Inhibitory effects of dietary soy isoflavone and gut microbiota on contact hypersensitivity in mice

Ellagic acid alleviates DSS-induced ulcerative colitis by inhibiting ROS/NLRP3 pathway activation and modulating gut microbiota in mice

Ulcerative colitis (UC) can cause severe oxidative stress in the colon, which can lead to tissue damage and an imbalance in the normal gut microbiota. Ellagic acid (EA) is one of the main types of plant polyphenols with improved pharmacological effects such as antioxidant, anti-inflammatory, and antibacterial properties. However, currently, the studies on the impact of EA on the gut microbiota and its potential to alleviate UC in mice through the ROS/NLRP3 pathway are limited. In this study, dextran sodium sulfate (DSS) was used to construct a UC mouse model, which was then treated with EA as an intervention for UC. The results revealed that EA alleviated the trend of liver, spleen, and weight changes in UC mice and improved colon oxidative stress, inflammation, and pathological damage. Mechanistically, DSS-induced UC indicated a significant increase in ROS/NLRP3 pathway-related factors, whereas EA intervention activated the Nrf2 pathway to reduce these factors. Furthermore, the DSS group had a reduced abundance of Firmicutes (59.02%) and an increased abundance of Bacteroides and Proteobacterium by 1.8 times and 10.16%; however, EA intervention reversed these changes, thus alleviating UC. The findings of this study revealed that EA could significantly enhance the composition of gut microbiota in UC and reduce the inflammatory response, colonic damage as well as oxidative stress caused by DSS by regulating the ROS/NLRP3 pathway. These results provide novel perspectives on the prevention and treatment strategies of UC and highlight the therapeutic benefits of EA in managing colitis.

Exploring Black Soybean Extract Cream for Inflammatory Dermatitis-Toward Radiation Dermatitis Relief

We aimed to evaluate the effect of black soybean extract cream (BSEC) on 2,4-dinitrochlorobenzene (DNCB)-induced dermatitis in murine models mimicking inflammatory dermatitis observed in humans. In this DNCB-induced model, BALB/c mice were spread with 100 μL of 2% DNCB twice a week for two weeks to induce skin inflammation on the shaved back skin; then, a placebo or BSEC that consisted of the volatile fraction derived from the seeds of Glycine max (L.) Merr. was applied to the DNCB-sensitized mice for 7 days. Gross visual analysis was conducted to assess the impact of BSEC on dermatitis, and an enzyme-linked immunosorbent assay (ELISA) was subsequently performed to detect inflammatory cytokines in the presence or absence of BSEC after DNCB sensitization. Lastly, the possible mechanisms responsible for the effects of BSEC on inflammatory dermatitis were investigated in a human leukemia monocytic cell line, THP-1. Our study showed that BSEC displayed antioxidant and anti-inflammatory effects. BSEC has the ability to diminish dermatitis, and all three experiments demonstrated that BSEC effectively reduced the progression of dermatitis while significantly suppressing inflammatory responses in the preclinical models. Consequently, BSEC exhibited promising phytotherapy for inflammatory dermatitis, potentially attributed to its anti-inflammatory and antioxidant properties.

Soybean Isoflavones Ameliorates Lactation Performance in Postpartum Mice by Alleviating Oxidative Stress and Regulating Gut Microflora

Postpartum dysgalactiae syndrome (PPDS) is one of the key issues affecting breastfeeding, usually occurring as breast swelling, a low milk yield, and at length a stop of breast milk secretion. Therefore, there is a need to investigate the effectiveness of Traditional Chinese Medicine (TCM) diet therapy in treating or preventing PPDS. This study aims to analyze the effect of soybean isoflavone (SIF), a natural estrogen found in plants, on postpartum lactation performance in mice and to evaluate its potential as a treatment for PPDS. Adult female BALB/c mice at 8 weeks of age (25 ± 3 g) are randomly divided into four groups fed with different levels of SIF and a normal diet for 14 days. SIF (0, 50, 100, 200 mg kg-1 BW) is provided via intra-gastric route to the experimental mice. Using a high-throughput sequencing of microbial diversity and mammary gland metabolites, it is found that SIF-treated mice potentially show an improved milk performance via enhanced antioxidant capacity and altered gut microbiota. SIF from plant sources at a high dosage promotes the lactation in normal postpartum mice.

Modulation of allergic contact dermatitis via gut microbiota modified by diet, vitamins, probiotics, prebiotics, and antibiotics

Allergic contact dermatitis is one of the most common recorded occupational diseases. There are many different substances that the skin comes into contact with on a daily basis and that can cause ACD, e.g., preservatives, surfactants, and antimicrobial agents. The development of a mouse model of ACD has provided insight into the immune mechanisms involved. Drugs used in the treatment of skin diseases have many side effects. Therefore, alternative methods of suppressing the immune response to reduce the symptoms of skin diseases are being sought. In recent years, high hopes have been placed on dietary modulation and supplementation to affect the intestinal microbial composition and promote anti-inflammatory responses. In addition, other studies have shown the crucial role of intestinal microbiota in many immune-mediated diseases. Recognition and characterization of pro- and anti-inflammatory nutrients and supplements may be crucial to support the treatment of diseases such as atopic dermatitis, acne vulgaris, psoriasis, and allergic contact dermatitis.

Effects of Lactobacillus plantarum FZU3013-Fermented Laminaria japonica on Lipid Metabolism and Gut Microbiota in Hyperlipidaemic Rats

In this study, we explored the effect of Lactobacillus plantarum FZU3013-fermented Laminaria japonica (LPLJ) supplementation to prevent hyperlipidaemia in rats fed with a high-fat diet (HFD). The results indicate that LPLJ supplementation improved serum and hepatic biochemical indicators (p < 0.05), elevated short-chain fatty acid levels, reduced HFD-induced accumulation of lipid droplets in the liver, modulated the relative abundance of some microbial phylotypes, and reduced hyperlipidaemia in HFD-fed rats by adjusting the aminoacyl-tRNA, phenylalanine, tyrosine, and tryptophan biosynthetic pathways, as well as the phenylalanine, D-glutamine and D-glutamate, and glutathione metabolic pathways. Additionally, hepatic mRNA levels of the genes involved in lipid metabolism and bile acid homeostasis were significantly reduced by LPLJ intervention (p < 0.05). These results suggest that LPLJ has a positive effect on modulating lipid metabolism and has the potential to be a functional food that can help prevent hyperlipidaemia.

Microbiome-metabolomic analyses of the impacts of dietary stachyose on fecal microbiota and metabolites in infants intestinal microbiota-associated mice

BACKGROUND

The intestinal microbiota and metabolites play an important role in human health and immunity. However, few studies have investigated the long-term effects of stachyose on the human intestinal microbiota and metabolism. Therefore, in this study, the feces of infants were transplanted into germ-free mice, and the effect of long-term stachyose intake on intestinal metabolism was examined by comparing the results of microbiome and metabolome analyses. Ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was used to study the effects of stachyose intake on the metabolites and metabolic pathways of the transplanted human intestinal microbiota.

RESULTS

We observed that stachyose significantly altered the composition of the intestinal microbiota and metabolites, up-regulated production of the metabolite taurocholic acid, down-regulated amino acid metabolism, and significantly regulated the metabolism of taurine and hydroxytaurine, pantothenate and coenzyme A (CoA) biosynthesis, and other signaling pathways.

CONCLUSION

These findings may provide a basis for elucidating the mechanism by which stachyose promotes host health. © 2020 Society of Chemical Industry.

Ganoderic acid A from Ganoderma lucidum ameliorates lipid metabolism and alters gut microbiota composition in hyperlipidemic mice fed a high-fat diet

Ganoderic acid A (GA) is one of the most abundant triterpenoids in Ganoderma lucidum, and has been proved to possess a wide range of beneficial health effects. The aim of the current study is to investigate the amelioration effects and mechanism of GA on improving hyperlipidemia in mice fed a high-fat diet (HFD). The results showed that GA intervention significantly inhibited the abnormal growth of body weight and epididymal white adipose tissue (eWAT), prevented the hypertrophy of epididymal adipocytes, and ameliorated the biochemical parameters of serum and liver related to lipid metabolism in HFD-fed mice. Histological analysis also showed that the excessive accumulation of lipid droplets in the liver induced by HFD-feeding was greatly alleviated by GA intervention. In addition, GA intervention also increased the level of short chain fatty acids (SCFAs) in the intestine and promoted the excretion of bile acids (BAs) through feces. High-throughput sequencing of bacterial full-length 16S rDNA revealed that daily supplementation with GA made significant structural changes in the gut microbial population of mice fed with HFD, in particular modulating the relative abundance of some function related microbial phylotypes. The relationships between lipid metabolic parameters and gut microbial phylotypes were also revealed by correlation analysis based on a heatmap and network. The result showed that 46 key gut microbial phylotypes (OTUs) were markedly correlated with at least one lipid metabolic parameter. Moreover, UPLC-QTOF/MS-based liver metabolomics showed that 111 biomarkers (47 up-regulated metabolites and 64 down-regulated metabolites) were significantly changed after high-dose GA intervention (75 mg kg^-1 day^-1), compared with the HFD-fed hyperlipidemic mice. Metabolic pathway enrichment analysis of the differential hepatic metabolites demonstrated that GA intervention had significant regulatory effects on primary bile acid biosynthesis, fatty acid biosynthesis, amino sugar and nucleotide sugar metabolism, inositol phosphate metabolism, and so on. In addition, GA intervention regulated the mRNA levels of hepatic genes involved in fatty acid metabolism and bile acid homeostasis. These findings present new evidence supporting that GA from G. lucidum has the potential to alleviate lipid metabolic disorders and ameliorate the imbalance of gut microflora in a positive way.

Black Raspberries and Protocatechuic Acid Mitigate DNFB-Induced Contact Hypersensitivity by Down-Regulating Dendritic Cell Activation and Inhibiting Mediators of Effector Responses

Contact hypersensitivity (CHS) is the most common occupational dermatological disease. Dendritic cells (DCs) mediate the sensitization stage of CHS, while T-cells facilitate the effector mechanisms that drive CHS. Black raspberry (Rubus occidentalis, BRB) and BRB phytochemicals possess immunomodulatory properties, but their dietary effects on CHS are unknown. We examined the effects of diets containing BRB and protocatechuic acid (PCA, a constituent of BRB and an anthocyanin metabolite produced largely by gut microbes), on CHS, using a model induced by 2,4-dinitrofluorobenze (DNFB). Mice were fed control diet or diets supplemented with BRB or PCA. In vitro bone-marrow derived DCs and RAW264.7 macrophages were treated with BRB extract and PCA. Mice fed BRB or PCA supplemented diets displayed decreased DNFB-induced ear swelling, marked by decreased splenic DC accumulation. BRB extract diminished DC maturation associated with reduced Cd80 expression and Interleukin (IL)-12 secretion, and PCA reduced IL-12. Dietary supplementation with BRB and PCA induced differential decreases in IL-12-driven CHS mediators, including Interferon (IFN)-γ and IL-17 production by T-cells. BRB extracts and PCA directly attenuated CHS-promoting macrophage activity mediated by nitric oxide and IL-12. Our results demonstrate that BRB and PCA mitigate CHS pathology, providing a rationale for CHS alleviation via dietary supplementation with BRB or BRB derived anthocyanins.

Diets containing pomegranate polyphenol and soy isoflavone attenuate contact hypersensitivity in mice

Contact hypersensitivity (CHS) is frequently used as an animal model for human allergic contact dermatitis (ACD). Diets of pomegranate polyphenols (PPs) or soy isoflavones (SIs) each alleviated CHS symptoms; however, the effect of diets containing a mixture of PPs and SIs on CHS is unclear. We investigated the CHS-inhibitory effects of diets supplemented with a mixture of PPs and SIs at human physiologically relevant doses. Consuming the mixture of PPs and SIs attenuated ear swelling and reduced infiltration of Gr-1-positive cells. Ear swelling decreased in the PP and SI-treated mice compared to the SI-treated mice. The auricle tissues of the PP and SI-fed mice exhibited decreased production of CXCL2 and MCP-5 compared to the SI- and PP-treated mice, respectively. These results suggest that dietary supplementation with a mixture of PPs and SIs may have ACD-preventive effects and may prove more beneficial than supplementation with PPs or SIs alone.

Dietary soyasaponin attenuates 2,4-dinitrofluorobenzene-induced contact hypersensitivity via gut microbiota in mice

Soyasaponins (SSs) are abundant in soybeans and display inhibitory activity against contact hypersensitivity (CHS), which is often used as a mouse model for allergic contact dermatitis (ACD); however, their therapeutic mechanisms remain unknown. Here, we attempted to clarify the role of gut microbiota in the inhibition of CHS by dietary soyasaponins. For antibiotic treatment, mice were administered a mixture of ciprofloxacin and metronidazole or vancomycin. These antibiotics and SSs were given to mice via drinking water 3-weeks prior to CHS induction with 2,4-dinitrofluorobenzene, and the mice were analysed for ear swelling, tissue oedema, infiltration of Gr-1-positive immune cells, the composition of faecal microbiota and regulatory T (Treg ) cells. The soyasaponin diets attenuated ear swelling and tissue oedema, and reduced the number of Gr-1-positive cells infiltrating ear tissues. CHS caused changes in the structure of the gut microbiota, but dietary SSs blocked the changes in the microbiota composition. Ciprofloxacin and metronidazole treatments significantly enhanced the severity of CHS symptoms, whereas vancomycin treatment blocked the suppressive effect of dietary SSs on CHS. These antibiotic treatments differed in their effects on the gut microbiota composition. Treg cells in auricular lymph node and spleen increased under SS-enriched diets, but this increase was blocked by vancomycin treatment. These results suggest that dietary SSs exert their inhibitory activity on CHS via the gut microbiota in mice, suggesting that dietary supplementation with SSs may have beneficial effects on ACD patients, but that the gut microbiota is a critical determinant of the therapeutic value of dietary SSs.

Impact of soymilk consumption on 2,4-dinitrofluorobenzene-induced contact hypersensitivity and gut microbiota in mice

Soymilk is rich in phytochemicals such as soy isoflavones (SIs) and soyasaponins (SSs). Dietary SIs and SSs display inhibitory effects on contact hypersensitivity (CHS), which was reported in a mouse model for allergic contact dermatitis (ACD); however, the beneficial effects of soymilk consumption on CHS remain unknown. Here, we studied the effects of drinking soymilk on CHS and gut microbiota. Soymilk consumption attenuated ear oedema and swelling, decreased the infiltration of Gr-1-positive cells into ear tissues, and reduced the production of chemokine (C-X-C motif) ligand 2 and triggering receptor expressed on myeloid cells-1 in ear tissues. The analysis of bacterial 16S ribosomal RNA gene sequences indicated that CHS caused changes in the gut microbiota structure and that consuming soymilk reduced these changes. These results suggest that soymilk consumption may be of therapeutic value for patients with ACD and may help control the balance of intestinal microbiota.