Inhibition of wheat bran and it's active compoments on α-glucosidase in vitro
Jie Tu1, Jun Chen2, Shuyun Zhu3, Chunxiao Zhang2, Hua Chen2, Youbing Liu2
1 Department of Food Quality and Safety, School of Food and Biological Engineering, Jiangsu University, Zhenjiang, Jiangsu, 212013; Department of Biotechnology and Engineering,College of Biology and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu, 212018, China 2 Department of Chinese Medicine and Pharmacology, School of Pharmacy, Jiangsu University, Zhenjiang, Jiangsu, 212013, China 3 Department of Food Quality and Safety, School of Food and Biological Engineering, Jiangsu University, Zhenjiang, Jiangsu, 212013, China
Correspondence Address:
Jun Chen Department of Chinese Medicine and Pharmacology, School of Pharmacy, Jiangsu University, 301, Xuefu Road, Zhenjiang, Jiangsu Province, 212013 China
 Source of Support: This work was supported by the Education Department
of Jiangsu Province, China (Project No.1223000131), Conflict of Interest: None  | Check |
DOI: 10.4103/0973-1296.117826
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Background: Wheat bran is a traditional Chinese medicine; however, it is mostly used as feedstuff in China. Wheat bran is widely accepted as an important ingredient in many low-glycemic index foods in modern western societies; however, its glycemic control mechanism is unknown. Objective: To determine potent α-glucosidase inhibitory compounds from wheat bran and to identify the inhibition on α-glucosidase . Materials and Methods: Ethanolic extract of wheat bran was prepared to evaluate the inhibitory activity on α-glucosidase, then fractionation of the extract was guided by in vitro enzyme-inhibition assay, and the potent α-glucosidase inhibitory compounds were identified by high performance liquid chromatography and atmospheric pressure chemical ionization-mass spectrometry; finally the enzyme inhibition process was studied using the Michaelis-Menton and the Lineweaver-Burk equations. Results: Both baker's yeast and rat intestinal enzymes were mostly inhibited (87.9% and 66.8% inhibition, respectively) at concentration 0.6 mg/mL of the ethanolic extract of wheat bran. The petroleum ether fraction in the ethanolic extract of wheat bran showed significant activity against rat intestinal α-glucosidase, and revealed a dose-dependent effect. The inhibition was 76.57% at 0.3 mg/mL and 100% at 0.6 mg/mL. The active fraction 13 of petroleum ether fraction was identified as alkylresorcinols (ARs). ARs showed strong inhibition towards α-glucosidase and its IC 50 value was found to be 37.58 ΅g/mL. The enzyme kinetic studies showed that, in the presence of ARs, the Michaelis-Menton constant (Km ) remains constant whereas the maximal velocity (Vmax ) decreases, revealing a non-competitive type of inhibition. Conclusion: The therapeutic potentiality of ARs in the management of the postprandial hyperglycemia will proliferate the utilization of wheat bran in controlling type 2 diabetes. |