Pharmacological and biochemical studies on protective effects of mangiferin and its interaction with nitric oxide (NO) modulators in adjuvant-induced changes in arthritic parameters, inflammatory, and oxidative biomarkers in rats

Therapeutic potential of phytocompounds in rheumatoid arthritis: Molecular insights and clinical applications

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by systemic involvement, inflammation, and the destruction of synovial joints. RA can be categorized as anti-citrullinated protein antibodies-positive or negative based on genetic risk factors and autoantibodies. This review systematically sourced articles related to RA, phytocompounds, signaling pathways, and clinical insights from primary medical databases, including Scopus, PubMed, and Web of Science. This review explores the therapeutic potential of phytocompounds in treating RA by targeting key inflammation and immunological response signaling pathways. Phytocompounds such as curcumin, resveratrol, and flavonoids alter essential molecular pathways in RA pathophysiology, including nuclear factor kappa-light-chain-enhancer of activated B cells, mitogen-activated protein kinases, janus kinase-signal transducer and activator of transcription, and the inflammasome. These substances possess pro-resolving, anti-apoptotic, and antioxidant properties, which enhance their therapeutic efficacy. Alternative medicine, including dietary, herbal, and nutritional supplements, may help reduce RA symptoms. In vitro, in vivo, and clinical studies have demonstrated the effectiveness of these treatments. Phytocompounds have potential as a treatment for RA by altering signaling pathways, reducing oxidative stress, and protecting cartilage and bone. However, few clinical trials confirm its long-term safety, bioavailability, and effectiveness. Further clinical trials and translational research are needed to validate the effectiveness, safety, and pharmacokinetics of phytocompounds, while identifying novel plant-derived bioactive chemicals could improve patient outcomes.

L-arginine administration exacerbates myocardial injury in diabetics via prooxidant and proinflammatory mechanisms along with myocardial structural disruption

BACKGROUND

L-arginine (L-Arg) is one of the most widely used amino acids in dietary and pharmacological products. However, the evidence on its usefulness and dose limitations, especially in diabetics is still controversial.

AIM

To investigate the effects of chronic administration of different doses of L-Arg on the cardiac muscle of type 2 diabetic rats.

METHODS

Of 96 male rats were divided into 8 groups as follows (n = 12): Control, 0.5 g/kg L-Arg, 1 g/kg L-Arg, 1.5 g/kg L-Arg, diabetic, diabetic + 0.5 g/kg L-Arg, diabetic + 1 g/kg L-Arg, and diabetic + 1.5 g/kg L-Arg; whereas L-Arg was orally administered for 3 months to all treated groups.

RESULTS

L-Arg produced a moderate upregulation of blood glucose levels to normal rats, but when given to diabetics a significant upregulation was observed, associated with increased nitric oxide, inflammatory cytokines, and malonaldehyde levels in diabetic rats treated with 1 g/kg L-Arg and 1.5 g/kg L-Arg. A substantial decrease in the antioxidant capacity, superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione concentrations, and Nrf-2 tissue depletion were observed at 1 g/kg and 1.5 g/kg L-Arg diabetic treated groups, associated with myocardial injury, fibrosis, α-smooth muscle actin upregulation, and disruption of desmin cardiac myofilaments, and these effects were not noticeable at normal treated groups. On the other hand, L-Arg could significantly improve the lipid profile of diabetic rats and decrease their body weights.

CONCLUSION

L-Arg dose of 1 g/kg or more can exacerbates the diabetes injurious effects on the myocardium, while 0.5 g/kg dose can improve the lipid profile and decrease the body weight.

Mangiferin mitigates methotrexate-induced liver injury and suppresses hepatic stellate cells activation in rats: Imperative role of Nrf2/NF-κB/NLRP3 signaling axis

ETHNOPHARMACOLOGICAL RELEVANCE

Mangifera indica (family Anacardiaceae), often acknowledged as mango and renowned for being a plant of diverse ethnopharmacological background since ancient times, harbors the polyphenolic bioactive constituent, mangiferin (MNG). MNG is a major phytochemical of Mangifera indica and other plants with a wide range of reported pharmacological activities, including antioxidant, anti-inflammatory, neuroprotective and hepatoprotective effects. MNG has also been utilized in traditional medicine; it is reportedly a major bioactive element in over 40 polyherbal products in traditional Chinese medicine (TCM), and two prominent anti-inflammatory, immunomodulatory and antiviral Cuban formulations. Despite the availability of evidence in support of MNG hepatoprotective properties, its hepatoprotective potential against MTX-induced liver injury and fibrosis has not been explored yet.

AIM

To unravel the hepatoprotective potential of MNG against MTX-induced hepatic injury and fibrosis and elucidate the possible underlying molecular mechanisms.

MATERIALS AND METHODS

Male Sprague-Dawley rats were, randomly, distributed into five groups; two of which were administered MNG 50 mg/kg and MNG 100 mg/kg intraperitoneally (i.p.) for ten days, and a single i.p. injection of MTX 40 mg/kg on the seventh day to establish hepatotoxicity. Blood and liver tissue samples were retrieved from all study groups and analyzed for liver functions, histopathological alterations, and oxidative stress, inflammatory, and fibrotic biomarkers.

RESULTS

MNG restored the MTX-induced degenerations in hepatic architecture and function. Moreover, it combated the MTX-elicited oxidative stress evidently by the significantly attenuated hepatic tissue levels of malondialdehyde, and the significantly elevated reduced glutathione and Nrf2 levels. MNG also halted inflammation depicted by the downregulation of the NF-κB/NLRP3 inflammasome axis. It further demonstrated anti-fibrogenic potential as evidenced by the significant reduction in fibrous tissue deposition and hepatic expression of α-SMA.

CONCLUSION

The current study proved the hepatoprotective, and anti-fibrogenic effects of MNG against MTX-induced hepatotoxicity via the downregulation of NF-κB/NLRP3 inflammasome signaling axis, preceded by the amelioration of oxidative stress and Nrf2 signaling upregulation.

Transdermal Delivery of Methotrexate Loaded in Chitosan Nanoparticles to Treat Rheumatoid Arthritis

INTRODUCTION

Methotrexate shows high efficiency in the treatment of Rheumatoid arthritis, but its adverse effects cannot be tolerated by many patients. Additionally, Methotrexate suffers from rapid clearance from blood. Polymeric nanoparticles were used to solve these problems including chitosan.

METHODS

Herein, a new nanoparticulate system to deliver Methotrexate (MTX) using chitosan nanoparticles (CS NPs) was developed to be used transdermally. CS NPs were prepared and characterized. The drug release was studied in vitro and ex vivo using rat skin. The drug performance in vivo was investigated on rats. Formulations were applied topically once a day on the paws and knee joints of arthritis rats for 6 weeks. Paw thickness was measured and synovial fluid samples were collected.

RESULTS

The results showed that CS NPs were monodispersed, and spherical with a size of 279.9 nm and a charge above ± 30mV. Further, 88.02% of MTX was entrapped in the NPs. CS NPs prolonged MTX release and enhanced its permeation (apparent permeability ⁓35.00cm/h) and retention (retention capacity ⁓12.01%) through rats' skin. The transdermal delivery of MTX-CS NPs improves the progress of the disease compared to free MTX, as reflected by the lower arthritic index values, lower proinflammatory cytokines (TNF-α and IL-6), and higher anti-inflammatory cytokine (IL-10) in the synovial fluid. Further, the oxidative stress activities were significantly higher in the group treated with the MTX-CS NPs, as indicated by GSH. Finally, MTX-CS NPs were more effective in reducing lipid peroxidation in synovial fluid.

CONCLUSION

In conclusion, loading Methotrexate in chitosan nanoparticles controlled its release and enhance its effectiveness against rheumatoid when applied dermally.

A Mango Leaf Extract (Zynamite®) Combined with Quercetin Has Exercise-Mimetic Properties in Human Skeletal Muscle

Zynamite PX^®, a mango leaf extract combined with quercetin, enhances exercise performance by unknown molecular mechanisms. Twenty-five volunteers were assigned to a control (17 males) or supplementation group (8 males, receiving 140 mg of Zynamite^® + 140 mg quercetin/8 h for 2 days). Then, they performed incremental exercise to exhaustion (IE) followed by occlusion of the circulation in one leg for 60 s. Afterwards, the cuff was released, and a 30 s sprint was performed, followed by 90 s circulatory occlusion (same leg). Vastus lateralis muscle biopsies were obtained at baseline, 20 s after IE (occluded leg) and 10 s after Wingate (occluded leg), and bilaterally at 90 s and 30 min post exercise. Compared to the controls, the Zynamite PX^® group showed increased basal protein expression of Thr²⁸⁷-CaMKIIδ_D (2-fold, p = 0.007) and Ser⁹-GSK3β (1.3-fold, p = 0.005) and a non-significant increase of total NRF2 (1.7-fold, p = 0.099) and Ser⁴⁰-NRF2 (1.2-fold, p = 0.061). In the controls, there was upregulation with exercise and recovery of total NRF2, catalase, glutathione reductase, and Thr²⁸⁷-CaMKIIδ_D (1.2-2.9-fold, all p < 0.05), which was not observed in the Zynamite PX^® group. In conclusion, Zynamite PX^® elicits muscle signaling changes in resting skeletal muscle resembling those described for exercise training and partly abrogates the stress kinases responses to exercise as observed in trained muscles.

Pharmacological, Biochemical and Immunological Studies on Protective Effect of Mangiferin in 6-Hydroxydopamine (6-OHDA)-Induced Parkinson's Disease in Rats

Background:

Parkinson’s disease is a neurodegenerative disorder and is marked by inflammation and death of neurons in the striatum region of the midbrain. It has been reported that expression of NF-κB increases during Parkinson’s disease, which promotes oxidative stress, stimulates release of proinflammatory cytokines, and induces expression of nitric oxide. Therefore, in this study, we have used mangiferin a specific NF-κB inhibitor. Mangiferin is a polyphenolic compound traditionally used for its antioxidant and anti-inflammatory properties.

Methods:

The study utilized male Wistar rats weighing 200–250 g (56 rats; n = 8/group). On day “0,” stereotaxic surgery of rats was done to induce 6-hydroxydopamine lesioning in rats. Coordinates for substantia nigra were anteroposterior-2 mm, mediolateral-5 mm and dorsoventral-8.2 mm. After 14 days, those rats which show at least 210 contralateral rotations after administration of apomorphine (0.5 mg/kg S.C.) were selected for the study and were given treatment for 28 days. On day 28 of treatment, rats were subjected to behavioral studies to evaluate the effect of mangiferin and their brains were taken out after euthanasia to perform biochemical, molecular and immunological studies.

Results:

Treatment with mangiferin significantly improves the key parameters of locomotor activity and oxidative stress and reduces the parameters of inflammatory stress. Also, the activity of caspases was reduced. Significant decrease in activity of both cyclooxygenase 1 and 2 was also observed. Maximum improvement in all parameters was observed in rats treated with grouping of mangiferin 45 µg/kg and levodopa 10 mg/kg. Treatment with levodopa alone has no significant effect on biochemical and molecular parameters though it significantly improves behavioral parameters.

Conclusion:

Current treatment of Parkinson’s disease does not target progression of Parkinson’s disease. Results of this study suggest that mangiferin has protective effect in hemi-Parkinsonian rats. Therefore, the combination therapy of mangiferin and levodopa can be helpful in management of Parkinson’s disease.

Mangiferin exert protective effects on joints of adjuvant-induced arthritis rats by regulating the MAPKs/NF-κB pathway of fibroblast-like synoviocytes

BACKGROUND

Mangiferin (MF) is a bioactive ingredient predominantly isolated from the mango tree, that has been reported to have antioxidant, anti-inflammatory, and immunomodulatory effects. This study was aimed to investigate the protective effect of MF on the joints of arthritic rats and explore the underlying mechanisms of this function.

METHODS

Adjuvant-induced arthritis (AA) rat model was established and clinical severity of AA was evaluated by arthritis index, paw edema, plasma, and synovium homogenate parameters. The severity of joint destruction was assessed by radiological and histopathological. Immunohistochemical analysis was employed to detect the protein expression of MMP-3, MMP-13 in synovium and cartilage tissues. The vitro effects of MF on proliferation, migration, apoptosis, and production of inflammatory mediators in RA- FLSs were determined by the CCK8 assay, transwell assay, flow cytometry, and real-time PCR, respectively.

RESULTS

The results demonstrated that MF treatment significantly alleviated arthritis index, paw swelling and decreased the secretion of inflammatory cytokines in plasma and synovium. Meanwhile, MF inhibited synovial inflammation, pannus formation, and bone erosion in AA rats. It also ameliorated the oxidative stress state of arthritic rats via modulating the level of MDA, SOD, CAT, GSH, NO. In addition, MF effectively attenuated the destructive behavior of RA-FLSs by inhibiting proliferation, migration, and secretion of inflammatory mediators, and promoting apoptosis. The further mechanistic analysis demonstrated that MF might exert an antiarthritic effect via inhibiting the pathway of MAPKs (ERK2 and p38) and NF-κ B.

CONCLUSION

Taken together, our results demonstrated that MF would be a promising anti-arthritic agent candidate for further research.

Mangiferin Promotes Bregs Level, Activates Nrf2 Antioxidant Signaling, and Inhibits Proinflammatory Cytokine Expression in Murine Splenic Mononuclear Cells In Vitro

Recent studies indicated that regulatory B cells (Bregs) and nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant signaling pathway play important roles in the pathogenesis of chronic graft-versus-host disease (cGVHD). Mangiferin (MA), a polyphenol compound, has been reported to activate Nrf2/antioxidant-responsive element (ARE) signaling pathway. This study was aimed to investigate the effects of MA on Bregs and Nrf2 antioxidant signaling in murine splenic mononuclear cells (MNCs) in vitro. Our results revealed that MA could increase the Bregs level in murine splenic MNCs. Moreover, MA up-regulated the expression of Bregs-associated immunosuppressive factor interleukin-10 (IL-10) by activating the Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) and extracellular signal-regulated kinase (ERK) signaling in murine splenic MNCs. Meanwhile, MA inhibited the proinflammatory cytokines IL-2 and interferon-γ (INF-γ) at both mRNA and protein levels. MA also enhanced the transcription and protein expression of Nrf2 and NADPH quinine oxidoreductase 1 (NQO1), whereas decreased that of Kelch-like ECH-associated protein 1 (Keap1) in murine splenic MNCs. Moreover, MA promoted the proliferation and inhibited the apoptosis of murine splenic MNCs. These results suggested that MA exerts immunosuppressive effects by upregulating the Bregs level, activating the Nrf2 antioxidant pathway, and inhibiting the expression of pro-immunoinflammatory factors. MA, as a natural immunomodulatory and anti-inflammatory agent, may have a potential role in the prophylaxis and treatment of cGVHD.

Activation of the Nrf2/HO-1 signaling pathway by dimethyl fumarate ameliorates complete Freund's adjuvant-induced arthritis in rats

The nuclear factor erythroid 2-related factor (Nrf2) signaling pathway has recently emerged as a novel therapeutic target in treating various diseases. Therefore, the present study aimed to assess the protective role of the Nrf2 activator, dimethyl fumarate (DMF) in the complete Freund's adjuvant (CFA)- induced arthritis model. DMF (25, 50, and 100 mg/kg) and dexamethasone (2 mg/kg) were orally administered for 14 days. Pain-related tests, paw volume, and arthritic scores were measured weekly. Serum TNF-α, IL-1β, cyclic citrullinated peptide (CCP), C-reactive protein (CRP), and rheumatoid factor (RF) levels were estimated. Nitrite, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione (GSH), catalase (CAT), and myeloperoxidase (MPO) levels were also evaluated. NF-κB, Nrf2, HO-1, and COX-2 levels were estimated in the joint tissue. DMF treatment exerted anti-arthritic activity by enhancing the nociceptive threshold, improving arthritis scores, and reducing paw edema. Also, DMF suppressed changes in oxidative stress markers and inflammatory mediators and enhanced Nrf2 and HO-1 levels in CFA-injected rats. These findings indicate that the anti-arthritic activity of DMF may be mediated by the activation of the Nrf2/HO-1 pathway, which reduced oxidative damage and inflammation.

Glabridin Relaxes Vascular Smooth Muscles by Activating BKCa Channels and Inhibiting Phosphodiesterase in Human Saphenous Vein

The aim of the current study was to investigate the pharmacological activity of glabridin on the isolated human saphenous vein (SV) and explore the underlying mechanisms. Samples of patients' SVs were removed during bypass surgery, and 4-mm lengths of the vessels were placed in Krebs solution at +4°C and hung in an isolated organ bath to assess their contraction/relaxation responses. The contraction/relaxation responses were recorded to observe if the cyclic guanosine monophosphate (cGMP)/protein kinase G (PKG) pathway mediates the relaxant effect of glabridin after treatment with blockers like ODQ (a guanylate cyclase inhibitor), KT5823 (a PKG inhibitor), isobutylmethylxanthine [IBMX, a phosphodiesterase (PDE) inhibitor], and cantharidin [Cant, a myosin light-chain phosphatase (MLCP) inhibitor]. Moreover, nitric oxide (NO), cGMP, and PKG levels in SV tissues were determined by ELISA after incubation with glabridin, N(ω)-nitro-L-arginine methyl ester (L-Name, a NO synthetase inhibitor), phenylephrine (PE), ODQ, IBMX, and KT5823. The results showed that glabridin relaxed the vascular smooth muscle of human SV pretreated with PE in a dose-dependent manner, which was independent of the endothelium. The vasorelaxant effect of glabridin was only inhibited by iberiotoxin (IbTX), Cant, and KT5823. Glabridin increased cGMP and PKG levels in SV homogenates, whereas it did not alter the NO level. The enhancing effects of cGMP and PKG levels by glabridin were abolished by ODQ and KT5823. In conclusion, glabridin has a vasorelaxant effect, which is associated with the activation of BK_Ca channels and inhibition of PDE.

Mangiferin prevents the impairment of mitochondrial dynamics and an increase in oxidative stress caused by excessive fluoride in SH-SY5Y cells

Previous studies both invivo and in vitro have revealed that high levels of fluoride cause neurotoxicity. Mangiferin has been reported to possess antioxidant, antiapoptotic, and anti-inflammatory properties. The present study was designed to characterize the mechanisms by which mangiferin protects against NaF-induced neurotoxicity. Increased levels of proapoptotic Bax, Caspase-3, Caspase-9, and cleaved-caspase 3, as well as a decreased level of antiapoptotic Bcl-2 induced by fluoride in human neuroblastoma SH-SY5Y cells, these effects were prevented by pretreatment of mangiferin. In addition, mangiferin attenuated the enhancement of p-JNK, reductions of Nrf2 and HO-1, and increased level of the mitochondrial fission proteins Drp1 caused by fluoride. Moreover, oxidative stress, as reflected in the levels of reactive oxygen species, 8-hydroxy-2'-deoxyguanosine, and 4-hydroxynonenal, was elevated by fluoride and these effects were again ameliorated by mangiferin. In conclusion, protection by mangiferin against fluoride-induced neurotoxicity involves normalizing the impaired mitochondrial apoptotic pathway and dynamics and reducing oxidative stress via inactivation of the JNK and activation of the Nrf2/HO-1 pathways.

Micronutrients: Essential Treatment for Inflammatory Arthritis?

PURPOSE OF REVIEW

Synovial inflammation is characteristic of inflammatory chronic arthropathies and can cause progressive articular damage, chronic pain, and functional loss. Scientific research has increasingly focused on investigating anti-inflammatory micronutrients present in fruits, vegetables, spices, seeds, tea, and wine. This review aims to examine the anti-inflammatory effect of polyphenols (phytonutrients present in plants) and other micronutrients described in randomized clinical trials conducted in patients with chronic inflammatory arthropathies.

RECENT FINDINGS

There is an increasing evidence that differences in micronutrient intake might play an essential role in pathogenesis, therapeutic response, and remission of synovitis. Randomized clinical trials with specific micronutrient- or nutrient-enriched food intake show improvement of symptoms and modulation of both pro- and anti-inflammatory mediators. We found convincing evidence of the anti-inflammatory effect of several micronutrients in arthritis symptoms and inflammation. Although in clinical practice nutritional recommendations to patients with chronic joint inflammation are not consistently prescribed, the addition of these nutrients to day-to-day eating habits could potentially change the natural history of inflammatory arthritis. Future research is needed for a consensus on the specific nutritional recommendations for patients with chronic synovial inflammation.

Supplementation with a Mango Leaf Extract (Zynamite®) in Combination with Quercetin Attenuates Muscle Damage and Pain and Accelerates Recovery after Strenuous Damaging Exercise

Prolonged or unusual exercise may cause exercise-induced muscle damage (EIMD). To test whether Zynamite®, a mango leaf extract rich in the natural polyphenol mangiferin, administered in combination with quercetin facilitates recovery after EIMD, 24 women and 33 men were randomly assigned to two treatment groups matched by sex and 5 km running performance, and ran a 10 km race followed by 100 drop jumps to elicit EIMD. One hour before the competition, and every 8 hours thereafter for 24 hours, they ingested placebo (728 mg of maltodextrin) or 140 mg of Zynamite® combined with 140 mg of quercetin (double-blind). Although competition times were similar, polyphenol supplementation attenuated the muscle pain felt after the competition (6.8 ± 1.5 and 5.7 ± 2.2 a.u., p = 0.035) and the loss of jumping performance (9.4 ± 11.5 and 3.9 ± 5.2%, p = 0.036; p = 0.034) and mechanical impulse (p = 0.038) 24 hours later. The polyphenols attenuated the increase of serum myoglobin and alanine aminotransferase in men, but not in women (interaction p < 0.05). In conclusion, a single dose of 140 mg Zynamite® combined with 140 mg of quercetin, administered one hour before competition, followed by three additional doses every eight hours, attenuates muscle pain and damage, and accelerates the recovery of muscle performance.