Antioxidative attributes of rice bran extracts in ameliorative effects of atherosclerosis-associated risk factors

Xian Wen Tan; Kazuko Kobayashi; Lianhua Shen; Junko Inagaki; Masahiro Ide; Siaw San Hwang; Eiji Matsuura

doi:10.1016/j.heliyon.2020.e05743

Antioxidative attributes of rice bran extracts in ameliorative effects of atherosclerosis-associated risk factors

Heliyon. 2020 Dec 21;6(12):e05743. doi: 10.1016/j.heliyon.2020.e05743. eCollection 2020 Dec.

Authors

Xian Wen Tan¹, Kazuko Kobayashi², Lianhua Shen³, Junko Inagaki¹, Masahiro Ide^{1

4}, Siaw San Hwang⁵, Eiji Matsuura^{1

2

6}

Affiliations

¹ Department of Cell Chemistry, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan.
² Collaborative Research Center for OMIC, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan.
³ Department of Pathophysiology, Zunyi Medical University, Guizhou, China.
⁴ Food Function Research Team, Saito Laboratories, Japan Food Research Laboratories, Osaka, Japan.
⁵ School of Chemical Engineering and Science, Faculty of Engineering, Computing and Science, Swinburne University of Technology Sarawak Campus, Sarawak, Malaysia.
⁶ Neutron Therapy Research Center, Okayama University, Okayama, Japan.

Abstract

Oxidative stress, chronic inflammation, dyslipidemia, hyperglycemia, and shear stress (physical effect) are risk factors associated with the pathogenesis of atherosclerosis. Rice bran, a by-product of rice milling process, is known to house polyphenols and vitamins which exhibit potent antioxidant and anti-inflammatory properties. Through recent emerging knowledge of rice bran in health and wellness, the present study was aimed to assess the ameliorative effects of rice bran extracts (RBE) derived from Japanese colored rice varieties in modulating risk factors of atherosclerosis via in vitro and in vivo study models. Pre-treatment of lipopolysaccharide (LPS)-stimulated murine J774A.1 macrophage-like cells with RBE alleviated nitric oxide (NO) overproduction and downregulated gene expressions of pro-inflammatory modulators: tumor necrosis factor-α (TNF-α), interleukin (IL)-α (IL-1α), IL-1β, IL-6, and inducible nitric oxide synthase (iNOS). In addition, RBE also significantly attenuated LPS-stimulated protein expressions of iNOS, TNF-α, IL-1α, and IL-6 in J774A.1 macrophage-like cells as compared to non-treated LPS control group. In in vivo, 12 weeks of RBE dietary supplementations significantly reduced (p < 0.05) total cholesterol, triglycerides, and pro-atherogenic oxidized LDL/β2-glycoprotein I (oxLDL/β2GPI) complexes at plasma levels, in high fat diet (HFD) induced low density lipoprotein receptor knockout (Ldlr ^-/-) mice. En face pathological assessments of murine aortas also revealed significant reductions by 38% (p < 0.05) in plaque sizes of RBE-supplemented HFD mice groups as compared to non RBE-supplemented HFD control mice group. Moreover, gene expressions of aortic (iNOS, TNF-α, IL-1β) and hepatic (TNF-α, IL-1α, IL-1β) pro-inflammatory modulators were also downregulated in RBE-supplemented mice groups. Present study has revealed the potent health attributes and application of RBE as a dietary supplement to attenuate risks of inadvertent oxidative damage and chronic inflammation underlying the pathogenesis of atherosclerosis. Intrinsically, present preliminary findings may provide global health prospects for future dietary implementation of RBE in management of atherosclerosis.

Keywords: Anti-inflammation; Antioxidant; Atherosclerosis; Food analysis; Food science; Functional food; Inflammation; Oxidative stress; Oxidized lipoprotein (oxLDL); Phytochemicals; Rice bran extract (RBE).