Rb2 inhibits α-glucosidase and regulates glucose metabolism by activating AMPK pathways in HepG2 cells. (January 2017)

• Record Type: Journal Article
• Authors: Teng, Hui; Chen, Lei; Fang, Ting; Yuan, Benyao; Lin, Qiyang
• Is Part Of: Journal of functional foods. Volume 28(2017)
• Page Start: 306
• Page End: 313
• Publication Date: 2017-01
• Subjects: Rb2 -- α-Glucosidase -- α-Amylase -- Glucose metabolism -- AMPK; Functional foods -- Analysis -- Periodicals; Food -- Biotechnology -- Periodicals; Nutrition -- Periodicals; 613.2
• DOI: 10.1016/j.jff.2016.10.033
• Languages: English
• ISSNs: 1756-4646

Abstract

Highlights: Rb2 and Rd, but not Rc, Re, or Rg exhibited α-glucosidase and α-amylase inhibition. A kinetics model was built to study the inhibition mechanism of α-glucosidase. An experiment was built to verify the inhibition type of Rb2 and Rd. The phosphorylation of AMPK was increased by treatment with Rb2. Abstract: Five ginsenosides were evaluated as α-glucosidase and α-amylase inhibitors by enzymatic kinetics analysis, compared with the market diabetes healer, acarbose. The results indicated that Rb2 and Rd exhibited strong α-glucosidase and α-amylase inhibition. Concentration of Rb2 and Rd to inhibit 50% of α-glucosidase (IC50 ) were 32.2 and 38.8 μM, IC50 for α-amylase were 128 and 167.4 μM, respectively. The enzyme kinetic studies revealed that, in the presence of the most potent α-glucosidase inhibitors, Rb2 and Rd, the Michaelis-Menton constant ( Km ) remained constant but the maximal velocity ( Vmax ) decreased, revealing a non-competitive type of inhibition. Moreover, Rb2 and Rd were shown to be reversible inhibitors of yeast α-glucosidase with Ki values of 19.4 and 24.5 μM, respectively. Moreover, we investigated the effects of Rb2 on metabolism and demonstrated that Rb2 significantly increased glucose consumption in HepG2 cells. The phosphorylation of AMP-activated protein kinase (AMPK) was increased by treatment with Rb2.