Oat avenanthramides induce heme oxygenase-1 expression via Nrf2-mediated signaling in HK-2 cells

Overview on the Polyphenol Avenanthramide in Oats (Avena sativa Linn.) as Regulators of PI3K Signaling in the Management of Neurodegenerative Diseases

Avenanthramides (Avns) and their derivatives, a group of polyphenolic compounds found abundantly in oats (Avena sativa Linn.), have emerged as promising candidates for neuroprotection due to their immense antioxidant, anti-inflammatory, and anti-apoptotic properties. Neurodegenerative diseases (NDDs), characterized by the progressive degeneration of neurons, present a significant global health burden with limited therapeutic options. The phosphoinositide 3-kinase (PI3K) signaling pathway plays a crucial role in cell survival, growth, and metabolism, making it an attractive target for therapeutic intervention. The dysregulation of PI3K signaling has been implicated in the pathogenesis of various NDDs including Alzheimer's and Parkinson's disease. Avns have been shown to modulate PI3K/AKT signaling, leading to increased neuronal survival, reduced oxidative stress, and improved cognitive function. This review explores the potential of Avn polyphenols as modulators of the PI3K signaling pathway, focusing on their beneficial effects against NDDs. Further, we outline the need for clinical exploration to elucidate the specific mechanisms of Avn action on the PI3K/AKT pathway and its potential interactions with other signaling cascades involved in neurodegeneration. Based on the available literature, using relevant keywords from Google Scholar, PubMed, Scopus, Science Direct, and Web of Science, our review emphasizes the potential of using Avns as a therapeutic strategy for NDDs and warrants further investigation and clinical exploration.

Genome Tectonics: Linking Dynamic Genome Organization with Cellular Nutrients

BACKGROUND

Our daily intake of food provides nutrients for the maintenance of health, growth, and development. The field of nutrigenomics aims to link dietary intake/nutrients to changes in epigenetic status and gene expression.

SUMMARY

Although the relationship between our diet and our genes in under intense investigation, there is still a significant aspect of our genome that has received little attention with regard to this. In the past 15 years, the importance of genome organization has become increasingly evident, with research identifying small-scale local changes to large segments of the genome dynamically repositioning within the nucleus in response to/or mediating change in gene expression. The discovery of these dynamic processes and organization maybe as significant as dynamic plate tectonics is to geology, there is little information tying genome organization to specific nutrients or dietary intake.

KEY MESSAGES

Here, we detail key principles of genome organization and structure, with emphasis on genome folding and organization, and link how these contribute to our future understand of nutrigenomics.

Nutraceutical Properties of Medicago sativa L., Agave Spp., Zea mays L. and Avena sativa L.: A Review of Metabolites and Mechanisms

Plants are the main sources of bioactive compounds (nutraceuticals) that function under different mechanisms of action for the benefit of human health. Mexico ranks fifth in the world in biodiversity, offering opportunities for healthy food. An important variety of crops are produced in the state of Hidalgo, e.g., based on the 2021 production, alfalfa, oats, maguey, and corn. The present review presents the latest findings of these crops, regarding the benefits they provide to health (bioactivity, nutraceuticals), and presents the compounds and mechanisms identified by which the benefit is provided. The knowledge compiled here is for the benefit of the recovery of the crops, the recognition of their bioactivities, in search of identifying the best routes of action for prevention, treatment and possible cure of chronic degenerative diseases (thereby promoting crop valorization). Exhaustive bibliographic research was carried out by means of engines and scientific databases. Articles published between 2001 and 2022 that included specific keywords (Scopus, EMBASE, EBSCO, PubMed, Science Direct, Web of Science, Google Scholar). Outstanding activities have been identified for the compounds in the crops, such as antiinflammatory, anticholesterolemic, antihypertensive, antidiabetic, anticancer, antimicrobial, antioxidant, and chelating. The compounds that provide these properties are total phenols, phenolic acids, tannins, anthocyanins, carotenoids, iso-flavones, phytosterols, saponins, fructans, glycosides, glucans, avenanthramides, and polysaccharides.

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.

Multiple Antioxidative and Bioactive Molecules of Oats (Avena sativa L.) in Human Health

Oats (Avena sativa L.) are rich in protein, fiber, calcium, vitamins (B, C, E, and K), amino acids, and antioxidants (beta-carotene, polyphenols, chlorophyll, and flavonoids). β-glucan and avenanthramides improve the immune system, eliminate harmful substances from the body, reduce blood cholesterol, and help with dietary weight loss by enhancing the lipid profile and breaking down fat in the body. β-glucan regulates insulin secretion, preventing diabetes. Progladins also lower cholesterol levels, suppress the accumulation of triglycerides, reduce blood sugar levels, suppress inflammation, and improve skin health. Saponin-based avanacosidase and functional substances of flavone glycoside improve the immune function, control inflammation, and prevent infiltration in the skin. Moreover, lignin and phytoestrogen prevent hormone-related cancer and improve the quality of life of postmenopausal women. Sprouted oats are rich in saponarin in detoxifying the liver. The literatures have been reviewed and the recent concepts and prospects have been summarized with figures and tables. This review discusses recent trends in research on the functionality of oats rather than their nutritional value with individual immunity for self-medication. The oat and its acting components have been revisited for the future prospect and development of human healthy and functional sources.

Bisavenathramide Analogues as Nrf2 Inductors and Neuroprotectors in In Vitro Models of Oxidative Stress and Hyperphosphorylation

Oxidative stress is crucial to the outbreak and advancement of neurodegenerative diseases and is a common factor to many of them. We describe the synthesis of a library of derivatives of the 4-arylmethylen-2-pyrrolin-5-one framework by sequential application of a three-component reaction of primary amines, β-dicarbonyl compounds, and α-haloketones and a Knoevenagel condensation. These compounds can be viewed as cyclic amides of caffeic and ferulic acids, and are also structurally related to the bisavenanthramide family of natural antioxidants. Most members of the library showed low cytotoxicity and good activity as inductors of Nrf2, a transcription factor that acts as the master regulator of the antioxidant response associated with activation of the antioxidant response element (ARE). Nrf2-dependent protein expression was also proved by the significant increase in the levels of the HMOX1 and NQO1 proteins. Some compounds exerted neuroprotective properties in oxidative stress situations, such as rotenone/oligomycin-induced toxicity, and also against protein hyperphosphorylation induced by the phosphatase inhibitor okadaic acid. Compound 3i, which can be considered a good candidate for further hit-to-lead development against neurodegenerative diseases due to its well-balanced multitarget profile, was further characterized by proving its ability to reduce phosphorylated Tau levels.

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.

Oat polyphenol avenanthramide-2c confers protection from oxidative stress by regulating the Nrf2-ARE signaling pathway in PC12 cells

Accumulating evidence has demonstrated that cellular antioxidant systems play essential roles in retarding oxidative stress-related diseases, such as Parkinson's disease. Because nuclear factor erythroid 2-related factor 2 (Nrf2) is a chief regulator of cellular antioxidant systems, small molecules with Nrf2-activating ability may be promising neuroprotective agents. Avenanthramide-2c (Aven-2c), avenanthramide-2f (Aven-2f) and avenanthramide-2p (Aven-2p) are the most abundant avenanthramides in oats, and they have been documented to possess multiple pharmacological benefits. In this work, we synthesized these three compounds and evaluated their cytoprotective effect against oxidative stress-induced PC12 cell injuries. Aven-2c displayed the best protective potency among them. Aven-2c conferred protection on PC12 cells by scavenging free radicals and activating the Nrf2-ARE signaling pathway. Pretreatment of PC12 cells with Aven-2c efficiently enhanced Nrf2 nuclear accumulation and evoked the expression of a set of cytoprotective molecules. The mechanistic study also supports that Nrf2 activation is the molecular basis for the cellular action of Aven-2c. Collectively, this study demonstrates that Aven-2c is a potent Nrf2 agonist, shedding light on the potential usage of Aven-2c in the treatment of neuroprotective diseases.

Wheat, Barley, and Oat Breeding for Health Benefit Components in Grain

Cereal grains provide half of the calories consumed by humans. In addition, they contain important compounds beneficial for health. During the last years, a broad spectrum of new cereal grain-derived products for dietary purposes emerged on the global food market. Special breeding programs aimed at cultivars utilizable for these new products have been launched for both the main sources of staple foods (such as rice, wheat, and maize) and other cereal crops (oat, barley, sorghum, millet, etc.). The breeding paradigm has been switched from traditional grain quality indicators (for example, high breadmaking quality and protein content for common wheat or content of protein, lysine, and starch for barley and oat) to more specialized ones (high content of bioactive compounds, vitamins, dietary fibers, and oils, etc.). To enrich cereal grain with functional components while growing plants in contrast to the post-harvesting improvement of staple foods with natural and synthetic additives, the new breeding programs need a source of genes for the improvement of the content of health benefit components in grain. The current review aims to consider current trends and achievements in wheat, barley, and oat breeding for health-benefiting components. The sources of these valuable genes are plant genetic resources deposited in genebanks: landraces, rare crop species, or even wild relatives of cultivated plants. Traditional plant breeding approaches supplemented with marker-assisted selection and genetic editing, as well as high-throughput chemotyping techniques, are exploited to speed up the breeding for the desired genotуpes. Biochemical and genetic bases for the enrichment of the grain of modern cereal crop cultivars with micronutrients, oils, phenolics, and other compounds are discussed, and certain cases of contributions to special health-improving diets are summarized. Correlations between the content of certain bioactive compounds and the resistance to diseases or tolerance to certain abiotic stressors suggest that breeding programs aimed at raising the levels of health-benefiting components in cereal grain might at the same time match the task of developing cultivars adapted to unfavorable environmental conditions.

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.

Quantitative Analysis and Anti-inflammatory Activity Evaluation of the A-Type Avenanthramides in Commercial Sprouted Oat Products

Avenanthramides (AVAs) are unique phytochemicals in oat that contain two distinct groups of compounds. The first group is constituted by N-cinnamoylanthranilic acids with a single double bond (referred to as C type), and the other group is constituted by N-avenalumoylanthranilic acids with two double bonds (referred to as A type). C-type AVAs have been reported with their chemical profiles and levels in commercial oat products as well as their bioactivities. However, the accurate levels of A-type AVAs in commercial sprouted oat products and their bioactivity are still unknown. In this study, we purified seven A-type AVAs from sprouted oat bran and characterized their structures with corresponding mass spectrometry and nuclear magnetic resonance data. Among them, five compounds were isolated from oat bran for the first time. The purified A-type AVAs were used as authentic standards to establish the chemical profile of A-type AVAs in oat and to quantify the levels of all individual A-type AVAs in six commercial sprouted oat products using ultra-high-performance liquid chromatography with tandem mass spectrometry. The total A-type AVA contents in the various oat products ranged from 7.85 to 133.3 μg/g. Furthermore, the inhibition of lipopolysaccharide-induced nitric oxide production and inducible nitric oxide synthase expression by A- and C-type AVAs in macrophages were compared. The most abundant A-type AVAs (2p_d, 2c_d, and 2f_d) have similar anti-inflammatory activity to the major C-type AVAs (2p, 2c, and 2f). To the best of our knowledge, this is the first report on the bioactivity of A-type AVAs.

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.

Overview of the Anticancer Profile of Avenanthramides from Oat

Cancer represents one of the leading causes of death worldwide. Progresses in treatment of cancer have continued at a rapid pace. However, undesirable side effects and drug resistance remain major challenges for therapeutic success. Natural products represent a valuable starting point to develop new anticancer strategies. Polyphenols, well-known as antioxidant, exert anticancer effects through the modulation of multiple pathways and mechanisms. Oat (Avena sativa L., Poaceae) is a unique source of avenanthramides (AVAs), a group of polyphenolic alkaloids, considered as its signature compounds. The present review aims to offer a comprehensive and critical perspective on the chemopreventive and chemotherapeutic potential of AVAs. AVAs prevent cancer mainly by blocking reactive species. Moreover, they exhibit potential therapeutic activity through the modulation of different pathways including the activation of apoptosis and senescence, the block of cell proliferation, and the inhibition of epithelial mesenchymal transition and metastatization. AVAs are promising chemopreventive and anticancer phytochemicals, which need further clinical trials and toxicological studies to define their efficacy in preventing and reducing the burden of cancer diseases.

Avenanthramide A triggers potent ROS-mediated anti-tumor effects in colorectal cancer by directly targeting DDX3

Colorectal cancer (CRC) is a common malignant gastrointestinal tumor with high mortality worldwide. Drug resistance and cytotoxicity to normal cells are the main causes of chemotherapeutic treatment failure in CRC. Therefore, extracting the bioactive compounds from natural products with anti-carcinogenic activity and minimal side-effects is a promising strategy against CRC. The present study aims to evaluate the anti-carcinogenic properties of avenanthramides (AVNs) extracted from oats bran and clarify the underlying molecular mechanisms. We demonstrated that AVNs treatment suppressed mitochondrial bioenergetic generation, resulting in mitochondrial swelling and increased reactive oxygen species (ROS) production. Further study indicated that AVNs treatment significantly reduced DDX3 expression, an oncogenic RNA helicase highly expressed in human CRC tissues. DDX3 overexpression reversed the ROS-mediated CRC apoptosis induced by AVNs. Of note, we identified Avenanthramide A (AVN A) as the effective ingredient in AVNs extracts. AVN A blocked the ATPase activity of DDX3 and induced its degradation by directly binding to the Arg287 and Arg294 residues in DDX3. In conclusion, these innovative findings highlight that AVNs extracts, in particular its bioactive compound AVN A may crack the current hurdles in the way of CRC treatment.

Cytoprotective effects of Avenathramide C against oxidative and inflammatory stress in normal human dermal fibroblasts

Natural polyphenols are promising anti-aging compounds not only for their antioxidant activity, but also their ability to activate specific cellular pathways mediating the aging process. Avenanthramide C (Avn C), found exclusively in oats, is a natural antioxidant associated with free radical scavenging; however, it is how this compound elicits other protective effects. We investigated the intracellular antioxidant activity of Avn C and other cytoprotective potential in normal human skin fibroblasts exposed to extracellular stress. Avn C reduced H2O2-induced oxidative stress by reducing intracellular free radical levels and antioxidant gene transcripts. Avn C also resulted in decreased levels of gene transcripts encoding pro-inflammatory cytokines in response to H2O2 or tumor necrosis factor-α (TNF-α). This reduction in cytokine gene transcription occurred concomitantly with reduced phosphorylated nuclear factor-κB (NF-κB) p65, and decreased NF-κB DNA binding. Avn C further induced heme oxygense-1 (HO-1) expression through increased Nrf2 DNA binding activity, demonstrating a second mechanism by which Avn C attenuates cellular stress. Collectively, our findings indicate that Avn C protects normal human skin fibroblasts against oxidative stress and inflammatory response through NF-κB inhibition and Nrf2/HO-1 activation.

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.

Biological Activities, Health Benefits, and Therapeutic Properties of Avenanthramides: From Skin Protection to Prevention and Treatment of Cerebrovascular Diseases

Oat (Avena sativa) is a cereal known since antiquity as a useful grain with abundant nutritional and health benefits. It contains distinct molecular components with high antioxidant activity, such as tocopherols, tocotrienols, and flavanoids. In addition, it is a unique source of avenanthramides, phenolic amides containing anthranilic acid and hydroxycinnamic acid moieties, and endowed with major beneficial health properties because of their antioxidant, anti-inflammatory, and antiproliferative effects. In this review, we report on the biological activities of avenanthramides and their derivatives, including analogs produced in recombinant yeast, with a major focus on the therapeutic potential of these secondary metabolites in the treatment of aging-related human diseases. Moreover, we also present recent advances pointing to avenanthramides as interesting therapeutic candidates for the treatment of cerebral cavernous malformation (CCM) disease, a major cerebrovascular disorder affecting up to 0.5% of the human population. Finally, we highlight the potential of foodomics and redox proteomics approaches in outlining distinctive molecular pathways and redox protein modifications associated with avenanthramide bioactivities in promoting human health and contrasting the onset and progression of various pathologies. The paper is dedicated to the memory of Adelia Frison.

Avenanthramide Aglycones and Glucosides in Oat Bran: Chemical Profile, Levels in Commercial Oat Products, and Cytotoxicity to Human Colon Cancer Cells

Avenanthramides (AVAs), unique phytochemicals in oat, have attracted an increasing amount of attention due to their outstanding health benefits. However, the chemical profile and the levels of AVAs in commercial oat products as well as their health benefits have not been examined in detail. In the present study, a total of 29 AVA aglycones and AVA glucosides were identified and characterized from oat bran using NMR (1D and 2D NMR) and LC-MS techniques. Among them, 17 novel AVA glucosides were reported in oat bran for the first time. The most abundant AVA glucoside, 2c-3'- O-glc, had a similar growth inhibitory activity with the major AVA, 2c, against HCT-116 and HT-29 human colon cancer cells, indicating glucosylation does not affect the growth inhibitory effects of AVAs. Furthermore, the levels of all individual AVAs in 13 commercial oat products were analyzed using HPLC-MS/MS. The total AVAs contents in various oat products ranged from 9.22 to 61.77 mg/kg (fresh weight).

High Levels of Avenanthramides in Oat-Based Diet Further Suppress High Fat Diet-Induced Atherosclerosis in Ldlr-/- Mice

Oats, in addition to cholesterol-lowering properties, contain unique antioxidants called avenanthramides (Avns), which inhibit both inflammatory cytokines and adhesion molecules in endothelial cells in culture. This study evaluated the effects of Avns of oats on atherosclerosis in Ldlr^-/- mice, one of the most commonly used atherosclerosis mouse models with their similar cholesterol distributions to humans. The Ldlr^-/- mice were fed a low fat, high fat, high fat containing regular oat brans with low levels of Avns (HFLA), or high fat containing regular oat brans with high levels of Avns (HFHA) diet. After 16 weeks of intervention, blood cholesterol and extent of aortic lesions were evaluated. We found that both oat-based diets reduced high fat diet-induced atheroma lesions in the aortic valve (p < 0.01). Furthermore, the effects of oat-based diets are more profound in HFHA mice than mice fed HFLA. Total plasma cholesterol levels were similarly reduced in both oat-supplemented mice. We concluded that oat bran diets reduce atheroma lesions and higher levels of Avns further reduce aortic lesions compared to regular oat bran. These preliminary in vivo data indicate that consumption of oats bran, with high Avns, has demonstrable beneficial effects on prevention of cardiovascular disease.

Ethnobotanic, Ethnopharmacologic Aspects and New Phytochemical Insights into Moroccan Argan Fruits

This review summarizes available data on argan fruit botany, geographical distribution, traditional uses, environmental interest, socioeconomic role, phytochemistry, as well as health beneficial effects and examination of future prospects. In particular, ethnomedical uses of argan fruits are carried out throughout Morocco where it has been used against various diseases. Different classes of bioactive compounds have been characterized including essential oils, fatty acids, triacylglycerols, flavonoids and their newly reported acylglycosyl derivatives, monophenols, phenolic acids, cinnamic acids, saponins, triterpenes, phytosterols, ubiquinone, melatonin, new aminophenols along with vitamin E among other secondary metabolites. The latter have already shown a wide spectrum of in vitro, and ex vivo biologicalactivities including antioxidant, anti-inflammatory, anti-diabetic, antihypertensive, anti-hypercholesterolemia, analgesic, antimicrobial, molluscicidal anti-nociceptive and anticancer potential. Argan flesh (pulp) contains a broad spectrum of polyphenolic compounds which may have utility for incorporation into nutraceuticals and cosmeceuticals relevant to the food, cosmetic and health industries. Further research is recommended, especially on the health beneficial effects of the aminophenols.

Identification of methylated metabolites of oat avenanthramides in human plasma using UHPLC QToF-MS

Oat avenanthramides (AVAs) are a group of phenolic alkaloids, consisting of an anthranilic acid and a hydroxycinnamic acid linked by a pseudo-peptide bond. Bioavailability of AVA is poor in humans, suggesting transformations for rapid excretion. Thus, we aim to identify metabolites of AVA isomers in plasma of humans after consuming AVA-enriched oats. After lipid removal, AVA and their metabolites in plasma were extracted with ethyl acetate and analysed using an Agilent UHPLC-QToF-MS. Pharmacokinetics of AVA-O showed a bimodal distribution with C_max1 and 2 for AVA-O at 5.9 ± 5.2 and 7.9 ± 7.0 ng/mL and T_max1 and 2 at 1.7 ± 0.7 and 3.1 ± 1.2 h, respectively. Only the methyl-AVA-O showed a single C_max at 14 ± 9.9 ng/mL AVA-O equivalents and a T_max of 2.4 ± 2.7 h. This analysis is the first to identify methylated metabolites of AVAs and AVA aglycones in human blood after acute AVA consumption.

Natural antioxidants in the treatment and prevention of diabetic nephropathy; a potential approach that warrants clinical trials

Diabetic nephropathy is the major cause of end-stage renal disease and effective and new therapeutic approaches are needed in diabetic nephropathy and chronic kidney diseases. Oxidative stress and inflammatory process are important factors contributing to kidney damage by increasing production of oxidants. KEAP1/Nrf2/ARE pathway regulates the transcription of many antioxidant genes and modulation of the pathway up regulates antioxidants. NFB controls the expression of genes involved in the inflammatory response. Natural substances have antioxidant and anti-inflammatory activities and have an impact on NFB and KEAP1/Nrf2/ARE pathways. The preclinical studies explored the effectiveness of whole herbs, plants or seeds and their active ingredients in established diabetic nephropathy. They ameliorate oxidative stress induced kidney damage, enhance antioxidant system, and decrease inflammatory process and fibrosis; most likely by activating KEAP1/Nrf2/ARE pathway and by deactivating NFB pathway. Whole natural products contain balanced antioxidants that might work synergistically to induce beneficial therapeutic outcome. In this context, more clinical studies involving whole plants or herbal products or mixtures of different herbs and plants and their active ingredients might change our strategies for the management of diabetic nephropathy. The natural products might be useful as preventive interventions and studies are required in this field.

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.

Avenanthramides Prevent Osteoblast and Osteocyte Apoptosis and Induce Osteoclast Apoptosis in Vitro in an Nrf2-Independent Manner

Oats contain unique bioactive compounds known as avenanthramides (AVAs) with antioxidant properties. AVAs might enhance the endogenous antioxidant cellular response by activation of the transcription factor Nrf2. Accumulation of reactive oxygen species plays a critical role in many chronic and degenerative diseases, including osteoporosis. In this disease, there is an imbalance between bone formation by osteoblasts and bone resorption by osteoclasts, which is accompanied by increased osteoblast/osteocyte apoptosis and decreased osteoclast apoptosis. We investigated the ability of the synthethic AVAs 2c, 2f and 2p, to 1-regulate gene expression in bone cells, 2-affect the viability of osteoblasts, osteocytes and osteoclasts, and the generation of osteoclasts from their precursors, and 3-examine the potential involvement of the transcription factor Nrf2 in these actions. All doses of AVA 2c and 1 and 5 µM dose of 2p up-regulated collagen 1A expression. Lower doses of AVAs up-regulated OPG (osteoprotegerin) in OB-6 osteoblastic cells, whereas 100 μM dose of 2f and all concentrations of 2c down-regulated RANKL gene expression in MLO-Y4 osteocytic cells. AVAs did not affect apoptosis of OB-6 osteoblastic cells or MLO-Y4 osteocytic cells; however, they prevented apoptosis induced by the DNA topoisomerase inhibitor etoposide, the glucocorticoid dexamethasone, and hydrogen peroxide. AVAs prevented apoptosis of both wild type (WT) and Nrf2 Knockout (KO) osteoblasts, demonstrating that AVAs-induced survival does not require Nrf2 expression. Further, KO osteoclast precursors produced more mature osteoclasts than WT; and KO cultures exhibited less apoptotic osteoclasts than WT cultures. Although AVAs did not affect WT osteoclasts, AVA 2p reversed the low apoptosis of KO osteoclasts. These in vitro results demonstrate that AVAs regulate, in part, the function of osteoblasts and osteocytes and prevent osteoblast/osteocyte apoptosis and increase osteoclast apoptosis; further, these regulatory actions are independent of Nrf2.