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

Inhibitory Effects of Fermented Sprouted Oat Extracts on Oxidative Stress and Melanin Overproduction

Hyperpigmentation occurs due to irregular secretion of melanin pigment in the skin. This can affect quality of life depending on its severity, so prevention and management are essential. Oats (Avena sativa L.), a grain consumed worldwide, are known to offer improved health benefits upon germination and fermentation. This study is aimed to investigate the protective effects of lactobacilli-fermented sprouted oat extracts on oxidative stress and melanin overproduction in vitro. The anti-melanogenic effect was investigated using melanin content and tyrosinase activity assays in B16F10 cells, as well as a mushroom tyrosinase-based enzyme inhibition assay. The results showed that L. casei-fermented oat extracts were the most effective for reducing melanin formation by reducing the mRNA expression of microphthalmia-associated transcription factor, tyrosinase, and tyrosinase-related protein 2. Furthermore, L. casei fermentation was effective in improving the total phenolic, flavonoid, and avenanthramide A contents of sprouted oat extracts. The results also demonstrated the antioxidant effects of L. casei-fermented sprouted oat extracts in promoting DPPH radical-scavenging activity, superoxide dismutase-like activity, and reduction in reactive oxygen species levels. Overall, the findings indicate that fermented sprouted oat extracts are promising candidates for antioxidant and anti-hyperpigmentation treatments.

Comprehensive study of the effect of oat grain germination on the content of avenanthramides

The chemical profile and the levels of AVNs in oat varieties after germination have been examinated. In the present study, 12 distinct oat varieties were germinated for 0-192 h and a total of 28 AVNs and 3 AVN-hexosides were determined in these samples. Among them, three novel AVNs were synthesized (AVN 1a, AVN 2a, and AVN 2ad), characterized using NMR techniques (1D- and 2D-NMR), and assessed in real samples for the first time. The most abundant AVNs in the samples were AVN 2c, AVN 2p, AVN 2f, and their long-chained analogues AVN 2 cd, AVN 2pd, AVN 2fd, together representing 75-85 % of the total AVNs content. The highest total AVN level was observed on average after 48-72 h of germination time and it reached a value 1-1.2 mg/g. Out of 12 investigated oat varieties, CDC Boyer, Diadem, and Rozmar have proved to be the most suitable genotypes for germination.

Fermented Oats as a Novel Functional Food

Fermented oats are gaining popularity due to their nutritional value and the increasing consumer demand for health-conscious foods. These oats are believed to offer enhanced phytochemical and nutritional profiles compared to unfermented oats. The increased nutritional content of fermented oats is associated with various health benefits, including anti-inflammatory and antioxidant activities, which could potentially reduce the risk of chronic diseases. Further investigations are warranted to elucidate the nutritional benefits of fermented oats in human nutrition. This mini review provides a comprehensive overview of fermented oat products available on the market and the various production methods employed for fermenting oats. Furthermore, this review investigates how fermentation affects the chemical composition and biological functions of oats. Additionally, this manuscript presents some future perspectives on fermented oat products by discussing potential research directions and opportunities for further development. The findings presented in this review contribute to the expanding body of knowledge on fermented oats as a promising functional food, paving the way for future studies and applications in the field of nutrition and health.

Effect of Dynamic High-Pressure Microfluidizer on Physicochemical and Microstructural Properties of Whole-Grain Oat Pulp

By avoiding the filtration step and utilizing the whole components of oats, the highest utilization rate of raw materials, improving the nutritional value of products and reducing environmental pollution, can be achieved in the production of whole-grain oat drinks. This study innovatively introduced a dynamic high-pressure microfluidizer (DHPM) into the processing of whole-grain oat pulp, which aimed to achieve the efficient crushing, homogenizing and emulsification of starch, dietary fiber and other substances. Due to DHPM processing, the instability index and slope value were reduced, whereas the β-glucan content, soluble protein content and soluble dietary fiber content were increased. In the samples treated with a pressure of 120 MPa and 150 MPa, 59% and 67% more β-glucan content was released, respectively. The soluble dietary fiber content in the samples treated with a pressure of 120 MPa and 150 MPa was increased by 44.8% and 43.2%, respectively, compared with the sample treated with a pressure of 0 MPa. From the perspective of the relative stability of the sample and nutrient enhancement, the processing pressure of 120 MPa was a good choice. In addition, DHPM processing effectively reduced the average particle size and the relaxation time of the water molecules of whole-grain oat pulp, whereas it increased the apparent viscosity of whole-grain oat pulp; all of the above changes alleviated the gravitational subsidence of particles to a certain extent, and thus the overall stability of the system was improved. Furthermore, CLSM and AFM showed that the samples OM-120 and OM-150 had a more uniform and stable structural system as a whole. This study could provide theoretical guidance for the development of a whole-grain oat drink with improved quality and consistency.

The Adapted POM Analysis of Avenanthramides In Silico

POM analysis and related approaches are significant tools based on calculating various physico-chemical properties and predicting biological activity, ADME parameters, and toxicity of a molecule. These methods are used to evaluate a molecule's potential to become a drug candidate. Avenanthramides (AVNs) are promising secondary metabolites specific to Avena spp. (oat). They comprise the amides of anthranilic acid linked to various polyphenolic acids with or without post-condensation molecule transformation. These natural compounds have been reported to exert numerous biological effects, including antioxidant, anti-inflammatory, hepatoprotective, antiatherogenic, and antiproliferative properties. To date, almost 50 various AVNs have been identified. We performed a modified POM analysis of 42 AVNs using MOLINSPIRATION, SWISSADME, and OSIRIS software. The evaluation of primary in silico parameters revealed significant differences among individual AVNs, highlighting the most promising candidates. These preliminary results may help coordinate and initiate other research projects focused on particular AVNs, especially those with predicted bioactivity, low toxicity, optimal ADME parameters, and promising perspectives.

Fuligopyrones from the Fruiting Bodies of Myxomycete Fuligo septica Offer Short-Term Protection from Abiotic Stress Induced by UV Radiation

The myxomycete Fuligo septica, colloquially referred to as "dog vomit fungus", forms vibrant yellow fruiting bodies (aethalia) on wood chips during warm and humid conditions in spring. In 2018, ideal climatic conditions in Sydney, Australia, provided a rare opportunity to access abundant quantities of F. septica aethalia, which enabled the isolation, purification, structure elucidation, and biological screening of two avenalumamide pyrones, fuligopyrone (1) and fuligopyrone B (2). While 1 and 2 did not exhibit any appreciable biological activity, their significant UV absorption at 325 nm suggested they may be acting as transient sunscreens to help protect the fruiting mass from exposure to sunlight. In support of this hypothesis, exposing a solution of 2 to direct sunlight for 5 min resulted in rapid equilibration with a mixture of 2E,4Z-fuligopyrone B (10) and 2Z,4E-fuligopyrone B (11) photoisomers.

Narrative Review on the Effects of Oat and Sprouted Oat Components on Blood Pressure

Hypertension (HTN) is a major risk factor for cardiovascular disease (CVD) and cognitive decline. Elevations in blood pressure (BP) leading to HTN can be found in young adults with increased prevalence as people age. Oats are known to decrease CVD risk via an established effect of β-glucan on the attenuation of blood cholesterol. Many past studies on CVD and oats have also reported a decrease in BP; however, a thorough assessment of oats and BP has not been conducted. Moreover, oats deliver several beneficial dietary components with putative beneficial effects on BP or endothelial function, such as β-glucan, γ-amino butyric acid (GABA), and phytochemicals such as avenanthramides. We conducted a comprehensive search for systematic reviews, meta-analyses, and clinical intervention studies on oats and BP and identified 18 randomized controlled trials (RCTs) and three meta-analyses that supported the role of oats in decreasing BP. Emerging data also suggest oat consumption may reduce the use of anti-hypertensive medications. The majority of these studies utilized whole oats or oat bran, which include a vast array of oat bioactives. Therefore, we also extensively reviewed the literature on these bioactives and their putative effect on BP-relevant mechanisms. The data suggest several oat components, such as GABA, as well as the delivery of high-quality plant protein and fermentable prebiotic fiber, may contribute to the anti-HTN effect of oats. In particular, GABA is enhanced in oat sprouts, which suggests this food may be particularly beneficial for healthy BP management.

Oat Seedlings Extract Inhibits RANKL-Induced c-Fos/NFATc1 Transcription Factors in the Early Stage of Osteoclast Differentiation

Osteoporosis is a common disease that increases the risk of fractures due to decreased bone density and weakens the bone microstructure. Preventing and diagnosing osteoporosis using the available drugs can be a costly affair with possible side effects. Therefore, natural product-derived therapeutics are promising alternatives. Our study demonstrated that the oat seedlings' extract (OSE) inhibited the receptor activator of the nuclear factor κB ligand (RANKL)-induced osteoclastogenesis from the bone marrow-derived macrophages (BMMs). The OSE treatment significantly attenuated the RANKL-mediated induction of the tartrate-resistant acid phosphatase (TRAP) activity as well as the number of TRAP-positive (TRAP+) multinucleated cells (MNCs) counted through the TRAP staining in a dose-dependent manner. It was also confirmed that the OSE suppressed the formation of the TRAP + MNCs in the early stage of differentiation and not in the middle and late stages. The results of the real-time quantitative polymerase chain reaction (qPCR) and the western blotting showed that the OSE dramatically inhibited the mRNA and protein expressions of the osteoclastogenesis-mediated transcription factors such as the c-Fos and the nuclear factor-activated T cells c1 (NFATc1). In addition, the OSE strongly attenuated the mRNA induction of the c-Fos/NFATc1-dependent molecules such as the TRAP, the osteoclast-associatedimmunoglobulin-like receptor (OSCAR), the dendritic cell-specific transmembrane protein (DC-STAMP), and the cathepsin K. These results suggest that the naturally derived OSE may be useful for preventing bone diseases.

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.

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.

Novel Steroidal Saponins in Oat Identified by Molecular Networking Analysis and Their Levels in Commercial Oat Products

Through the use of the Global Natural Product Social (GNPS) feature-based networking system, a series of newly identified steroidal saponins were discovered in oat. The structures of the three new major steroidal saponins, sativacosides A-C (1-3), were characterized by analyzing their high-resolution MS, 1D and 2D NMR spectra, and an additional eight new steroidal saponins were also tentatively identified (4-11) based on their tandem mass spectra and typical fragments. Using ultrahigh-performance liquid chromatography with tandem mass spectrometry techniques, a complete profile of the new sativacoside series was established, and the contents of sativacosides A-C were quantified in 18 different commercial oat products. The total levels of sativacosides A-C varied from 62.2 to 192.9 μg/g in these 18 products, in which oat bran (11 samples) and oatmeal (3 samples) had higher levels than cold oat cereal (4 samples).

Antioxidant Activity and Mechanism of Avenanthramides: Double H+/e- Processes and Role of the Catechol, Guaiacyl, and Carboxyl Groups

Avenanthramides (AVAs), unique phenolic compounds in oats, have attracted increasing interest due to their health benefits. Eight representative AVAs were studied using the density functional theory (DFT) method to elucidate their antioxidant activity and mechanism. Preference of different mechanisms was evaluated based on thermodynamic descriptors involved in double (2H⁺/2e^-) free radical scavenging reactions. It was found that the hydrogen atom transfer (HAT) mechanism is more favorable in the gas and benzene phases, while sequential proton loss electron transfer (SPLET) is preferred in polar media. The results suggest the feasibility of the double HAT and double SPLET mechanisms for 2s and c-series AVAs. The sequential triple proton loss double electron transfer (StPLdET) mechanism represents the dominant pathway in aqueous solution at physiological pH. In addition, the sequential proton loss hydrogen atom transfer (SPLHAT) mechanism provides an alternative pathway to trap free radicals. Results also revealed the important role of the catechol, guaiacyl, and carboxyl moieties.

Triterpenoid Saponins in Oat Bran and Their Levels in Commercial Oat Products

Oats are commonly consumed as whole grains and generally considered as a healthy food. However, the bioactive compounds in oats have not been fully investigated. In this study, we reported for the first time the purification, structure elucidation, and chemical profile of the major triterpenoid saponins in oat bran as well as the quantification of the major triterpenoid saponins in commercial oat products. Thirteen triterpenoid saponins (1-13) were purified from oat bran. Their structures were characterized by analyzing their high-resolution mass spectrometry (MS), one-dimensional (1-D), and two-dimensional (2-D) NMR spectra. All of the purified triterpenoid saponins have been reported from oat bran for the first time, in which compounds (1-8) are newly discovered compounds and compound (9) is a new natural product. Using ultra-high-performance liquid chromatography with tandem mass spectrometry techniques, a complete profile of oat triterpenoid saponins was established, and the contents of the 13 purified triterpenoid saponins were quantitated in 19 different commercial oat products. The total levels of the 13 triterpenoid saponins varied from 1.77 to 18.20 μg/g in these 19 products, in which oat bran (11 samples) and oatmeal (three samples) had higher levels than cold oat cereal (five samples). Among the 11 commercial oat bran samples, the average total levels of the 13 triterpenoid saponins in the five sprouted oat samples are slightly higher than those in the regular oat bran products.

The Chemistry and Health Benefits of Dietary Phenolamides

Phenolamides, also known as hydroxycinnamic acid amides or phenylamides, have been reported throughout the plant kingdom, while a few of these amine-conjugated hydroxycinnamic acids are unique in foods. The current knowledge of their specific functions in plant development and defense is readily available as is their biosynthesis; however, their functionality in humans is still largely unknown. Of the currently known phenolamides, the most common are avenanthramides, which are unique in oats and similar to the well-known drug Tranilast, which possess anti-inflammatory, antioxidant, anti-itch, and antiatherogenic activities. While recent data have brought to light more information regarding the other known phenolamides, such as hordatines, dimers of agmatine conjugated to hydroxycinnamic acid, and kukoamines, spermine-derived phenolamides, the information is still severely limited, leaving their potential health benefits to speculation. Herein, to highlight the importance of dietary phenolamides to human health, we review and summarize the four major subgroups of phenolamides, including their chemical structures, dietary sources, and reported health benefits. We believe that the studies on phenolamides are still in the infancy stage and additional health benefits of these phenolamides may yet be identified.