Abstract
BACKGROUND: The production of rice-derived by-products has increased owing to the growing use of processed rice products. The objective of this study was to isolate highly purified proteins from a rice by-product, rice syrup meal, and to examine their hepatoprotective effects in vitro and in vivo. RESULTS: Soluble rice protein (SRP70) was obtained via enzymatic processing of rice syrup meal using Termamyl SC and Alcalase. Mass spectrometry analysis showed that SRP70 contained low-molecular-weight (<600Da) peptides. SRP70 did not affect the viability of rat primary hepatocytes and ameliorated tert-butyl hydroperoxide (t-BHP)-induced cytotoxicity. t-BHP-induced elevations in hepatocyte alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase activities were reduced by SRP70 in a dose-dependent manner. In addition, t-BHP exposure increased the level of malondialdehyde, a toxic reactive aldehyde, which was dose-dependently decreased by SRP70 treatment. These SRP70-induced decreases in biochemical parameters were also observed in vivo in mice. In particular, SRP70 increased the activities of liver antioxidant enzymes in t-BHP-treated mice, including catalase and glutathione peroxidase, as well as increasing the level of glutathione, an antioxidant peptide. SRP70-mediated activation of antioxidant enzymes was shown to be due to the up-regulation in their gene expressions, while nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) oxidase 4 (NOX4), a pro-oxidant enzyme, was down-regulated by SRP70. Hematoxylin and eosin staining also showed that SRP70 protected the liver from histopathological changes induced by t-BHP. CONCLUSION: Taken together, these data showed that SRP70, which is derived from a rice-processing by-product, had hepatoprotective effects in vitro and in vivo.
Original language | English |
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Pages (from-to) | 685-694 |
Number of pages | 10 |
Journal | Journal of the Science of Food and Agriculture |
Volume | 96 |
Issue number | 2 |
DOIs | |
Publication status | Published - 2016 Jan 30 |
Bibliographical note
Publisher Copyright:© 2015 Society of Chemical Industry.
Keywords
- Hepatoprotective effect
- Mice
- Primary hepatocytes
- SRP70
- t-BHP
ASJC Scopus subject areas
- Biotechnology
- Food Science
- Agronomy and Crop Science
- Nutrition and Dietetics