Bioactive Peptide F2d Isolated from Rice Residue Exerts Antioxidant Effects via Nrf2 Signaling Pathway.

Jinliang Liu,Ting Guo,Feijun Luo,Yaping Zhou,Qinlu Lin,Yi Luo,Tianyi Guo,Feiyan Yang,Shuai Han,Tao Yang,Qiang Wu,Ana Lloret

doi:10.1155/2021/2637577

Abstract

Studies have shown that the peroxidation caused by oxygen free radicals is an important reason of vascular endothelial dysfunction and multiple diseases. In this study, active peptides (F2ds) were isolated from the fermentation product of rice dregs and its antioxidant effects were approved. Human umbilical vein endothelial cells (HUVECs) stimulated by H2O2 were used to evaluate the antioxidation effect and its molecular mechanism in the oxidative stress model. F2d protected H2O2-induced damage in HUVECs in a dosage-dependent manner. F2d can reduce the expression of Keap1, promote the expression of Nrf2, and activate the downstream target HO-1, NQO1, etc. It means F2d can modulate the Nrf2 signaling pathway. Using Nrf2 inhibitor ML385 to block the Nrf2 activation, the protective function of F2d is partially lost in the damage model. Our results indicated that F2d isolated from rice exerts antioxidant effects via the Nrf2 signaling pathway in H2O2-induced damage, and the work will benefit to develop functional foods.

Highlights

Rice residue is a by-product of rice processing and its protein content is up to 60%
Human umbilical vein endothelial cell Keap1 (HUVEC) cells in good condition in the logarithmic growth phase were inoculated in six-well plates after digestion; active peptide F2d was added to make the final concentration of F2d 0 μg/mL, 12.5 μg/mL, 25 μg/mL, and 50 μg/mL; and Hydrogen peroxide HO-1 (H2O2) was added; the total RNA was extracted according to the instruction manual of TRIzol kit after 12 h
The experimental results showed (Figure 8) that when F2d was treated with H2O2, the expression levels of Nuclear transcription-related factor 2 (Nrf2) and its downstream genes were significantly reduced after the inhibitor ML385 was added, which proved that ML385 blocks the protein

Summary

Introduction

Rice residue is a by-product of rice processing and its protein content is up to 60%. Tsai et al [16] isolated active peptide IF from potato and used hypertensive rat model to evaluate antioxidition of the peptide; they found that the Nrf2dependent antioxidant pathway played a potential protective role in the hypertension-related ROS-mediated renal damage. Based on these experiments, it was speculated that the antioxidant mechanism of active peptide from rice residue mediated through the Nrf signaling pathway. This article provides experimental basis for the role of active peptides from rice residues at the molecular and cellular levels through molecular biology methods, in order to provide new methods for the development and utilization of rice and its by-product and evidences for further research on active peptides from rice residues

Materials and Methods

Results

Discussion