Isolation of a Novel Anti-Diabetic α-Glucosidase Oligo-Peptide Inhibitor from Fermented Rice Bran

Jingfei Hu; Xiaohua Lai; Xudong Wu; Huanyu Wang; Nanhai Weng; Jing Lu; Mingsheng Lyu; Shujun Wang

doi:10.3390/foods12010183

Isolation of a Novel Anti-Diabetic α-Glucosidase Oligo-Peptide Inhibitor from Fermented Rice Bran

Foods. 2023 Jan 1;12(1):183. doi: 10.3390/foods12010183.

Authors

Jingfei Hu^{1

2}, Xiaohua Lai^{1

2}, Xudong Wu^{1

2}, Huanyu Wang^{1

2}, Nanhai Weng^{1

2}, Jing Lu^{1

2}, Mingsheng Lyu^{1

2}, Shujun Wang^{1

2}

Affiliations

¹ Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang 222005, China.
² Co-Innovation Center of Jiangsu Marine Bio-Industry Technology, Jiangsu Ocean University, Lianyungang 222005, China.

Abstract

At present, the incidence rate of diabetes is increasing gradually, and inhibiting α-glucosidase is one of the effective methods used to control blood sugar. This study identified new peptides from rice bran fermentation broth and evaluated their inhibitory activity and mechanism against α-glucosidase. Rice bran was fermented with Bacillus subtilis MK15 and the polypeptides of <3 kDa were isolated by ultrafiltration and chromatographic column, and were then subjected to LC-MS/MS mass spectrometry analysis. The results revealed that the oligopeptide GLLGY showed the greatest inhibitory activity in vitro. Docking studies with GLLGY on human α-glucosidase (PDB ID 5NN8) suggested a binding energy of −7.1 kcal/mol. GLLGY acts as a non-competitive inhibitor and forms five hydrogen bonds with Asp282, Ser523, Asp616, and His674 of α-glucosidase. Moreover, it retained its inhibitory activity even in a simulated digestion environment in vitro. The oligopeptide GLLGY could be developed into a potential anti-diabetic agent.

Keywords: Bacillus subtilis; bioactive oligo-peptides; molecular docking; rice bran; α-glucosidase.

Abstract

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