Huangshui Polysaccharide Exerts Intestinal Barrier Protective Effects through the TLR4/MyD88/NF-κB and MAPK Signaling Pathways in Caco-2 Cells

Lactucin alleviates liver fibrosis by regulating the TLR4-MyD88-MAPK/NF-κB signaling pathway through intestinal flora

ETHNOPHARMACOLOGICAL RELEVANCE

Cichorium glandulosum (CG) is a kind of traditional Chinese medicine, mainly produced in Xinjiang and Inner Mongolia, and its medicinal part is mainly the dried root of CG. CG is a commonly used medicine in Uygur medicine, which has good pharmacological effects. Lactucin (LC) in this study is the main sesquiterpene monomer compound obtained from the ethyl acetate extract of CG. The purity of LC obtained by our research group in the previous stage reached 98.1 %, which met the purity requirements of chemical control of traditional Chinese medicine. At present, the research on the pharmacological action of CG mainly focuses on the extract of CG, and there is little research on the monomer compounds and exact pharmacological action mechanism in CG.

AIM OF THE STUDY

The aim of this study is to investigate the mechanism of lactucin (LC) in alleviating liver fibrosis by regulating TLR4-related inflammatory pathway through intestinal flora-intestine-liver axis.

MATERIALS AND METHODS

Firstly, the content of LC was determined by HPLC. In vitro, hepatic fibrosis cell model was induced and cytotoxicity was detected by MTT assay. QRT-PCR and Western Blot were used to detect the effect of LC on the expression of proteins related to TLR4-MyD88-MAPK/NF-κB signaling pathway. In vivo, carbon tetrachloride and dextran sodium sulfate were used to induce liver fibrosis and enteritis in rats. Detection of liver fibrosis index, H&E staining, Sirius red staining, immunofluorescence and Western Blot were used to detect the degree and action pathway of liver fibrosis. 16S rRNA analysis and bile acid targeted metabolism were used to explore the role of intestinal flora in liver fibrosis.

RESULTS

In vitro, LC can significantly inhibit the mRNA levels of TLR4 and related inflammatory factors, inhibit the expression of TLR4-MyD88-MAPK/NF-κB pathway protein, and reduce the level of intracellular reactive oxygen species, with the same effect as TLR4 inhibitors. In vivo, experimental results show that LC can reduce the degree of liver fibrosis and colitis, significantly reduce the levels of MDA and MPO in colon tissue, increase the level of SOD, reduce the activities of HYP, AKP, AST, ALT, TBA and γ-GT in serum, and increase the level of Alb. LC can also inhibit the expression of TLR4-MyD88-MAPK/NF-κB pathway, and inhibit the expression of TLR4 protein in liver and increase the expression of ZO-1 protein in colon. In addition, LC can regulate the flora composition of liver fibrosis and improve bile acid metabolism.

CONCLUSION

This study found that LC can alleviate liver fibrosis, and suggested that the beneficial effect of LC on liver fibrosis may be achieved by regulating TLR4-MyD88-MAPK pathway and improving intestinal flora through intestinal liver axis. At the same time, it is revealed that LC is the main component of CG for treating liver fibrosis, which lays a theoretical foundation for the research and development of new drugs and clinical research of CG in the later period.

The Regulatory Effect of Huangshui Polysaccharides on Intestinal Microbiota and Metabolites during In Vitro Fermentation

Huangshui polysaccharides (HSPs) have attracted extensive attention recently for their biological activity and physicochemical property. This research investigated the extraction, structural characterization, and prebiotic activity of three different HSPs (HSP40-0, HSP60-0, and HSP80-0) in vitro to reveal the scientific support for the high-value utilization of Huangshui. HSPs were heteropolysaccharide with diverse structures and surface morphologies. Comprehensive analysis was conducted through 16S rRNA gene sequencing and metabolite profiling techniques, and results showed that HSPs had different potentials to regulate the gut microbiota due to their different structures; for instance, both HSP40-0 and HSP80-0 could notably increase the relative abundance of Bacteroidota, whereas HSP60-0 could increase the relative abundance of Phascolarctobacterium. In addition, HSPs upregulated beneficial differential metabolites, especially short-chain fatty acids (SCFAs). Fermentation products containing these metabolites exhibited anti-inflammatory effects on LPS-treated Caco-2 cells. This study will provide reference for exploring the relationship between the natural polysaccharide structure and the prebiotic activity and widen the application of Huangshui.

Current situation, trend, and prospects of research on functional components from by-products of baijiu production: A review

In the present scenario marked by energy source shortages and escalating concerns regarding carbon dioxide emissions, there is a growing emphasis on the optimal utilization of biomass resources. Baijiu, as the Chinese national spirit, boasts remarkably high sales volumes annually. However, the production of baijiu yields various by-products, including solid residues (Jiuzao), liquid wastewater (Huangshui and waste alcohol), and gaseous waste. Recent years have witnessed dedicated research aimed at exploring the composition and potential applications of these by-products, seeking sustainable development and comprehensive resource utilization. This review systematically summarizes recent research, shedding light on both the baijiu brewing process and the bioactive compounds present baijiu production by-products (BPBPs). The primary focus lies in elucidating the potential extraction methods and applications of BPBPs, offering a practical approach to comprehensive utilization of by-products in functional food, medicine, cosmetic, and packaging fields. These applications not only contribute to enhancing production efficiency and mitigating environmental pollution, but also introduce innovative concepts for the sustainable advancement of associated industries. Future research avenues may include more in-depth compositional analysis, the development of utilization technologies, and the promotion of potential industrialization.

Urolithin A conjugation with NSAIDs inhibits its glucuronidation and maintains improvement of Caco-2 monolayers' barrier function

Urolithin A (UA) is an ellagitannin-derived postbiotic metabolite which emerged as a promising health-boosting agent, promoting mitophagy, improving skeletal muscle function, and suppressing the inflammatory response. However, phase II intestinal metabolism severely limits its biopotency, leading to the formation of nonactive glucuronides. To address this constraint, a set of new UA derivatives (UADs), conjugated with nonsteroidal anti-inflammatory drugs (NSAIDs), was synthesized. The bioavailability and inhibitory activity of UADs against UA-glucuronidation were evaluated using differentiated Caco-2 cell monolayers. Parallelly, after the administration of tested substances, the transepithelial electrical resistance (TEER) of the cell monolayers was continuously monitored using the CellZscope device. Though investigated UADs did not penetrate Caco-2 monolayers, all of them significantly suppressed the glucuronidation rate of UA, while conjugates with diclofenac increased the concentration of free molecule on the basolateral side. Moreover, esters of UA with diclofenac (DicloUA) and aspirin (AspUA) positively influenced cell membrane integrity. Western blot analysis revealed that some UADs, including DicloUA, increased the expression of pore-sealing tight junction proteins and decreased the level of pore-forming claudin-2, which may contribute to their beneficial activity towards the barrier function. To provide comprehensive insight into the mechanism of action of DicloUA, Caco-2 cells were subjected to transcriptomic analysis. Next-generation sequencing (NGS) uncovered substantial changes in the expression of genes involved, for instance, in multivesicular body organization and zinc ion homeostasis. The results presented in this study offer new perspectives on the beneficial effects of modifying UA's structure on its intestinal metabolism and bioactivity in vitro.

The Prebiotic Activity of a Novel Polysaccharide Extracted from Huangshui by Fecal Fermentation In Vitro

A novel polysaccharide, HSP80-2, with an average molecular weight of 13.8 kDa, was successfully isolated by the gradient ethanol precipitation (GEP) method from Huangshui (HS), the by-product of Chinese Baijiu. It was mainly composed of arabinose, xylose, and glucose with a molar ratio of 4.0:3.1:2.4, which was completely different from the previous reported HS polysaccharides (HSPs). Morphological observations indicated that HSP80-2 exhibited a smooth but uneven fragmented structure. Moreover, HSP80-2 exerted prebiotic activity evaluated by in vitro fermentation. Specifically, HSP80-2 was utilized by gut microbiota, and significantly regulated the composition and abundance of beneficial microbiota such as Phascolarctobacterium, Parabacteroides, and Bacteroides. Notably, KEGG pathway enrichment analysis illustrated that HSP80-2 enriched the pathways of amino sugar and nucleotide sugar metabolism (Ko00520), galactose metabolism (ko00052), and the citrate cycle (TCA cycle) (ko00020). Meanwhile, the contents of short-chain fatty acids (SCFAs) mainly including acetic acid, propionic acid, and butyric acid in the HSP80-2 group were remarkably increased, which was closely associated with the growth of Lachnoclostridium and Parabacteroides. These results showed that HSP80-2 might be used as a potential functional factor to promote human gut health, which further extended the high value utilization of HS.