Rice Bran Phenolic Compounds Regulate Genes Associated with Antioxidant and Anti-Inflammatory Activity in Human Umbilical Vein Endothelial Cells with Induced Oxidative Stress.

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 (25-250 µg/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'-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.

Polyphenols: Modulators of Platelet Function and Platelet Microparticle Generation?

Platelets and platelet microparticles (PMPs) play a key role in the pathophysiology of vascular disorders such as coronary artery disease and stroke. In atherosclerosis, for example, the disruption of the plaque exposes endogenous agonists such as collagen, which activates platelets. Platelet hyper-activation and the high levels of PMPs generated in such situations pose a thrombotic risk that can lead to strokes or myocardial infarctions. Interestingly, dietary polyphenols are gaining much attention due to their potential to mimic the antiplatelet activity of treatment drugs such as aspirin and clopidogrel that target the glycoprotein VI (GPVI)-collagen and cyclooxygenease-1 (COX-1)-thromboxane platelet activation pathways respectively. Platelet function tests such as aggregometry and flow cytometry used to monitor the efficacy of antiplatelet drugs can also be used to assess the antiplatelet potential of dietary polyphenols. Despite the low bioavailability of polyphenols, several in vitro and dietary intervention studies have reported antiplatelet effects of polyphenols. This review presents a summary of platelet function in terms of aggregation, secretion, activation marker expression, and PMP release. Furthermore, the review will critically evaluate studies demonstrating the impact of polyphenols on aggregation and PMP release.

Chemopreventive Potential of Cereal Polyphenols.

It has been identified that diet is one of the major contributing factors associated with the development of cancer and other chronic pathologies. In the recent years, supplementing regular diet with food and/or its components that contain chemopreventive properties has been considered an effective approach in reducing the incidence of cancer and other lifestyle associated diseases. This systematic review provides an exhaustive summary of the chemopreventive properties exhibited by everyday dietary ingredients such as rice, barley, oats, and sorghum. The studies both in vitro and in vivo reviewed have highlighted the potential role of their polyphenolic content as chemopreventive agents. Polyphenolic compounds including anthocyanins, tricin, protocatechualdehyde, avenanthramide, and 3-deoxyanthocyanins found in rice, barley, oats, and sorghum, respectively, were identified as compounds with potent bioactivity. Studies demonstrated that cereal polyphenols are likely to have chemopreventive activities, particularly those found in pigmented varieties. In conclusion, findings suggest that the consumption of pigmented cereals could potentially have an important role as a natural complementary cancer preventive therapeutic. However, further studies to develop a complete understanding of the mechanisms by which phenolic compounds inhibit cancerous cell proliferation are warranted.

The effect of anthocyanin supplementation in modulating platelet function in sedentary population: a randomised, double-blind, placebo-controlled, cross-over trial.

The anti-thrombotic properties of anthocyanin (ACN) supplementation was evaluated in this randomised, double-blind, placebo (PBO) controlled, cross-over design, dietary intervention trial in sedentary population. In all, sixteen participants (three males and thirteen females) consumed ACN (320 mg/d) or PBO capsules for 28 d followed by a 2-week wash-out period. Biomarkers of thrombogenesis and platelet activation induced by ADP; platelet aggregation induced by ADP, collagen and arachidonic acid; biochemical, lipid, inflammatory and coagulation profile were evaluated before and after supplementation. ACN supplementation reduced monocyte-platelet aggregate formation by 39 %; inhibited platelet endothelial cell adhesion molecule-1 expression by 14 %; reduced platelet activation-dependant conformational change and degranulation by reducing procaspase activating compound-1 (PAC-1) (↓10 %) and P-selectin expression (↓14 %), respectively; and reduced ADP-induced whole blood platelet aggregation by 29 %. Arachidonic acid and collagen-induced platelet aggregation; biochemical, lipid, inflammatory and coagulation parameters did not change post-ACN supplementation. PBO treatment did not have an effect on the parameters tested. The findings suggest that dietary ACN supplementation has the potential to alleviate biomarkers of thrombogenesis, platelet hyperactivation and hyper-aggregation in sedentary population.

Mildly elevated unconjugated bilirubin is associated with reduced platelet activation-related thrombogenesis and inflammation in Gilbert's syndrome.

Gilbert's syndrome (GS) is associated with a mild unconjugated hyperbilirubinemia, increased circulating antioxidant capacity, and reduced cardiovascular disease (CVD) risk. The current study investigated whether mildly elevated circulating unconjugated bilirubin (UCB) is negatively associated with multiple thrombotic risk factors including platelet activity, hemostatic function, and inflammation in individuals with GS. Blood samples were collected from matched GS and control subjects (14 per group). Activation-dependent platelet surface marker expression of PAC-1 (binds to GPIIb/IIIa surface receptors on activated platelets) and CD62P (marker for P-selectin released from activated degranulated platelets) was assessed in adenosine diphosphate (ADP)-stimulated platelets using flow cytometry. Exogenous agonists, ADP, collagen, and arachidonic acid (AA), were used to stimulate platelet aggregation. A statistically significant decrease in the expression of P-selectin (P = 0.030) on activated platelets was observed in GS subjects. Collagen and AA-induced platelet aggregation were significantly (P = 0.018; P = 0.032 for respective agonists) reduced in GS versus control group. Elevated UCB (P = 0.001) and high density lipoprotein (P = 0.033) in addition to reduced low density lipoprotein (P = 0.024) and high sensitive C-reactive protein (P = 0.043) were also observed in GS when compared to the control group. Reduced P-selectin expression suggests decreased platelet activation-dependent degranulation, while reduced platelet aggregation by AA and collagen indicates a quantitative decrease in platelet aggregation consequently targeting the cyclooxygenase-1 and GP VI pathways, respectively. These findings are the first to demonstrate that the activation of platelets is mildly inhibited in individuals with GS, an effect that might contribute to protection from platelet hyperactivation-induced thrombosis and thus cardiovascular mortality in individuals with benign hyperbilirubinemia.

Black Sorghum Phenolic Extract Modulates Platelet Activation and Platelet Microparticle Release.

Platelet hyper-activation and platelet microparticles (PMPs) play a key role in the pathogenesis of cardiovascular diseases. Dietary polyphenols are believed to mimic antiplatelet agents by blunting platelet activation receptors via its antioxidant phenomenon. However, there is limited information on the anti-platelet activity of grain-derived polyphenols. The aim of the study is to evaluate the effects of sorghum extract (Shawaya short black 1 variety), an extract previously characterised for its high antioxidant activity and reduction of oxidative stress-related endothelial dysfunction, on platelet aggregation, platelet activation and PMP release. Whole blood samples collected from 18 healthy volunteers were treated with varying non-cytotoxic concentrations of polyphenol-rich black sorghum extract (BSE). Platelet aggregation study utilised 5 µg/mL collagen to target the GPVI pathway of thrombus formation whereas adenine phosphate (ADP) was used to stimulate the P2Y1/P2Y12 pathway of platelet activation assessed by flow cytometry. Procaspase-activating compound 1 (PAC-1) and P-selectin/CD62P were used to evaluate platelet activation- related conformational changes and degranulation respectively. PMPs were isolated from unstimulated platelets and quantified by size distribution and binding to CD42b. BSE treatment significantly reduced both collagen-induced platelet aggregation and circulatory PMP release at 40 µg/mL (p < 0.001) when compared to control. However, there was no significant impact of BSE on ADP-induced activation-dependent conformational change and degranulation of platelets. Results of this study suggest that phenolic rich BSE may confer cardio-protection by modulating specific signalling pathways involved in platelet activation and PMP release.

Rice Bran Phenolic Extracts Modulate Insulin Secretion and Gene Expression Associated with ß-Cell Function.

Oxidative stress is known to modulate insulin secretion and initiate gene alterations resulting in impairment of ß-cell function and type 2 diabetes mellitus (T2DM). Rice bran (RB) phenolic extracts contain bioactive properties that may target metabolic pathways associated with the pathogenesis of T2DM. This study aimed to examine the effect of stabilized RB phenolic extracts on the expression of genes associated with ß-cell function such as glucose transporter 2 (Glut2), pancreatic and duodenal homeobox 1 (Pdx1), sirtuin 1 (Sirt1), mitochondrial transcription factor A (Tfam), and insulin 1 (Ins1) in addition to evaluating its impact on glucose-stimulated insulin secretion. It was observed that treatment with different concentrations of RB phenolic extracts (25-250 µg/mL) significantly increased the expression of Glut2, Pdx1, Sirt1, Tfam, and Ins1 genes and glucose-stimulated insulin secretion under both normal and high glucose conditions. RB phenolic extracts favourably modulated the expression of genes involved in ß-cell dysfunction and insulin secretion via several mechanisms such as synergistic action of polyphenols targeting signalling molecules, decreasing free radical damage by its antioxidant activity, and stimulation of effectors or survival factors of insulin secretion.

The Antioxidant and Anti-Inflammatory Properties of Rice Bran Phenolic Extracts.

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 µg/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-α (TNF-α), interleukin-12, p70 (IL-12p70), and interferon-γ (IFN-γ) 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-γ) 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.

The anti-inflammatory and antioxidant effects of acute consumption of pigmented rice in humans.

The pathogenesis of lifestyle diseases has been significantly correlated to high levels of oxidative stress and pro-inflammation. The antioxidant and anti-inflammatory properties of polyphenols in coloured rice varieties could have potential to neutralize oxidative stress and modulate inflammatory responses. A cross-over design, randomised, dietary intervention human clinical trial was conducted on a pre-screened healthy population (n = 24) investigating the antioxidant and anti-inflammatory potential of pigmented rice (purple, red and brown) varieties. Post baseline blood samples collection volunteers consumed a serve of cooked pigmented rice. Blood samples were collected at 30-minutes, 1, 2 and 4-hours post rice consumption. A one-week wash-out period between each supplementation bout (rice variety) was conducted. Blood and biochemical parameters were analysed on baseline blood samples. Antioxidant activity, malondialdehyde (MDA) and a pro-inflammatory cytokine panel were analysed on the blood samples collected. Post purple rice consumption, antioxidant activity increased (p < 0.0001) by 70.5% and maintained elevated for all time points. The red rice variety Yunlu29, significantly (p < 0.005) reduced MDA levels by 9.2% at the 30-minute time point. Purple rice demonstrated a significant (p < 0.05) decrease by 4.0% at the 30-minute time point only. Purple rice significantly decreased TNF-α levels at the 1-hour (p < 0.05) and 4-hour (p < 0.005) time points by 21.9% and 25.4% respectively. IL-6 concentrations were significantly reduced at 1 and 2-hour post Purple (p < 0.05; 11.7%) and Yunlu29 (red) (p < 0.01; 14.1%) consumption respectively. The brown rice variety did not affect any parameters tested. The outcomes of this study, highlight that polyphenols found in pigmented rice may play a key role in targeting specific oxidative stress and inflammatory therapeutic pathways. Pigmented rice varieties may serve as a potential functional food in reducing risk factors associated with lifestyle diseases.

Rice Bran Derived Bioactive Compounds Modulate Risk Factors of Cardiovascular Disease and Type 2 Diabetes Mellitus: An Updated Review.

Cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM) are two chronic diseases that have claimed more lives globally than any other disease. Dietary supplementation of functional foods containing bioactive compounds is recognised to result in improvements in free-radical-mediated oxidative stress. Emerging evidence indicates that bioactive compounds derived from rice bran (RB) have therapeutic potential against cellular oxidative stress. This review aims to describe the mechanistic pathways behind CVD and T2DM development and the therapeutic potential of polyphenols derived from RB against these chronic diseases.

The anti-inflammatory and antioxidant effects of pigmented rice consumption in an obese cohort.

The development of lifestyle diseases in the obese has been attributed to higher levels of inflammation and free radical mediated oxidative stress. The antioxidant and anti-inflammatory properties of polyphenols in pigmented rice varieties could have potential to neutralize oxidative stress and modulate inflammatory responses in the obese. A cross-over dietary intervention human clinical trial was conducted with three pigmented rice varieties chosen from previous chemical and in vitro antioxidant and anti-inflammatory screening. Obese (n = 22, BMI > 30) sedentary participants consumed one cup of pigmented rice (Reiziq (brown), Purple (purple) and Yunlu29 (red)). Blood samples were collected prior consumption (baseline) and at set time points of 30 minutes, 1 hour, 2 hours and 4 hours post rice consumption. The collected blood samples were analysed for antioxidant and inflammatory biomarkers. Total antioxidant activity increased (p < 0.001) at the 1 hour time point by 40.3% post purple rice consumption. The red rice variety, Yunlu29 increased antioxidant activity at the 30 minute (p < 0.001) and 1 hour (p < 0.01) time point by 29.5% and 21.2% respectively. Lipid peroxidation biomarker, malondialdehyde (MDA), decreased (p < 0.05) at the 30 minute time point by 6.8% post purple rice consumption. At the 4 hour time point MDA levels was significantly reduced (p < 0.001) by the red rice variety Yunlu29, by 9.6%. Pro-inflammatory cytokine, interleukin-10 (IL-10), was significantly (p < 0.0001) reduced by 3.1% 30 minutes post purple rice consumption. In contrast, Yunlu29 (red) reduced interleukin-6 levels by 13.6% and 11.0% at the 30 minute and 1 hour time points respectively. Both the purple (p < 0.01) and red (p < 0.001) varieties significantly reduced interleukin-12p70 concentrations at 30 minutes by 8.7% and 10.3% respectively. Reiziq (brown) did not affect any of the biomarkers analysed in this study. The outcomes of this study highlight that polyphenols found in pigmented rice may play a key role in targeting specific therapeutic pathways in obesity-related oxidative stress and inflammation.

Dietary polyphenols: Structures, bioavailability and protective effects against atherosclerosis.

Epidemiological studies have demonstrated that nutritional habits, like those based on high consumption of fruits and vegetables, have been associated with a longer life expectancy and a significant decrease in the incidence and prevalence of several chronic diseases with inflammatory basis, such as cardiovascular diseases (CVD). This beneficial activity has been related to the content of several bioactive compounds in fruit and vegetables, such as polyphenols. The cardioprotective effects of polyphenols have been linked mainly to its antioxidant properties; however, recent findings attribute its anti-atherosclerotic potential to modulate simultaneous signaling and mechanistic pathways. Emerging data suggest that polyphenols can regulate cellular lipid metabolism; vascular and endothelial function; haemostasis; as well as platelet function; which represent primary conditions for atherosclerotic plaque formation and development. This review presents the results of a selection of experimental studies and clinical trials regarding the atheroprotective effects of the most common dietary polyphenols.

Q-TOF LC/MS identification and UHPLC-Online ABTS antioxidant activity guided mapping of barley polyphenols.

The polyphenol composition and antioxidant activity of seven Australian-grown barley varieties were characterized in this study. UHPLC with an online ABTS system was used to identify individual polyphenols while simultaneously measuring their antioxidant activity. The Q-TOF LC/MS system was utilized to identify the phenolic compounds that demonstrated substantial antioxidant activity. The variety, Hindmarsh, showed the highest total phenolic content and antioxidant activity. There was no significant difference observed amongst the other varieties in their total phenolic content, however, they did have significant variation in proanthocyanidin content and antioxidant activity (p < 0.05). Prodelphinidin B3 was the most abundant polyphenol with the highest antioxidant activity amongst all the barley varieties tested. Other polyphenols identified with antioxidant activity included procyanidin, glycosides of catechin and flavan-3-ols. Polyphenol characterization of Australian grown barley varieties demonstrated that they have significant antioxidant activity, hence, promoting the value of whole grain barley as a potential functional food ingredient.

Pigmented Rice-Derived Phenolic Compounds Reduce Biomarkers of Oxidative Stress and Inflammation in Human Umbilical Vein Endothelial Cells.

SCOPE: Endothelial dysfunction pathogenesis is significantly associated with increased oxidative stress (OS) and inflammation. Rice-derived phenolic compounds have been demonstrated to have antioxidant and anti-inflammatory potential. This study aims to determine if phenolic extracts (PE) from pigmented rice varieties (Purple, Yunlu29-red, and Reiziq-brown) at varying concentrations modulate biomarkers of OS and inflammation in human umbilical vein endothelial cells under induced OS conditions. METHODS AND RESULTS: 2,7-dichlorofluorescein diacetate and superoxide dismutase-1 (SOD-1) enzyme-linked immuno-sorbent assay quantification demonstrate that Purple PE significantly decreases reactive oxygen species and increases SOD-1 by 27% and 226%, respectively. Yunlu29 PE (50 µg mL-1 ) is the most effective in reducing (p < 0.0001) interleukin-8 (61%) and interleukin-6 (57.2%). Yunlu29 (50 µg mL-1 ) reduces intracellular-adhesion molecule-1 (p < 0.0001) expression by 34%, followed by Reiziq (31.9%) and Purple (30.2%). Flow cytometric analysis demonstrates that vascular cell-adhesion molecule-1 expression is reduced (p < 0.0001) by 53.5% by Yunlu29 followed by Purple (46.8%) and Reiziq (46.7%). Yunlu29 is the most effective in reducing nuclear factor kappa-B expression by 50.1%, followed by purple (48.8%) and Reiziq (38.6%). CONCLUSION: This study indicates that colored rice PE may potentially target OS and inflammatory pathways associated with the pathogenesis of endothelial dysfunction.

Inhibitory Effects of Pulse Bioactive Compounds on Cancer Development Pathways.

Previous studies suggest that pulses may have the potential to protect against cancer development by inhibiting pathways that result in the development of cancer. These pathways include those that result in inflammation, DNA damage, cell proliferation, and metastasis. Other studies have demonstrated extracts from pulses have the capacity to induce apoptosis specifically in cancer cells. Compounds reported to be responsible for these activities have included phenolic compounds, proteins and short chain fatty acids. The majority of the studies have been undertaken using in vitro cell culture models, however, there are a small number of in vivo studies that support the hypothesis that pulse consumption may inhibit cancer development. This review highlights the potential benefit of a diet rich in pulse bioactive compounds by exploring the anti-cancer properties of its polyphenols, proteins and short chain fatty acids.

Coloured rice-derived polyphenols reduce lipid peroxidation and pro-inflammatory cytokines ex vivo.

Rice-derived polyphenols have been demonstrated to alleviate obesity-related oxidative stress and inflammation. The aim of the study was to investigate if coloured rice polyphenol extracts (PE) reduce malondialdehyde, interleukin-6 and tumour necrosis factor-α (TNF-α) levels in obese individuals ex vivo. Malondialdehyde and pro-inflammatory cytokines were quantified using high-performance liquid chromatography and flow cytometry respectively. Fasting blood samples were treated with PE from three coloured rice varieties (purple, red and brown rice) at varying concentrations (10, 20, 50, 100, 200 and 500 µg mL-1). PE treatment demonstrated a dose-dependent reduction in malondialdehyde and TNF-α levels. Purple PE reduced plasma malondialdehyde concentration by 59% compared to red (21%) and brown (25.5%) rice PE. Brown rice PE at 50 µg mL-1 reduced TNF-α levels by 98% compared to red (80%) and purple rice PE (74%). Rice PE did not modulate plasma interleukin-6 concentrations. Coloured rice may be of therapeutic benefit as a potential functional food alternative in targeting specific pathways associated with obesity.