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Tu J, Adhikari B, Brennan MA, Bai W, Cheng P, Brennan CS. Shiitake polysaccharides acted as a non-competitive inhibitor to α-glucosidase and inhibited glucose transport of digested starch from Caco-2 cells monolayer. Food Res Int 2023; 173:113268. [PMID: 37803584 DOI: 10.1016/j.foodres.2023.113268] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 07/09/2023] [Accepted: 07/11/2023] [Indexed: 10/08/2023]
Abstract
The inhibition mechanism of shitake mushroom polysaccharides (Lentinula edodes polysaccharides, LEP) against α-glucosidase was studied by enzyme kinetic assay, fluorescence quenching and molecular docking. The effect of LEP on glucose transport of digested starch was investigated via an in vitro digestion/Caco-2 transwell model. LEP exhibited a stronger inhibiting effect (IC50 = 0.66 mg/mL) than acarbose and presented a non-competitive inhibition mechanism. The interaction between LEP and α-glucosidase primarily involved electrostatic interaction and hydrogen bonding. Molecular docking modelling showed that the four structures of LEP were bound to the allosteric tunnel or adjacent pocket of α-glucosidase via electrostatic force and hydrogen bonds. The (1 → 6)-linkages in LEP structures favoured its binding affinity to the α-glucosidase. The α-glucosidase inhibiting activity of LEP was also found to emanate from the reduction in glucose transport of digested starch as deducted from the in vitro digestion/Caco-2 transwell data. The release of glucose from digested starch cooked with LEP was significantly reduced (33.7%) compared to the digested starch without LEP. The findings from the current study suggest that LEP could be a promising ingredient to inhibit α-glucosidase activity as well as control the level of postprandial blood glucose when incorporated into starchy foods.
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Affiliation(s)
- Juncai Tu
- School of Science, RMIT University, GPO Box 2474, Melbourne, VIC 3001, Australia
| | - Benu Adhikari
- School of Science, RMIT University, GPO Box 2474, Melbourne, VIC 3001, Australia.
| | - Margaret Anne Brennan
- School of Science, RMIT University, GPO Box 2474, Melbourne, VIC 3001, Australia; Department of Wine, Food and Molecular Biosciences, Lincoln University, PO Box 84, Lincoln 7647, Christchurch, New Zealand
| | - Weidong Bai
- College of Light Industry and Food Sciences, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Ping Cheng
- College of Light Industry and Food Sciences, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
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Hao Y, Guo T, Ren J, Wang Y, Wang L, Shi Y, Feng W. Characterization of a thermostable, protease-tolerant inhibitor of α-glycosidase from carrot: A potential oral additive for treatment of diabetes. Int J Biol Macromol 2022; 209:1271-1279. [PMID: 35460754 DOI: 10.1016/j.ijbiomac.2022.04.110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/03/2022] [Accepted: 04/15/2022] [Indexed: 11/05/2022]
Abstract
Inhibiting α-glucosidase activity is important in controlling postprandial hyperglycemia and, thus, helping to manage type-2 diabetes mellitus (T2DM). In the present study, we purified a hypothetical protein of carrots called DCHP (Daucus Carrot hypoglycemic peptide), and their inhibitory effects on α-glucosidase, as well as related mechanisms, were investigated. The recombinant DCHP protein with a molecular weight of 8 kDa showed strong inhibitory activity against α-glycosidase and maintained good stability in solution. DCHP exhibited no inhibitory activity but was tolerant to trypsin and chymotrypsin. Cellular experiments demonstrated that glucose consumption and lactic acid production increased rapidly when treated with DCHP in Caco-2 and HepG2 cells. DCHP crystal was generated, and the crystal structure, which was similar to that of rBTI and consisted of a central α-helix and a two-stranded β-sheet with a unique loop region. The interaction between DCHP and α-glycosidase was investigated by molecular docking and site-directed mutation, which revealed that Glu43, Pro46, Thr47 Thr48 and Gln49 are the key residues in DCHP that inhibit α-glycosidase activity. This work provides potential bioactive peptides as functional foods or nutraceutical supplements in preventing and managing T2DM.
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Affiliation(s)
- Yang Hao
- Key Laboratory of Chemical Biology and Molecular Engineering, Ministry of Education, China; Institute of Biotechnology, Shanxi University, Taiyuan 030006, China
| | - Tao Guo
- Key Laboratory of Chemical Biology and Molecular Engineering, Ministry of Education, China; Institute of Biotechnology, Shanxi University, Taiyuan 030006, China
| | - Jinqi Ren
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Yaxin Wang
- Key Laboratory of Chemical Biology and Molecular Engineering, Ministry of Education, China; Institute of Biotechnology, Shanxi University, Taiyuan 030006, China
| | - Lei Wang
- Key Laboratory of Chemical Biology and Molecular Engineering, Ministry of Education, China; Institute of Biotechnology, Shanxi University, Taiyuan 030006, China
| | - Yawei Shi
- Key Laboratory of Chemical Biology and Molecular Engineering, Ministry of Education, China; Institute of Biotechnology, Shanxi University, Taiyuan 030006, China.
| | - Wei Feng
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
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Development of a novel trypsin affinity material using a recombinant buckwheat trypsin inhibitor mutant with enhanced activity. Lebensm Wiss Technol 2021. [DOI: 10.1016/j.lwt.2021.111382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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