Gallic acid ameliorates dextran sulfate sodium-induced ulcerative colitis in mice via inhibiting NLRP3 inflammasome

Harnessing nature's pharmacy: investigating natural compounds as novel therapeutics for ulcerative colitis

Backgrounds

Ulcerative colitis (UC) is a form of chronic inflammatory bowel disease, and UC diagnosis rates continue to rise throughout the globe. The research and development of new drugs for the treatment of UC are urgent, and natural compounds are an important source. However, there is a lack of systematic summarization of natural compounds and their mechanisms for the treatment of UC.

Methods

We reviewed the literature in the databases below from their inception until July 2023: Web of Science, PubMed, China National Knowledge Infrastructure, and Wanfang Data, to obtain information on the relationship between natural compounds and UC.

Results

The results showed that 279 natural compounds treat UC through four main mechanisms, including regulating gut microbiota and metabolites (Mechanism I), protecting the intestinal mucosal barrier (Mechanism II), regulating intestinal mucosal immune response (Mechanism III), as well as regulating other mechanisms (Mechanism Ⅳ) such as cellular autophagy modulation and ferroptosis inhibition. Of these, Mechanism III is regulated by all natural compounds. The 279 natural compounds, including 62 terpenoids, 57 alkaloids, 52 flavonoids, 26 phenols, 19 phenylpropanoids, 9 steroids, 9 saponins, 8 quinonoids, 6 vitamins, and 31 others, can effectively ameliorate UC. Of these, terpenoids, alkaloids, and flavonoids have the greatest potential for treating UC. It is noteworthy to highlight that a total of 54 natural compounds exhibit their therapeutic effects by modulating Mechanisms I, II, and III.

Conclusion

This review serves as a comprehensive resource for the pharmaceutical industry, researchers, and clinicians seeking novel therapeutic approaches to combat UC. Harnessing the therapeutic potential of these natural compounds may significantly contribute to the improvement of the quality of life of patients with UC and promotion of disease-modifying therapies in the future.

Establishment and Evaluation of a Mouse Model of Experimental Ulcerative Colitis Induced by the Gavage Administration of Dextran Sulfate Sodium

Given the critical role of dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) mouse models in the appraisal of associated therapeutic drugs, the optimization of the administration method and dosages is of paramount importance. Therefore, UC was induced in mice through the gavage administration of a DSS solution instead of free drinking water. The effects of varying daily dosages (2, 4, 6, and 8 g/kg) and frequencies (once or twice) of administration on the body weight and survival rate of the model mice were evaluated. Concurrently, the inflammatory indicators and tissue sections of the model mice were thoroughly evaluated. The results revealed that when the daily dosage reached 8 g/kg, the dosage exhibited a high level of toxicity, resulting in a high mortality rate among the mice. The DSS administration of 6 g/kg*2 not only elicited conspicuous symptoms, significant weight loss, substantial shortening of the colon, and significant changes in various inflammatory indicators, such as myeloperoxidase (MPO), nitric oxide (NO), reactive oxygen species (ROS), and glutathione (GSH), but it also maintained a high survival rate in the UC mice. The findings from this experiment lay a solid experimental foundation for future research on drugs intended for the treatment of UC.

Exploring the anti-inflammatory ingredients and potential of golden buckwheat (Fagopyrum dibotrys) on the TLR4/NLRP3 pathway in acute lung injury

Golden buckwheat, also called Fagopyrum dibotrys (D. Don) H. Hara, is a plant of the genus Buckwheat in the buckwheat family. The aim of this study was to screen the bioactive ingredients of golden buckwheat extract and investigate the protective effect on acute lung injury (ALI). The ethyl acetate extract (EAE) was identified as the active fraction in LPS-induced RAW264.7 cells, with gallic acid, proanthocyanidin B2, and epicatechin at 0.0563%, 0.3707%, and 0.3868%, respectively. At the same time, 20 compounds (mainly flavonoids and organic acids) were identified by UPLC-Q-Exactive Orbitrap-HRMS in EAE. Furthermore, the EAE reduced lung histopathology scores in mice with ALI, decreased the dry-to-wet weight ratio of lung tissue, and significantly inhibited the concentrations of IL-1β, TNFα, and IL-6 in bronchoalveolar lavage fluid (BALF). It also reduced the number of leukocytes, decreased the activity of MPO in lung tissue, and inhibited the levels of TLR4/NLRP3 pathway mRNA and protein in lung tissue. Our study indicated that golden buckwheat as a source of functional food prevents or treats associated lung diseases by modulating the activation of the TLR4/NLRP3 signaling pathway.

Gallic acid attenuates LPS-induced inflammation in Caco-2 cells by suppressing the activation of the NF-κB/MAPK signaling pathway

Inflammatory bowel disease (IBD) is a chronic inflammatory disease characterized by intestinal barrier dysfunction, inflammatory synergistic effects and excessive tissue injury. Gallic acid (GA) is renowned for its remarkable biological activity, encompassing anti-inflammatory and antioxidant properties. However, the underlying mechanisms by which GA protects against intestinal inflammation have not been fully elucidated. The aim of this study is to investigate the effect of GA on the inflammation of a lipopolysaccharide (LPS)-stimulated human colon carcinoma cell line (Caco-2) and on the intestinal barrier dysfunction, and explore the underlying molecular mechanism involved. Our findings demonstrate that 5 μg/mL GA restores the downregulation of the mRNA and protein levels of Claudin-1, Occludin, and ZO-1 and decreases the expressions of inflammatory factors such as IL-6, IL-1β and TNF-α induced by LPS. In addition, GA exhibits a protective effect by reducing the LPS-enhanced early and late apoptotic ratios, downregulating the mRNA levels of pro-apoptotic factors ( Bax, Bad, Caspase-3, Caspase-8, and Caspase-9), and upregulating the mRNA levels of anti-apoptotic factor Bcl-2 in Caco-2 cells. GA also reduces the levels of reactive oxygen species increased by LPS and restores the activity of antioxidant enzymes, namely, superoxide dismutase and catalase, as well as the level of glutathione. More importantly, GA exerts its anti-inflammatory effects by inhibiting the LPS-induced phosphorylation of key signaling molecules in the NF-κB/MAPK pathway, including p65, IκB-α, p38, JNK, and ERK, in Caco-2 cells. Overall, our findings show that GA increases the expressions of tight junction proteins, reduces cell apoptosis, relieves oxidative stress and suppresses the activation of the NF-κB/MAPK pathway to reduce LPS-induced intestinal inflammation in Caco-2 cells, indicating that GA has potential as a therapeutic agent for intestinal inflammation.

Anti-inflammatory and anti-hyperalgesic effects induced by an aqueous aged black garlic extract in rodent models of ulcerative colitis and colitis-associated visceral pain

Inflammatory bowel disease (IBD) is a morbid condition characterized by relapsing-remitting inflammation of the colon, accompanied by persistent gut dysmotility and abdominal pain. Different reports demonstrated biological activities of aged black garlic (ABG), including anti-inflammatory and antioxidant effects. We aimed to investigate beneficial effects exerted by ABGE on colon inflammation by using ex vivo and in vivo experimental models. We investigated the anti-inflammatory effects of an ABG water extract (ABGE) on rat colon specimens exposed to E. coli lipopolysaccharide (LPS), a known ex vivo experimental model of ulcerative colitis. We determined gene expression of various biomarkers involved in inflammation, including interleukin (IL)-1β, IL-6, nuclear factor-kB (NF-kB), tumor necrosis factor (TNF)-α. Moreover, we studied the acute effects of ABGE on visceral pain associated with colitis induced by 2,4-di-nitrobenzene sulfonic acid (DNBS) injection in rats. ABGE suppressed LPS-induced gene expression of IL-1β, IL-6, NF-kB, and TNF-α. In addition, the acute administration of ABGE (0.03-1 g kg-1) dose-dependently relieved post-inflammatory visceral pain, with the higher dose (1 g kg-1) able to significantly reduce both the behavioral nociceptive response and the entity of abdominal contraction (assessed by electromyography) in response to colorectal distension after the acute administration in DNBS-treated rats. Present findings showed that ABGE could represent a potential strategy for treatment of colitis-associated inflammatory process and visceral pain. The beneficial effects induced by the extract could be related to the pattern of polyphenolic composition, with particular regard to gallic acid and catechin.

Mid-infrared spectroscopic identification of the right-baked rhubarb for ulcerative colitis therapy

Clinical and experimental evidences have confirmed the significant therapeutic effects of rhubarb on ulcerative colitis (UC), but the strong purgative function of rhubarb also aggravates UC symptoms such as bloody diarrhea. Stir-baking to scorch is a traditional Chinese medicinal processing method that can eliminate the adverse purgative function while keep or even enhance the UC therapeutic function of rhubarb. However, the under-baked rhubarb still have the undesirable purgative function, but the over-baked rhubarb may lose the required medicinal functions. Therefore, the determination of the right endpoint is the primary quality concern about the baking process of rhubarb. In this research, typical anthraquinone compounds and mid-infrared (MIR) spectra were recruited to determine the best baking degree of rhubarb for UC therapy. Raw rhubarb slices were baked at 180 °C with rotation to prepare the rhubarbs with different baking degrees. The right-baked rhubarb was defined according to the UC therapeutic responses as well as the traditional color criterion. Referring to the typical anthraquinone compounds in rhubarb slices and extracts, the baking degree of rhubarb may be assessed by the conversion ratio of anthraquinone glycosides to anthraquinone aglycones. MIR spectra showed the gradual decompositions of organic compounds including anthraquinone glycosides and tannins during the baking process. Rhubarbs with different baking degrees can be distinguished clearly by MIR-based principal component analysis. In conclusion, the ratio of anthraquinone glycosides to anthraquinone aglycones may be a reasonable chemical indicator of the right-baked rhubarb. Meanwhile, MIR spectroscopy can identify the right-baked rhubarb simply and rapidly.

Therapeutic Implications of Phenolic Acids for Ameliorating Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic inflammatory intestinal disorder, and its complex etiology makes prevention and treatment challenging. Research on new drugs and treatment strategies is currently a focal point. Phenolic acids are widely present in plant-based diets and have demonstrated the potential to alleviate colitis due to their powerful antioxidant and anti-inflammatory properties. In this review, we provide an overview of the structures and main dietary sources of phenolic acids, encompassing benzoic acid and cinnamic acid. Additionally, we explore the potential of phenolic acids as a nutritional therapy for preventing and treating IBD. In animal and cell experiments, phenolic acids effectively alleviate IBD induced by drug exposure or genetic defects. The mechanisms include improving intestinal mucosal barrier function, reducing oxidative stress, inhibiting excessive activation of the immune response, and regulating the balance of the intestinal microbiota. Our observation points towards the need for additional basic and clinical investigations on phenolic acids and their derivatives as potential novel therapeutic agents for IBD.

Research advancements and perspectives of inflammatory bowel disease: A comprehensive review

Inflammatory bowel disease (IBD) is a chronic inflammatory disease with increasing incidence, such as Crohn's disease and ulcerative colitis. The accurate etiology and pathogenesis of IBD remain unclear, and it is generally believed that it is related to genetic susceptibility, gut microbiota, environmental factors, immunological abnormalities, and potentially other factors. Currently, the mainstream therapeutic drugs are amino salicylic acid agents, corticosteroids, immunomodulators, and biological agents, but the remission rates do not surpass 30-60% of patients in a real-life setting. As a consequence, there are many studies focusing on emerging drugs and bioactive ingredients that have higher efficacy and long-term safety for achieving complete deep healing. This article begins with a review of the latest, systematic, and credible summaries of the pathogenesis of IBD. In addition, we provide a summary of the current treatments and drugs for IBD. Finally, we focus on the therapeutic effects of emerging drugs such as microRNAs and lncRNAs, nanoparticles-mediated drugs and natural products on IBD and their mechanisms of action.

Gallic Acid-Modified Polyethylenimine-Polypropylene Carbonate-Polyethylenimine Nanoparticles: Synthesis, Characterization, and Anti-Periodontitis Evaluation

The aim of the research was to develop novel gallic acid (GA)-modified amphiphilic nanoparticles of polyethylenimine (PEI)-polypropylene carbonate (PPC)-PEI (PEPE) and comprehensively assess its properties as an antiperiodontitis nanoparticle targeting the Toll-like receptor (TLR). The first step is to evaluate the binding potential of GA to the core trigger receptors TLR2 and TLR4/MD2 for periodontitis using molecular docking techniques. Following this, we conducted NMR, transmission electron microscopy, and dynamic light scattering analyses on the synthesized PEPE nanoparticles. As the final step, we investigated the synthetic results and in vitro antiperiodontitis properties of GA-PEPE nanoparticles. The investigation revealed that GA exhibits potential for targeted binding to TLR2 and the TLR4/MD2 complex. Furthermore, we successfully developed 91.19 nm positively charged PEPE nanoparticles. Spectroscopic analysis indicated the successful synthesis of GA-modified PEPE. Additionally, CCK8 results demonstrated that GA modification significantly reduced the biotoxicity of PEPE. The in vitro antiperiodontitis properties assessment illustrated that 6.25 μM of GA-PEPE nanoparticles significantly reduced the expression of pro-inflammatory factors TNF-α, IL-1β, and IL-6. The GA-PEPE nanoparticles, with their targeted TLR binding capabilities, were found to possess excellent biocompatibility and antiperiodontitis properties. GA-PEPE nanoparticles will provide highly innovative input into the development of anti- periodontitis nanoparticles.

Study on network pharmacology of Ginkgo biloba extract against ischaemic stroke mechanism and establishment of UPLC-MS/MS methods for simultaneous determination of 19 main active components

INTRODUCTION

Ginkgo biloba extract (GBE) is an effective substance from traditional Chinese medicine (TCM) G. biloba for treating ischaemic stroke (IS). However, its active ingredients and mechanism of action remain unclear.

OBJECTIVES

This study aimed to reveal the potential active component group and possible anti-IS mechanism of GBE.

MATERIALS AND METHODS

The network pharmacology method was used to reveal the possible anti-IS mechanism of these active ingredients in GBE. An ultra-high-performance liquid chromatography triple quadrupole electrospray tandem mass spectrometry (UPLC-MS/MS) method was established for the simultaneous detection of the active ingredients of GBE.

RESULTS

The active components of GBE anti-IS were screened by literature integration. Network pharmacology results showed that the anti-IS effect of GBE is achieved through key active components such as protocatechuic acid, bilobalide, ginkgolide A, and so on. Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that the possible anti-IS mechanism of GBE is regulating the PI3K-Akt signalling pathway and other signal pathways closely related to inflammatory response and apoptosis regulation combined with AKT1, MAPK, TNF, ALB, CASP3, and other protein targets. Nineteen main constituents in seven batches of GBE were successfully analysed using the established UPLC-MS/MS method, and the results showed that the content of protocatechuic acid, gallic acid, ginkgolide A, and so forth was relatively high, which was consistent with network pharmacology results, indicating that these ingredients may be the key active anti-IS ingredients of GBE.

CONCLUSION

This study revealed the key active components and the anti-IS mechanism of GBE. It also provided a simple and sensitive method for the quality control of related preparations.

Gallic acid ameliorates colitis by trapping deleterious metabolite ammonia and improving gut microbiota dysbiosis

Gut microbiota dysbiosis is causally related to inflammatory bowel disease (IBD), and increased levels of the gut metabolite ammonia have been proposed to contribute to IBD development. In this study, we aimed to clarify the anti-colitis mechanism of gallic acid (GA) based on its ability to trap the deleterious metabolite ammonia and improve gut microbiota. Aminated product was detected in the fecal samples of mice after oral gavage of gallic acid (GA) and identified as 4-amino-substituted gallic acid (4-NH2-GA), thus confirming the ability of GA to trap ammonia in vivo. Then, we compared the beneficial effects of GA and 4-NH2-GA on dextran sulfate sodium (DSS)-induced colitis mouse and found that both compounds managed to alleviate colitis phenotypes, indicating ammonia trapping had no adverse effect on the original anti-colitis activity of GA. In addition, both GA and 4-NH2-GA improved the gut microbiota dysbiosis induced by DSS, and fecal microbiota transplantation was subsequently performed, which further revealed that the gut microbiota mediated the anti-colitis activity of both GA and 4-NH2-GA. In summary, this study clarified that GA alleviated colitis by targeting both the symptoms and root causes: it directly reduced the deleterious metabolite ammonia by forming aminated metabolites without compromising the original anti-colitis activity, and it also improved gut microbiota dysbiosis, which in turn contributed to the alleviation of colitis. Since the GA structure is presented in various polyphenols as a common building block, the novel anti-colitis mechanism obtained from GA may also apply to other complex polyphenols.IMPORTANCEThe dysbiosis of the gut microbiota and its metabolism directly cause the emergence of IBD. In this study, we aimed to clarify the anti-colitis mechanism of GA in sight of gut microbiota and its metabolite ammonia. We discovered that GA directly captured and reduced the harmful metabolite ammonia in vivo to produce the aminated metabolite 4-NH2-GA, while the amination of GA had no adverse effect on its initial anti-colitis activity. In addition, both GA and its aminated metabolite improved the gut microbiota in colitis mice, and the modified gut microbiota, in turn, helped to relieve colitis. Since the GA structure is presented in diverse polyphenols as a common building block, the novel anti-colitis mechanism targeting the symptoms and root causes might also apply to other complex polyphenols.

Casuarina glauca branchlets' extract as a potential treatment for ulcerative colitis: chemical composition, in silico and in vivo studies

Ulcerative colitis (UC) is an inflammatory bowel disease that is often resistant to current treatment options, leading to a need for alternative therapies. Herbal products have shown promise in managing various conditions, including UC. However, the potential of Casuarina glauca branchlets ethanolic extract (CGBRE) in treating UC has not been explored. This study aimed to analyze the chemical composition of CGBRE and evaluate its efficacy in UC treatment through in silico and in vivo experiments. LC-ESI-MS/MS was used to identify 86 compounds in CGBRE, with 21 potential bioactive compounds determined through pharmacokinetic analysis. Network pharmacology analysis revealed 171 potential UC targets for the bioactive compounds, including EGFR, LRRK2, and HSP90 as top targets, which were found to bind to key CGBRE compounds through molecular docking. Molecular docking findings suggested that CGBRE may be effective in the prevention or treatment of ulcerative colitis mediated by these proteins, where key CGBRE compounds exhibited good binding affinities through formation of numerous interactions. In vivo studies in rats with acetic acid-induced UC demonstrated that oral administration of 300 mg/kg CGBRE for 6 days reduced UC symptoms and colonic expression of EGFR, LRRK2, and HSP90. These findings supported the therapeutic potential of CGBRE in UC and suggested the need for further preclinical and clinical investigation.

Cyclizine-induced proinflammatory responses through Akt-NFκB pathway in macrophages

Cyclizine exhibits sedation and treatment of nausea, vomiting, and motion sickness due to antihistaminic and antimuscarinic effects. Cyclizine has the potential for abuse due to the hallucinogenic and euphoric effect. The response of overdose and illegal abuse of cyclizine includes confusion, tremors, chest pain, ataxia, seizures, and lead to suicide. Macrophage plays the important role in the innate immunity. However, over activation of macrophages results in pro-inflammatory responses in peripheral tissues. In the present study, cyclizine was found to enhanced the generation of pro-inflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6. We further found that secretion of nitrogen oxide (NO) induced by cyclizine via expression of inducible nitric oxide synthases (iNOS). Cyclizine exhibited parallel stimulation of phosphorylation of nuclear factor-κB (NFκB) p65, and its up-stream factor Akt. These results indicated that the expression of pro-inflammatory cytokines, pro-inflammatory mediators, and adhesion molecules would be induced by cyclizine via activation of Akt-NFκB pathway in macrophages.

Rosa Roxburghii Tratt Fruit Extract Prevents Dss-Induced Ulcerative Colitis in Mice by Modulating the Gut Microbiota and the IL-17 Signaling Pathway

Ulcerative colitis (UC) is a non-specific inflammatory bowel illness characterized by intestinal mucosal barrier degradation, inflammation, oxidative damage, and gut microbiota imbalances. Rosa roxburghii Tratt Fruit extract (RRTE) was extracted from Rosa roxburghii Tratt fruit, exhibiting an excellent prevention effect against UC; RRTE could prevent the damage of DSS-induced human normal colonic epithelial (NCM 460) cells, especially in cell viability and morphology, and oxidative damage. Additionally, in UC mice, RRTE could limit the intestinal mucosal barrier by increasing the expression of intestinal tight junction proteins and mucin, reducing inflammation and oxidative damage in colon tissue. More importantly, RRTE can increase the abundance of beneficial bacteria to regulate gut microbiota such as Ruminococcus, Turicibacter, and Parabacteroides, and reduce the abundance of harmful bacteria such as Staphylococcus and Shigella. Furthermore, transcriptomics of colonic mucosal findings point out that the beneficial effect of RRTE on UC could be attributed to the modulation of inflammatory responses such as the IL-17 and TNF signaling pathways. The qPCR results confirm that RRTE did involve the regulation of several genes in the IL-17 signaling pathway. In conclusion, RRTE could prevent DSS-induced damage both in vitro and in vivo.

Terminalia bellirica Fruit Extract Alleviates DSS-Induced Ulcerative Colitis by Regulating Gut Microbiota, Inflammatory Mediators, and Cytokines

Ulcerative colitis (UC) is a chronic inflammatory disease significantly impacting patients' lives. This study aimed to elucidate the alleviating effect of ethyl acetate extract (TBEA) from Terminalia bellirica fruit on UC and to explore its mechanism. TBEA was the fraction with the best anti-inflammatory activity screened using in vitro anti-inflammatory assays, and HPLC initially characterized its composition. The mice model of ulcerative colitis was established after free drinking of 2.5% dextran sulfate sodium for six days, and the experimental group was treated with 50 mg/kg and 100 mg/kg TBEA for seven days. We found that TBEA significantly alleviated symptoms in UC mice, including a physiologically significant reduction in disease activity index and pathological damage to colonic tissue. TBEA dramatically slowed down oxidative stress and inflammatory process in UC mice, as evidenced by decreasing myeloperoxidase and malondialdehyde activities and increasing glutathione and catalase levels by reducing the concentrations of IL-6, IL-1β, TNF-α, and NO in UC mice, as well as by regulating key proteins in the IL-6/JAK2/STAT3 pathway. Meanwhile, TBEA maintained intestinal homeostasis by regulating intestinal flora structure. Our study provides new ideas for developing TBEA into a new drug to treat UC.

Margaritaria nobilis L.f. (Phyllanthaceae) Ethanolic Extract: Low Acute Oral Toxicity and Antinociceptive Activity

Margaritaria nobilis L.f. (Phyllanthaceae), a native Brazilian tree occurring mainly in the Amazon, is used in folk medicine for the treatment of abscesses (bark) and cancer-like symptoms (leaves). The present study evaluates the safety of its acute oral administration and its effects on nociception and plasma leakage. The chemical constitution of the leaf's ethanolic extract is determined by ultra-performance liquid chromatography-high-resolution mass spectrometry (LC-MS. Its acute oral toxicity is evaluated in female rats at a dose of 2000 mg/kg, evaluating the occurrence of deaths and Hippocratic, behavioral, hematological, biochemical, and histopathological changes, as well as food and water consumption and weight gain. Antinociceptive activity is evaluated in male mice with acetic-acid-induced peritonitis (APT) and formalin (FT) tests. An open field (OF) test is performed to verify possible interferences in the animals' consciousness or locomotion. LC-MS analysis shows the presence of 44 compounds classified as phenolic acid derivatives, flavonoids and O-glycosylated derivatives, and hydrolyzable tannins. No deaths or significant behavioral, histological, or biochemical changes are observed in the toxicity assessment. In nociception tests, M. nobilis extract significantly reduces abdominal contortions in APT, demonstrating selectivity for inflammatory components (FT second phase), not interfering in neuropathic components (FT first phase) or consciousness and locomotion levels in OF. Additionally, M. nobilis extract inhibits plasma acetic-acid-induced leakage. These data demonstrate the low toxicity of M. nobilis ethanolic extract, as well as its effectiveness in modulating inflammatory nociception and plasma leakage, possibly related to the flavonoids and tannins present in its composition.