Proceedings of The Physiological Society

Europhysiology 2018 (London, UK) (2018) Proc Physiol Soc 41, PCA158

Poster Communications

Rice bran protein hydrolysates exhibit antioxidant and modulatory effects on lymphocyte activation and proliferation

V. Kukongviriyapan1, P. Samatiwat2, K. Boonloh1, U. Kukongviriyapan3, C. Thongraung4

1. Department of Pharmacology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Khon Kaen, Thailand. 2. Department of Pharmacology, Faculty of Medicine, Srinakharinwirot University, Bangkok, Thailand. 3. Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand. 4. Department of Food Technology, Faculty of Agro-industry, Prince of Songkla University, Songkla, Thailand.

Maintenance of immune cell homeostasis is essential in protection of various diseases. Rice bran, the bye-product from rice milling process contains a number of biologically active compounds. Protein is an important component of rice bran possessing nutritional and non-nutritional constituents. Protein from non-glutinous rice is suggested to be hypoallergenic and confers insulin sensitizing effect, vascular protection and antihypertension. The study was conducted to investigate whether protein from rice bran affect immunological functions of lymphocytes. Protein was extracted from a cold-pressed defatted Thai Sung-Yod rice bran. Rice bran was subjected to alkaline solubilization and proteolysis by protease enzyme. The rice bran protein hydrolysates (RBH) were freeze-dried for long-term storage. RBH showed the radical scavenging activity with EC50 of 0.35±0.09 mg/mL, compared with ascorbate of 5.0±2 μg/mL by diphenylpicrylhydrazyl assay and possessed a reducing power as ascorbate equivalent to 15±0.3 mg/g RBH by ferric reducing antioxidant power assay. RBH suppressed nitric oxide formation in murine RAW 264.7 cells induced by lipopolysaccharide and inhibited human lymphocyte proliferation induced by phytohemagglutinin (PHA) or combination of anti-CD3/anti-CD28 antibodies. Moreover, PHA remarkably induced increased expression of IL-2, IFN-γ and IL-4 in lymphocytes by 36.1±5.1, 64.0±24.2 and 12.7±8.4 fold from controls at 6 h of incubation, where RBH significantly suppressed the induction of cytokines by 42.1±2.5, and 49.9±4.0 and 46.2±10.3 % of the induced state, respectively. RBH from Sung-Yod rice bran have a potential effect in modulating the dysregulated immune cell function.

Where applicable, experiments conform with Society ethical requirements