Trikatu, an herbal compound ameliorates rheumatoid arthritis by the suppression of inflammatory immune responses in rats with adjuvant-induced arthritis and on cultured fibroblast like synoviocytes via the inhibition of the NFκB signaling pathway

Targeting chemokine-receptor mediated molecular signaling by ethnopharmacological approaches

ETHNOPHARMACOLOGICAL RELEVANCE

Infection and inflammation are critical to global human health status and the goal of current pharmacological interventions intends formulating medications/preventives as a measure to deal with this situation. Chemokines and their cognate receptors are major regulatory molecules in many of these ailments. Natural products have been a keen source to the drug development industry, every year contributing significantly to the growing list of FDA approved drugs. A multiverse of natural resource is employed as a part of curative regimen in folk/traditional/ethnomedicine which can be employed to discover, repurpose, and design potent medications for the diseases of clinical concern.

AIM OF THE STUDY

This review aims to systematically document the ethnopharmacologically active agents targeting the infectious-inflammatory diseases through the chemokine-receptor nexus.

MATERIALS AND METHODS

Articles related to chemokine/receptor modulating ethnopharmacological anti-inflammatory, anti-infectious natural sources, bioactive compounds, and formulations have been examined with special emphasis on women related diseases. The available literature has been thoroughly scrutinized for the application of traditional medicines in chemokine associated experimental methods, their regulatory outcomes, and pertinence to women's health wherever applicable. Moreover, the potential traditional regimens under clinical trials have been critically assessed.

RESULTS

A systematic and comprehensive review on the chemokine-receptor targeting ethnopharmaceutics from the available literature has been provided. The article discusses the implication of traditional medicine in the chemokine system dynamics in diverse infectious-inflammatory disorders such as cardiovascular diseases, allergic diseases, inflammatory diseases, neuroinflammation, and cancer. On this note, critical evaluation of the available data surfaced multiple diseases prevalent in women such as osteoporosis, rheumatoid arthritis, breast cancer, cervical cancer and urinary tract infection. Currently there is no available literature highlighting chemokine-receptor targeting using traditional medicinal approach from women's health perspective. Moreover, despite being potent in vitro and in vivo setups there remains a gap in clinical translation of these formulations, which needs to be strategically and scientifically addressed to pave the way for their successful industrial translation.

CONCLUSIONS

The review provides an optimistic global perspective towards the applicability of ethnopharmacology in chemokine-receptor regulated infectious and inflammatory diseases with special emphasis on ailments prevalent in women, consecutively addressing their current status of clinical translation and future directions.

Pathophysiology, diagnosis, and herbal medicine-based therapeutic implication of rheumatoid arthritis: an overview

Rheumatoid arthritis (RA) stands as an autoimmune disorder characterized by chronic joint inflammation, resulting in profound physiological alterations within the body. Affecting approximately 0.4-1.3% of the global population, this condition poses significant challenges as current therapeutic approaches primarily offer symptomatic relief, with the prospect of complete recovery remaining elusive. This review delves into the contemporary advancements in understanding the pathophysiology, diagnosis, and the therapeutic potential of herbal medicine in managing RA. Notably, early diagnosis during the initial stages emerges as the pivotal determinant for successful recovery post-treatment. Utilizing tools such as Magnetic Resonance Imaging (MRI), anti-citrullinated peptide antibody markers, and radiography proves crucial in pinpointing the diagnosis of RA with precision. Unveiling the intricate pathophysiological mechanisms of RA has paved the way for innovative therapeutic interventions, incorporating plant extracts and isolated phytoconstituents. In the realm of pharmacological therapy for RA, specific disease-modifying antirheumatic drugs have showcased commendable efficacy. However, this conventional approach is not without its drawbacks, as it is often associated with various side effects. The integration of methodological strategies, encompassing both pharmacological and plant-based herbal therapies, presents a promising avenue for achieving substantive recovery. This integrated approach not only addresses the symptoms but also strives to tackle the underlying causes of RA, fostering a more comprehensive and sustainable path towards healing.

Advances of the small molecule drugs regulating fibroblast-like synovial proliferation for rheumatoid arthritis

Rheumatoid arthritis (RA) is a type of chronic autoimmune and inflammatory disease. In the pathological process of RA, the alteration of fibroblast-like synoviocyte (FLS) and its related factors is the main influence in the clinic and fundamental research. In RA, FLS exhibits a uniquely aggressive phenotype, leading to synovial hyperplasia, destruction of the cartilage and bone, and a pro-inflammatory environment in the synovial tissue for perpetuation and progression. Evidently, it is a highly promising way to target the pathological function of FLS for new anti-RA drugs. Based on this, we summed up the pathological mechanism of RA-FLS and reviewed the recent progress of small molecule drugs, including the synthetic small molecule compounds and natural products targeting RA-FLS. In the end, there were some views for further action. Compared with MAPK and NF-κB signaling pathways, the JAK/STAT signaling pathway has great potential for research as targets. A small number of synthetic small molecule compounds have entered the clinic to treat RA and are often used in combination with other drugs. Meanwhile, most natural products are currently in the experimental stage, not the clinical trial stage, such as triptolide. There is an urgent need to unremittingly develop new agents for RA.

Deciphering the impact and mechanism of Trikatu, a spices-based formulation on alcoholic liver disease employing network pharmacology analysis and in vivo validation

Trikatu Churna (TC) comprising Zingiber officinale rhizome, Piper longum, and Piper nigrum fruit, is effective in treating liver diseases and has high nutraceutical values. However, the efficacy of TC in treating alcoholic liver disease (ALD) and its mechanism remain largely unknown. This study evaluated the hepatoprotective effects of different doses of TC as well as to identify the bioactive components and determine their mechanism of action against ethanol-induced ALD. A compound-target network analysis model of TC was established to identify its potential bioactive compounds and pathways that might regulate its hepatoprotective effects. Further, in-vivo studies were performed to validate the potential of TC (200 mg/kg and 400 mg/kg b.w.) in the treatment and management of ALD. The study revealed that both the dosages of TC demonstrate significant (p > 0.0001) hepatoprotective effects by improving body weight, total bilirubin, serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), serum alkaline phosphate (ALP), total cholesterol, total protein, globulin, albumin, and liver morphology. The High-performance thin-layer chromatography (HPTLC) fingerprinting of TC showed the presence of piperine. Network pharmacology identifies the role of TC in regulating various signaling processes including Advanced glycation end products-receptor for advanced glycation end products (AGE-RAGE), Hypoxia-inducible factors (HIF-1), Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-Kappa B), and Phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling to exert its anti-inflammatory, antioxidant and anti-apoptotic role in managing ALD. Based on the bioinformatics analysis, some of the key targets of TC were found to be Prostaglandin-Endoperoxide Synthase 2 (PTGS2) or Cyclooxygenase-2 (COX-2), Sirtuin 1 (SRT1), and caspase-3. These effects may serve as a novel therapeutic option for the treatment of ALD. These preclinical validation studies for the ethnopharmacological potential of TC in ALD treatment further paved the way for researchers to perform next-level translational and clinical studies. Further, in-depth experimental studies for the validation of these bioinformatics-based results will give a clearer picture of mechanisms.

Is Trikatu; an ayurvedic formulation effective for the management of flu-like illness? A narrative review

OBJECTIVES

The aim of this review is to summarise and appraise the findings of various studies on Trikatu.

CONTENT

COVID-19 or SARS-CoV-2 disease a pandemic principally contaminating the respiratory tract and bringing about Severe Acute Respiratory Syndrome is liable for significant mortality around the world. Far-fetched, there is no exact treatment accessible till today. Consequently, it is critical to discover the alternative methodology which can decrease the weight of illness. Trikatu powder recommended by authorities for the management of mild cases of COVID-19 is a conventional ayurvedic formulation containing three spices; Zingiber officinale, Piper nigrum, and Piper longum. A comprehensive search of the articles published since inception to 01/08/2020 on Trikatu was carried out. Major electronic medical databases such as Pub Med/MEDLINE and Cochrane Database of Systematic Reviews were used for the literature search.

SUMMARY

A total of 21 records were identified by electronic searches between since inception to 01/08/2020 of which 13 records were included for review. The reviewed articles highlight Trikatu as a safe, anti-inflammatory, and immune-modulatory property by suppression of the production of pro-inflammatory cytokines TNF-a, IL-1b, IL-6, IL-17, alteration in levels of circulating immune complexes, anti-dyslipidaemia agent by reduced triglycerides and LDL cholesterol and increased HDL cholesterol, enhancing bio-availability of co-drug by reducing the elimination half-life (t1/2β) and zero time intercept of the elimination phase.

OUTLOOK

The findings of this review seem to show Trikatu as a potential anti-inflammatory, anti-dyslipidaemia, and immune-modulatory ayurvedic formulation can be used for combating flu like illnesses and also in the management of COVID-19 as an adjuvant. However, rigorous double blind randomized controlled trials with larger sample size are warranted for better validation in such clinical conditions.

HIGHLIGHTS

– COVID-19 has affected the lives of millions worldwide and unfortunately no precise treatment available till today. – Trikatu an ayurvedic formulation suggested by various authorities in India. – Trikatu found to be a potential anti-inflammatory; anti-dyslipidaemia and immune-modulatory drug can be used for combating flu like illnesses.

Role of natural products in alleviation of rheumatoid arthritis-A review

Rheumatoid arthritis (RHA) is one of the most prevalent complex, chronic, inflammatory diseases, manifested by elevated oxidative stress and inflammatory biomarkers. Prolonged administration of NSAIDs, steroids, and DMARDs, used in the treatment of RHA, is associated with deleterious side effects. This necessitates the urge of new and safe approaches for RHA management, based on the complementary and alternative system of medicine. Documented evidences have suggested that supplementation with nutritional, dietary, and herbal components; can play a crucial role as an adjuvant, in the alleviation of the RHA symptoms, through their influence on the pathological inflammatory processes. Dietary phenolic compounds, flavonoids, carotenoids, and alkaloids with their ability to modulate prooxidant and pro-inflammatory pathways, have been effective in delaying the arthritic disease progression. Moreover, in scientific explorations, herbs containing phenolic compounds, alkaloids, carotenoids flavonoids, spices such as ginger, turmeric, Ayurvedic formulations, different diets such as Mediterranean diet, vegan diet, beverages, and oils such as sesame oil, rice bran oil, vitamins, and probiotics are proven to modulate the action of inflammatory molecules, involved in RHA pathology. Subsequently, the purpose of this review article is to summarize various in vitro, in vivo, and clinical studies in RHA, which have documented remarkable insights into the anti-inflammatory, antioxidant, analgesic, and immunomodulatory, bone erosion preventing properties of dietary, nutritional, and herbal components with the focus on their molecular level mechanisms involved in RHA. Even though major findings were derived from in vitro studies, several in vivo and clinical studies have established the use of diet, herbal, and nutritional management in RHA treatment. PRACTICAL APPLICATIONS: Thickening of the synovial membrane, bone erosion, and cartilage destruction is known to trigger rheumatoid arthritis causing inflammation and pain in bone joints. Continuous intake of NSAIDs, steroids, and DMARD therapy are associated with detrimental side effects. These side effects can be overcome by the use of dietary, nutritional, and herbal interventions based on the complementary and alternative therapy. This concept portrays the food components and other natural components having the potential to promote health, improve general well-being, and reduce the risk of RHA.

Hydrogen Sulfide: a Novel Immunoinflammatory Regulator in Rheumatoid Arthritis

Hydrogen sulfide (H₂S), an endogenous, gaseous, signaling transmitter, has been shown to have vasodilative, anti-oxidative, anti-inflammatory, and cytoprotective activities. Increasing evidence also indicates that H₂S can suppress the production of inflammatory mediators by immune cells, for example, T cells and macrophages. Inflammation is closely related to an immune response in several diseases such as rheumatoid arthritis (RA), multiple sclerosis (MS), systemic lupus erythematosus (SLE), and cancer. Considering these biological effects of H₂S, a potential role in the treatment of immune-related RA is being exploited. In the present review, we will provide an overview of the therapeutic potential of H₂S in RA treatment.

Spice-infused palmyra palm syrup improved cell-mediated immunity in Wistar Albino rats

Spices attract tremendous attention in the management of viral infections. However, scientific validation is vital to recommend spices as nutraceuticals or functional foods. In the present work, we have selected three spices based on Ayurvedic knowledge and developed a nutraceutical for immunomodulation. Trikatu, a blend of ginger, black pepper, and long pepper, is used in the Indian Ayurvedic system, along with many herbs, for various ailments. We formulated a "Trikatu syrup" (TS) using these three spices and palmyra palm neera. Carbon clearance assay, neutrophil adhesion test, and sheep red blood cell (SRBC)-induced delayed-type hypersensitivity (DTH) reaction was performed to investigate the immunomodulatory potential of TS in Wistar Albino rats. The rats fed with TS showed a dose-dependent increase in footpad thickness compared to control rats, suggesting cell-mediated immunity. The major bioactive piperine in TS was isolated and quantified. PRACTICAL APPLICATIONS: Spices are consumed worldwide as a flavor enhancer in food. Besides, spices have an array of bioactive molecules with a multitude of health benefits. In the backdrop of COVID-19, immunomodulation and antiviral properties of spices are discussed widely. The present study is intended to explore the potential of three selected spices (ginger, black pepper, and long pepper) beyond its application in typical food preparations. The syrup formulated in this study by using these three spices improved cell-mediated immunity in Wistar Albino rats. The study warrants further validation studies of the formulated product for providing indisputable claims for the immunomodulation properties.

Investigation of toll-like receptor (TLR) 4 inhibitor TAK-242 as a new potential anti-rheumatoid arthritis drug

BACKGROUND

Proper blocking of toll-like receptor (TLR) activation during disease progression has been reported to have inhibitory effect on the pathogenesis of rheumatoid arthritis (RA). We tested whether the TLR4 inhibitor TAK-242 had potential as a remedy for rheumatoid arthritis.

METHODS

The therapeutic effect of TAK-242 was tested in vitro using the human rheumatoid fibroblast-like synoviocyte (FLS) line MH7A or primary human FLS and in an adjuvant-induced arthritis (AIA) rat model.

RESULTS

TAK-242 dose dependently inhibited the increased expression of IL-6, IL-8, MMP-1, and VEGF in LPS-stimulated MH7A cells. It also inhibited the expression of IL-6 and IL-8 in poly(I:C), TLR3 activator-stimulated primary FLS, but not in IL-1β-stimulated primary FLS. These findings suggest that TAK-242 blocks a specific signaling pathway to some degree. Further, TAK-242 slightly inhibited mobilization of NF-κB into nuclei. In the AIA rat model, TAK-242 significantly reversed the body weight and paw thickness of AIA rats to the normal state at a dose of 5 mg/kg, but not at 3 mg/kg, and reduced the increased serum level of IL-6 and VEGF in AIA rats. It also significantly ameliorated inflammatory symptoms of joint tissues at day 21 of treatment, according to histology and RT-PCR.

CONCLUSIONS

Based on the drug repositioning concept, TAK-242, which is used for the treatment of TLR4-mediated inflammatory diseases, shows potential for cost-effective development as a remedy for rheumatoid arthritis or to control the progression of RA.

MAST3 modulates the inflammatory response and proliferation of fibroblast-like synoviocytes in rheumatoid arthritis

Via promoting synovitis, pannus growth and cartilage/bone destruction, fibroblast-like synovial cells (FLSs) play a significant role in the pathogenesis of rheumatoid arthritis (RA). In our study, rats were induced with complete freund's adjuvant (CFA) to be animal models for studying the RA pathogenesis. Microtubule-associated Serine/Threonine-protein kinase 3 (MAST3) has been documented to play a critical role in regulating the immune response of IBD (Inflammatory bowel disease) and involved in the process of cytoskeleton organization, intracellular signal transduction and peptidyl-serine phosphorylation, but its role in the progression of RA remains unknown and is warranted for investigation. So, we tried our best to investigate the mechanism and signaling pathway of MAST3 in RA progression. In the synovial tissue and FLSs of AA rats, we have found that MAST3 was significantly up-regulated than normal. Furthermore, MAST3 overexpression could promote proliferation and inflammatory response of FLSs. In the aspect of mechanism, we discovered that the expression of MAST3 might involve in NF-κB signaling pathway in RA. On the whole, our results suggested that MAST3 might promote the proliferation and inflammation of FLSs by regulating NF-κB signaling pathway.

Dihydromyricetin Inhibits Inflammation of Fibroblast-Like Synoviocytes through Regulation of Nuclear Factor-κB Signaling in Rats with Collagen-Induced Arthritis

Dihydromyricetin (DMY), the main flavonoid of Ampelopsis grossedentata, has potent anti-inflammatory activity. However, the effect of DMY on chronic autoimmune arthritis remains undefined. In this study, we investigated the therapeutic effects of DMY on collagen-induced arthritis (CIA). Wistar rats were immunized with bovine type II collagen to establish CIA and were then administered DMY intraperitoneally (5, 25, and 50 mg/kg) every other day for 5 weeks. Paw swelling, clinical scoring, and histologic analysis were assessed to determine the therapeutic effects of DMY on the development of arthritis in CIA rats. The results showed that treatment with DMY significantly reduced erythema and swelling in the paws of CIA rats. Pathologic analysis of the knee joints and peripheral blood cytokine assay results confirmed the antiarthritic effects of DMY on synovitis and inflammation. Fibroblast-like synoviocytes (FLSs) were isolated from the synovium of CIA rats and treated with 10 ng/ml interleukin (IL)-1β DMY significantly inhibited the proliferation, migration, and inflammation of IL-1β-induced FLSs, whereas it significantly increased IL-1β-induced FLS apoptosis in a dose-dependent manner (6.25-25 μM). Moreover, DMY suppressed phosphorylation of IκB kinase (IKK) and inhibitor of NF-κB α and subsequently reduced the IL-1β-induced nucleus translocation of NF-κB in FLSs. Through a molecular docking assay, we demonstrated that DMY could directly bind to the Thr9 and Asp88 residues in IKKα and the Asp95, Asn142, and Gln167 residues in IKKβ These findings demonstrate that DMY could alleviate inflammation in CIA rats and attenuate IL-1β-induced activities in FLSs through suppression of NF-κB signaling.

Plasma interleukin-38 in patients with rheumatoid arthritis

Previous studies have indicated that interleukin-38 (IL-38) is involved in rheumatoid arthritis (RA). The present study aims to assess plasma levels of IL-38 in RA and discuss the potential of IL-38 as a biomarker for RA. Protein concentrations of IL-38 were examined by enzyme-linked immunosorbent assay, and the mRNA level of IL-38 was tested by quantitative real-time polymerase chain reaction. Plasma IL-38 was first compared in a training cohort, including 130 RA patients and 53 healthy controls, given the optimal cutoff. Then, we validated the levels of IL-38 in a further cohort of 519 patients, including 250 with RA, 63 systemic lupus erythematosus, 62 primary Sjogren's syndrome, 51 gout, 63 osteoarthritis, and 30 psoriatic arthritis, as well as 60 healthy controls. To further discuss the changes in IL-38 after treatment and the relationship with disease activity, we tested IL-38 expression in RA patients from the training cohort under follow-up. In the training cohort, plasma levels of IL-38 were higher in RA patients compared with healthy controls (681.00 [234.45-826.47] versus 152.04 [70.06-246.80] pg/mL, P < 0.001). The IL-38 mRNA level was elevated in RA patients as compared with healthy controls (P < 0.001). Expression of IL-38 was significantly higher in RA patients compared with that in non-RA patients in the validation cohort (all P < 0.001). Treatment significantly reduced IL-38 expression. IL-38 expression was related to parameters of inflammation both at baseline and in the follow-up studies. The area under the curve (AUC) of the receiver-operating characteristic curve showed that IL-38 may be a potential biomarker for RA. At the optimal cutoff value of 341.90 pg/mL, the sensitivity, specificity, and AUC were 72.30%, 90.60%, and 0.840, respectively, in the training cohort. Similar results were noted in the validation cohort. In conclusion, IL-38 expression correlated with RA disease activity, and plasma IL-38 might be a promising diagnostic biomarker for RA.

Combined gemfibrozil (peroxisome proliferator-activated receptor alpha agonist) with reduced steroid dose gives a similar management picture as the full steroid dose in a rat adjuvant-induced arthritis model

Objectives: The study aimed to evaluate the efficacy of combined gemfibrozil with prednisolone in the management of adjuvant-induced arthritis (AIA) rat model. Methods: Seventy two adult male Wistar albino rats were divided equally into 1-control group, three diseased groups: 2- Adjuvant induced arthritis (AIA), 3- high fat diet (HF), and 4- combined AIA-HF, and treated groups: 5- gemfibrozil 30 mg/kg treated AIA group (AIA-G) and the combined AIA-HF treated groups: 6- prednisolone equivalent to human 10 mg (AIA-HF-P10), 7- prednisolone equivalent to human 5 mg (AIA-HF-P5) 8- gemfibrozil (HF-AIA-G) and 9- combined treatment (HF-AIA-G-P5) Results: HF diet represents a precipitating factor for knee arthritis. Gemfibrozil improved the inflammatory findings in both AIA and AIA-HF groups. Combined administration of gemfibrozil with reduced steroid dose gave a similar therapeutic effect to the full steroid dose. Fortunately, we reported more reduction in the nuclear factor kappa-B (NF-κB) and high mobility group box 1 (HMGB1) in the HF-AIA-G-P5 compared with the HF-AIA-P10 group. The improvement was proved by the histological findings. Conclusion: Combined reduced prednisolone dose with gemfibrozil potentiates its anti-inflammatory activity. This could be a target in the management of rheumatoid arthritis.

Data-driven analysis of biomedical literature suggests broad-spectrum benefits of culinary herbs and spices

Spices and herbs are key dietary ingredients used across cultures worldwide. Beyond their use as flavoring and coloring agents, the popularity of these aromatic plant products in culinary preparations has been attributed to their antimicrobial properties. Last few decades have witnessed an exponential growth of biomedical literature investigating the impact of spices and herbs on health, presenting an opportunity to mine for patterns from empirical evidence. Systematic investigation of empirical evidence to enumerate the health consequences of culinary herbs and spices can provide valuable insights into their therapeutic utility. We implemented a text mining protocol to assess the health impact of spices by assimilating, both, their positive and negative effects. We conclude that spices show broad-spectrum benevolence across a range of disease categories in contrast to negative effects that are comparatively narrow-spectrum. We also implement a strategy for disease-specific culinary recommendations of spices based on their therapeutic tradeoff against adverse effects. Further by integrating spice-phytochemical-disease associations, we identify bioactive spice phytochemicals potentially involved in their therapeutic effects. Our study provides a systems perspective on health effects of culinary spices and herbs with applications for dietary recommendations as well as identification of phytochemicals potentially involved in underlying molecular mechanisms.

NLRC5 promotes cell proliferation via regulating the NF-κB signaling pathway in Rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease and the pathogenesis remains unclear. Previous studies suggested that fibroblast-like synoviocytes (FLSs) play an important role in RA pathogenesis, including the injury of cartilage, the hyperplasia of the synovium and the release of inflammatory cytokines. We used complete Freund's adjuvant (CFA) induced rats as animal models for studying the RA pathogenesis. NLRC5 as the largest member of the NLR family has been reported to play a critical role in regulating immune responses. Increasing evidence suggests that NLRC5 is an pivotal negative modulator of inflammatory pathways. We investigated the mechanisms and signaling pathways of NLRC5 in RA progression. Significantly increased expression of NLRC5 was found in AA rats synovial tissues and cells. And high expression of inflammatory cytokine and cell proliferation of FLSs accompanied with NLRC5 overexpression, but inhibited in cells with NLRC5 silencing treatment. Interestingly, we found that overexpression of NLRC5 also coordinated the activation of NF-κB signaling pathway. These results suggested that NLRC5 promotes RA progression via the NF-κB signaling pathway potentially.

Tamarixinin A Alleviates Joint Destruction of Rheumatoid Arthritis by Blockade of MAPK and NF-κB Activation

Background: Tamarixinin A, a natural tannin isolated from Myricaria bracteata, has been confirmed to have moderate anti-inflammatory effects in vitro and in vivo. However, how it effects rheumatoid arthritis (RA) is still unknown. Therefore, the aim of this study is to investigate the therapeutic effects of tamarixinin A on experimental RA, and explore the underlying mechanism.

Methods: The anti-arthritic effects of tamarixinin A were evaluated on collagen-induced arthritis (CIA) mice and adjuvant-induced arthritis (AIA) rats. The hind paw thickness, inflammatory cytokine levels in serum, and histopathological assessments were determined. The arthritis score was evaluated. Activation of p38 and p65 in AIA rats was also determined. The anti-inflammatory effect in vitro was also tested in LPS induced macrophages, and its related anti-inflammatory signaling pathways were explored.

Results: Treatment with tamarixinin A significantly suppressed the progression and development of RA in CIA mice and AIA rats. Both in CIA mice and AIA rats, arthritis scores decreased, paw swelling and thickness were reduced, and joint destruction was alleviated. In AIA rats, tamarixinin A significantly inhibited the expression of p38, p-p38 and p65. In addition, tamarixinin A inhibited the production of pro-inflammatory mediators, the phosphorylation of p38, ERK, JNK and p65, as well as the nuclear translocation of p38 in LPS- induced macrophages.

Conclusion: Tamarixinin A is a potential effective candidate compound for human RA treatment, which executes anti-arthritic effects potentially through down-regulating MAPK and NF-κB signal pathway activation.