Avenanthramide supplementation attenuates eccentric exercise-inflicted blood inflammatory markers in women

Phenolic amides (avenanthramides) in oats - an update review

Oats (Avena sativa L.) are one of the worldwide cereal crops. Avenanthramides (AVNs), the unique plant alkaloids of secondary metabolites found in oats, are nutritionally important for humans and animals. Numerous bioactivities of AVNs have been investigated and demonstrated in vivo and in vitro. Despite all these, researchers from all over the world are taking efforts to learn more knowledge about AVNs. In this work, we highlighted the recent updated findings that have increased our understanding of AVNs bioactivity, distribution, and especially the AVNs biosynthesis. Since the limits content of AVNs in oats strictly hinders the demand, understanding the mechanisms underlying AVN biosynthesis is important not only for developing a renewable, sustainable, and environmentally friendly source in both plants and microorganisms but also for designing effective strategies for enhancing their production via induction and metabolic engineering. Future directions for improving AVN production in native producers and heterologous systems for food and feed use are also discussed. This summary will provide a broad view of these specific natural products from oats.

Drug discovery inspired by bioactive small molecules from nature

Natural products (NPs) have greatly contributed to the development of novel treatments for human diseases such as cancer, metabolic disorders, and infections. Compared to synthetic chemical compounds, primary and secondary metabolites from medicinal plants, fungi, microorganisms, and our bodies are promising resources with immense chemical diversity and favorable properties for drug development. In addition to the well-validated significance of secondary metabolites, endogenous small molecules derived from central metabolism and signaling events have shown great potential as drug candidates due to their unique metabolite-protein interactions. In this short review, we highlight the values of NPs, discuss recent scientific and technological advances including metabolomics tools, chemoproteomics approaches, and artificial intelligence-based computation platforms, and explore potential strategies to overcome the current challenges in NP-driven drug discovery.

Coarse cereals modulating chronic low-grade inflammation: review

Chronic low-grade inflammation (CLGI) is closely associated with various chronic diseases. Researchers have paid attention to the comprehensive application and development of food materials with potential anti-inflammatory activity. Owing to their abundant nutrients and biological activities, coarse cereals have emerged as an important component of human diet. Increasing evidence has revealed their potential protective effects against CLGI in chronic conditions. However, this property has not been systematically discussed and summarized. In the present work, numerous published reports were reviewed to systematically analyze and summarize the protective effects of coarse cereals and their main active ingredients against CLGI. Their current utilization state was investigated. The future prospects, such as the synergistic effects among the active compounds in coarse cereals and the biomarker signatures of CLGI, were also discussed. Coarse cereals show promise as food diet resources for preventing CLGI in diseased individuals. Their active ingredients, including β-glucan, resistant starch, arabinoxylan, phenolic acids, flavonoids, phytosterols and lignans, function against CLGI through multiple possible intracellular signaling pathways and immunomodulatory effects. Therefore, coarse cereals play a crucial role in the food industry due to their health effects on chronic diseases and are worthy of further development for possible application in modulating chronic inflammation.

The effects of whole-body vibration amplitude on glucose metabolism, inflammation, and skeletal muscle oxygenation

Whole-body vibration (WBV) is an exercise mimetic that elicits beneficial metabolic effects. This study aims to investigate the effects of WBV amplitude on metabolic, inflammatory, and muscle oxygenation responses. Forty women and men were assigned to a high (HI; n = 20, Age: 31 ± 6 y) or a low-amplitude group (LO; n = 20, Age: 33 ± 6 y). Participants engaged in 10 cycles of WBV [1 cycle =1 min of vibration followed by 30 s of rest], while gastrocnemius muscle oxygen consumption (mVO2 ) was assessed using near-infrared spectroscopy (NIRS). Blood samples were collected PRE, POST, 1H, 3Hs, and 24H post-WBV and analyzed for insulin, glucose, and IL-6. In the LO group, Homeostatic Model Assessment for Insulin Resistant (HOMA-IR) at 3 h (0.7 ± 0.2) was significantly lower compared to PRE (1.1 ± 0.2; p = 0.018), POST (1.3 ± 0.3; p = 0.045), 1H (1.3 ± 0.3; p = 0.010), and 24H (1.4 ± 0.2; p < 0.001). In addition, at 24H, HOMA-IR was significantly lower in the LO when compared to the HI group (LO: 1.4 ± 0.2 vs. HI: 2.2 ± 0.4; p = 0.030). mVO2 was higher (p = 0.003) in the LO (0.93 ± 0.29 ml/min/100 ml) when compared to the HI group (0.63 ± 0.28 ml/min/100 ml). IL-6 at 3H (LO: 13.2 ± 2.7 vs. HI: 19.6 ± 4.0 pg·ml-1 ; p = 0.045) and 24H (LO: 4.2 ± 1.1 vs. HI: 12.5 ± 3.1 pg·ml-1 ; p = 0.016) was greater in the HI compared to the LO group. These findings indicate that low-amplitude WBV provides greater metabolic benefits compared to high-amplitude WBV.

The Progress of Nomenclature, Structure, Metabolism, and Bioactivities of Oat Novel Phytochemical: Avenanthramides

Oats are among the most commonly consumed whole grains and are widely grown worldwide, and they contain numerous nutrients, including proteins, lipids, vitamins, minerals, β-glucan, and unique phytochemical polyphenol avenanthramides (Avns). Recent studies have indicated that Avns play essential roles in mediating the health benefits of oats. This review systemically summarized the nomenclature and structures of Avns, effect of germination on promoting Avns production, and in vivo metabolites produced after Avns consumption. The classical functions and novel potential bioactivities of Avns were further elucidated. The classical functions of Avns in cancer prevention, antioxidative response, anti-inflammatory reaction, and maintaining muscle health were expounded, and the internal mechanisms of these functions were analyzed. The potential novel bioactivities of Avns in modulating gut microbiota, alleviating obesity, and preventing chronic diseases, such as atherosclerosis and osteoporosis, were further revealed. This review may provide new prospects and directions for the development and utilization of oat Avns.

A Review of Health-Beneficial Properties of Oats

Oat is among the food crops and ancient grains cultivated and consumed worldwide. It is gaining in popularity owing to its nutritional composition and multifunctional benefits of select bioactive compounds. Beta-glucan is an important component of dietary fiber found in oat grains. It is the major active compound in oats with proven cholesterol-lowering and antidiabetic effects. Oats also provide substantial levels of other bioactive compounds such as phenolic acids, tocols, sterols, avenacosides, and avenanthramides. The consumption of oats has been determined to be beneficial for human health by promoting immunomodulation and improving gut microbiota. In addition, oat consumption assists in preventing diseases such as atherosclerosis, dermatitis, and some forms of cancer. While much has been published in relation to oat nutrients and oat fibers and their impact on major diseases, the oat industries and consumers may benefit from greater knowledge and understanding of clinical effects, range of occurrence, distribution, therapeutic doses and food functional attributes of other oat bioactives such as avenanthramides and saponins as well as other anti-inflammatory agents found in the cereal. This review focuses on the various studies relevant to the contribution of the consumption of oats and oat-based products in preventing human diseases and promoting human health.

Effects of Oats (Avena sativa L.) on Inflammation: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: Oat and its compounds have been found to have anti-inflammatory effects. Through this systematic review and meta-analysis, we aimed to determine an evidence-based link between oat consumption and inflammatory markers. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. By the end of April 2021, we included randomized controlled trials (RCTs) that investigated the anti-inflammatory effect of oat and oat-related products through screening PubMed, Embase, Web of Science, ClinicalTrial.gov, and CENTRAL. Meta-analysis was conducted with a random-effect model on the standardized mean difference (SMD) of the change scores of inflammatory markers, including C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-8 (IL-8). Subgroup analyses were conducted to stratify confounding variables. The risk of bias was evaluated using the Cochrane risk of bias tool and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was applied to report the quality of evidence. This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO; CRD42021245844). Results: Systematic screening of five databases yielded 4,119 studies, of which 23 RCTs were finally selected. For the four systemic inflammatory markers analyzed, no significant alterations were found after oat consumption. However, oat intake was found to significantly decrease CRP levels in subjects with one or more health complications (SMD: -0.18; 95% CI: -0.36, 0.00; P = 0.05; I ² = 10%). Furthermore, IL-6 levels were significantly decreased in subjects with dyslipidemia (SMD = -0.34; 95% CI: -0.59, -0.10; P = 0.006; I ² = 0%). These beneficial effects might be attributed to the effects of avenanthramide and β-glucan. Conclusions: Overall evidence supporting the alleviation of inflammatory response by oat intake was poor, calling for future studies including a larger sample size to confirm the findings.

Effects of Dietary Strategies on Exercise-Induced Oxidative Stress: A Narrative Review of Human Studies

Exhaustive exercise can induce excessive generation of reactive oxygen species (ROS), which may enhance oxidative stress levels. Although physiological levels are crucial for optimal cell signaling and exercise adaptations, higher concentrations have been demonstrated to damage macromolecules and thus facilitate detrimental effects. Besides single dosages of antioxidants, whole diets rich in antioxidants are gaining more attention due to their practicality and multicomponent ingredients. The purpose of this narrative review is to summarize the current state of research on this topic and present recent advances regarding the antioxidant effects of whole dietary strategies on exercise-induced oxidative stress in humans. The following electronic databases were searched from inception to February 2021: PubMed, Scope and Web of Science. Twenty-eight studies were included in this narrative review and demonstrated the scavenging effects of exercise-induced ROS generation, oxidative stress markers, inflammatory markers and antioxidant capacity, with only one study not confirming such positive effects. Although the literature is still scarce about the effects of whole dietary strategies on exercise-induced oxidative stress, the majority of the studies demonstrated favorable effects. Nevertheless, the protocols are still very heterogeneous and further systematically designed studies are needed to strengthen the evidence.

Avenanthramide C Suppresses Matrix Metalloproteinase-9 Expression and Migration Through the MAPK/NF- κB Signaling Pathway in TNF-α-Activated HASMC Cells

In oat ingredients, flavonoids and phenolic acids are known to be the most important phenolic compounds. In phenolic compounds, wide-ranging biological responses, including antioxidative, anti-inflammatory, anti-allergic, and anti-cancer properties, were reported. Avenanthramide C (Avn C), a component of the phenolic compound of oats, has been reported to be highly antioxidant and anti-inflammatory, but its role in an anti-atherosclerosis response is unknown. The aim of this research was to assess the effect of Avn C on expression of MMP-9 on TNF-α-activated human arterial smooth-muscle cells (HASMC) and signaling involved in its anti-atherosclerosis activity. HASMC cells are known to produce inflammatory cytokines involving IL-6, IL-1β, and TNF-α during arteriosclerosis activity. Avn C specifically reduced IL-6 secretion in HASMC cells. Furthermore, we investigated whether Avn C could inhibit NF-κB nuclear protein translocation. Avn C suppressed nuclear protein translocation of NF-κB in TNF-α-stimulated HASMCs. The MMP-9 enzyme activity and expression are controlled through the MAPKs signaling path during the Avn C treatment. We confirmed that the levels of wound healing (p-value = 0.013, *p < 0.05) and migration (p-value = 0.007, **p < 0.01) are inhibited by 100 ng/ml TNF-α and 100 μM Avn C co-treated. Accordingly, Avn C inhibited the expression of MMP-9 and cell migration through the MAPK/NF-κB signaling pathway in TNF-α-activated HASMC. Therefore, Avn C can be identified and serve as disease prevention material and remedy for atherosclerosis.

Emerging science on benefits of whole grain oat and barley and their soluble dietary fibers for heart health, glycemic response, and gut microbiota

The aim of this work is to review the major mechanisms by which consumption of whole grain oats and barley, and β-glucans, reduces the risk of coronary heart disease, type 2 diabetes, and other noncommunicable chronic conditions. These effects have been predominantly explained by the role of soluble dietary fibers and smaller bioactive compounds, such as phenolic compounds, in oats and barley. These help to reduce the level of serum low-density lipoprotein cholesterol, decreasing postprandial blood glucose and modulating gut microbiota. In the present review, the role of viscosity development of the intestinal content by β-glucans in these mechanisms is discussed, as well as the impact of processing conditions altering the composition or the physicochemical characteristics of β-glucans.

Acute Effects of Oatmeal on Exercise-Induced Reactive Oxygen Species Production Following High-Intensity Interval Training in Women: A Randomized Controlled Trial

High-intensity interval training (HIIT) has been demonstrated to increase the generation of reactive oxygen species (ROS). Therefore, strategies to mitigate excessive ROS productions could be useful to reduce the negative consequences of oxidative damage for health, as well as for physical, performances. The aim of this study was to investigate the acute effects of pre-exercise oatmeal consumption on exercise-induced ROS generation in young, healthy women. Thirty-four participants were randomly allocated in one of two groups: oatmeal prior to HIIT (oatmeal; n = 17) or HIIT alone (control; n = 17). Blood samples were obtained at pre-meal, pre-HIIT, immediately post-HIIT, and 15 min after HIIT. Electron paramagnetic resonance (EPR) spectroscopy was used to analyze the concentrations of ROS in the capillary blood. In addition, the blood glucose and blood lactate levels were measured. Immediately post-HIIT, the ROS generation in the oatmeal group was significantly lower in contrast to the control group (p < 0.05). A significant interaction effect of time × meal (p < 0.05; η² = 0.234) was detected from the pre-meal to 15 post-HIIT for ROS production. Moreover, significant differences in the blood glucose levels were observed between the groups at pre-HIIT and immediately post-HIIT (p < 0.05). In conclusion, the consumption of oatmeal before HIIT may mitigate exercise-induced ROS production.

Characterization and antioxidant activity of avenanthramides from selected oat lines developed by mutagenesis technique

From a mutagenized oat population, produced by ethyl methanesulfonate mutagenesis, hulled grains from 17 lines with elevated avenanthramide (AVN) content were selected and their AVN structures, concentrations and antioxidant potentials were determined by HPLC-MS² and HPLC equipped with an on-line ABTS⁺ antioxidant detection system. The data obtained showed qualitative and quantitative differences in the synthesis of AVNs in the different lines, with a total AVN concentration up to 227.5 µg/g oat seed flour in the highest line, compared with 78.2 µg/g seed in the commercial line, SW Belinda. In total, 25 different AVNs were identified with avenanthramide B structures being among the most abundant, and AVN C structures having the highest antioxidant activity. The findings indicate the potential of oat mutagenesis in combination with a high precision biochemical selection method for the generation of stable mutagenized lines with a high concentration of total and/or individual AVNs in the oat seed grain.

A Short Overview of Changes in Inflammatory Cytokines and Oxidative Stress in Response to Physical Activity and Antioxidant Supplementation

Excessive release of inflammatory cytokines and oxidative stress (OS) are triggering factors in the onset of chronic diseases. One of the factors that can ensure health in humans is regular physical activity. This type of activity can enhance immune function and dramatically prevent the spread of the cytokine response and OS. However, if physical activity is done intensely at irregular intervals, it is not only unhealthy but can also lead to muscle damage, OS, and inflammation. In this review, the response of cytokines and OS to exercise is described. In addition, it is focused predominantly on the role of reactive oxygen and nitrogen species (RONS) generated from muscle metabolism and damage during exercise and on the modulatory effects of antioxidant supplements. Furthermore, the influence of factors such as age, sex, and type of exercise protocol (volume, duration, and intensity of training) is analyzed. The effect of antioxidant supplements on improving OS and inflammatory cytokines is somewhat ambiguous. More research is needed to understand this issue, considering in greater detail factors such as level of training, health status, age, sex, disease, and type of exercise protocol.

Avenanthramide supplementation reduces eccentric exercise-induced inflammation in young men and women

Background

Avenanthramides (AVA) are a group of di-phenolic acids found only in oats and have shown antioxidant and anti-inflammatory effects in vitro and in vivo. Eccentric muscle contraction is intimately involved in rigorous exercise that activates systemic and local inflammatory responses. The objective of the study is to evaluate whether chronic AVA supplementation could attenuate peripheral inflammatory and immunological markers in human subjects in response to an acute bout of downhill running (DR).

Methods

Eleven male and thirteen female subjects voluntarily participated in this double-blinded, randomized controlled study and were randomly divided into AVA-supplemented (AVA) or control (C) groups. All subjects conducted a DR protocol at − 10% grade with an intensity equivalent to 75% of their maximal heart rate. Blood samples were collected at rest and various time points (0-72 h) after DR (PRE). After an 8-week washout period, participants received two cookies daily containing either 206 mg/kg (AVA) or 0 mg/kg (C) AVA for 8 weeks. Following the oat supplementation regimen, the DR and blood sampling protocols were repeated (POST). Plasma inflammatory and immunological markers were measured using Multiplex immunoassay and muscle soreness was evaluated with pain rating scale.

Results

DR increased plasma creatine kinase (CK) activity (P < 0.01) during PRE, but the response was reduced at 24 and 48 h during POST vs. PRE regardless of AVA status (P < 0.05). Neutrophil respiratory burst (NRB) levels were elevated at 4 and 24 h (P < 0.05) during PRE but were significantly decreased at 0–48 h during POST vs. PRE (P < 0.05 or 0.01). Granulocyte-colony stimulating factor (G-CSF), the neutrophil stimulating cytokine, was also increased in response to DR but showed lower levels in AVA compared to C during POST vs. PRE (P < 0.05). Plasma interleukin-6 (IL-6) content showed an increase at 0 and 4 h during PRE and 0 h during POST (P < 0.01), whereas during POST there was a trend toward a lower IL-6 level in AVA vs. C (P = 0.082). Plasma levels of anti-inflammatory agent interleukin-1 receptor antagonist (IL-1Ra) showed an increase at 4 h during PRE, and was significantly elevated in AVA vs. C during POST. Both soluble vascular cell adhesion molecule-1 (sVCAM-1) and monocyte chemoattractant protein-1 (MCP-1) contents increased at 0 and 24 h post DR during PRE as well as POST sessions, however, sVCAM-1 content was lower in AVA vs. C during POST (P < 0.05) and MCP-1 levels were below resting level at 24, 48 and 72 h during POST (P < 0.05). DR increased muscle pain at all post-DR time points (P < 0.01), but the pain level was alleviated by oat supplementation at 48 and 72 h during POST regardless of AVA treatment (P < 0.05).

Conclusions

Oat AVA supplementation reduced circulatory inflammatory cytokines and inhibited expression of chemokines and cell adhesion molecules induced by DR.

Trial registration

ClinicalTrials.gov identifier: NCT02584946. Registered 23 October 2015.

Avenanthramide C suppresses hypoxia-induced cyclooxygenase-2 expression through sirtuin1 activation in non-small-cell lung cancer cells

Avenanthramide C (AVC), found mainly in oats, mediates anti-inflammatory activities by reducing the anti-inflammatory cytokine levels. This study investigated the effects of AVC on hypoxia-induced cyclooxygenase-2 (COX-2) expression in A549 cells. AVC suppressed the hypoxia-induced increase in COX-2 protein levels and promoter activity. We also observed that the effects of AVC were reversed by a SIRT1 inhibitor, indicating that the inhibitory effects of AVC on hypoxia-induced COX-2 expression are mediated by SIRT1. Therefore, AVC inhibits the hypoxic induction of COX-2 expression via SIRT1 activation. Our results suggest that AVC could be beneficial for preventing lung inflammation under hypoxia.

Endothelial Dysfunction in Diabetic Retinopathy

Diabetic retinopathy (DR) is a diabetic complication which affects retinal function and results in severe loss of vision and relevant retinal diseases. Retinal vascular dysfunction caused by multifactors, such as advanced glycosylation end products and receptors, pro-inflammatory cytokines and chemokines, proliferator-activated receptor-γ disruption, growth factors, oxidative stress, and microRNA. These factors promote retinal endothelial dysfunction, which results in the development of DR. In this review, we summarize the contributors in the pathophysiology of DR for a better understanding of the molecular and cellular mechanism in the development of DR with a special emphasis on retinal endothelial dysfunction.

Avenanthramide C from germinated oats exhibits anti-allergic inflammatory effects in mast cells

Mast cells play a crucial role in allergic diseases via the release of inflammatory mediators, particularly histamine and pro-inflammatory cytokines. Avenanthramide (Avn) C, a polyphenol found mainly in oats, is known to exhibit various biological properties. In this study, we aimed to evaluate the effectiveness of Avn C from germinated oats against mast cell-mediated allergic inflammation. For the in vitro study, RBL-2H3, mouse bone marrow-derived mast cells and rat peritoneal mast cells were used. Avn C (1–100 nM) inhibited the immunoglobulin (Ig)E-stimulated mast cells degranulation by suppressing phosphorylation of phosphoinositide 3-kinase and phospholipase Cγ1 and decreasing intracellular calcium levels. It inhibited IgE-stimulated secretion of inflammatory cytokines via suppression of FcεRI-mediated signaling proteins Lyn, Syk, Akt, and nuclear factor-κB. To verify the effects of Avn C in vivo, ovalbumin-induced active systemic anaphylaxis (ASA) and IgE-mediated passive cutaneous anaphylaxis (PCA) models were used. Oral administration of Avn C dose-dependently attenuated the ASA reactions, as evidenced by the inhibition of hypothermia and reduction of elevated serum histamine, IgE, and interleukin-4 levels. Avn C also inhibited the PCA reactions, such as ear swelling and plasma extravasation. Our results suggested that Avn C from germinated oats might be a possible therapeutic candidate for mast cell-mediated allergic inflammation.

Effects of oat protein supplementation on skeletal muscle damage, inflammation and performance recovery following downhill running in untrained collegiate men

The positive influence of animal-based protein supplementation during muscle-damaging exercise has been widely studied. However, the effects of plant-based proteins remain unclear and require further clarification. This study investigated the protective role of oat protein against exercise induced muscle damage (EIMD), subsequent inflammation, and loss of performance induced by downhill running. Subjects consumed either oat protein (25 g protein) or a placebo for 14 days prior to a downhill running test and then for 4 days thereafter. Treatments with oat protein for 19 days markedly alleviated eccentric exercise induced skeletal muscle soreness, and reduced the elevation of plasma IL-6 concentrations and serum creatine kinase, myoglobin and C reactive protein contents. In addition, oat protein supplementation significantly inhibited limb edema following damaging exercise, and the adverse effects on muscle strength, knee-joint range of motion, and vertical jump performance were lessened. Furthermore, the administration of oat protein facilitated recovery from exhaustive downhill running in this study. These findings demonstrated that oat protein supplementation has the potential to alleviate the negative effects of eccentric exercise in untrained young males.

Hemorheological alterations following an acute bout of nordic hamstring exercise in active male participants1

BACKGROUND

The Nordic hamstring exercise (NHE) has been proven to be an effective preventive technique for hamstring injuries. Hemorheological parameters (erythrocyte deformability and aggregation) play a critical role in exercise influencing oxygenation. Although previous studies presented hemorheological alterations induced by different types of exercise, changes in red blood cell (RBC) deformability and aggregation following NHE remain unknown. Present study was designed to explore possible alterations in hemorheological and oxidative parameters after an acute bout of NHE.

METHODS

10 healthy, male, active students (mean age 19.9±0.23, BMI: 21.56±0.54) participated to the study. They performed a single session of seven-repetitions of NHE followed by a familiarisation period. Blood samples were obtained before and immediately after the exercise from the antecubital vein. Hemorheological parameters were measured by an ektacytometer.

RESULTS

NHE did not change deformability, hematocrit and oxidative stress but, increased RBC aggregation index (AI, p = 0.011) and decreased RBC aggregation half time (t½, p = 0.009).

CONCLUSIONS

Our results suggest that, increased RBC aggregation following an acute bout of NHE may result in increased plasma skimming and thus ease the flow of blood.

Analysis of avenanthramides in oat products and estimation of avenanthramide intake in humans

Avenanthramides are phenolic compounds found only in oats, and are of interest due to suggested bioactivities, including anti-inflammatory effects and induction of apoptosis. The objective of this work was to optimise a high performance liquid chromatography (HPLC) method for analysis of avenanthramides in food, and analyse the avenanthramide content in 45 oat fractions and products. The optimised HPLC method was based on triplicate extraction of 100 mg sample with 1 ml 80% ethanol in phosphate buffer (pH 2.8) and used gallacetophenone as an internal standard. Avenalumic acid-derived avenanthramide homologues 2f_d and 2p_d were also present, making up to 20% of the total avenanthramides detected in oats. The amounts of avenanthramides detected in oat products was 2-82 µg/g. It was estimated that mean avenanthramide intake among oat consumers ranges from 0.3 to 2.1 mg/day, considerably lower than the amount used in studies that have investigated biological effects of avenanthramides in humans.

Remodeling of Retinal Architecture in Diabetic Retinopathy: Disruption of Ocular Physiology and Visual Functions by Inflammatory Gene Products and Pyroptosis

Diabetic patients suffer from a host of physiological abnormalities beyond just those of glucose metabolism. These abnormalities often lead to systemic inflammation via modulation of several inflammation-related genes, their respective gene products, homocysteine metabolism, and pyroptosis. The very nature of this homeostatic disruption re-sets the overall physiology of diabetics via upregulation of immune responses, enhanced retinal neovascularization, upregulation of epigenetic events, and disturbances in cells' redox regulatory system. This altered pathophysiological milieu can lead to the development of diabetic retinopathy (DR), a debilitating vision-threatening eye condition with microvascular complications. DR is the most prevalent cause of irreversible blindness in the working-age adults throughout the world as it can lead to severe structural and functional remodeling of the retina, decreasing vision and thus diminishing the quality of life. In this manuscript, we attempt to summarize recent developments and new insights to explore the very nature of this intertwined crosstalk between components of the immune system and their metabolic orchestrations to elucidate the pathophysiology of DR. Understanding the multifaceted nature of the cellular and molecular factors that are involved in DR could reveal new targets for effective diagnostics, therapeutics, prognostics, preventive tools, and finally strategies to combat the development and progression of DR in susceptible subjects.

Anti-inflammatory effect of avenanthramides via NF-κB pathways in C2C12 skeletal muscle cells

Avenanthramides (Avns), the polyphenol compounds found only in oats, have been shown to exhibit anti-inflammatory effects mainly by inhibiting nuclear factor (NF)-κB activation in select cell lines. However, the molecular mechanism by which Avns regulate the NF-κB pathway is still unclear. The purpose of this study was to investigate (1) the molecular mechanism by which three main fractions of Avns (AvnA, AvnB and AvnC) interact with IκB Kinase β (IKKβ); and (2) whether this interaction results in reduced inflammatory responses in skeletal muscle cells. The protein-ligand docking and molecular dynamics simulation studies suggest that Avns acted as an allosteric inhibitor for modulating IKKβ's affinity for the NF-κB complex. Thus, Avns reduced IKKβ kinase activity in response to tert-butyl hydroperoxide (tBHP) stimulation and attenuated tBHP-induced TNFα and IL-1β mRNA expression. Furthermore, the three-fold increases in cyclooxygenase-2 (COX-2) protein and luciferase activity with tBHP treatment were reduced by 50% with Avns (P < .01), along with decreased prostaglandin E2 levels (P < .01). These data indicate that Avns are potent inhibitors of NFκB-mediated inflammatory response due to the downregulation of IKKβ activity in C2C12 cells.

Natural and synthetic avenanthramides activate caspases 2, 8, 3 and downregulate hTERT, MDR1 and COX-2 genes in CaCo-2 and Hep3B cancer cells

Avenanthramides inhibit proliferation of CaCo-2 and Hep3B cancer cells through induction of apoptosis and downregulation of pro-survival mechanisms.

Absorption and Elimination of Oat Avenanthramides in Humans after Acute Consumption of Oat Cookies

Background

Avenanthramides (AVA) are a group of diphenolic acids found only in oats that have anti-inflammatory and antioxidant effects. Absorption of AVAs in humans after oral consumption of natural oat flour is unknown.

Objective

To examine the appearance of AVAs in plasma after oral ingestion of oat cookies and estimate key pharmacokinetic parameters.

Methods

Male and female nonobese participants (n = 16) consumed three cookies made with oat flour containing high (229.6 mg/kg, H-AVA) or low (32.7 mg/kg, L-AVA) amounts of AVAs, including AVA-A, AVA-B, and AVA-C. Blood samples were collected at 0, 0.5, 1, 2, 3, 5, and 10 h after ingestion. Plasma total (conjugated and free) AVA concentrations were quantified using UPLC-MS, and pharmacokinetic parameters for each AVA were estimated.

Results

AVAs reached peak concentrations in plasma between 2 and 3 h for the H-AVA group and between 1 and 2 h for the L-AVA group. Maximal plasma concentrations for AVAs were higher in the H-AVA than in the L-AVA group. AVA-B demonstrated a longer half-life and slower elimination rate than AVA-A and AVA-C.

Conclusions

AVAs found naturally in oats are absorbed in the plasma after oral administration in humans. AVA-B has the slowest elimination rate and the longest half-life compared to AVA-A and AVA-C, while AVA-C demonstrated the lowest plasma concentrations. This study is registered with ClinicalTrials.gov identifier NCT02415374.

New findings of oxidative stress biomarkers in nutritional research

PURPOSE OF REVIEW

The aim of this article is to present a brief overview of recently published articles assessing oxidative stress markers in nutritional studies.

RECENT FINDINGS

Intervention and observational studies were carried out in both, healthy subjects and patients and describe the association of foodstuffs as well as isolated nutrients with biomarkers of oxidative stress. The results from human intervention studies on healthy participants and patients are controversial. Long-term interventions (>8 weeks) seem to be more effective than short-term or single-dose interventions. Results are difficult to compare because not only the methods used, also the assessed biomarkers and outcomes were very diverse. In addition, studies vary in the compounds and doses used, duration, participants and so on. Different biomarkers (damaged molecules together with antioxidants from different compartments) should be assessed to evaluate the true 'redox-status' of an individual and the impact of a nutritional intervention.

SUMMARY

Both observational and interventional studies performed in healthy participants and patients show possible beneficial effects of nutrients and foodstuffs by improving oxidative stress markers and antioxidant enzyme activities. Biomarkers should be standardized to allow better comparison of results of antioxidant intervention studies.

Whole grain oats, more than just a fiber: Role of unique phytochemicals

Oats are a good source of soluble dietary fiber, especially β-glucan, which has outstanding functional and nutritional properties. β-Glucan is considered to be the major active component of oats because of its cholesterol-lowering and antidiabetic effects. However, the nutritional benefits of oats appear to go beyond fiber to bioactive phytochemicals with strong antioxidant and anti-inflammatory effects. In this review, we summarize current knowledge on the chemistry, stability, bioavailability, and health effects of two unique phytochemicals in oats, avenanthramides, and avenacosides A and B. We conclude that studies on the beneficial effects of avenanthramides and avenacosides A and B are still in their infancy, and additional health benefits of these unique oat components may yet be identified.