Alpha-Glucosidase Inhibitory Peptides: Sources, Preparations, Identifications, and Action Mechanisms.

With the change in people's lifestyle, diabetes has emerged as a chronic disease that poses a serious threat to human health, alongside tumor, cardiovascular, and cerebrovascular diseases. α-glucosidase inhibitors, which are oral drugs, have proven effective in preventing and managing this disease. Studies have suggested that bioactive peptides could serve as a potential source of α-glucosidase inhibitors. These peptides possess certain hypoglycemic activity and can effectively regulate postprandial blood glucose levels by inhibiting α-glucosidase activity, thus intervening and regulating diabetes. This paper provides a systematic summary of the sources, isolation, purification, bioavailability, and possible mechanisms of α-glucosidase inhibitory peptides. The sources of the α-glucosidase inhibitory peptides were introduced with emphasis on animals, plants, and microorganisms. This paper also points out the problems in the research process of α-glucosidase inhibitory peptide, with a view to providing certain theoretical support for the further study of this peptide.

Functional Perspective of Leeks: Active Components, Health Benefits and Action Mechanisms.

Leek (Allium fistulosum L.), a common and widely used food ingredient, is a traditional medicine used in Asia to treat a variety of diseases. Leeks contain a variety of bioactive substances, including sulfur compounds, dietary fiber, steroid compounds and flavonoid compounds. Many studies have shown that these active ingredients produce the following effects: promotion of blood circulation, lowering of cholesterol, relief of fatigue, anti-inflammation, anti-bacteria, regulation of cell metabolism, anti-cancer, anti-oxidation, and the lowering of fat and blood sugar levels. In this paper, the main bioactive components and biological functions of leeks were systemically reviewed, and the action mechanisms of bioactive components were discussed. As a common food, the health benefits of leeks are not well known, and there is no systematic summary of leek investigations. In light of this, it is valuable to review the recent progress and provide reference to investigators in the field, which will promote future applications and investigations of leeks.

Polysaccharides from Phellinus linteus: A systematic review of their extractions, purifications, structures and functions.

Phellinus linteus (P. linteus) is a famous Chinese medicine and has a long history in China. In recent years, P. linteus polysaccharides (PLPs) have attracted extensive attention because of their biological activities such as anti-bacteria, anti-aging, anti-oxidation, anti-inflammation, anti-tumor, hepatoprotective effect and hypoglycemic effect. In this review, we systemically summarized the advances in extractions, purifications and structural characterizations of PLPs, and also analyzed their biological functions and molecular mechanisms. Meanwhile, the structure-activity relationships of PLPs are closely related to their anti-oxidation and anti-tumor activities. So far, the applications of PLPs are still very limited, further exploring structure-activity relationships, biological functions and their mechanisms of PLPs will promote to develop functional foods.

Targeting mTOR Signaling by Dietary Polysaccharides in Cancer Prevention: Advances and Challenges.

Cancer is the most serious problem for public health. Traditional treatments often come with unavoidable side effects. Therefore, the therapeutic effects of natural products with wide sources and low toxicity are attracting more and more attention. Polysaccharides have been shown to have cancer-fighting potential, but the molecular mechanisms remain unclear. The mammalian target of rapamycin (mTOR) pathway has become an attractive target of antitumor therapy research in recent years. The regulation of mTOR pathway not only affects cell proliferation and growth but also has an important effect in tumor metabolism. Recent studies indicate that dietary polysaccharides play a vital role in cancer prevention and treatment by regulating mTOR pathway. Here, the progress in targeting mTOR signaling by dietary polysaccharides in cancer prevention and their molecular mechanisms are systemically summarized. It will promote the understanding of the anticancer effects of polysaccharides and provide reference to investigators of this cutting edge field.

Laminarin ameliorates alcohol-induced liver damage and its molecular mechanism in mice.

Alcoholic liver disease (ALD) has become a health issue globally. Laminarin, a low molecular weight marine-derived ß-glucan, has been identified with multiple biological activities. In this study, the ameliorative effect on ALD of laminarin isolated from brown algae was investigated. Phenotypic, pathological alterations and biochemical characteristics indicated that laminarin administration (100 mg/kg/day) significantly alleviated liver injury and improved liver function in the alcohol-induced mice. Gene chip results indicated that laminarin treatment caused 52 up-regulated and 13 down-regulated genes in the hepatic tissues of alcohol-induced damage mice, and most of these genes are associated with regulation of oxidative stress (such as CYP450/glutathione-dependent antioxidation), Wnt signaling pathway, retinol metabolism, and cAMP pathway based on GO and KEGG analysis. PPI network analysis indicated that the downstream target genes lied in the hub of the net. Our experiments also confirmed the changed expressions of some target genes. Taken together, these results suggest that laminarin can ameliorate alcohol-induced damage in mice and its molecular mechanism lies in modulating anti-oxidation pathway, WNT pathway, and cAMP pathway, which regulate the expressions of downstream target genes and alleviate alcohol-induced damage. Our study provides new clue to prevent alcohol-induced damage and will be benefit to develop functional foods. PRACTICAL APPLICATIONS: This study verified the positive effect on alcoholic liver disease (ALD) of laminarin, a water-soluble brown algae-derived ß-glucan, linked by ß-(1,3) glycosidic bonds with ß-(1,6) branches. Laminarin significantly alleviated liver injury and improved liver function of ALD mice. Moreover, transcriptomics and bioinformatics analysis further revealed the gene expression patterns, hub targets, and signalings including CYP450/glutathione, Wnt, retinol metabolism, cAMP pathways regulated by laminarin. This research is the first evidence for hepatoprotective effect of laminarin against ALD and its molecular mechanism, which will be advantage to develop functional foods or adjuvant therapy of ALD.

Targeting AMPK Signaling by Dietary Polyphenols in Cancer Prevention.

Cancer is a serious public health problem in the world and a major disease affecting human health. Dietary polyphenols have shown good potential in the treatment of various cancers. It is worth noting that cancer cells usually exhibit metabolic abnormalities of high glucose intake and inefficient utilization. AMPK is the key molecule in the regulation of energy metabolism and is closely related with obesity and diabetes. Recent studies indicate that AMPK also plays an important role in cancer prevention and regulating cancer-related genes and pathways, and dietary polyphenols can significantly regulate AMPK activity. In this review, the progress of dietary polyphenols preventing carcinogenesis via AMPK pathway is systemically summarized. From the viewpoint of interfering energy metabolism, the anti-cancer effects of dietary polyphenols are explained. AMPK pathway modulated by different dietary polyphenols affects pathways and target genes are summarized. Dietary polyphenols exert anti-cancer effect through the target molecules regulated by AMPK, which broadens the understanding of polyphenols anti-cancer mechanisms and provides value reference for the investigators of the novel field.

Dietary Supplementation of Octacosanol Improves Exercise-Induced Fatigue and Its Molecular Mechanism.

Several publications report that octacosanol (OCT) has different biological functions. This study was designed to evaluate the antifatigue effect and molecular mechanism of octacosanol (200 mg/(kg day)) in forced exercise-induced fatigue models of trained male C57BL/6 mice. Results showed that octacosanol ameliorated the mice's autonomic activities, forelimb grip strength, and swimming endurance, and the levels of liver glycogen (LG), muscle glycogen (MG), blood lactic acid (BLA), lactate dehydrogenase (LDH), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) were also regulated. Gene analysis results showed that treatment with OCT upregulated 29 genes, while 38 genes were downregulated in gastrocnemius tissue. Gene ontology (GO) analyses indicated that these genes enriched functions in relation to myofibril, contractile fiber, and calcium-dependent adenosinetriphosphatase (ATPase) activity. Octacosanol supplementation significantly adjusted the messenger RNA (mRNA) and protein expression levels related to fatigue performance. Octacosanol has an observably mitigating effect in exercise-induced fatigue models, and its molecular mechanism may be related to the regulation of tripartite motif-containing 63 (Trim63), periaxin (Prx), calcium voltage-gated channel subunit α1 H (Cacna1h), and myosin-binding protein C (Mybpc3) expression.