inhibition of 70.26% against S. cerevisiae α-glucosidase was observed in the case of the combination of 250 μg/ml VBP and 1.75 μg/ml trifuhalol A. Kinetics study revealed that VBP and trifuhalol A were noncompetitive inhibition type against S. cerevisiae α-glucosidase, while VBP and trifuhalol A combined treatment was a mixed inhibition type against S. cerevisiae α-glucosidase. These results indicated that VBP and trifuhalol A, alone or combined, had high free radical scavenging activity and inhibitory activity against S. cerevisiae a-glucosidase, suggesting that VBP and trifuhalol A could be used as candidates for the development of natural antidiabetic drugs or functional food. PRACTICAL APPLICATIONS: The present study showed that VBP and trifuhalol A, alone or combined, had potential antioxidant and antidiabetic activities, suggesting that VBP and trifuhalol A could be developed to a novel nutraceutical or natural antidiabetic drugs in the management of obesity or diabetes. This finding will be beneficial for all peoples who are directly or indirectly associated with obesity or diabetes.
Keywords: antidiabetic; antioxidant; combination; trifuhalol A; vanadium-binding protein.
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