GC × GC-MS analysis and hypolipidemic effects of polyphenol extracts from Shanxi-aged vinegar in rats under a high fat diet

Research progress on the regulation of oxidative stress by phenolics: the role of gut microbiota and Nrf2 signaling pathway

In recent years, the increase in high-calorie diets and sedentary lifestyles has made obesity a global public health problem. An unbalanced diet promotes the production of proinflammatory cytokines and causes redox imbalance in the body. Phenolics have potent antioxidant activity and cytoprotective ability. They can scavenge free radicals and reactive oxygen species, and enhance the activity of antioxidant enzymes, thus combating the body's oxidative stress. They can also improve the body's inflammatory response, enhance the enzyme activity of lipid metabolism, and reduce the contents of cholesterol and triglyceride. Most phenolics are biotransformed and absorbed into the blood after the action by gut microbiota; these metabolites then undergo phase I and II metabolism and regulate oxidative stress by scavenging free radicals and increasing expression of antioxidant enzymes. Phenolics induce the expression of genes encoding antioxidant enzymes and phase II detoxification enzymes by stimulating Nrf2 to enter the nucleus and bind to the antioxidant response element after uncoupling from Keap1, thereby promoting the production of antioxidant enzymes and phase II detoxification enzymes. The absorption rate of phenolics in the small intestine is extremely low. Most phenolics reach the colon, where they interact with the microbiota and undergo a series of metabolism. Their metabolites will reach the liver via the portal vein and undergo conjugation reactions. Subsequently, the metabolites reach the whole body to exert biological activity by traveling with the systemic circulation. Phenolics can promote the growth of probiotics, reduce the ratio of Firmicutes/Bacteroidetes (F/B), and improve intestinal microecological imbalance. This paper reviews the nutritional value, bioactivity, and antioxidant mechanism of phenolics in the body, aiming to provide a scientific basis for the development and utilization of natural antioxidants and provide a reference for elucidating the mechanism of action of phenolics for regulating oxidative stress in the body. © 2023 Society of Chemical Industry.

Analysis of the mechanism of action of quercetin in the treatment of hyperlipidemia based on metabolomics and intestinal flora

Hyperlipidemia (HLP) is one of the main factors leading to cardiovascular diseases. Quercetin (QUE) is a naturally occurring polyhydroxy flavonoid compound that has a wide range of pharmacological effects. However, the potential mechanism for treating HLP remains unclear. Thus, the study aimed to investigate the role of QUE in HLP development and its underlying mechanisms in HLP rats based on the analysis of gut microbiota and plasma metabolomics. Following the establishment of an HLP model in rats, QUE was orally administered. Plasma samples and fecal samples were collected from HLP rats for microbiome 16S rDNA sequencing and metabolic UPLC-Q-Exactive-MS analysis. The results suggested that QUE could regulate dyslipidemia and inhibit the levels of TC, TG, and LDL-c. Additionally, histopathological findings revealed that QUE could reduce lipid deposition, ameliorate hepatic injury and steatosis in HFD-induced rats, and have a protective effect on the liver. The analysis and identification of plasma metabolomics showed that the intervention effect of QUE on HLP rats was related to 60 differential metabolites and signal pathways such as lactosamine, 11b-hydroxyprogesterone, arachidonic acid, glycerophospholipid, sphingolipid, glycerolipid, and linoleic acid metabolism. Combined with fecal microbiological analysis, it was found that QUE could significantly change the composition of intestinal flora in HLP rats, increase beneficial bacteria, and reduce the composition of harmful bacteria, attenuating the Firmicutes/Bacteroidetes ratio. The results of correlation analysis showed that the relative abundance level of Firmicutes, Deironobacterium, Fusobacterium, Bacteroides, and Escherichia coli was closely related to the change of differential metabolites. In summary, combined with metabolomics and gut microbiota studies, it is found that QUE can reduce lipid levels and improve liver function. The potential mechanism may be the regulation of metabolism and intestinal flora that play a role in reducing lipid levels, to achieve the purpose of treatment of HLP.

Gougunao tea polysaccharides ameliorate high-fat diet-induced hyperlipidemia and modulate gut microbiota

Many natural polysaccharides have been proven to have ameliorative effects on high-fat diet-induced hyperlipidemia with fewer side effects. However, similar data on Gougunao tea polysaccharides remain obscure. In this study, we aimed to investigate the role of Gougunao tea polysaccharides (GTP40) in the alleviation of hyperlipidemia and regulation of gut microbiota in C57BL/6J mice induced by a high-fat diet. The results indicated that GTP40 intervention inhibited the abnormal growth of body weight and the excessive accumulation of lipid droplets in the livers and ameliorated the biochemical parameters of serum/liver related to lipid metabolism in hyperlipidemia mice. The elevated levels of antioxidant enzyme and anti-inflammation cytokine in serum, as well as the up-regulating anti-inflammation gene in the liver, reflected that GTP40 might mitigate the oxidative and inflammatory stress induced by a high-fat diet. In addition, GTP40 could modulate the composition, abundance, and diversity of gut microbiota in hyperlipidemia mice. Besides, Spearman's correlation analysis implied that GTP40 intervention could enrich beneficial bacteria (e.g., Akkermansia, Bacteroides, Roseburia, and Alistipes), and decrease harmful bacteria (e.g., Blautia, Faecalibaculum, Streptococcus, and norank_f_Desulfovibrionaceae), which were correlated with the lipid metabolic parameters associated with hyperlipidemia. Moreover, it also indicated that there was a significant correlation between gut microbiota and SCFAs. Thus, GTP40 may be a novel strategy against fat accumulation, oxidative stress, and inflammation, as well as restoring the normal microbial balance of the gut in hyperlipidemia mice.

Immunomodulatory effects of vinegar-egg juice: Potential pharmacological effects of a traditional Chinese food remedy?

Thousands of years of historical practice have proven that the ancient Chinese food, vinegar-egg juice, has immune-boosting effects with the presence of many nutritional factors. However, its mechanism of action in the body remains unclear. In this research project, vinegar-egg juice was chosen to analyze its immune-enhancing effects on mice. The immune enhancing effects of egg, vinegar and vinegar egg juice on lymphocytes of mouse spleen were compared. The effects on immune function of mice were analyzed by studying the organ index, natural killer(NK) cell activity, lymphocyte transformation function and cytokine changes in immune organs after treatment with vinegar-egg juice. The mechanism of immune enhancement was speculated by analyzing the changes of total IKKα/β/IκBα/NF-κB and its phosphorylated protein kinase by Western blot. Experiments have shown that vinegar and eggs have less immune regulation than vinegar-egg juice. Vinegar-egg juice can regulate the cellular and humoral immunity of spleen lymphocytes, increase the phosphorylated kinases of IKKα/β, reduce the total protein expression of IκBα, and activate the signaling pathway of IKK/IκB/NF-κB. In addition, compared with the control group, vinegar-egg juice reduced the Firmicutes/Bacteroidetes ratio and increased the relative abundance of beneficial bacteria. Furthermore, vinegar-egg juice can raise phosphatidylserine (PS) and serotonin (5-HT) levels in the body. The results showed that the vinegar-egg juice had obvious immunomodulatory activity. It was speculated that the intake of vinegar-egg juice can increase the activity of NK cells, T lymphocytes and B lymphocytes by increasing 5-HT levels, ultimately enhancing the body's immune function. PRACTICAL APPLICATIONS: In this work, we evaluated the immune regulation of vinegar, egg and vinegar-egg juice in mice. In addition, we investigated the effects of vinegar-egg juice on gut microbiota. And combined with the composition of the vinegar-egg juice, it was found that the intake of vinegar-egg juice could increase the activity of NK cells, T lymphocytes and B lymphocytes by increasing 5-HT levels, ultimately enhancing the body's immune function. On the basis of the results of this study, we recommend vinegar-egg juice can be a potential health food to resist the epidemic and improve autoimmunity in special times of the novel coronavirus outbreak.

Putative Mechanisms Underlying the Beneficial Effects of Polyphenols in Murine Models of Metabolic Disorders in Relation to Gut Microbiota

The beneficial effects of polyphenols on metabolic disorders have been extensively reported. The interaction of these compounds with the gut microbiota has been the focus of recent studies. In this review, we explored the fundamental mechanisms underlying the beneficial effects of polyphenols in relation to the gut microbiota in murine models of metabolic disorders. We analyzed the effects of polyphenols on three murine models of metabolic disorders, namely, models of a high-fat diet (HFD)-induced metabolic disorder, dextran sulfate sodium (DSS)-induced colitis, and a metabolic disorder not associated with HFD or DSS. Regardless of the model, polyphenols ameliorated the effects of metabolic disorders by alleviating intestinal oxidative stress, improving inflammatory status, and improving intestinal barrier function, as well as by modulating gut microbiota, for example, by increasing the abundance of short-chain fatty acid-producing bacteria. Consequently, polyphenols reduce circulating lipopolysaccharide levels, thereby improving inflammatory status and alleviating oxidative imbalance at the lesion sites. In conclusion, polyphenols likely act by regulating intestinal functions, including the gut microbiota, and may be a safe and suitable therapeutic agent for various metabolic disorders.

Polyphenols extracted from Shanxi-aged vinegar exert hypolipidemic effects on OA-induced HepG2 cells via the PPARα-LXRα-ABCA1 pathway

Hyperlipidemia is one of the key risk factors causing many chronic diseases, and lowering blood lipid levels can prevent many diseases. In this paper, a hyperlipidemic cell model of oleic acid (OA) induced hepatocellular carcinoma cells (HepG2) was established using polyphenols extracted from Shanxi-aged vinegar (SAVEP). The effects of SAVEP on nuclear damage, mitochondrial membrane potential, apoptosis, cellular lipid deposition, and lipid metabolism protein expression in HepG2 hyperlipidemic cells were examined to investigate the lipid-lowering mechanism of SAVEP at the cellular level. The results showed that SAVEP could reduce the content of TC/TG index, repair the nuclear damage, reduce lipid accumulation and finally decrease the rate of apoptosis by up-regulating the expression of key proteins such as PPARα, LXRα, and ABCA1 in the process of lipid metabolism. PRACTICAL APPLICATIONS: In this thesis, the hypolipidemic activity of polyphenol extracts from Shanxi-aged vinegar was analyzed on the level of HepG2 cells. The hypolipidemic mechanism of oxidative stress, lipid metabolism and inflammatory stress was also elucidated. It provided a theoretical basis for the in-depth understanding of the hypolipidemic health effects of Shanxi-aged vinegar.

Cereal Vinegar Sediment Alleviates Spontaneous Ulcerative Colitis in Il-10 Deficient Mice

SCOPE

Cereal vinegar sediment (CVS) is precipitation generated during the preservation of vinegar. It has various functions such as anti-inflammatory, anti-tumor, hypoglycemic, and hypolipidemic. This study evaluates the effects of CVS on spontaneous colitis in Il-10^-/- mice.

METHODS AND RESULTS

CVS (1 g kg^-1 body weight) is administered to mice for 42 days. CVS alleviated epithelium damage, inhibited myeloperoxidase (MPO) activity and malondialdehyde (MDA) level, decreased gene expression of tumor necrosis factor (Tnf )-a, inducible nitric oxide synthase (Inos), Interleukin(Il-23) in colon tissues is found. CVS also inhibited secretion of IL-2, IL-6, IL-13, Granulocyte colony stimulating factor (G-CSF), granulocyte macrophage colony-stimulating factor (GMCSF), Interferon (IFN)-γ, and Regulated upon Activation, Normal T Cell Expressed and Presumably Secreted (RANTES) in serum. While CVS enhanced Regenerating Family Member 3 Gamma (Reg3γ), Mucin (Muc2, Muc3, and Muc4 gene expression, promoted intestinal epithelial cells to secrete Muc-2, and increased the content of acetic acid in intestinal tract of Il-10^-/- mice. Additionally, CVS altered the composition of the gut microbiota by promoting the abundance of Akkermansia, Alistipes, and Lactobacillus, while inhibiting Desulfovibrio and Clostridium sensu stricto 1. These changes may be related to the regulation of steroid, fatty acids, and bile acid biosynthesis.

CONCLUSION

This study demonstrated that CVS ameliorates spontaneous ulcerative colitis in Il-10^-/- mice, which suggests CVS supplementation may serve as a protective dietary nutrient against colitis.

Elucidation and Regulation of Polyphenols in the Smoking Process of Shanxi Aged Vinegar

Polyphenols (PPs) are the main contributors to the health functions of Shanxi aged vinegar (SAV) and are mainly produced during the smoking process. This study aimed to explore the feasibility of regulating the accumulation of total water-soluble PPs (TWSP) by changing environmental factors based on the distribution of PPs. A total of eleven PPs, such as vanillin, vanillic acid, and (e)-ferulic acid, were detected during the smoking process. During the smoking process, the content of TWSP gradually increased and was accompanied by changes in environmental factors. Spearman correlation analysis and verification experiments showed that temperature, amino acids, and reducing sugars, as the main influencing factors, promoted the accumulation of TWSP. The in situ regulation strategy of changing environmental factors significantly increased the accumulation of TWSP by 12.24%.

Polyphenols Extracted from Shanxi-Aged Vinegar Inhibit Inflammation in LPS-Induced RAW264.7 Macrophages and ICR Mice via the Suppression of MAPK/NF-κB Pathway Activation

Shanxi-aged vinegar, a traditional Chinese grain-fermented food that is rich in polyphenols, has been shown to have therapeutic effects on a variety of diseases. However, there has been no comprehensive evaluation of the anti-inflammatory activity of polyphenols extracted from Shanxi-aged vinegar (SAVEP) to date. The anti-inflammatory activities of SAVEP, both in RAW 264.7 macrophages and mice, were extensively investigated for the potential application of SAVEP as a novel anti-inflammatory agent. In order to confirm the notion that polyphenols could improve inflammatory symptoms, SAVEP was firstly detected by gas chromatography mass spectrometry (GC-MS). In total, 19 polyphenols were detected, including 12 phenolic acids. The study further investigated the protective effect of SAVEP on lipopolysaccharide-induced inflammation in RAW264.7 macrophages and ICR mice. The results showed that compared with those of the model group, SAVEP could remarkably recover the inflammation of macrophage RAW264.7 and ICR mice. SAVEP can normalise the expression of related proteins via the suppression of MAPK/NF-κB pathway activation, inhibiting the expression of iNOS and COX-2 proteins, and consequently the production of inflammatory factors, thus alleviating inflammatory stress. These results suggest that SAVEP may have a potential function against inflammation.

Health Promoting Properties of Cereal Vinegars

Vinegar has been used for its health promoting properties since antiquity. Nowadays, these properties are investigated, scientifically documented, and highlighted. The health benefits of vinegar have been associated with the presence of a variety of bioactive components such as acetic acid and other organic acids, phenolic compounds, amino acids, carotenoids, phytosterols, vitamins, minerals, and alkaloids, etc. These components are known to induce responses in the human body, such as antioxidant, antidiabetic, antimicrobial, antitumor, antiobesity, antihypertensive, and anti-inflammatory effects. The diversity and levels of bioactive components in vinegars depend on the raw material and the production method used. Cereal vinegars, which are more common in the Asia-Pacific region, are usually made from rice, although other cereals, such as millet, sorghum, barley, malt, wheat, corn, rye, oats, bran and chaff, are also used. A variety of bioactive components, such as organic acids, polyphenols, amino acids, vitamins, minerals, alkaloids, melanoidins, butenolides, and specific compounds such as γ-oryzanol, tetramethylpyrazine, γ-aminobutyric acid, etc., have been associated with the health properties of cereal vinegars. In this work, the bioactive components and the related health effects of cereal vinegars are reviewed, and the most recent scientific literature is presented and discussed.