Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8328831 | International Journal of Biological Macromolecules | 2018 | 12 Pages |
Abstract
Glycemic control which can be efficaciously regulated by inhibiting α-glucosidase activity is an effective therapy for diabetes mellitus. This work is to investigate the kinetics and inhibition mechanism of oleanolic acid and ursolic acid on α-glucosidase. Oleanolic acid and ursolic acid exhibited potent inhibitory activities with IC50 values of (6.35 ± 0.02) Ã 10â6 and (1.69 ± 0.03) Ã 10â5 mol Lâ1 respectively in a reversible and non-competitive manner. Both of them binding to α-glucosidase induced the conformational change and intrinsic fluorescence quenching of α-glucosidase. The binding constants of oleanolic acid and ursolic acid with α-glucosidase at 298 K were (2.04 ± 0.02) Ã 103 and (1.87 ± 0.02) Ã 103 L molâ1, respectively. Docking results showed that oleanolic acid and ursolic acid bound in different allosteric sites of cavity 2 and cavity 4 on α-glucosidase, respectively, which triggered allosteric regulation to perturb conformational dynamics of α-glucosidase, eventually leading to a decrease of catalytic activity of the enzyme. The substrate was not catalyzed by α-glucosidase to generate further products due to formation of a nonreactive ternary complex of oleanolic acid- or ursolic acid-α-glucosidase-substrate. The combination of oleanolic acid and ursolic acid displayed a significant synergistic inhibition on α-glucosidase.
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Authors
Huafang Ding, Xing Hu, Ximing Xu, Guowen Zhang, Deming Gong,