Pure total flavonoids from citrus attenuate non-alcoholic steatohepatitis via regulating the gut microbiota and bile acid metabolism in mice

A Scoping Review on Hepatoprotective Mechanism of Herbal Preparations through Gut Microbiota Modulation

Liver diseases cause millions of deaths globally. Current treatments are often limited in effectiveness and availability, driving the search for alternatives. Herbal preparations offer potential hepatoprotective properties. Disrupted gut microbiota is linked to liver disorders. This scoping review aims to explore the effects of herbal preparations on hepatoprotective mechanisms, particularly in the context of non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), and hepatic steatosis, with a focus on gut microbiota modulation. A systematic search was performed using predetermined keywords in four electronic databases (PubMed, Scopus, EMBASE, and Web of Science). A total of 55 studies were included for descriptive analysis, covering study characteristics such as disease model, dietary model, animal model, intervention details, comparators, and study outcomes. The findings of this review suggest that the hepatoprotective effects of herbal preparations are closely related to their interactions with the gut microbiota. The hepatoprotective mechanisms of herbal preparations are shown through their effects on the gut microbiota composition, intestinal barrier, and microbial metabolites, which resulted in decreased serum levels of liver enzymes and lipids, improved liver pathology, inhibition of hepatic fatty acid accumulation, suppression of inflammation and oxidative stress, reduced insulin resistance, and altered bile acid metabolism.

The impact of traditional Chinese medicine and dietary compounds on modulating gut microbiota in hepatic fibrosis: A review

Traditional Chinese medicine (TCM) and dietary compounds have a profound influence on the regulation of gut microbiota (GM) in hepatic fibrosis (HF). Certain substances found in both food and herbs that are edible and medicinal, such as dietary fiber, polyphenols, and polysaccharides, can generate beneficial metabolites like short-chain fatty acids (SCFAs), bile acids (BAs), and tryptophan (Trp). These compounds contribute to regulate the GM, reduce levels of endotoxins in the liver, and alleviate fibrosis and inflammation in the liver. Furthermore, they enhance the composition and functionality of GM, promoting the growth of beneficial bacteria while inhibiting the proliferation of harmful bacteria. These mechanisms mitigate the inflammatory response in the intestines and maintain the integrity of the intestinal barrier. The purpose of this review is to analyze how the GM regulates the pathogenesis of HF, evaluate the regulatory effect of TCM and dietary compounds on the intestinal microflora, with a particular emphasis on modulating flora structure, enhancing gut barrier function, and addressing associated pathogenic factors, thereby provide new insights for the treatment of HF.

Mechanistic study of fructus aurantii (Quzhou origin) in regulating ileal reg3g in the treatment for NASH

BACKGROUND

Non-alcoholic steatohepatitis (NASH) is a critical stage in the progression of non-alcoholic fatty liver disease (NAFLD), characterized by obvious inflammation and fibrosis. Because of its high incidence rate and serious consequences, NASH is becoming a global health problem. The influence of endotoxin translocation on NASH is receiving attention. As a traditional Chinese herb that effectively improves hepatic inflammation, Fructus Aurantii (Quzhou origin, FAQ) is widely used in the clinical treatment of NASH. However, the intervention mechanism of FAQ on reg3g and related endotoxin translocation remains unclear.

AIM

To study the mechanism of the impact by which ileal regenerating family member 3 gamma (reg3g) deficiency and subsequent endotoxin translocation impact the progression of NASH; To elucidate the efficacy and mechanism of FAQ in the treatment of NASH.

METHODS

Clinical serum, ileal tissue, and dynamic NASH model-related analyses collectively confirmed that reg3g is a pivotal gene associated with NASH. Reg3g-/- mice were used to assess the impact of reg3g on liver injury, inflammation, and fibrosis, as well as the underlying mechanism involved. In vitro studies elucidated the regulatory effects of FAQ on reg3g, intestinal barrier function, and intestinal permeability. Subsequently, the efficacy of FAQ was investigated in NASH mouse models. Pathological examinations combined with Western blotting (WB), immunohistochemistry (IHC), and multiplex immunohistochemical (mIHC) analyses were used to evaluate the effects of FAQ on mucosal repair and barrier function. Transepithelial electrical resistance (TEER), fluorescein isothiocyanate-dextran 4 (FD-4) experiments, coupled with enzyme linked immunosorbent assay (ELISA) and chromogenic LAL endotoxin assay were used to confirm intestinal permeability and endotoxin translocation. The results of WB and mIHC reflected the levels of endotoxin recruitment and M1 macrophage polarization in the liver. Parameters such as body weight, transaminases, and cholesterol were utilized to assess the metabolic effects of FAQ.

RESULTS

Decreased expression of reg3g was associated with the progression of NASH. Ileal deficiency in reg3g resulted in damage to the intestinal barrier and permeability, leading to the recruitment of endotoxins via the 'gut-liver' axis to the liver, causing the polarization of M1 macrophages, release of inflammatory factors, excessive inflammation, and activation of hepatic stellate cells (HSCs), leading to fibrosis. FAQ significantly upregulated ileal reg3g expression and the expression of intestinal barrier-related proteins tight junction protein 1 (ZO-1) and occludin (OLCN) in mice (p < 0.05), thereby improving intestinal barrier function and permeability. Reduced intestinal permeability led to decreases in endotoxins entering the bloodstream and accumulating in the liver (p < 0.05). The expression of CD68 suggested reduced polarization of M1 macrophages. Expression levels of actin alpha 2, smooth muscle actin (α-SMA) and extracellular matrix (ECM)-related proteins also decreased, indicating improved liver fibrosis.

CONCLUSION

FAQ ameliorates NASH by upregulating the expression of reg3g. The upregulation of reg3g contributes to the repair of the intestinal barrier and permeability, reducing the recruitment of endotoxins and subsequent polarization of M1 macrophages, excessive inflammation, and fibrosis.

Farnesoid X receptor: From Structure to Function and Its Pharmacology in Liver Fibrosis

The farnesoid X receptor (FXR), a ligand-activated transcription factor, plays a crucial role in regulating bile acid metabolism within the enterohepatic circulation. Beyond its involvement in metabolic disorders and immune imbalances affecting various tissues, FXR is implicated in microbiota modulation, gut-to-brain communication, and liver disease. The liver, as a pivotal metabolic and detoxification organ, is susceptible to damage from factors such as alcohol, viruses, drugs, and high-fat diets. Chronic or recurrent liver injury can culminate in liver fibrosis, which, if left untreated, may progress to cirrhosis and even liver cancer, posing significant health risks. However, therapeutic options for liver fibrosis remain limited in terms of FDA-approved drugs. Recent insights into the structure of FXR, coupled with animal and clinical investigations, have shed light on its potential pharmacological role in hepatic fibrosis. Progress has been achieved in both fundamental research and clinical applications. This review critically examines recent advancements in FXR research, highlighting challenges and potential mechanisms underlying its role in liver fibrosis treatment.

Pure total flavonoids from Citrus ameliorate NSAIDs-induced intestinal mucosal injury via regulation of exosomal LncRNA H19 and protective autophagy

Introduction

Non-steroid anti-inflammatory drugs (NSAIDs) are a class of prescription drugs with antipyretic, analgesic, anti-inflammatory, and antiplatelet effects. However, long-term use of NSAIDs will disrupt the intestinal mucosal barrier, causing erosion, ulcers, bleeding, and even perforation. Pure total flavonoids from Citrus (PTFC) is extracted from the dried peel of Citrus, showing a protective effect on intestinal mucosal barrier with unclear mechanisms.

Methods

In the present study, we used diclofenac (7.5 mg kg-1, i.g.) to induce a rat model of NSAIDs-related intestinal lesions. PTFC (50, 75, 100 mg·kg-1 d-1, i.g.) was administered 9 days before the initial diclofenac administration, followed by co-administration on the last 5 days. Exosomes were identified by western blotting and transmission electron microscopy (TEM), and then co-cultured with IEC-6 cells. The expression of long non-coding RNA (lncRNA) H19, autophagy-related 5 (Atg5), ZO-1, Occludin, and Claudin-1 were detected by quantitative real-time PCR (qRT-PCR). The expression of light chain 3 (LC3)-I, LC3-II, ZO-1, Occludin and Claudin-1 proteins was tested by western blotting. The localization of both exosomes and autophagosomes was examined by immunofluorescent technique.

Results

The treatment of PTFC attenuated intestinal mucosal mechanical barrier function disturbance in diclofenac-induced NSAIDs rats. IEC-6 cells co-cultured with NSAIDs rats-derived exosomes possessed the lowest levels of protective autophagy, and severe intestinal barrier injuries. Cells co-cultured with the exosomes extracted from rats administrated PTFC exhibited an improvement of autophagy and intestinal mucosal mechanical barrier function. The prevention effect was proportional to the concentration of PTFC administered.

Conclusion

PTFC ameliorated NSAIDs-induced intestinal mucosal injury by down-regulating exosomal lncRNA H19 and promoting autophagy.

Flavonoids, gut microbiota, and host lipid metabolism

Flavonoids are widely distributed in nature and have a variety of beneficial biological effects, including antioxidant, anti-inflammatory, and anti-obesity effects. All of these are related to gut microbiota, and flavonoids also serve as a bridge between the host and gut microbiota. Flavonoids are commonly used to modify the composition of the gut microbiota by promoting or inhibiting specific microbial species within the gut, as well as modifying their metabolites. In turn, the gut microbiota extensively metabolizes flavonoids. Hence, this reciprocal relationship between flavonoids and the gut microbiota may play a crucial role in maintaining the balance and functionality of the metabolism system. In this review, we mainly highlighted the biological effects of antioxidant, anti-inflammatory and antiobesity, and discussed the interaction between flavonoids, gut microbiota and lipid metabolism, and elaborated the potential mechanisms on host lipid metabolism.

Naringin Alleviates Intestinal Fibrosis by Inhibiting ER Stress-Induced PAR2 Activation

Fibrosis characterized by intestinal strictures is a common complication of Crohn's disease (CD), without specific antifibrotic drugs, which usually relies on surgical intervention. The transcription factor XBP1, a key component of endoplasmic reticulum (ER) stress, is required for degranulation of mast cells and linked to PAR2 activation and fibrosis. Many studies have confirmed that naringin (NAR) can inhibit ER stress and reduce organ fibrosis. We hypothesized that ER stress activated the PAR2-induced epithelial-mesenchymal transition process by stimulating mast cell degranulation to release tryptase and led to intestinal fibrosis in CD patients; NAR might play an antifibrotic role by inhibiting ER stress-induced PAR2 activation. We report that the expression levels of XBP1, mast cell tryptase, and PAR2 are upregulated in fibrotic strictures of CD patients. Molecular docking simulates the interaction of NAR and spliced XBP1. ER stress stimulates degranulation of mast cells to secrete tryptase, activates PAR2-induced epithelial-mesenchymal transition process, and promotes intestinal fibrosis in vitro and vivo experiments, which is inhibited by NAR. Moreover, F2rl1 (the coding gene of PAR2) deletion in intestinal epithelial cells decreases the antifibrotic effect of NAR. Hence, the ER stress-mast cell tryptase-PAR2 axis can promote intestinal fibrosis, and NAR administration can alleviate intestinal fibrosis by inhibiting ER stress-induced PAR2 activation.

Hepatoprotective effects of natural drugs: Current trends, scope, relevance and future perspectives

BACKGROUND

The liver is a well-known player in the metabolism and removal of drugs. Drug metabolizing enzymes in the liver detoxify drugs and xenobiotics, ultimately leading to the acquisition of homeostasis. However, liver toxicity and cell damage are not only related to the nature and dosage of a particular drug but are also influenced by other factors such as aging, immune status, environmental contaminants, microbial metabolites, gender, obesity, and expression of individual genes Furthermore, factors such as drugs, alcohol, and environmental contaminants could induce oxidative stress, thereby impairing the regenerative potential of the liver and causing several diseases. Persons suffering from other ailments and those with comorbidities are found to be more prone to drug-induced toxicities. Moreover, drug composition and drug-drug interactions could further aggravate the risk of drug-induced hepatotoxicity. A plethora of mechanisms are responsible for initiating liver cell damage and further aggravating liver cell injury, followed by impairment of homeostasis, ultimately leading to the generation of reactive oxygen species, immune-suppression, and oxidative stress.

OBJECTIVE

To summarize the potential of phytochemicals and natural bioactive compounds to treat hepatotoxicity and other liver diseases.

STUDY DESIGN

A deductive qualitative content analysis approach was employed to assess the overall outcomes of the research and review articles pertaining to hepatoprotection induced by natural drugs, along with analysis of the interventions.

METHODS

An extensive literature search of bibliographic databases, including Web of Science, PUBMED, SCOPUS, GOOGLE SCHOLAR, etc., was carried out to understand the role of hepatoprotective effects of natural drugs.

RESULTS

Bioactive natural products, including curcumin, resveratrol, etc., have been seen as neutralizing agents against the side effects induced by the drugs. Moreover, these natural products are dietary and are readily available; thus, could be supplemented along with drugs to reduce toxicity to cells. Probiotics, prebiotics, and synbiotics have shown promise of improving overall liver functioning, and these should be evaluated more extensively for their hepatoprotective potential. Therefore, selecting an appropriate natural product or a bioactive compound that is free of toxicity and offers a reliable solution for drug-induced liver toxicity is quintessential.

CONCLUSIONS

The current review highlights the role of natural bioactive products in neutralizing drug-induced hepatotoxicity. Efforts have been made to delineate the possible underlying mechanism associated with the neutralization process.

Effect of Cichorium glandulosum on intestinal microbiota and bile acid metabolism in db/db mice

This study aims to investigate the effects of Chorum glandulosum Boiss. et Huet (CG) on the intestinal microbiota and serum bile acid (BA) in db/db mice. A total of 12 db/db mice were randomly divided into model (MOD), high-dose CG (CGH), and control (CON) groups. The CON and MOD groups received distilled water by gavage for 8 weeks. Whereas, the CGH group received an alcohol extract of CG at a dose of 200 mg/kg/day. Results showed that CG can reduce blood lipid levels. It change the composition of the intestinal microbiota, and increase the relative abundances of Muribaculaceae, Prevotellaceae, Bifidobacterium_pseudolongum, Bacteroidaceae in db/db mice as well. LC-MS metabolomics results showed that CG adjusted the serum BA levels. The results reduced the levels of primary BAs, such as cholic acid (CA) and chenodeoxycholic acid (CDCA). The results decreased the primary BA/secondary BA (PSA/SBA) ratio in db/db mice. Correlation analysis showed that the abundances of Bifidobacterium_pseudolongum and Bacteroidaceae were positively correlated with acetic acid level and negatively correlated with ursocholic acid (UCA), α-muricholic acid (αMCA), triglyceride (TG), and total cholesterol levels (TC), indicating an interaction between the intestinal microbiota and serum BAs. CG may play a positive role in the interaction between the intestinal microbiota and BAs in lipid metabolism.

Identification of Polymethoxyflavones (PMFs) from Orange Peel and Their Inhibitory Effects on the Formation of Trimethylamine (TMA) and Trimethylamine-N-oxide (TMAO) Using cntA/B and cutC/D Enzymes and Molecular Docking

This study investigates the inhibitory effects of polymethoxyflavones (PMFs) on enzymes involved in the production of trimethylamine (TMA) and trimethylamine-N-oxide (TMAO). PMFs were isolated from Valencia orange peel and identified using column separation and NMR techniques. The findings reveal that nobiletin and 3,6,7,8,2',5'-hexamethoxyflavone significantly suppress cntA/B and cutC/D, respectively. Furthermore, 3,6,7,8,2',5'-hexamethoxyflavone decreases the level of TMAO formation by suppressing the FMO3 mRNA level. This study elucidates that specific structural features of PMFs can contribute to their interactions with enzymes. Our study represents the first demonstration of the ability of PMFs to mitigate the risk of cardiovascular disease (CVD) by inhibiting enzymes responsible for TMA production, which are generated by gut microbiomes. Furthermore, we introduce a novel model system utilizing TMA-induced HepG2 cells to assess and compare the inhibitory effects of PMFs on TMAO production. These findings could pave the way for the development of novel therapeutic approaches to manage CVD.

Interactions between gut microbiota and polyphenols: A mechanistic and metabolomic review

BACKGROUND

Polyphenols are a class of naturally sourced compounds with widespread distribution and an extensive array of bioactivities. However, due to their complex constituents and weak absorption, a convincing explanation for their remarkable bioactivity remains elusive for a long time. In recent years, interaction with gut microbiota is hypothesized to be a reasonable explanation of the potential mechanisms for natural compounds especially polyphenols.

OBJECTIVES

This review aims to present a persuasive explanation for the contradiction between the limited bioavailability and the remarkable bioactivities of polyphenols by examining their interactions with gut microbiota.

METHODS

We assessed literatures published before April 10, 2023, from several databases, including Scopus, PubMed, Google Scholar, and Web of Science. The keywords used include "polyphenols", "gut microbiota", "short-chain fatty acids", "bile acids", "trimethylamine N-oxide", "lipopolysaccharides" "tryptophan", "dopamine", "intestinal barrier", "central nervous system", "lung", "anthocyanin", "proanthocyanidin", "baicalein", "caffeic acid", "curcumin", "epigallocatechin-3-gallate", "ferulic acid", "genistein", "kaempferol", "luteolin", "myricetin", "naringenin", "procyanidins", "protocatechuic acid", "pterostilbene", "quercetin", "resveratrol", etc. RESULTS: The review first demonstrates that polyphenols significantly alter gut microbiota diversity (α- and β-diversity) and the abundance of specific microorganisms. Polyphenols either promote or inhibit microorganisms, with various factors influencing their effects, such as dosage, treatment duration, and chemical structure of polyphenols. Furthermore, the review reveals that polyphenols regulate several gut microbiota metabolites, including short-chain fatty acids, dopamine, trimethylamine N-oxide, bile acids, and lipopolysaccharides. Polyphenols affect these metabolites by altering gut microbiota composition, modifying microbial enzyme activity, and other potential mechanisms. The changed microbial metabolites induced by polyphenols subsequently trigger host responses in various ways, such as acting as intestinal acid-base homeostasis regulators and activating on specific target receptors. Additionally, polyphenols are transformed into microbial derivatives by gut microbiota and these polyphenols' microbial derivatives have many potential advantages (e.g., increased bioactivity, improved absorption). Lastly, the review shows polyphenols maintain intestinal barrier, central nervous system, and lung function homeostasis by regulating gut microbiota.

CONCLUSION

The interaction between polyphenols and gut microbiota provides a credible explanation for the exceptional bioactivities of polyphenols. This review aids our understanding of the underlying mechanisms behind the bioactivity of polyphenols.

A local dark tea - Liubao tea - extract exhibits remarkable performance in oral tissue regeneration, inflammation relief and oral microbiota reconstruction

The prevalence of oral health problems is ubiquitous in contemporary society, with particular emphasis placed on the central role of oral flora in mitigating this issue. Both ancient literature and modern research have highlighted the promising application of tea with substantial bioactive properties, particularly dark tea, in preserving and promoting oral health. Liubao tea, a widely consumed dark tea with increasing popularity in recent years, has been reported to possess abundant bioactive constituents, exhibit remarkable antioxidant and anti-inflammatory effects, modulate the flora structure and so on. It may be a promising candidate for addressing oral health problems. In this study, Liubao tea was meticulously extracted, purified and identified, followed by an investigation of its potential to modulate oral microecology by virtue of an acetic acid-induced oral disorder murine model. The results revealed that Liubao tea extract (LTE) application commendably reconstructed the oral mucosal barrier, promoted tissue regeneration and mitigated micro-inflammation. Furthermore, LTE treatment could also ameliorate the oral flora composition by decreasing the abundance of Proteobacteria and increasing the abundance of Firmicutes and Actinobacteria at the phylum level, as well as inhibiting pernicious bacteria such as Streptococcus and Delftia acidovorans. So, it could promote the generation of a beneficial microenvironment and regulate the immune process. Overall, LTE demonstrated remarkable potential in regulating the balance of oral microecology, suggesting that it may represent a promising therapeutic strategy for oral health concerns.

Pure total flavonoids from citrus alleviate oxidative stress and inflammation in nonalcoholic fatty liver disease by regulating the miR-137-3p/NOXA2/NOX2 pathway

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) has become a global health issue owing to its large disease population and high morbidity. We previously reported that the improvement in oxidative stress (OS) using pure total flavonoids from citrus (PTFC), flavonoids isolated from the peel of Citrus changshan-huyou Y.B. Chan, is a crucial strategy for NAFLD treatment. However, OS-associated intervention pathways in NAFLD remain unclear.

METHODS

In this study, we used microRNA (miR)- and mRNA-sequencing to identify the pathway by which PTFC improve OS in NAFLD. Clinical data, mimic/inhibitor assays, and a dual-luciferase reporter assay were selected to verify the regulatory relationships of this pathway. Moreover, in vivo and in vitro experiments were used to confime the regulatory effect of PTFC on this pathway.

RESULTS

miR-seq, mRNA-seq, and bioinformatics analyses revealed that the miR-137-3p/neutrophil cytosolic factor 2 (NCF2, also known as NOXA2)/cytochrome b-245 beta chain (CYBB, also known as NOX2) pathway may be a target pathway for PTFC to improve OS and NAFLD. Additionally, bivariate logistic regression analysis combining the serum and clinical data of patients revealed NOX2 and NOXA2 as risk factors and total antioxidant capacity (indicator of OS level) as a protective factor for NAFLD. miR-137-3p mimic/inhibitor assays revealed that the upregulation of miR-137-3p is vital for improving cellular steatosis, OS, and inflammation. Dual-luciferase reporter assay confirmed that NOXA2 acts as an miR-137-3p sponge. These results co-determined that miR-137-3p/NOXA2/NOX2 is an essential pathway involved in NAFLD pathogenesis, including lipid accumulation, OS, and inflammation. In vivo and in vitro experiments further confirmed that the miR-137-3p/NOXA2/NOX2 pathway is regulated by PTFC.

CONCLUSION

PTFC alleviates OS and inflammation in NAFLD by regulating the miR-137-3p/NOXA2/NOX2 pathway.

The great potential of flavonoids as candidate drugs for NAFLD

Non-alcoholic fatty liver disease (NAFLD) has a global prevalence of approximately 25 % and is associated with high morbidity and high mortality. NAFLD is a leading cause of cirrhosis and hepatocellular carcinoma. Its pathophysiology is complex and still poorly understood, and there are no drugs used in the clinic to specifically treat NAFLD. Its pathogenesis involves the accumulation of excess lipids in the liver, leading to lipid metabolism disorders and inflammation. Phytochemicals with the potential to prevent or treat excess lipid accumulation have recently received increasing attention, as they are potentially more suitable for long-term use than are traditional therapeutic compounds. In this review, we summarize the classification, biochemical properties, and biological functions of flavonoids and how they are used in the treatment of NAFLD. Highlighting the roles and pharmacological uses of these compounds will be of importance for enhancing the prevention and treatment of NAFLD.

Effect and Correlation of Rosa roxburghii Tratt Fruit Vinegar on Obesity, Dyslipidemia and Intestinal Microbiota Disorder in High-Fat Diet Mice

To investigate the effect of Rosa roxburghii Tratt fruit vinegar (RFV) on the intervention of obesity and hyperlipidemia and its potential mechanism, a high-fat diet (HFD)-induced obesity model in mice was established and gavaged with RFV, saline and xuezhikang for 30 consecutive days, respectively. The results showed that RFV supplementation significantly reduced fat accumulation, and improved dyslipidemia and liver inflammation in HFD mice. RFV intervention for 30 days significantly improved the diversity of gut microbiota and altered the structure of gut microbiota in HFD mice. Compared with the model group (MC), the ratio of Firmicutes to Bacteroidetes at least decreased by 15.75% after RFV treatment, and increased the relative abundance of beneficial bacteria (Proteobacteria, Bacteroidetes, Lactobacillaceae, Bacteroides, Akkermansia,) and decreased the relative abundance of harmful bacteria (Ruminococcaceae, Erysipelotrichaceae, Ruminococcaceae _UCG-013, Lachnospiraceae, Allobaculum, Actinobacteria). Spearman’s correlation analysis revealed that Erysipelotrichaceae, Allobaculum, Lachnospiraceae, Ruminococcaceae, Ruminococcaceae_UCG-013, uncultured_bacterium_f_Lachnospiraceae and Desulfobacterota were positively correlated (p < 0.05) with the body weight of mice, while Proteobacteria was negatively correlated (p < 0.05) with the body weight of mice. The two main bacteria that could promote dyslipidemia in obese mice were Actinobacteria and Firmicutes, while those that played a mitigating role were mainly Bacteroidetes. It is concluded that RFV plays an important role in the intervention of obesity and related complications in HFD mice by regulating their gut microbiota.

Aronia melanocarpa polysaccharide ameliorates liver fibrosis through TGF-β1-mediated the activation of PI3K/AKT pathway and modulating gut microbiota

The purpose of this experiment was to investigate the anti-hepatic fibrosis effect of Aronia melanocarpa polysaccharide (AMP) on TAA-induced liver fibrosis mice and its mechanism, as well as the changes in intestinal flora in vivo. This was established with a dose of 200 mg/kg TAA (i.p) once every three days, lasting for eight weeks. Colchicine with 0.4 mg/kg, and AMP (200 and 400 mg/kg) were given by intragastric administration (i.g) after 28 days of intraperitoneal injection of TAA. AMP treatment significantly inhibited the activities of liver injury markers ALT and AST in serum. Histopathological staining demonstrated that AMP significantly reversed TAA-induced hepatocyte necrosis and collagen deposition. In addition, AMP treatment block TGF- β1/Smads pathway inhibited the production of ECM and alleviates liver fibrosis. Furthermore, AMP treatment enhanced the phosphorylation of PI3K/AKT and decreased the expression of its downstream apoptosis-related proteins in liver, thus effectively alleviating TAA-induced liver fibrosis. In addition, 16S rDNA gene sequencing analysis showed that AMP treatment helped restore the imbalanced ecosystem of gut microbes, increased the proportion of Bacteroidetes and Proteobacteria, and increased species richness. Above findings clearly show that AMP is an effective method for treating liver fibrosis, possibly by improving the gut microbiota.

The new exploration of pure total flavonoids extracted from Citrus maxima (Burm.) Merr. as a new therapeutic agent to bring health benefits for people

The peel and fruit of Citrus varieties have been a raw material for some traditional Chinese medicine (TCM). Pure total flavonoids from Citrus maxima (Burm.) Merr. (PTFC), including naringin, hesperidin, narirutin, and neohesperidin, have been attracted increasing attention for their multiple clinical efficacies. Based on existing in vitro and in vivo research, this study systematically reviewed the biological functions of PTFC and its components in preventing or treating liver metabolic diseases, cardiovascular diseases, intestinal barrier dysfunction, as well as malignancies. PTFC and its components are capable of regulating glycolipid metabolism, blocking peroxidation and persistent inflammation, inhibiting tumor progression, protecting the integrity of intestinal barrier and positively regulating intestinal microbiota, while the differences in fruit cultivation system, picking standard, manufacturing methods, delivery system and individual intestinal microecology will have impact on the specific therapeutic effect. Thus, PTFC is a promising drug for the treatment of some chronic diseases, as well as continuous elaborate investigations are necessary to improve its effectiveness and bioavailability.

Glycine-β-muricholic acid antagonizes the intestinal farnesoid X receptor-ceramide axis and ameliorates NASH in mice

Nonalcoholic steatohepatitis (NASH) is a rapidly developing pathology around the world, with limited treatment options available. Some farnesoid X receptor (FXR) agonists have been applied in clinical trials for NASH, but side effects such as pruritus and low-density lipoprotein elevation have been reported. Intestinal FXR is recognized as a promising therapeutic target for metabolic diseases. Glycine-β-muricholic acid (Gly-MCA) is an intestine-specific FXR antagonist previously shown to have favorable metabolic effects on obesity and insulin resistance. Herein, we identify a role for Gly-MCA in the pathogenesis of NASH, and explore the underlying molecular mechanism. Gly-MCA improved lipid accumulation, inflammatory response, and collagen deposition in two different NASH models. Mechanistically, Gly-MCA decreased intestine-derived ceramides by suppressing ceramide synthesis-related genes via decreasing intestinal FXR signaling, leading to lower liver endoplasmic reticulum (ER) stress and proinflammatory cytokine production. The role of bile acid metabolism and adiposity was excluded in the suppression of NASH by Gly-MCA, and a correlation was found between intestine-derived ceramides and NASH severity. This study revealed that Gly-MCA, an intestine-specific FXR antagonist, has beneficial effects on NASH by reducing ceramide levels circulating to liver via lowering intestinal FXR signaling, and ceramide production, followed by decreased liver ER stress and NASH progression. Intestinal FXR is a promising drug target and Gly-MCA a novel agent for the prevention and treatment of NASH.

Intervention Effects of Okra Extract on Brain-Gut Peptides and Intestinal Microorganisms in Sleep Deprivation Rats

Objective

Okra, possessing various bioactive components, is used to treat different diseases. This study sought to estimate the intervention effects of okra extract (OE) on brain-gut peptides (BGPs) and intestinal microorganisms in sleep deprivation (SD) rats.

Methods

SD rat models were established using the modified multiple platform method and then treated with normal saline, diazepam tablets, or different doses of OE. Body weight and average daily water consumption of rats were recorded. Depressive behaviors of rats were assessed by the open field test and sucrose preference test. Serum levels of noradrenaline, melatonin, inflammatory factors (IL-1β/IL-6/TNF-α/IL-4/IL-10), and BGP indexes, including gastrin (GAS), motilin (MTL), 5-hydroxytryptamine (5-HT), cholecystokinin (CCK), and vasoactive intestinal peptide (VIP) were measured by ELISA. Additionally, the DNA relative contents of representative intestinal microorganisms in the collected rat feces were determined using RT-qPCR.

Results

SD decreased body weight and average daily water consumption and induced depressive behaviors as well as stress and inflammatory responses in rats. SD rats exhibited lowered GAS, MTL, 5-HT, and VIP but elevated CCK and showed diminished DNA relative contents of Bacteroidetes and probiotics (Bifidobacteria and Lactobacilli) but increased Clostridium perfringens. OE at different doses ameliorated the depressive behaviors and mitigated the stress and inflammatory responses in SD rats, raised the serum contents of GAS, MTL, 5-HT, and VIP, reduced CCK level, elevated the DNA relative contents of Bacteroidetes and probiotics, but diminished Clostridium perfringens. OE exhibited similar intervention effects to diazepam tablets (positive control).

Conclusion

OE exerts intervention effects on BGPs and intestinal microorganisms in SD rats.

Natural flavonoids: Potential therapeutic strategies for non-alcoholic fatty liver disease

The incidence of non-alcoholic fatty liver disease (NAFLD) is increasing rapidly worldwide; however, there are currently limited treatments for NAFLD. The disease spectrum includes simple fatty liver, non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and progression to hepatocellular carcinoma (NASH-HCC). The therapeutic effects of NAFLD remain controversial. Although researchers have conducted studies on the pathogenesis of NAFLD, its pathogenesis and anti-NAFLD mechanisms have not been fully elucidated. Previous studies have found that flavonoids, as natural substances with extensive pharmacological activity and good therapeutic effects, have excellent antioxidant, anti-inflammatory, metabolic disease improvement, anti-tumor, and other properties and can significantly alleviate NAFLD. Flavonoids could be further developed as therapeutic drugs for NAFLD. In this paper, the pathogenesis of NAFLD and the mechanisms of flavonoids against NAFLD are summarized to provide a theoretical basis for screening flavonoids against non-alcoholic liver injury.

Citrus aurantium ‘Changshan-huyou’—An ethnopharmacological and phytochemical review

Citrus fruits are composed of oil cells layer, white membrane layer, pulp and seeds. The cultivar Citrus aurantium ‘Changshan-huyou’ (CACH) is a hybridization of Citrus grandis Osbeck and C. sinensis Osbeck. It is a rutaceae plant, and mainly grows in Changshan, Zhejiang, China. With the exploration of its high traditional values, it has been paid more and more attention by the scientific community in recent years. At present, one hundred and two chemical constituents have been identified from the pulp and peel of CACH, including volatile oils, terpenoids, phenols, limonins, sugars, etc., As the representative active component of CACH, phenols have been widely investigated. Studies have shown that CACH shows a variety of significant pharmacological activities, such as anti-inflammatory, antioxidant, hepatoprotective activity, respiratory system protection and intestinal regulation activity. This review mainly introduces the chemical constituents and pharmacological activities of CACH, and discusses its future research and development directions. It will provide theoretical basis for further research of its pharmacodynamic substances, functional mechanism and rational utilization.

Flavonoids affect the endophytic bacterial community in Ginkgo biloba leaves with increasing altitude

Altitude affects plant growth and metabolism, but the effect of altitude on plant endophytic microorganisms is still unclear. In this study, we selected 16 Ginkgo biloba trees to study the response of leaves' endophytes to flavonoids and altitude (from 530 m to 1,310 m). HPLC results showed that flavonoids in Ginkgo biloba leaves increased by more than 150% with attitude rising from 530 m to 1,310 m, which revealed a positive correlation with altitude. Ginkgo biloba might regulate the increased flavonoids in leaves to resist the increasing light intensity. 16S rDNA sequencing results showed that the endophytic bacterial communities of Ginkgo biloba at different altitudes significantly differed. Ginkgo leaf endophytes' alpha diversity decreased with increasing flavonoids content and altitude. The increased flavonoids might increase the environmental pressure on endophytes and affect the endophytic community in Ginkgo biloba leaves. The bacterial network in Ginkgo biloba leaves became more complex with increasing altitude, which might be one of the strategies of leaf endophytes to cope with increasing flavonoids. Metagenomes results predicted with PICRUSt showed that the abundance of flavonoid biosynthesis and photosynthesis genes were significantly decreased with the increase of flavonoid contents. High flavonoid content in leaves appeared to inhibit microbial flavonoid synthesis. Our findings indicate that altitude can modulate microbial community structure through regulating plant metabolites, which is important to uncovering the interaction of microbes, host and the environment.

Penthorum chinense Pursh. extract attenuates non-alcholic fatty liver disease by regulating gut microbiota and bile acid metabolism in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Penthorum chinense Pursh. (PCP) is commonly used as a Miao ethnomedicine and health food for liver protection in China. Gansukeli (WS3-B-2526-97) is made from the extract of PCP (PCPE) for the treatment of viral hepatitis. In recent years, PCPE has been reported in the treatment of non-alcoholic fatty liver disease (NAFLD), however its potential mechanism is not fully elucidated.

AIM OF THE STUDY

To investigate the ameliorating effect of PCPE on high-fat diet (HFD)-induced NAFLD mice and demonstrate whether its protective effect is gut microbiota dependent and associated with bile acid (BA) metabolism.

MATERIALS AND METHODS

The alleviating effect of PCPE on NAFLD was conducted on male C57BL/6J mice fed an HFD for 16 weeks, and this effect associated with gut microbiota dependent was demonstrated by pseudo-germfree mice treated with antibiotics and fecal microbiota transplantation (FMT). The composition of the gut microbiota in the cecum contents was analyzed by 16S rRNA sequencing, and the levels of BAs in liver and fecal samples were determined by UPLC/MS-MS.

RESULTS

The results showed that administration of PCPE for 8 weeks could potently ameliorate HFD-induced NAFLD and alleviate dyslipidemia and insulin resistance. Moreover, PCPE treatment alleviated gut dysbiosis, especially reducing the relative abundance of bile salt hydrolase (BSH)-producing bacteria. Furthermore, PCPE significantly increased the levels of taurine-conjugated BAs in feces, such as tauro-β-muricholic acid (T-βMCA), tauroursodesoxycholic acid (TUDCA), and taurochenodeoxycholic acid (TCDCA), and increased hepatic chenodeoxycholic acid (CDCA). The protein and mRNA expression of farnesoid X receptor (FXR) and fibroblast growth factor 15 (FGF15) were decreased in intestine, increased taurine-conjugated BAs inhibited the intestinal signaling pathway, which was associated with increased genes expression of enzymes in the alternative BA synthesis pathway that reduced the levels of cholesterol. The increased CDCA produced via the alternative BA synthesis pathway promoted hepatic FXR activation and BA excretion.

CONCLUSION

Our study is the first time to demonstrate that PCPE could ameliorate NAFLD in HFD-induced mice by regulating the gut microbiota and BA metabolism, and from a novel perspective, to clarify the mechanism of PCPE in NAFLD.

Protective effect of flavonoids extract of Hippophae rhamnoides L. on alcoholic fatty liver disease through regulating intestinal flora and inhibiting TAK1/p38MAPK/p65NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The therapeutic properties of Hippophae rhamnoides L. were already known in ancient Greece as well as in Tibetan and Mongolian medicine. Modern studies have indicated that Hippophae rhamnoides L. fermentation liquid protected against alcoholic fatty liver disease (AFLD). However, the underlying mechanism of Hippophae rhamnoides L. flavonoids extract (HLF) treating AFLD remains elusive.

AIM OF THE STUDY

This study aimed to investigate the hepatoprotective effect of HLF in mice with AFLD and the interaction between AFLD and gut microbiota.

MATERIALS AND METHODS

Chemical constituents of HLF were analyzed by Liquid Chromatography-Ion Trap-ESI-Mass Spectrometry. The Hepatoprotective effect of HLF was evaluated in mice with AFLD induced by alcohol (six groups, n = 10) daily at doses of 0.1, 0.2, and 0.4 g/kg for 30 consecutive days. At the end of experiment, mice were sacrificed and the liver, serum and feces were harvested for analysis. The liver histological changes were observed by H&E staining and oil red O staining. Moreover, the alterations of fecal microflora were detected by 16S rRNA gene sequencing. The inflammatory related genes were determined by qRT-PCR and western blotting respectively.

RESULTS

The results showed that the oral administration of HLF remarkably alleviated hepatic lipid accumulation by decreasing the levels of ALT, AST, TG and TC. The levels of TNF-α, TGF-β, and IL-6 were also reduced after treatment with HLF. Meanwhile, the protein and mRNA expression of NF-kB p65, MAPK p38 and TAK-1 in the liver of mice with AFLD were all reduced by HLF compared with model group. Furthermore, the 16S rRNA gene sequencing analysis demonstrated that HLF treatment can help restore the imbalance of intestinal microbial ecosystem and reverse the changes in Fimicutes/Bacterodietes, Clostridiales, Lachnospiraceae, S24-7, and Prevotella in mice with AFLD.

CONCLUSION

HLF can effectively ameliorate liver injury in mice with AFLD, and regulate the composition of gut microbiota. Its regulatory mechanism may be related to TAK1/p38MAPK/p65NF-κB pathway. This study may provide novel insights into the mechanism of HLF on AFLD and a basis for promising clinical usage.

Dihydroflavonoids as Bioactive Components of Penthorum chinense, a Miao Ethnomedicine, against NAFLD through Bile Acid Metabolism Pathway

Penthorum chinense Pursh. is a traditional herbal medicine of Miao, and its extracts (PCPE) have been used for treatment of liver diseases in the clinic including nonalcoholic fatty liver disease (NAFLD). However, the active components and pharmacological mechanisms of PCPE for treating NAFLD remain unclear. This study aimed to explore potential mechanisms of action through network pharmacology, molecular docking combined with experimental in vitro. A total of five dihydroflavonoids (1-5) with the same parent nucleus of pinocembrin (PCB) from PCPE, were selected as bioactive ingredients and 109 potential targets related to NAFLD were obtained from public databases and literature mining. The core targets related to the bile secretion signaling were selected based on PPI network and KEGG enrichment analysis for exploring the mechanism of PCPE against NAFLD. Molecular docking results showed good interaction between the core targets in bile secretion signaling pathway and the five compounds predicted to be bioactive. With the strong binding activity to retinoid X receptor-alpha (RXRA) and farnesoid X receptor (FXR) protein, pinocembrin-7-O-β-D-glucoside (PCBG, the highest content in PCPE) and its metabolite PCB, could significantly increase the expression of RXRA, FXR and bile salt export pump (BSEP) in L02 cells, and significantly decrease the expression of cholesterol 7α-hydroxylase (CYP7A1) at mRNA and protein levels. This study provided favorable evidence for mechanism of the main dihydroflavonoids of PCPE against NAFLD, and presented a paradigm for the study of ethnomedicine.

Tectorigenin ameliorated high-fat diet-induced nonalcoholic fatty liver disease through anti-inflammation and modulating gut microbiota in mice

Nonalcoholic fatty liver disease (NAFLD) is a complex pathogenesis of liver disease combined with liver inflammation and gut microbiota dysbiosis. Tectorigenin (Tg) is derived from many plants with excellent anti-inflammation activity. However, the beneficial effect of Tg on NAFLD associated with gut microbiota remained unclear. This study aimed to investigate the underlying beneficial effect of Tg on NAFLD in high-fat diet (HFD)-fed mice. Results showed that Tg alleviated lipid profiles and liver steatosis, and reduced serum lipopolysaccharide (LPS) and total bile acid (TBA) levels. Besides, RT-qPCR and Western blot suggested that Tg alleviated hepatic lipid accumulation through inhibiting the lipogenesis and promoting the lipolysis, prevented gut-derived LPS-induced liver inflammatory via restoring intestinal barrier and restraining pro-inflammatory cytokines release, meanwhile, promoted the BA circulation via activating BA receptor and promoting BA synthesis. Moreover, Tg reverted the HFD-induced gut microbial dysbiosis by promoting the growth of beneficial Akkermansia, and inhibiting the proportions of harmful microbes, including Blautia, Lachnoclostridium, Lachnospiraceae_UCG-006, Roseburia, Romboutsia and Faecalibaculum, which were highly correlated with NAFLD-related parameters in serum and liver. Thus, Tg could attenuate NAFLD through mediating the liver-gut axis, and it could be used as a dietary supplement for NAFLD treatment via its anti-inflammatory and prebiotic effects.

Therapeutic Potential of Natural Plants Against Non-Alcoholic Fatty Liver Disease: Targeting the Interplay Between Gut Microbiota and Bile Acids

Non-alcoholic fatty liver disease (NAFLD) remains a common disease with a significant health and economic burden worldwide. The gut microbiota (GM) and bile acids (BAs), which play important roles in the gut-liver axis, have been confirmed to jointly participate in the development of NAFLD. GM not only regulate bile acids’ synthesis, transport, and reabsorption by regulating other metabolites (such as trimetlyl amine oxide, butyrate), but also regulate dehydrogenation, dehydroxylation and desulfurization of bile acids. Meanwhile, disordered bile acids influence the gut microbiota mainly through promoting the bacterial death and lowering the microbial diversity. Although weight loss and lifestyle changes are effective in the treatment of NAFLD, the acceptability and compliance of patients are poor. Recently, increasing natural plants and their active ingredients have been proved to alleviate NAFLD by modulating the joint action of gut microbiota and bile acids, and considered to be promising potential candidates. In this review, we discuss the efficacy of natural plants in treating NAFLD in the context of their regulation of the complex interplay between the gut microbiota and bile acids, the crosstalk of which has been shown to significantly promote the progression of NAFLD. Herein, we summarize the prior work on this topic and further suggest future research directions in the field.

Polygoni Multiflori Radix Praeparata Ethanol Extract Exerts a Protective Effect Against High-Fat Diet Induced Non-Alcoholic Fatty Liver Disease in Mice by Remodeling Intestinal Microbial Structure and Maintaining Metabolic Homeostasis of Bile Acids

In the prescription of Traditional Chinese Medicine for lipid metabolism, Polygoni Multiflori Radix Preparata (ZhiHeShouWu, RPMP) was widely used. In recent years, RPMP ethanol extract has been reported for the treatment of non-alcoholic fatty liver disease (NAFLD). However, the role of RPMP ethanol extract in the treatment of NAFLD has not been fully elucidated. Therefore, we examined the optimal therapeutic dose of RPMP ethanol extracts. Afterward, a mouse model of non-alcoholic fatty liver induced by a high-fat diet (HFD) was treated with RPMP ethanol extract to further evaluate the mechanism of action of RPMP ethanol extract treatment. And the serum lipid metabolism indexes and liver function indexes showed that the RPMP ethanol extract in the 1.35 g/kg dose group exhibited better therapeutic effects than the 2.70 g/kg dose group. Meanwhile, RPMP ethanol extract can regulate the biochemical indicators of serum and liver to normal levels, and effectively reduce liver steatosis and lipid deposition. RPMP ethanol extract treatment restored HFD-induced disruption of the compositional structure of the intestinal microbial (IM) and bile acids (BAs) pools. And restore the reduced expression of intestinal barrier-related genes caused by HFD administration, which also effectively regulates the expression of genes related to the metabolism of BAs in mice. Thus, RPMP ethanol extract can effectively improve the abnormal lipid metabolism and hepatic lipid accumulation caused by HFD, which may be related to the regulation of IM composition, maintenance of intestinal barrier function, and normal cholesterol metabolism in the body.

Novel Sesquiterpene Glycoside from Loquat Leaf Alleviates Type 2 Diabetes Mellitus Combined with Nonalcoholic Fatty Liver Disease by Improving Insulin Resistance, Oxidative Stress, Inflammation, and Gut Microbiota Composition

Nonalcoholic fatty liver disease (NAFLD) is strongly associated with type 2 diabetes mellitus (T2DM). Sesquiterpene glycosides from loquat leaf achieved beneficial effects on metabolic syndromes such as NAFLD and diabetes; however, their specific activity and underlying mechanism on T2DM-associated NAFLD have not yet been fully understood. In the present study, we found that sesquiterpene glycoside 3 (SG3), a novel sesquiterpene glycoside isolated from loquat leaf, was able to prevent insulin resistance (IR), oxidative stress, and inflammation. In db/db mice, SG3 administration (25 and 50 mg/kg/day) inhibited obesity, hyperglycemia, and the release of inflammatory cytokines. SG3 (5 and 10 μM) also significantly alleviated hepatic lipid accumulation, oxidative stress, and inflammatory response induced by high glucose combined with oleic acid in HepG2 cells. Western blotting analysis showed that these effects were related to repair the abnormal insulin signaling and inhibit the cytochrome P450 2E1 (CYP2E1) and NOD-like receptor family pyrin domain-containing 3 (NLRP3), both in vivo and in vitro. In addition, SG3 treatment could decrease the ratio of Firmicutes/Bacteroidetes and increase the relative abundance of Lachnospiraceae, Muribaculaceae, and Lactobacillaceae after a high-throughput pyrosequencing of 16S rRNA to observe the changes of related gut microbial composition in db/db mice. These findings proved that SG3 could protect against NAFLD in T2DM by improving IR, oxidative stress, inflammation through regulating insulin signaling and inhibiting CYP2E1/NLRP3 pathways, and remodeling the mouse gut microbiome. It is suggested that SG3 could be considered as a new functional additive for a healthy diet.

The Relieving Effects of a Polyherb-Based Dietary Supplement ColonVita on Gastrointestinal Quality of Life Index (GIQLI) in Older Adults with Chronic Gastrointestinal Symptoms Are Influenced by Age and Cardiovascular Disease: A 12-Week Randomized Placebo-Controlled Trial

Chronic gastrointestinal symptoms (CGS) negatively affect the quality of life in about 15–30% of the population without effective drugs. Recent studies suggest that dietary supplement may improve CGS, but inconsistent results exist. The goal of this study is to evaluate the effect of a polyherbal-based supplement ColonVita on the gastrointestinal quality of life index (GIQLI) in 100 old adults with CGS (63.1 ± 9.6 years) who were randomly assigned to daily ColonVita or placebo tablets (n = 50/group) for 12 weeks in a double-blind, randomized controlled trial design. No significant fibrdifferences were found between ColonVita and placebo in the baseline total GIQLI score (101.12 ± 16.87 vs. 101.80 ± 16.48) (P > 0.05) or postintervention total GIQLI score (114.78 ± 9.62 vs. 111.74 ± 13.01) (P > 0.05). However, ColonVita significantly improved 16 scores of the 19 core GI symptoms compared with 10 items improved by placebo. The ColonVita group significantly improved the remission rate of 5 core GI symptoms compared to placebo and significantly improved the total GIQLI scores (118.09 ± 7.88 vs. 109.50 ± 16.71) (P < 0.05) and core GI symptom scores (64.61 ± 3.99 vs. 60.00 ± 8.65) (P < 0.05) in people ≥60 years of age (n = 49) but not in those under 60 y (n = 51). ColonVita significantly improved the total GIQLI scores and core GI symptom scores in people without cardiovascular diseases (CVD) (n = 56) (116.74 ± 9.38 vs. 110.10 ± 14.28) (P < 0.05) and (63.11 ± 4.53 vs. 59.93 ± 8.03) (P=0.07), respectively, but not in those with CVD (n = 44). Thus, ColonVita was beneficial for old adults with CGS, especially those ≥60 years of age and without CVD. Because a heterogenous pathogenesis of CGS-like irritable bowel syndrome (IBS) and inflammatory bowel disease (ISD) is differentially associated with CVD, different comorbidities may have influenced the outcomes of different trials that should be controlled in further studies.