Quercetin mitigates rheumatoid arthritis by inhibiting adenosine deaminase in rats

Abstract

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease characterized by synovial proliferation and bone destruction. Adenosine deaminase (ADA) is a key inflammatory enzyme that increases joint stiffness and pain in RA. In this study, we evaluated the in-silico, and in vivo inhibitory effect of quercetin isolated from Egyptian Fenugreek on ADA enzyme activity. We also determined the combinatorial effect of quercetin on methotrexate mediated anti-inflammatory efficacy and toxicity. In-silico molecular docking was conducted and confirmed in an in vivo RA rat model. The results showed that the inhibition constant of quercetin on joint ADA by docking and in-vitro was 61.9 and 55.5 mM, respectively. Therefore, quercetin exhibits anti-inflammatory effect in a rat RA model as evidenced by reducing the specific activity of ADA in joint tissues, lower jaw volume, enhance body weight, downregulate ADA gene expression, reduce levels of RA cytokines interleukin-1β, interleukin-6, tumor necrosis factor-α, also, rheumatoid factor, C-reactive protein, and anti-cyclic citrullinated peptide RA biomarker levels. These findings demonstrate that the purified quercetin has a promising anti-inflammatory effect against RA disease through its inhibitory effects on the ADA enzyme. Furthermore, isolated quercetin improved the anti-inflammatory efficacy of methotrexate, reduced its toxic effects by increasing antioxidant enzymes and reducing oxidative stress.

Pharmacological Aspects of Natural Quercetin in Rheumatoid Arthritis

“…24 But, interestingly, combined administration of QUE and methotrexate (MTX) exhibited no greater protection than administration of QUE alone for CIA mice. 26 As well, in AA model, oral or intra-cutaneous QUE significantly decreased arthritis index score 27,28 and paw thickness, increased paw thermal latency, reduced infiltration of inflammatory cells and decreased p-P65 level in histological analysis of joint tissue. [28][29][30][31][32] What's more, intra-cutaneous QUE simultaneously with adjuvant induced and prior to the appearance of clinical signs also resulted in reduction of clinical scores, suggesting the preventive property of QUE on RA.…”

“…26 As well, in AA model, oral or intra-cutaneous QUE significantly decreased arthritis index score 27,28 and paw thickness, increased paw thermal latency, reduced infiltration of inflammatory cells and decreased p-P65 level in histological analysis of joint tissue. [28][29][30][31][32] What's more, intra-cutaneous QUE simultaneously with adjuvant induced and prior to the appearance of clinical signs also resulted in reduction of clinical scores, suggesting the preventive property of QUE on RA. 27 However, another study indicated that, in AA rats treated with QUE group, the changes in arthritis score observed were not obvious compared to the AA group, which were, partly, in contradiction with the related experimental results observed in zymosan-induced arthritis, CIA and AA model.…”

“…Furthermore, clinical trials of RA patients with different disease activity, larger sample size, gender difference, NF-κB 21 CIA model 150 mg•kg −1 •0.5 mL −1 three times a week orally administrated for 17 or 28 days; 23 0, 50, 100mg/kg/d orally administrated for 5 weeks; 24 150mg/kg daily orally administrated for 14 days 22 or 21 days; 25 30mg/kg daily orally administrated for 49 days 26 Mitigated paw edema, inflammatory cells infiltration, synovium hyperplasia, cartilage and bone erosion, decreased TNF-α, IL-1β, IL-6, PGE2, and NLRP3 inflammasome (NLRP3, Caspase-1 and IL-1β) [22][23][24][25][26] SIRT1/PGC-1α/NRF1/ TFAM and HMGB1/TLR4/ p38/ERK1/2/NF-κB p65 24 AA model 150 mg/rat (30 mg every 2 days, orally administrated for 10 days) or 25, 50 mg/rat (5 or 10 mg every 2 days, intra-cutaneous injection following the appearance of first arthritic symptoms); 27 Reduced arthritis scores, paw thickness and inflammatory infiltration, increase paw thermal latency. [27][28][29][30][31][32] Increased IL-4 and IL-10, decreased TNF-α, NO, IFN-γ, IL-6, IL-1β, MCP-1, MPO, [27][28][29][30]32,33 decreased 12/15-LOX in liver and lung. 33 Decreased ADA enzyme activity and gene expression in sera and joints 28 GSK-3β, NF-κB and ERK 30,32,33 Human RAFLS 50 nmol/L; 37 0, 20, 100, 200μM 38 Decreased IL-1β stimulated COX-2 and PGE2, 38 decreased TNF-αinduced IL-1β, IL-6, IL-8 and MCP-1 36,37 MAPKs (ERK, p-38, JNK) 38 and NF-κB, 36,38 lncRNA XIST/miR-485/PSMB8 axis 37 Inhibition of oxidative stress Zymosaninduced arthritis mice 0, 10, 30, 100 mg/kg s.c. 30 min before z...…”

“…30 QUE could counteract the oxidative stress associated with AA-induced in the joint tissues and plasma of rats. 28,33 Also, QUE reduced ROS level and increased catalase activity in serum in complete Freund's adjuvant (CFA)-induced arthritis. 42 As well, in zymosan-induced arthritis mice, QUE decreased gp91 phox (a subunit of NADPH oxidase) mRNA expression, increased GSH levels, nuclear factor erythroid 2 related factor 2 (Nrf2) and heme oxygenase (HO-1) mRNA expression, indicating these antioxidant molecular effects of QUE might be associated with Nrf2/HO-1 signaling pathway.…”

“…22,24 A recent study indicated that QUE could diminish the sera levels of anti-cyclic citrullinated peptide antibody (anti-CCP) and rheumatoid factor (RF) in AA rats model. 28 Ectonucleoside triphosphate diphosphohydrolase (E-NTPDase) and ectoadenosine deaminase (E-ADA) in lymphocytes are involved in the pathogenesis of RA. 53,54 QUE could reverse the increase of E-NTPDase activity and the decrease of E-ADA activity in lymphocytes.…”