Changes in metabolites with harvest times of seedlings of various Korean oat (Avena sativa L.) cultivars and their neuraminidase inhibitory effects

Characterization of Seven New Steroidal Saponins from Korean Oat Cultivars by UPLC-QTOF-MS and UPLC-MS/MS

Oat saponins are composed of triterpenoid and steroidal saponins, and their potential biological activities, such as antibacterial, antifungicidal, osteogenic, and anticancer activities, have been reported. In this study, qualitative and quantitative analyses of oat saponins were conducted by using UPLC-QToF-MS and UPLC-Triple Q-MS/MS. A total of 22 saponins were analyzed in seven Korean oat cultivars. Among them, 7 saponins were identified as new compounds in this source, which were tentatively confirmed as nuatigenin-type saponins with 26-O-diglucoside and 3-O-malonylglucoside forms and (25S)-furost-5-en-3β,22,26-triol-type saponins. In addition, the total content of these saponins ranged from 70.61 to 141.38 mg/100 g dry weight, and it was affected by the type of oat cultivar and the presence or absence of hulling. These detailed profiles will be suggested as fundamental data for breeding superior oat cultivars, evaluating of related products, and various industries.

Oat (Avena sativa L.) Sprouts Restore Skin Barrier Function by Modulating the Expression of the Epidermal Differentiation Complex in Models of Skin Irritation

Oats (Avena sativa L.) are used as therapeutic plants, particularly in dermatology. Despite numerous studies on their skin moisturization, anti-inflammation, and antioxidation effects, the precise molecular mechanisms of these effects are only partially understood. In this study, the efficacy of oat sprouts in the treatment of allergic contact dermatitis (ACD) was investigated, and their specific phytoconstituents and exact mechanisms of action were identified. In the in vivo ACD model, by stimulating the mitogen-activated protein kinase signaling pathway, oat sprouts increased the expression levels of proteins associated with skin barrier formation, which are produced during the differentiation of keratinocytes. In addition, in a lipopolysaccharide-induced skin irritation model using HaCaT, steroidal saponins (avenacoside B and 26-deglucoavenacoside B) and a flavonoid (isovitexin-2-o-arabinoside) of oat sprouts regulated the genetic expression of the same proteins located on the adjacent locus of human chromosomes known as the epidermal differentiation complex (EDC). Furthermore, oat sprouts showed immunomodulatory functions. These findings suggest the potential for expanding the use of oat sprouts as a treatment option for various diseases characterized by skin barrier disruption.

Inhibitory Potential of Quercetin Derivatives Isolated from the Aerial Parts of Siegesbeckia pubescens Makino against Bacterial Neuraminidase

This study aimed to isolate bacterial neuraminidase (BNA) inhibitory O-methylated quercetin derivatives from the aerial parts of S. pubescens. All the isolated compounds were identified as O-methylated quercetin (1-4), which were exhibited to be noncompetitive inhibitors against BNA, with IC₅₀ ranging from 14.0 to 84.1 μM. The responsible compounds (1-4) showed a significant correlation between BNA inhibitory effects and the number of O-methyl groups on quercetin; mono (1, IC₅₀ = 14.0 μM) > di (2 and 3, IC₅₀ = 24.3 and 25.8 μM) > tri (4, IC₅₀ = 84.1 μM). In addition, the binding affinities between BNA and inhibitors (1-4) were also examined by fluorescence quenching effect with the related constants (K_SV, K_A, and n). The most active inhibitor 1 possessed a K_SV with 0.0252 × 10⁵ L mol^-1. Furthermore, the relative distribution of BNA inhibitory O-methylated quercetins (1-4) in S. pubescens extract was evaluated using LC-Q-TOF/MS analysis.

Neuroprotective Effects of Agri-Food By-Products Rich in Phenolic Compounds

Neurodegenerative diseases are known for their wide range of harmful conditions related to progressive cell damage, nervous system connections and neuronal death. These pathologies promote the loss of essential motor and cognitive functions, such as mobility, learning and sensation. Neurodegeneration affects millions of people worldwide, and no integral cure has been created yet. Here, bioactive compounds have been proven to exert numerous beneficial effects due to their remarkable bioactivity, so they could be considered as great options for the development of new neuroprotective strategies. Phenolic bioactives have been reported to be found in edible part of plants; however, over the last years, a large amount of research has focused on the phenolic richness that plant by-products possess, which sometimes even exceeds the content in the pulp. Thus, their possible application as an emergent neuroprotective technique could also be considered as an optimal strategy to revalorize these agricultural residues (those originated from plant processing). This review aims to summarize main triggers of neurodegeneration, revise the state of the art in plant extracts and their role in avoiding neurodegeneration and discuss how their main phenolic compounds could exert their neuroprotective effects. For this purpose, a diverse search of studies has been conducted, gathering a large number of papers where by-products were used as strong sources of phenolic compounds for their neuroprotective properties. Finally, although a lack of investigation is quite remarkable and greatly limits the use of these compounds, phenolics remain attractive for research into new multifactorial anti-neurodegenerative nutraceuticals.

The Potential Neuroprotective Effects of Extracts from Oat Seedlings against Alzheimer's Disease

The physiological or dietary advantages of germinated grains have been the subject of numerous discussions over the past decade. Around 23 million tons of oats are consumed globally, making up a sizeable portion of the global grain market. Oat seedlings contain more protein, beta-glucan, free amino acids, and phenolic compounds than seeds. The progressive neurodegenerative disorder of Alzheimer's is accompanied by worsening memory and cognitive function. A key indicator of this disorder is the unusual buildup of amyloid-beta protein (or Aβ) in human brains. In this context, oat seedling extract (OSE) has been identified as a new therapeutic candidate for AD, due to its antioxidant activity and AD-specific mechanism of action. This study directly investigated how OSE affected AD and its impacts by examining the cognitive function and exploring the inflammatory response mechanism. The dried oat seedlings were grounded finely with a grinder, inserted with 50% fermented ethanol 10 times (w/v), and extracted by stirring for 10 h at 45 °C. After filtering the extract by 0.22 um filter, some of it was used for UHPLC analysis. The results indicated that the treatment with OSE protects against Aβ25-35-induced cytotoxicity in BV2 cells. Tg-5Xfad AD mice had strong deposition of Aβ throughout their brains, while WT mice did not exhibit any such deposition within their brains. A drastic reduction was observed in terms of numbers, as well as the size, of Aβ plaques within Tg-5Xfad AD mice exposed to OSE. This study indicated OSE's neuroprotective impacts against neurodegeneration, synaptic dysfunction, and neuroinflammation induced by amyloid-beta. Our results suggest that OSE acts as a neuroprotective agent to combat AD-specific apoptotic cell death, neuroinflammation, amyloid-beta accumulation, as well as synaptic dysfunction in AD mice's brains. Furthermore, the study indicated that OSE treatment affects JNK/ERK/p38 MAPK signaling, with considerable inhibition in p-JNK, p-p38, and p-ERK levels seen in the brain of OSE-treated Tg-5Xfad AD mice.

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.

Enzymes-Assisted Extraction of Plants for Sustainable and Functional Applications

The scientific community and industrial companies have discovered significant enzyme applications to plant material. This rise imparts to changing consumers' demands while searching for 'clean label' food products, boosting the immune system, uprising resistance to bacterial and fungal diseases, and climate change challenges. First, enzymes were used for enhancing production yield with mild and not hazardous applications. However, enzyme specificity, activity, plant origin and characteristics, ratio, and extraction conditions differ depending on the goal. As a result, researchers have gained interest in enzymes' ability to cleave specific bonds of macroelements and release bioactive compounds by enhancing value and creating novel derivatives in plant extracts. The extract is enriched with reducing sugars, phenolic content, and peptides by disrupting lignocellulose and releasing compounds from the cell wall and cytosolic. Nonetheless, depolymerizing carbohydrates and using specific enzymes form and release various saccharides lengths. The latest studies show that oligosaccharides released and formed by enzymes have a high potential to be slowly digestible starches (SDS) and possibly be labeled as prebiotics. Additionally, they excel in new technological, organoleptic, and physicochemical properties. Released novel derivatives and phenolic compounds have a significant role in human and animal health and gut-microbiota interactions, affecting many metabolic pathways. The latest studies have contributed to enzyme-modified extracts and products used for functional, fermented products development and sustainable processes: in particular, nanocellulose, nanocrystals, nanoparticles green synthesis with drug delivery, wound healing, and antimicrobial properties. Even so, enzymes' incorporation into processes has limitations and is regulated by national and international levels.