Andrographolide derivative ameliorates dextran sulfate sodium-induced experimental colitis in mice

Recent developments and new directions in the use of natural products for the treatment of inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) represents a significant global health challenge, and there is an urgent need to explore novel therapeutic interventions. Natural products have demonstrated highly promising effectiveness in the treatment of IBD.

PURPOSE

This study systematically reviews the latest research advancements in leveraging natural products for IBD treatment.

METHODS

This manuscript strictly adheres to the PRISMA guidelines. Relevant literature on the effects of natural products on IBD was retrieved from the PubMed, Web of Science and Cochrane Library databases using the search terms "natural product," "inflammatory bowel disease," "colitis," "metagenomics", "target identification", "drug delivery systems", "polyphenols," "alkaloids," "terpenoids," and so on. The retrieved data were then systematically summarized and reviewed.

RESULTS

This review assessed the different effects of various natural products, such as polyphenols, alkaloids, terpenoids, quinones, and others, in the treatment of IBD. While these natural products offer promising avenues for IBD management, they also face challenges in terms of clinical translation and drug discovery. The advent of metagenomics, single-cell sequencing, target identification techniques, drug delivery systems, and other cutting-edge technologies heralds a new era in overcoming these challenges.

CONCLUSION

This paper provides an overview of current research progress in utilizing natural products for the treatment of IBD, exploring how contemporary technological innovations can aid in discovering and harnessing bioactive natural products for the treatment of IBD.

Tectorigenin inhibits inflammatory responses in murine inflammatory bowel disease and LPS-stimulated macrophages via inactivating MAPK signaling pathway

BACKGROUND

Considering the antihepatitis effects of Tectorigenin (TEC), and the same adenosine mitogen-activated protein kinase (MAPK) pathway in both hepatitis and inflammatory bowel disease (IBD) models, exploring the role of TEC in IBD is contributive to develop a new treatment strategy against IBD.

METHODS

The IBD mouse model was constructed by feeding with dextran sodium sulfate (DSS) and injection of TEC. Afterward, the mouse body weight, colon length, and disease activity index (DAI) were tested to assess the enteritis level. Mouse intestine lesions were detected by hematoxylin and eosin staining. Murine macrophages underwent lipopolysaccharide (LPS) induction to establish an inflammation model. Cell viability was determined by cell counting kit-8 assay. Enzyme-linked immunosorbent assay was performed to measure interleukin 6 (IL-6) and tumor necrosis factor-α (TNF-α) levels. Cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expressions were quantified via quantitative reverse transcription polymerase chain reaction. Levels of MAPK pathway-related proteins (p-P38, P38, p-Jun N-terminal kinase (JNK), JNK, signal-regulated kinase (ERK), p-ERK), COX-2 and iNOS were quantitated by Western blot.

RESULTS

TEC improved the inflammatory response through ameliorating weight loss, shortening colon, and increasing DAI score in IBD mouse. Expressions of intestinal inflammatory factors (IL-6, TNF-α, iNOS and COX-2) and MAPK pathway-related proteins (p-P38, p-JNK, and p-ERK) were increased both in DSS-induced mouse intestinal tissue, but TEC inhibited expressions of inflammatory factors. The same increased trend was identified in LPS-induced macrophages, but TEC improved macrophage inflammation, as evidenced by downregulation of inflammatory factors.

CONCLUSION

TEC mitigates IBD and LPS-induced macrophage inflammation in mice via inhibiting MAPK signaling pathway.

Andrographolide acts with dexamethasone to inhibit the growth of acute lymphoblastic leukemia CEM‑C1 cells via the regulation of the autophagy‑dependent PI3K/AKT/mTOR signaling pathway

Acute lymphoblastic leukemia (ALL) is one of the most common malignant tumor types of the circulatory system. Dexamethasone (DEX) acts on the glucocorticoid (GC) receptor (GR) and is a first-line chemotherapy drug for ALL. However, long-term or high-dose applications of the drug can not only cause adverse reactions, such as osteoporosis and high blood pressure, but can also cause downregulation of GR and lead to drug resistance. In the present study, reverse transcription-quantitative PCR, western blotting and LysoTracker Red staining were used to observe the effects of DEX and andrographolide (AND; a botanical with antitumorigenic properties) combined treatment. It was found that AND enhanced the sensitivity of CEM-C1 cells, a GC-resistant cell line, to DEX, and synergistically upregulated GR both at the transcriptional and post-transcriptional level with DEX. The combination of AND with DEX synergistically alkalized lysosomal lumen and downregulated the expression of autophagy-related genes Beclin1 and microtubule-associated 1 protein light chain 3 (LC3), thereby inhibiting autophagy. Knocking down LC3 expression enhanced GR expression, suggesting that GR was regulated by autophagy. Furthermore, compared with the monotherapy group (AND or DEX in isolation), AND interacted with DEX to activate the autophagy-dependent PI3K/AKT/mTOR signaling pathway by enhancing the phosphorylation of PI3K, AKT and mTOR, thereby decreasing GR degradation and increasing the sensitivity of cells to GCs. In conclusion, the present study demonstrated that AND exhibited a synergistic anti-ALL effect with DEX via upregulation of GR, which was orchestrated by the autophagy-related PI3K/AKT/mTOR signaling pathway. The results of the present study therefore provided novel research avenues and strategies for the treatment of ALL.

Toll-like receptors in inflammatory bowel disease: A review of the role of phytochemicals

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic inflammation within the gastrointestinal tract with a remarkable impact on patients' quality of life. Toll-like receptors (TLR), as a key contributor of immune system in inflammation, has a critical role in the pathogenesis of IBD and thus, can be a suitable target of therapeutic agents. Medicinal plants have long been considered as a source of bioactive agents for different diseases, including IBD.

PURPOSE

This review discusses current state of the art on the role of plant-derived compounds for the management of IBD with a focus on TLRs.

METHODS

Electronic database including PubMed, Web of Science, and Scopus were searched up to January 2023 and all studies in which anticolitis effects of a phytochemical was assessed via modulation of TLRs were considered.

RESULTS

Different categories of phytochemicals, including flavonoids, lignans, alkaloids, terpenes, saccharides, and saponins have demonstrated modulatory effects on TLR in different animal and cell models of bowel inflammation. Flavonoids were the most studied phytochemicals amongst others. Also, TLR4 was the most important type of TLRs which were modulated by phytochemicals. Other mechanisms such as inhibition of pro-inflammatory cytokines, nuclear factor-κB pathway, nitric oxide synthesis pathway, cyclooxygenase-2, lipid peroxidation, as well as induction of endogenous antioxidant defense mechanisms were also reported for phytochemicals in various IBD models.

CONCLUSION

Taken together, a growing body of pre-clinical evidence support the efficacy of herbal compounds for the treatment of IBD via modulation of TLRs. Future clinical studies are recommended to assess the safety and efficacy of these compounds in human.

Terpenes: Modulating anti-inflammatory signaling in inflammatory bowel disease

Inflammatory Bowel Disease (IBD) are autoimmune diseases characterized by chronic intestinal inflammation. Considered a western disease, IBD incidence in newly developed countries is skyrocketing. Accordingly, global prevalence is steadily increasing. There are two major IBD phenotypes, ulcerative colitis (UC) and Crohn's disease (CD). UC manifests as uninterrupted inflammation localized in the colon and rectum. Meanwhile, CD presents as interrupted inflammation that can occur throughout the digestive tract. As a result, therapeutics have focused on anti-inflammatory approaches for its treatment. Unfortunately, only 50% of patients benefit from current Food and Drug Administration approved treatments, and all are associated with serious adverse effects. Thus, there is a need for safer and novel therapeutics to increase the efficacy in this population. One aspect that is critical in understanding IBD is how food and phytochemicals therein may be associated with modifying the pathogenesis of IBD. A variety of retrospective and prospective studies, and clinical trials have shown benefits of plant-rich diets on the prevention and symptomatic improvement of IBD. The Mediterranean diet is rich in vegetables, fruits, legumes, and herbs; and characterized by the abundance of anti-inflammatory phytochemicals. An understudied phytochemical class enriched in this diet is terpenes; isoprene-based molecules are widely available in Mediterranean herbs and citrus fruits. Various terpenes have been evaluated in different IBD models. However, some present contradictory or inconclusive results. Therefore, in this review we evaluated preclinical studies of terpenes modulating basic inflammatory signaling related to IBD.

Andrographolide, a natural anti-inflammatory agent: An Update

Botanicals have attracted much attention in the field of anti-inflammatory due to their good pharmacological activity and efficacy. Andrographis paniculata is a natural plant ingredient that is widely used around the world. Andrographolide is the main active ingredient derived from Andrographis paniculata, which has a good effect on the treatment of inflammatory diseases. This article reviews the application, anti-inflammatory mechanism and molecular targets of andrographolide in different inflammatory diseases, including respiratory, digestive, immune, nervous, cardiovascular, skeletal, and tumor system diseases. And describe its toxicity and explain its safety. Studies have shown that andrographolide can be used to treat inflammatory lesions of various systemic diseases. In particular, it acts on many inflammation-related signalling pathways. The future direction of andrographolide research is also introduced, as is the recent research that indicates its potential clinical application as an anti-inflammatory agent.

Study on the mechanism of andrographolide activation

Andrographolide is a natural antibiotic that has the ability to dispel heat, detoxify, reduce inflammation, and relieve pain. Recent research has shown that it can exert anti-inflammatory effects via multiple pathways and multiple targets (mediated by NF-κB, JAK/STAT, T cell receptor, and other signaling pathways). It can inhibit human lung cancer cells, colon cancer cells, osteosarcoma cells, and other tumor cells, as well as reduce bacterial virulence and inhibit virus-induced cell apoptosis. It can also regulate inflammatory mediator expression to protect the nervous system and effectively prevent mental illness. Additionally, andrographolide regulates the immune system, treats cardiovascular and cerebral vascular diseases, protects the liver, and the gallbladder. It is clear that andrographolide has a huge range of potential applications. The mechanism of andrographolide’s anti-inflammatory, antibacterial, antiviral, and nervous system defense in recent years have been reviewed in this article.

Advances in ameliorating inflammatory diseases and cancers by andrographolide: Pharmacokinetics, pharmacodynamics, and perspective

Andrographolide, a well-known natural lactone having a range of pharmacological actions in traditional Chinese medicine. It has long been used to cure a variety of ailments. In this review, we cover the pharmacokinetics and pharmacological activity of andrographolide which supports its further clinical application in cancers and inflammatory diseases. Growing evidence shows a good therapeutic effect in inflammatory diseases, including liver diseases, joint diseases, respiratory system diseases, nervous system diseases, heart diseases, inflammatory bowel diseases, and inflammatory skin diseases. As a result, the effects of andrographolide on immune cells and the processes that underpin them are discussed. The preclinical use of andrographolide to different organs in response to malignancies such as colorectal, liver, gastric, breast, prostate, lung, and oral cancers has also been reviewed. In addition, several clinical trials of andrographolide in inflammatory diseases and cancers have been summarized. This review highlights recent advances in ameliorating inflammatory diseases as well as cancers by andrographolide and its analogs, providing a new perspective for subsequent research of this traditional natural product.

Andrographolide derivative as antagonist of vitamin D receptor to induce lipidation of microtubule associate protein 1 light chain 3 (LC3)

Lipidation of microtubule associated protein 1 light chain 3 (LC3) is the critical step in autophagosome formation, numerous efforts have been made to design and develop small molecules that trigger LC3 lipidation to activate autophagy. In this study, we discovered a series of andrographolide derivatives as potent antagonists of vitamin D receptor (VDR) by luciferase reporter assay. Structure-activity-relationship study revealed that andrographolide derivative ZAV-12 specifically inhibited VDR signaling but not NF-κB or STAT3 activation. Western blot analysis indicates that ZAV-12 markedly triggered lipidation of LC3 in MPP⁺-induced Parkinsonism in vitro in an mTOR-independent manner. The ZAV-12 triggered lipidation was mediated through SREBP2 activation instead of changing expression levels of lipid synthesis genes. Furthermore, ZAV-12 treatment increased the ratio of LC3-II/LC3-I and oligomerization of A53T α-synuclein (SNCA) in SNCA triggered neurotoxicity. Taken together, these results demonstrate the therapeutic potential of VDR antagonist as novel drug candidate for neurodegenerative diseases.

The Suppressive Effect of Mamiran Cream on Atopic Dermatitis-Like Skin Lesions In Vivo

BACKGROUND

The Chinese herbal formula Mamiran cream (MMC) has been known for its ameliorative effects on diverse skin diseases, such as eczema. Atopic dermatitis (AD; eczema) is a chronic recurrent skin disease dominated by T-helper type 2-driven inflammation (Th2).

OBJECTIVE

In this study, the inhibitory effect of MMC on AD was investigated in vivo.

METHODS

An animal model was established by sensitization with 2,4-dinitrochlorobenzene (DNCB) on the skin of SD rats. Cutaneous administration of MMC was applied, and its mechanism of action was investigated via RT-PCR and IHC assay.

RESULT

Our data showed that topical application of MMC reduced the skin severity scores and alleviated the histological changes. Furthermore, immunohistochemical analysis demonstrated that MMC significantly decreased the levels of Th2 cytokine IL-5 and IL-4Ra in the skin lesion. In addition, it was demonstrated that MMC downregulated the mRNA expression of TNF-α, IL-1β, IL-6, IL-10, and TLR4. Moreover, MMC inhibited the activation of NF-κB, JNK1, and STAT6 pathways in skin lesions.

CONCLUSIONS

Our findings suggest that MMC exhibits the inhibitory effect on AD, suggesting that MMC may be a potential therapeutic agent for this atopic disorder.

Network pharmacology for systematic understanding of Schisandrin B reduces the epithelial cells injury of colitis through regulating pyroptosis by AMPK/Nrf2/NLRP3 inflammasome

Ulcerative colitis (UC) is a chronic inflammatory disease with increasing incidence and prevalence in many countries. The purpose of this study is to explore the function of Schisandrin B and its underlying molecular mechanisms in colitis.

In this study, mice with colitis were induced by giving 2.0% dextran sulfate sodium (DSS, MP) in the drinking water for seven days. Furthermore, TCMSP server and GEO DataSets were used to analyze the mechanism of Schisandrin B in colitis.

It was found that Schisandrin B presented colitis in mice model. At the same time, Schisandrin B not only reduced inflammation in vivo and vitro model of colitis, but also suppressed the nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain-containing 3 (NLRP3) inflammasome in vivo and vitro model of colitis. In addition, Schisandrin B induced AMP-activated protein kinase (AMPK) / Nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway in model of colitis, and regulated AMPK protein at 316 sites. The inhibition of AMPK reduced the anti-inflammation effects of Schisandrin B on NLRP3 inflammasome. Apart from that, Schisandrin B decreased reactive oxygen species (ROS)-induced mitochondrial damage and reduced epithelial cells damage of colitis through regulating pyroptosis.

Collectively, our novel findings for first time showed that, Schisandrin B suppressed NLRP3 inflammasome activation-mediated interleukin-1beta (IL-1β) level and pyroptosis in intestinal epithelial cells of colitis model through the activation of AMPK/Nrf2 dependent signaling-ROS-induced mitochondrial damage, which may be a significant therapeutic approach in the treatment of acute colitis.

Biological properties of andrographolide, an active ingredient of Andrographis Paniculata: a narrative review

Andrographolide is a labdane diterpenoid isolated from Andrographis paniculata and traditionally used in Chinese and Indian medicine. Reported effects include anti-bacterial, anti-inflammatory and anti-cancer functions. Most of the studies support the hypothesis that andrographolide supplementation stimulates immune system, so the observed effects migh in fact be secondary to the stimulation of defense reactions. As andrographolide is involved in regulation of inflammation, it is not surprising that it is also evaluated in inflammation-mediated diseases such as ulcerative colitis. Anticancer effects of the andrographolide have been tested on various cancer panels. Colon cancer, breast cancer, and head and neck carcinomas were the most investigated, followed by prostate cancer and glioblastoma. The results looked promising. However, problems with solubility and low level of active substance in natural extract leads to preparation of chemical analogs. Objective of this short review is to summarize current knowledge of the biological effects of andragrapholide. We conclude that despite documented effects and some partly characterized mechanisms of action, more research is clearly needed. At present, the doses, types of treatment and possible negative side effects are not yet established. In addition, various isolations and compound formulas have been used for treatment of various diseases, making final conclusions problematic.

Targeting the NLRP3 inflammasome as new therapeutic avenue for inflammatory bowel disease

The incidence and prevalence of inflammatory bowel disease (IBD) are increasing worldwide. Current approved medication for IBD treatment in the clinic mainly includes corticosteroids and neutralization antibodies to pro-inflammatory cytokines. However, drug resistance and severe side effect hinder long-term efficacy of these agents. The NOD-like receptor family pyrin domain containing protein 3 (NLRP3) is exclusively expressed in several inflammatory and autoimmune diseases. Excessive expression, aberrant activation, polymorphism, and gain-of-function mutation of the NLRP3 inflammasome contribute to IBD pathogenesis. In this article, we summarize the regulatory factors to NLRP3, and review recently developed NLRP3 inhibitors and their preclinical and clinical applications in treating inflammatory and autoimmune diseases. We present our views on the therapeutic potential of NLRP3 inhibitors as emerging therapeutic avenue for IBD.

Andrographolide Exerts Antihyperglycemic Effect through Strengthening Intestinal Barrier Function and Increasing Microbial Composition of Akkermansia muciniphila

Accumulating evidence indicates that type 2 diabetes (T2D) is associated with intestinal barrier dysfunction and dysbiosis, implying the potential targets for T2D therapeutics. Andrographolide was reported to have several beneficial effects on diabetes and its associated complications. However, the protective role of andrographolide, as well as its underlying mechanism against T2D, remains elusive. Herein, we reported that andrographolide enhanced intestinal barrier integrity in LPS-induced Caco-2 cells as indicated by the improvement of cell monolayer barrier permeability and upregulation of tight junction protein expression. In addition, andrographolide alleviated LPS-induced oxidative stress by preventing ROS and superoxide anion radical overproduction and reversing glutathione depletion. In line with the in vitro results, andrographolide reduced metabolic endotoxemia and strengthened gut barrier integrity in db/db diabetic mice. We also found that andrographolide appeared to ameliorate glucose intolerance and insulin resistance and attenuated diabetes-associated redox disturbance and inflammation. Furthermore, our results indicated that andrographolide modified gut microbiota composition as indicated by elevated Bacteroidetes/Firmicutes ratio, enriched microbial species of Akkermansia muciniphila, and increased SCFAs level. Taken together, this study demonstrated that andrographolide exerted a glucose-lowering effect through strengthening intestinal barrier function and increasing the microbial species of A. muciniphila, which illuminates a plausible approach to prevent T2D by regulating gut barrier integrity and shaping intestinal microbiota composition.

Conjugated linoleic acid attenuates 2,4-dinitrofluorobenzene-induced atopic dermatitis in mice through dual inhibition of COX-2/5-LOX and TLR4/NF-κB signaling

Conjugated linoleic acid (CLA), commonly found in beef, lamb and dairy products, has been reported to exhibit anti-inflammatory and antipruritus effects and to inhibit the release of chemical mediators such as histamine and eicosanoid in laboratory rodents. The chief objective of the study is to assess the efficacy of CLA on atopic dermatitis (AD) in mice and to explore possible mechanisms with CLA treatments. To develop a new therapy for AD, the anti-AD potential of CLA was investigated by inducing AD-like skin lesions in mice using 2,4-dinitrofluorobenzene. We evaluated dermatitis severity; histopathological changes; serum levels of T helper (Th) cytokines (interferon-γ, interleukin-4); changes in protein expression by western blotting and immunohistochemistry staining for cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX), toll like receptor 4 (TLR-4), myeloid differentiation factor 88 (MyD88), nuclear factor-κB (NF-κB) and tumor necrosis factor α (TNF-α); and production of the proinflammatory lipid mediators, such as prostaglandin E₂ and leukotriene B4, in the skin lesions. Treatment with CLA ameliorated the development of AD-like clinical symptoms and effectively inhibited epidermal hyperplasia and infiltration of mast cells and CD4⁺ T cells in the AD mouse skin. Total serum immunoglobulin E levels and the expression levels of Th1/Th2 cytokines and lipid mediators in dorsal skin were dramatically suppressed by CLA. Furthermore, CLA down-regulated the expressions of COX-2, 5-LOX, TLR4, MyD88, NF-κB and TNF-α. Taken together, our findings demonstrate the potential usefulness of CLA as an anti-inflammatory dietary supplement or drug for the prevention and management of AD skin diseases by modulating the COX-2/5-LOX and TLR4/MyD88/NF-κB signaling pathways.