Marine Chitosan-Oligosaccharide Ameliorated Plasma Cholesterol in Hypercholesterolemic Hamsters by Modifying the Gut Microflora, Bile Acids, and Short-Chain Fatty Acids

Regulations of Citrus Pectin Oligosaccharide on Cholesterol Metabolism: Insights from Integrative Analysis of Gut Microbiota and Metabolites

(1) Background: Recently, academic studies are demonstrating that the cholesterol-lowering effects of pectin oligosaccharides (POSs) are correlated to intestinal flora. However, the mechanisms of POS on cholesterol metabolisms are limited, and the observations of intestinal flora are lacking integrative analyses. (2) Aim and methods: To reveal the regulatory mechanisms of POS on cholesterol metabolism via an integrative analysis of the gut microbiota, the changes in gut microbiota structure and metabolite composition after POS addition were investigated using Illumina MiSeq sequencing and non-targeted metabolomics through in vitro gut microbiota fermentation. (3) Results: The composition of fecal gut flora was adjusted positively by POS. POS increased the abundances of the cholesterol-related bacterial groups Bacteroidetes, Bifidobacterium and Lactobacillus, while it decreased conditional pathogenic Escherichia coli and Enterococcus, showing good prebiotic activities. POS changed the composition of gut microbiota fermentation metabolites (P24), causing significant changes in 221 species of fermentation metabolites in a non-targeted metabolomics analysis and promoting the production of short-chain fatty acids. The abundances of four types of cholesterol metabolism-related metabolites (adenosine monophosphate, cyclic adenosine monophosphate, guanosine and butyrate) were significantly higher in the P24 group than those in the control group without POS addition. (4) Conclusion: The abovementioned results may explain the hypocholesterolemic effects of POS and promotion effects on cholesterol efflux of P24. These findings indicated that the potential regulatory mechanisms of citrus POS on cholesterol metabolism are modulated by cholesterol-related gut microbiota and specific metabolites.

Bile acids metabolism involved in the beneficial effects of Danggui Shaoyao San via gut microbiota in the treatment of CCl4 induced hepatic fibrosis

ETHNOPHARMACOLOGICAL RELEVANCE

Danggui Shaoyao San (DSS) is a traditional Chinese medicine (TCM) first recorded in the Synopsis of the Golden Chamber. DSS has proven efficacy in treating hepatic fibrosis (HF). However, the effects and mechanisms of DSS on HF are not clear.

AIM OF THE STUDY

To investigate the effect of DSS on HF via gut microbiota and its metabolites (SCFAs, BAs).

MATERIALS AND METHODS

HF rats were induced with CCl4 and treated with DSS. Firstly, the therapeutic efficacy of DSS in HF rats and the protection of gut barrier were assessed. Then, 16S rRNA gene sequencing and untargeted fecal metabolomics preliminarily explored the mechanism of DSS in treating HF, and identified different microbiota and metabolic pathways. Finally, targeted metabolomics and RT-qPCR were used to further validate the mechanism of DSS for HF based on the metabolism of SCFAs and BAs.

RESULTS

After 8 weeks of administration, DSS significantly reduced the degree of HF. In addition, DSS alleviated inflammation in the ileum and reduced the levels of LPS and D-lactate. Furthermore, DSS altered the structure of gut microbiota, especially Veillonella, Romboutsia, Monoglobus, Parabacteroides, norank_f_Coriobacteriales_Incertae_Sedis. These bacteria have been linked to the production of SCFAs and the metabolism of BAs. Untargeted metabolomics suggested that DSS may play a role via BAs metabolism. Subsequently, targeted metabolomics and RT-qPCR further confirmed the key role of DSS in increasing SCFAs levels and regulating BAs metabolism.

CONCLUSIONS

DSS can alleviate CCl4-induced HF and protect the gut barrier. DSS may exert its beneficial effects on HF by affecting the gut microbiota and its metabolites (SCFAs, BAs).

Advances in Research on Marine-Derived Lipid-Lowering Active Substances and Their Molecular Mechanisms

Hyperlipidemia (HLP) is a metabolic disorder caused by abnormal lipid metabolism. Recently, the prevalence of HLP caused by poor dietary habits in the population has been increasing year by year. In addition, lipid-lowering drugs currently in clinical use have shown significant improvement in blood lipid levels, but are accompanied by certain side effects. However, bioactive marine substances have been shown to possess a variety of physiological activities such as hypoglycemic, antioxidant, antithrombotic and effects on blood pressure. Therefore, the hypolipidemic efficacy of marine bioactive substances with complex and diverse structures has also attracted attention. This paper focuses on the therapeutic role of marine-derived polysaccharides, unsaturated fatty acids, and bioactive peptides in HLP, and briefly discusses the main mechanisms by which these substances exert their hypolipidemic activity in vivo.