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Cereal bioactive compounds, especially polyphenols, are known to possess a wide range of disease preventive properties that are attributed to their antioxidant and anti-inflammatory activity. However, due to their low plasma concentrations after oral intake, there is controversy regarding their therapeutic benefits in vivo. Within the gastrointestinal tract, some cereal polyphenols are absorbed in the small intestine, with the majority accumulating and metabolised by the colonic microbiota. Chemical and enzymatic processes occurring during gastrointestinal digestion modulate the bioactivity and bioaccessibility of phenolic compounds. The interactions between the cereal polyphenols and the intestinal epithelium allow the modulation of intestinal barrier function through antioxidant, anti-inflammatory activity and mucin production thereby improving intestinal health. The intestinal microbiota is believed to have a reciprocal interaction with polyphenols, wherein the microbiome produces bioactive and bioaccessible phenolic metabolites and the phenolic compound, in turn, modifies the microbiome composition favourably. Thus, the microbiome presents a key link between polyphenol consumption and the health benefits observed in metabolic conditions in numerous studies. This review will explore the therapeutic value of cereal polyphenols in conjunction with their bioaccessibility, impact on intestinal barrier function and interaction with the microbiome coupled with plasma anti-inflammatory effects.

Oxidative stress and inflammation are known to be linked to the development of chronic inflammatory conditions, such as type 2 diabetes and cardiovascular disease. Dietary polyphenols have been demonstrated to contain potent bioactivity against specific inflammatory pathways. Rice bran (RB), a by-product generated during the rice milling process, is normally used in animal feed or discarded due to its rancidity. However, RB is known to be abundant in bioactive polyphenols including phenolic acids. This study investigates the antioxidant and anti-inflammatory effects of RB phenolic extracts (25, 50, 100, and 250 &micro, g/mL) on RAW264.7 mouse macrophage cells stimulated with hydrogen peroxide and lipopolysaccharide. Biomarkers of oxidative stress and inflammation such as malondialdehyde (MDA), intracellular reactive oxygen species, nitric oxide and pro-inflammatory cytokines such as interleukin-6 (IL-6), monocyte chemoattractant protein 1 (MCP-1), interleukin-10 (IL-10), tumor necrosis factor-&alpha, (TNF-&alpha, ), interleukin-12, p70 (IL-12p70), and interferon-&gamma, (IFN-&gamma, ) were measured in vitro. Treatment with RB extracts significantly decreased the production of MDA, intracellular reactive oxygen species, nitric oxide and pro-inflammatory cytokines (IL-6, IL-12p70, and IFN-&gamma, ) when compared to the control. It is proposed that RB phenolic extracts, via their metal chelating properties and free radical scavenging activity, target pathways of oxidative stress and inflammation resulting in the alleviation of vascular inflammatory mediators.

Inflammation and oxidative stress are the primary underlying causes of several chronic inflammatory diseases. Dietary polyphenols have been demonstrated to possess anti-inflammatory and antioxidant potential. This study aims to determine if chickpea hull phenolic extracts (CHPE) can modulate biomarkers of inflammation and oxidative stress in RAW 264.7 murine macrophage cells. Cells were pre-treated with varying concentrations of CHPE (20, 50, 100, 250, and 500 μg/mL) before inducing inflammatory conditions using lipopolysaccharide (LPS). The antioxidant and anti-inflammatory properties of CHPE was determined by measuring the activity of antioxidant enzymes and the expression of inflammatory mediators. CHPE pre-treatment significantly increased the activity of catalase and glutathione peroxidase (GPx). Pre-treatment with CHPE also significantly reduced the production of inflammatory markers such as nitric oxide (NO) and interleukin-6 (IL-6). Results obtained from this study suggest that CHPE may alleviate oxidative stress and inflammation by regulating pro-inflammatory markers and antioxidant enzymes associated with chronic inflammation.

Oxidative stress, inflammation and endothelial dysfunction are associated with the development of cardiovascular and metabolic diseases. Phenolic extracts derived from rice bran (RB) are recognised to have antioxidant and anti-inflammatory potential. However, the underlying mechanisms remain unknown. Therefore, this study aimed to evaluate the ability of RB-derived phenolic extracts to modulate genes associated with antioxidant and anti-inflammatory pathways in human umbilical vein endothelial cells (HUVECs) under induced oxidative stress conditions. HUVECs under oxidative stress were treated with varying concentrations of RB phenolic extracts (25&ndash, 250 &micro, g/mL). Using quantitative real-time polymerase chain reaction, the expression of candidate genes that regulate antioxidant and anti-inflammatory pathways were determined. This included nuclear factor erythroid 2-related factor 2 (Nrf2), nicotinamide adenine dinucleotide phosphate: quinone oxidoreductase 1 (NQO1), heme oxygenase 1 (HO1), nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4), intercellular adhesion molecule 1 (ICAM1), endothelial nitric oxide synthase (eNOS), ectonucleoside triphosphate diphosphohydrolase 1 (CD39) and ecto-5&prime, nucleotidase (CD73). Phenolic extracts derived from RB down-regulated the expression of four genes, ICAM1, CD39, CD73 and NOX4 and up-regulated the expression of another four genes, Nrf2, NQO1, HO1 and eNOS, indicating an antioxidant/ anti-inflammatory effect for RB against endothelial dysfunction.