Quercetin reduced inflammation and increased antioxidant defense in rat adjuvant arthritis

Metabolic effects of quercetin on inflammatory and autoimmune responses in rheumatoid arthritis are mediated through the inhibition of JAK1/STAT3/HIF-1α signaling

BACKGROUND

Rheumatoid arthritis, a chronic autoimmune disease, is characterized by synovial hyperplasia and cartilage erosion. Here, we investigated the potential mechanism of action of quercetin, the main component of flavonoids, in treating rheumatoid arthritis.

OBJECT

To examine the anti-arthritic effects of quercetin and elucidate the specific mechanisms that differentiate its metabolic effects on autoimmune and inflammatory responses at the synovial cell level.

METHODS

We created a collagen-induced arthritis (CIA) model in Wistar rats, which were administered quercetin (50 or 100 mg/kg) continuously for four weeks via stomach perfusion. The arthritis score, histopathological staining, radiological assessment, and serum biochemical parameters were used to study the impact of quercetin on disease improvement. Additionally, immunofluorescence was employed to detect JAK1/STAT3/HIF-1α expression in rat joints. Moreover, the effects of quercetin (20, 40, and 80 µmol/L) on the properties and behavior of synovial fibroblasts were evaluated in an in vitro MH7A cell model using flow cytometry, CCK8, and transwell assays. Further, the mRNA expression levels of inflammatory cytokines IL1β, IL6, IL17, and TNFα were assessed by quantitative real-time PCR. Glucose, lactate, lactate dehydrogenase, pyruvate, pyruvate dehydrogenase, and adenosine triphosphate assay kits were employed to measure the metabolic effects of quercetin on synovial fibroblasts. Finally, immunoblotting was used to examine the impact of quercetin on the JAK1/STAT3/HIF-1α signaling pathway in synovial fibroblasts.

RESULTS

In vivo experiments confirmed the favorable effects of quercetin in CIA rats, including an improved arthritis score and reduced ankle bone destruction, in addition to a decrease in the pro-inflammatory cytokines IL-1β, IL-6, IL-17, and TNF-α in serum. Immunofluorescence verified that quercetin may ameliorate joint injury in rats with CIA by inhibiting JAK1/STAT3/HIF-1α signaling. Various in vitro experiments demonstrated that quercetin effectively inhibits IL-6-induced proliferation of MH7A cells and reduces their migratory and invasive behavior, while inducing apoptosis and reducing the expression of the pro-inflammatory cytokines IL1β, IL6, IL17, and TNFα at the mRNA level. Quercetin caused inhibition of glucose, lactate, lactate dehydrogenase, pyruvate, and adenosine triphosphate and increased pyruvate dehydrogenase expression in MH7A cells. It was further confirmed that quercetin may inhibit energy metabolism and inflammatory factor secretion in MH7A cells through JAK1/STAT3/HIF-1α signaling.

CONCLUSIONS

Quercetin's action on multiple target molecules and pathways makes it a promising treatment for cartilage injury in rheumatoid arthritis. By reducing joint inflammation, improving joint metabolic homeostasis, and decreasing immune system activation energy, quercetin inhibits the JAK1/STAT3/HIF-1α signaling pathway to improve disease status.

Amelioration of Phytanic Acid-Induced Neurotoxicity by Nutraceuticals: Mechanistic Insights

Phytanic acid (PA) (3,7,11,15-tetramethylhexadecanoic acid) is a methyl-branched fatty acid that enters the body through food consumption, primarily through red meat, dairy products, and fatty marine foods. The metabolic byproduct of phytol is PA, which is then oxidized by the ruminal microbiota and some marine species. The first methyl group at the 3-position prevents the β-oxidation of branched-chain fatty acid (BCFA). Instead, α-oxidation of PA results in the production of pristanic acid (2,10,14-tetramethylpentadecanoic acid) with CO2. This fatty acid (FA) builds up in individuals with certain peroxisomal disorders and is historically linked to neurological impairment. It also causes oxidative stress in synaptosomes, as demonstrated by an increase in the production of reactive oxygen species (ROS), which is a sign of oxidative stress. This review concludes that the nutraceuticals (melatonin, piperine, quercetin, curcumin, resveratrol, epigallocatechin-3-gallate (EGCG), coenzyme Q10, ω-3 FA) can reduce oxidative stress and enhanced the activity of mitochondria. Furthermore, the use of nutraceuticals completely reversed the neurotoxic effects of PA on NO level and membrane potential. Additionally, the review further emphasizes the urgent need for more research into dairy-derived BCFAs and their impact on human health.

Quercetin and ibuprofen combination displayed anti-inflammatory effects and also extenuates the enteric neurons damage of arthritic rats

This study aimed to investigate the antioxidant and anti-inflammatory properties of quercetin on the cellular components of the Enteric Nervous System in the ileum of rats with arthritis. Rats were distributed into five groups: control (C), arthritic (AIA), arthritic treated with ibuprofen (AI), arthritic treated with quercetin (AQ) and arthritic treated with both ibuprofen and quercetin (AIQ). The ileum was processed for immunohistochemical techniques for HuC/D, calcitonin gene-related peptide, and vasoactive intestinal polypeptide. Measurements in histological sections, chemiluminescence assays, and total antioxidant capacity were also performed. Rheumatoid arthritis resulted in a decrease in neuronal density, yet neuroplasticity mechanisms were evident through observed changes in varicosities size and neuronal area compared to the control group. Reduced paw edema and neuroprotective effects were predominantly noted in both plexuses, as evidenced by the increased density preservation of HuC/D-IR neurons in the AIQ group. The increase of lipoperoxidation levels and paw edema volume in the AQ group was observed compared to the arthritic, whereas the AIQ group mainly showed similar results to those observed in the control. The enteropathy associated with arthritis proved to be significant in the field of gastroenterology, and the combination of quercetin and ibuprofen demonstrated promising anti-inflammatory and neuroprotective effects.

Fangji Huangqi Decoction alleviates rheumatoid arthritis through regulating HIF-1α mediated the angiogenesis and the balance between autophagy and apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Fangji Huangqi Decoction (FHD) is frequently prescribed for the clinical treatment of wind-cold and wind-dampness pathogenic superficial deficiency syndrome. It also has a notable curative effect on rheumatoid arthritis (RA).

AIM OF THE STUDY

The study aimed to explore the possible mechanism of FHD against RA and provided a theoretical basis for alternative therapies for RA.

MATERIALS AND METHODS

We used UPLC-Q-TOF-MS to analysis the ingredients and absorbed blood components of FHD. At the same time, the collagen-induced arthritis (CIA) rat model was established to estimate the therapeutic effects on FHD by considering body weight, arthritis score, paw swelling, autonomous movement ability, and synovial microvessel counts. Subsequently, immunofluorescence, immunohistochemistry, and Western blot were employed to detect the anti-angiogenic capacity of FHD in vivo, as well as the levels of apoptosis and autophagy in the synovial tissue. In addition, flow cytometry and Western blot were used to assess the effects of FHD on apoptosis and autophagy in MH7A cells. The effects of FHD on the proliferation and migration of MH7A cells were measured by CCK8 assay, cell migration and, invasion experiments. Finally, a tube formation assay was performed to evaluate the angiogenic capacity of FHD in co-cultures of MH7A cells and HUVEC cells.

RESULTS

Through testing of FHD's original formula, a total of 26 active ingredients have been identified, with 17 of them being absorbed into the bloodstream. FHD significantly improved the pathological symptoms and synovial hyperplasia of CIA rats. FHD could suppress the expression of HIF-1α, promote apoptosis in CIA rat synovial tissue, and suppress autophagy and angiogenesis. In vitro experiments showed that serum containing FHD inhibited the proliferation, migration, and invasion of MH7A cells, and also suppressed the expression of autophagy-related proteins while promoting apoptosis. FHD markedly repressed the expression of HIF-1α protein in TNF-α-stimulated MH7A cells and inhibited the tube formation capacity induced by MH7A cells in HUVEC cells.

CONCLUSIONS

The study had proven that FHD played an excellent anti-RA role, which may be attributed to its potential mechanism of regulating the balance between autophagy and apoptosis in RA FLS by suppressing the HIF-1α, thus contributing to its anti-angiogenic activities.

Silibinin's Effects against Methotrexate-Induced Hepatotoxicity in Adjuvant-Induced Arthritis Rat Model

Methotrexate (MTX) is the first drug of choice to treat several diseases, including rheumatoid arthritis. However, its administration is accompanied by severe side effects, most commonly hepatotoxicity. Hence, alternative therapies with a lower toxicity and fewer side effects are needed. This study aimed to investigate the antioxidant and hepatoprotective effects of silibinin (SIL, natural agent) against MTX-induced hepatotoxicity in an adjuvant-induced arthritis (AIA) rat model. Arthritic rats were treated with SIL (100 mg/kg) and/or methotrexate (2 mg/kg). Non-arthritic rats, arthritic untreated rats, and arthritic rats who received the vehicle were followed in parallel. SIL alleviated the systemic consequences of arthritis by restoring lost weight, decreasing the erythrocyte sedimentation rate, and ameliorating joint damage, which was evident both micro- and macroscopically. Additionally, SIL prevented the histopathological alterations in the liver and significantly reduced the liver damage caused by MTX and AIA, as shown by a decrease in the markers of liver damage (ALT and AST). Furthermore, SIL relieved the oxidative stress induced by AIA and MTX in liver tissue by decreasing the lipid peroxidation (MDA) levels and enhancing the antioxidant defense system (GSH levels; catalase and superoxide dismutase (SOD) activities). In conclusion, our results suggest that SIL is a potent antioxidant and hepatoprotective agent in arthritic rats. It markedly attenuated the progression and severity of the arthritic disease and eased the oxidative stress in liver tissue by improving the pro-oxidant/antioxidant balance.

Rheumatoid arthritis molecular targets and their importance to flavonoid-based therapy

Rheumatoid arthritis (RA) is a progressive, chronic, autoimmune, inflammatory, and systemic condition that primarily affects the synovial joints and adjacent tissues, including bone, muscle, and tendons. The World Health Organization recognizes RA as one of the most prevalent chronic inflammatory diseases. In the last decade, there was an expansion on the available RA therapeutic options which aimed to improve patient's quality of life. Despite the extensive research and the emergence of new therapeutic approaches and drugs, there are still significant unwanted side effects associated to these drugs and still a vast number of patients that do not respond positively to the existing therapeutic strategies. Over the years, several references to the use of flavonoids in the quest for new treatments for RA have emerged. This review aimed to summarize the existing literature about the flavonoids' effects on the major pathogenic/molecular targets of RA and their potential use as lead compounds for the development of new effective molecules for RA treatment. It is demonstrated that flavonoids can modulate various players in synovial inflammation, regulate immune cell function, decrease synoviocytes proliferation and balance the apoptotic process, decrease angiogenesis, and stop/prevent bone and cartilage degradation, which are all dominant features of RA. Although further investigation is necessary to determine the effectiveness of flavonoids in humans, the available data from in vitro and in vivo models suggest their potential as new disease-modifying anti-rheumatic drugs. This review highlights the use of flavonoids as a promising avenue for future research in the treatment of RA.

Hyaluronic acid/polyphenol sunscreens with broad-spectrum UV protection properties from tannic acid and quercetin

Currently, commercial sunscreens cause a number of biotoxicity and environmental issues, making it imperative to develop biocompatible alternatives. In this study, we aimed to develop an alternative sunscreen from two ecofriendly and biocompatible natural polyphenolic compounds, tannic acid (TA) and quercetin (Que). The sunscreen was prepared through a simple process using an oil-in-water emulsion as the medium and hyaluronic acid (HA) as the base polymer to improve biocompatibility. The HA/TA/Que. sunscreen prepared in this study exhibits 0 % transmittance in the UVB region and <15 % transmittance in the UVA region, resulting in excellent sun-protection properties (SPF 30). Remarkably, the as-prepared HA/TA/Que. sunscreen has a suitable viscosity and similar UV protection properties to those of commercial sunscreens. The HA/TA/Que. sunscreen also exhibits 90.4 % antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl, demonstrating an ability to effectively capture reactive oxygen species that directly affect the skin. In addition, the cell viability was >90 % at a concentration of 50 μg/mL after 7 days, indicating excellent cytocompatibility. Owing to its various advantageous features, the HA/TA/Que. sunscreen with excellent sun protection properties and multiple functionalities is expected to resolve many environmental and biological issues caused by commercial sunscreens.

Research progress in arthritis treatment with the active components of Herba siegesbeckiae

Arthritis is a group of diseases characterized by joint pain, swelling, stiffness, and limited movement. Osteoarthritis, rheumatoid arthritis, and gouty arthritis are the most common types of arthritis. Arthritis severely affects the quality of life of patients and imposes a heavy financial and medical burden on their families and society at large. As a widely used traditional Chinese medicine, Herba siegesbeckiae has many pharmacological effects such as anti-inflammatory and analgesic, anti-ischemic injury, cardiovascular protection, and hypoglycemic. In addition, it has significant therapeutic effects on arthritis. The rich chemical compositions of H. siegesbeckiae primarily include diterpenoids, sesquiterpenoids, and flavonoids. As one of the main active components of H. siegesbeckiae, kirenol and quercetin play a vital role in reducing arthritis symptoms. In the present study, the research progress in arthritis treatment with the active components of H. siegesbeckiae is reviewed.

Citrus flavonoids and adhesion molecules: Potential role in the management of atherosclerosis

Atherosclerosis as a chronic inflammatory disorder is accompanied with oxidative stress which causes a high morbidity and mortality. Adhesion molecules, including intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), P-selectin, and E-selectin, are amongst the most important contributors in atherosclerosis. In such cases, dietary interventions with functional foods containing natural antioxidant and anti-inflammatory constituents are of a great interest. Citrus fruits are rich sources of flavonoids as natural pigments with potent antioxidant and anti-inflammatory activities. This study aims to review current evidence regarding the role of citrus flavonoids in the management of atherosclerosis with a focus on their effect on adhesion molecules. Electronic databases including PubMed, Scopus, and Web of Science were searched with the names of adhesion molecules and flavonoids from inception until January 2023. The included articles highly support the beneficial effects of citrus flavonoids in preclinical models of atherosclerosis. Quercetin, naringin and naringenin, hesperidin and hesperetin, nobiletin, rutin, luteolin, apigenin, and kaempferol are the most common flavonoids in citrus fruits which could modulate adhesion molecules including ICAM-1, VCAM-1, E-selectin, and P-selectin. Additionally, markers of chronic inflammation such as interleukins, tumor necrosis factor-α, nuclear factor-κB, and nitric oxide signaling, as well as oxidative stress markers like superoxide dismutase and glutathione were all normalized upon administration of citrus flavonoids. Conclusively, this review confirms the modulatory role of flavonoids on adhesion molecules in atherosclerosis based on the preclinical evaluations. Thus, citrus fruits can be further studied in atherosclerotic patients regarding their activity in reducing adhesion molecules.

Mechanistic prospective and pharmacological attributes of quercetin in attenuation of different types of arthritis

Arthritis is a frequent autoimmune disease with undefined etiology and pathogenesis. Scientific community constantly fascinating quercetin (QUR), as it is the best-known flavonoid among others for curative and preventive properties against a wide range of diseases. Due to its multifaceted activities, the implementation of QUR against various types of arthritis namely, rheumatoid arthritis (RA), osteoarthritis (OA), gouty arthritis (GA) and psoriotic arthritis (PsA) has greatly increased in recent years. Many research evidenced that QUR regulates a wide range of pathways for instance NF-κB, MAK, Wnt/β-catenine, Notch, etc., that are majorly associated with the inflammatory mechanisms. Besides, the bioavailability of QUR is a major constrain to its therapeutic potential, and drug delivery techniques have experienced significant development to overcome the problem of its limited application. Hence, this review compiled the cutting-edge experiments on versatile effects of QUR on inflammatory diseases like RA, OA, GA and PsA, sources and bioavailability, therapeutic challenges, pharmacokinetics, clinical studies as well as toxicological impacts. The use of QUR in a health context would offer a tearing and potential therapeutic method, supporting the advancement of public health, particularly, of arthritic patients worldwide.

In vivo application of magnetic molecularly imprinted polymer in rheumatoid arthritis rat model

A magnetic molecularly imprinted polymer (MMIP) was synthesised and tested for an in vivo rheumatoid arthritis (RA) rat model. Magnetite coated with mesoporous silica (Fe2O3@mSi) was used as core for surface imprinting, dopamine was used as monomer and methotrexate (MTX) was loaded directly during polymerisation. The amount of MTX loaded on MMIPs reached 201.165 ± 0.315 µmol/g. Characterisation of the polymers was done via SEM, TEM, and FTIR. The pharmacological effect of the selected MMIP was evaluated in a Complete Freund's Adjuvant (CFA) induced arthritis rat model where a 3D magnet bearing construct was designed for targeted delivery of MMIPs. The parameters evaluated were the change in paw edoema, paw diameter, gait score, and animal's weight. Results revealed a tendency of MMIP to significantly improve the measured parameters which was confirmed with histopathological findings. In conclusion, the improvement in the arthritic signs associated with MMIP treatment compared to free MTX, indicated successful targeting of MMIPs to the site of inflammation.

Mechanism of action of quercetin in rheumatoid arthritis models: meta-analysis and systematic review of animal studies

Quercetin, a typical flavonoid derived from a common natural plant, has multiple biological activities. Previous research in animal models has demonstrated the effectiveness of quercetin in treating rheumatoid arthritis (RA). The pharmacological effects and probable mechanisms of quercetin were evaluated in this study. Three databases, PubMed, Web of Science, and Embase, were searched for relevant studies from the creation of the databases to November 2022. Methodological quality was assessed using the SYRCLE risk of bias tool. STATA 15.1 was used to perform the statistical analysis. This research included 17 studies involving 251 animals. The results indicated that quercetin was able to reduce arthritis scores, paw swelling, histopathological scores, interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-17 (IL-17), tumor necrosis factor-α (TNF-α), monocyte chemotactic protein-1 (MCP-1), C-reactive protein (CRP), malondialdehyde (MDA), reactive oxygen species (ROS), thiobarbituric acid reactive substances (TBARS), nuclear factor kappa B (NF-kB) and increase interleukin-10 (IL-10), catalase (CAT), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), glutathione (GSH), and heme oxygenase-1 (HO-1). These may be related to quercetin's potential anti-inflammatory, anti-oxidative stress, and osteoprotective properties. However, more high-quality animal studies are needed to assess the effect of quercetin on RA. Additionally, the safety of quercetin requires further confirmation. Given the importance of the active ingredient, dose selection and the improvement of quercetin's bioavailability remain to be explored.

Efficacy and safety of dietary polyphenols in rheumatoid arthritis: A systematic review and meta-analysis of 47 randomized controlled trials

Objective

To evaluate safety and efficacy of dietary polyphenols in the treatment of rheumatoid arthritis (RA).

Methods

CNKI, Pubmed, Cochrane library, Embase were searched to collect randomized controlled trials (RCTs) of dietary polyphenols in the treatment of RA. The databases were searched from the time of their establishment to November 8nd, 2022. After 2 reviewers independently screened the literature, extracted data, and assessed the risk of bias of the included studies, Meta-analysis was performed using RevMan5.4 software.

Results

A total of 49 records (47 RCTs) were finally included, involving 3852 participants and 15 types of dietary polyphenols (Cinnamon extract, Cranberry extract, Crocus sativus L. extract, Curcumin, Garlic extract, Ginger extract, Hesperidin, Olive oil, Pomegranate extract, Puerarin, Quercetin, Resveratrol, Sesamin, Tea polyphenols, Total glucosides of paeony). Pomegranate extract, Resveratrol, Garlic extract, Puerarin, Hesperidin, Ginger extract, Cinnamon extract, Sesamin only involve in 1 RCT. Cranberry extract, Crocus sativus L. extract, Olive oil, Quercetin, Tea polyphenols involve in 2 RCTs. Total glucosides of paeony and Curcumin involve in more than 3 RCTs. These RCTs showed that these dietary polyphenols could improve disease activity score for 28 joints (DAS28), inflammation levels or oxidative stress levels in RA. The addition of dietary polyphenols did not increase adverse events.

Conclusion

Dietary polyphenols may improve DAS28, reduce C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), and improve oxidative stress, etc. However, more RCTs are needed to verify or modify the efficacy and safety of dietary polyphenols.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022315645.

Therapeutic effect of oral quercetin in hamsters infected with Leishmania Viannia braziliensis

Leishmaniasis is a parasitic disease caused by several species of intracellular protozoa of the genus Leishmania that present manifestations ranging from cutaneous ulcers to the fatal visceral form. Leishmania Viannia braziliensis is an important species associated with American tegumentary leishmaniasis and the main agent in Brazil, with variable sensitivity to available drugs. The search for new therapeutic alternatives to treat leishmaniasis is an urgent need, especially for endemic countries. Not only is quercetin well known for its antioxidant activity in radical scavenging but also several other biological effects are described, including anti-inflammatory, antimicrobial, and pro-oxidant activities. This study aimed to investigate the flavonoid quercetin's therapeutic potential in L. (V.) braziliensis infection. Quercetin showed antiamastigote (IC50 of 21 ± 2.5 µM) and antipromastigote (25 ± 0.7 µM) activities and a selectivity index of 22. The treatment of uninfected or L. (V.) braziliensis-infected macrophages with quercetin increased reactive oxygen species (ROS)/H202 generation without altering Nitric Oxide (NO) production. Oral treatment with quercetin of infected hamsters, starting at 1 week of infection for 8 weeks, reduced the lesion thickness (p > 0.01) and parasite load (p > 0.001). The results of this study suggest that the antiamastigote activity of the flavonoid quercetin in vitro is associated, at least in part, with the modulation of ROS production by macrophages. The efficacy of oral quercetin treatment in hamsters infected with L. (V.) braziliensis was presented for the first time and shows its promising therapeutic potential.

Epimedii Herba: An ancient Chinese herbal medicine in the prevention and treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, progressive inflammatory and systemic autoimmune disease resulting in severe joint destruction, lifelong suffering and considerable disability. Diverse prescriptions of traditional Chinese medicine (TCM) containing Epimedii Herba (EH) achieve greatly curative effects against RA. The present review aims to systemically summarize the therapeutic effect, pharmacological mechanism, bioavailability and safety assessment of EH to provide a novel insight for subsequent studies. The search terms included were "Epimedii Herba", "yinyanghuo", "arthritis, rheumatoid" and "Rheumatoid Arthritis", and relevant literatures were collected on the database such as Google Scholar, Pubmed, Web of Science and CNKI. In this review, 15 compounds from EH for the treatment of RA were summarized from the aspects of anti-inflammatory, immunoregulatory, cartilage and bone protective, antiangiogenic and antioxidant activities. Although EH has been frequently used to treat RA in clinical practice, studies on mechanisms of these activities are still scarce. Various compounds of EH have the multifunctional traits in the treatment of RA, so EH may be a great complementary medicine option and it is necessary to pay more attention to further research and development.

Promising natural products against SARS-CoV-2: Structure, function, and clinical trials

The corona virus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus type 2 (SARS-COV-2) poses a severe threat to human health and still spreads globally. Due to the high mutation ratio and breakthrough infection rate of the virus, vaccines and anti-COVID-19 drugs require continual improvements. Drug screening research has shown that some natural active products can target the critical proteins of SARS-CoV-2, including 3CLpro, ACE2, FURIN, and RdRp, which could produce great inhibitory effects on SARS-COV-2. In addition, some natural products have displayed activities of immunomodulation, antiinflammatory, and antihepatic failure in COVID-19 clinical trials, which may relate to their non-monomeric structures. However, further evaluation and high-quality assessments, including safety verification tests, drug interaction tests, and clinical trials, are needed to substantiate natural products' multi-target and multi-pathway effects on COVID-19. Here, we review the literature on several promising active natural products that may act as vaccine immune enhancers or provide targeted anti-COVID-19 drugs. The structures, mechanisms of action, and research progress of these natural products are analyzed, to hopefully provide effective ideas for the development of targeted drugs that possess better structure, potency, and safety.

Non-Esterified Fatty Acid Induces ER Stress-Mediated Apoptosis via ROS/MAPK Signaling Pathway in Bovine Mammary Epithelial Cells

Elevated concentrations of non-esterified fatty acid (NEFA) induced by negative energy balance (NEB) during the transition period of dairy cows is known to be toxic for multiple bovine cell types. However, the effect of NEFA in bovine mammary epithelial cells (BMECs) remains unclear. The present study aimed to explore the role and molecular mechanism of NEFA in endoplasmic reticulum (ER) stress and the subsequent apoptosis in BMECs. The results showed that NEFA increased ER stress and activated the three unfolded protein response (UPR) signaling sub-pathways by upregulating the expression of GRP78, HSP70, XBP1, ATF6, phosphor-PERK, and phosphor-IRE1α. We also found that NEFA dose-dependently induced apoptosis in BMECs, as indicated by flow cytometry analysis and increased apoptotic gene expression. RNA-seq analysis revealed that NEFA induced apoptosis in BMECs, probably via the ATF4-CHOP axis. Mechanistically, our data showed that NEFA increased reactive oxygen species (ROS) levels, resulting in the activation of the MAPK signaling pathway. Moreover, quercetin, a well-known antioxidant, was found to alleviate ER stress-mediated apoptosis in NEFA-treated BMECs. Collectively, our results suggest that NEFA induces ER stress-mediated apoptosis, probably via the ROS/MAPK signaling pathway, as quercetin has been shown to alleviate ER stress-mediated apoptosis in NEFA-treated BMECs.

Biological Activities Underlying the Therapeutic Effect of Quercetin on Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic autoimmune disorder stemming from unrestrained immune activation and subsequent destruction of colon tissue. Genetic susceptibility, microbiota remodeling, and environmental cues are involved in IBD pathogenesis. Up to now, there are limited treatment options for IBD, so better therapies for IBD are eagerly needed. The therapeutic effects of naturally occurring compounds have been extensively investigated, among which quercetin becomes an attractive candidate owing to its unique biochemical properties. To facilitate the clinical translation of quercetin, we aimed to get a comprehensive understanding of the cellular and molecular mechanisms underlying the anti-IBD role of quercetin. We summarized that quercetin exerts the anti-IBD effect through consolidating the intestinal mucosal barrier, enhancing the diversity of colonic microbiota, restoring local immune homeostasis, and restraining the oxidative stress response. We also delineated the effect of quercetin on gut microbiome and discussed the potential side effects of quercetin administration. Besides, quercetin could serve as a prodrug, and the bioavailability of quercetin is improved through chemical modifications or the utilization of effective drug delivery systems. Altogether, these lines of evidence hint the feasibility of quercetin as a candidate compound for IBD treatment.

Pharmacological Aspects of Natural Quercetin in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease that can lead to severe joint damage, disability and mortality. Quercetin (QUE) is a natural flavonoid that is ubiquitous in fruits and vegetables. This article reviews the effect of QUE on articular and extra-articular manifestations of RA in vitro and in vivo. In general, for articular manifestations, QUE inhibited synovial membrane inflammation by reducing inflammatory cytokines and mediators, decreasing oxidative stress, inhibiting proliferation, migration and invasion, and promoting apoptosis of fibroblast-like synoviocytes (FLS), regulated autoimmune response through modulating Th17/Treg imbalance and Th17 cells differentiation, reducing autoantibodies levels and regulating ectonucleoside triphosphate diphosphohydrolase (E-NTPDase)/ectoadenosine deaminase (E-ADA) activities, reduced bony damage via lowering matrix metalloproteinase (MMP)-1, MMP-3, receptor activator of nuclear factor kappa B ligand (RANKL) expression and osteoclasts formation. For extra-articular manifestations, QUE could reverse the neurodegenerative processes of the enteric nervous system (ENS) and exhibited cytoprotective, genoprotective and hepatoprotective effects. In addition, we also summarize some contradictory experimental results and explore the possibility for these differences to form a sound basis for the clinical application of QUE for RA.

Phytochemicals from medicinal plants from African forests with potentials in rheumatoid arthritis management

OBJECTIVES

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by inflammation, pain, and cartilage and bone damage. There is currently no cure for RA. It is however managed using nonsteroidal anti-inflammatory drugs, corticosteroids and disease-modifying anti-rheumatic drugs, often with severe side effects. Hidden within Africa's lush vegetation are plants with diverse medicinal properties including anti-RA potentials. This paper reviews the scientific literature for medicinal plants, growing in Africa, with reported anti-RA activities and identifies the most abundant phytochemicals deserving research attention. A search of relevant published scientific literature, using the major search engines, such as Pubmed/Medline, Scopus, Google Scholar, etc. was conducted to identify medicinal plants, growing in Africa, with anti-RA potentials.

KEY FINDINGS

Twenty plants belonging to 17 families were identified. The plants are rich in phytochemicals, predominantly quercetin, rutin, catechin, kaempferol, etc., known to affect some pathways relevant in RA initiation and progression, and therefore useful in its management.

SUMMARY

Targeted research is needed to unlock the potentials of medicinal plants by developing easy-to-use technologies for preparing medicines from them. Research attention should focus on how best to exploit the major phytochemicals identified in this review for the development of anti-RA 'green pharmaceuticals'.

Quercetin Impedes Th17 Cell Differentiation to Mitigate Arthritis Involving PPARγ-Driven Transactivation of SOCS3 and Redistribution Corepressor SMRT from PPARγ to STAT3

SCOPE

Quercetin (QU) is one of the most abundant flavonoids in plants and has attracted the attention of researchers because of its remarkable antirheumatoid arthritis (RA) effects and extremely low adverse reactions. However, the underlying mechanism needs further study.

METHODS AND RESULTS

Flow cytometry, immunofluorescence, enzyme linked immunosorbent assay （ELISA）, and quantitative real-time polymerase chain reaction （qRT-PCR） reveal the obvious inhibitory effects of QU on Th17 cell differentiation in arthritic mice. More importantly, QU markedly limits the development of Th17 cell polarization, which is virtually compromised by the treatment with peroxisome proliferator activated receptor γ (PPARγ) inhibitor GW9662 and knockdown of PPARγ. Additionally, molecular dynamics simulation and immunofluorescence exhibit QU directly binds to PPARγ and increases PPARγ nuclear translocation. Besides, QU confers its moderation effect on suppressor of cytokine signaling protein (SOCS3)/signal transducer and activator of transcription 3 (STAT3) axis partially depending on PPARγ. Furthermore, coimmunoprecipitation shows QU redistributes the corepressor silencing mediator for retinoid and thyroid-hormone receptors (SMRT) from PPARγ to STAT3. Finally, the inhibition of Th17 response and the antiarthritic effect of QU are nullified by GW9662 treatment in arthritic mice.

CONCLUSION

QU targets PPARγ and consequently inhibits Th17 cell differentiation by dual inhibitory activity of STAT3 to exert antiarthritic effect. The findings facilitate its development and put forth a stage for uncovering the mechanism of other naturally occurring compounds with chemical structures similar to QU.

Anti-rheumatic, and analgesic effects by the parent tuberous roots of Aconitum jaluense in adjuvant induced arthritis rats

AIM OF THE STUDY

The aim of this study was to test the anti-rheumatic effects of A. jaluense tubers in acute and chronic arthritis rats, and to assign its ingredients through UHPLC-TOF/MS.

MATERIALS AND METHODS

Subcutaneous injection of carrageenan for acute arthritis and complete Freund's adjuvant (CFA) for chronic arthritis was carried out in the hind paw of SD rats. The paw volume was measured by a plethysmometer thermal hyperalgesia was tested using a thermal plantar tester, and mechanical hyperalgesia was evaluated by ankle flexion evoked vocalizations. The expression of c-Fos in the brain hippocampus was measured with the avidin-biotin-peroxidase technique. The ingredients were assigned by UHPLC-TOF/MS, chromatography was performed by UHPLC system with DAD detector and BEH C₁₈ column, and spectroscopy was conducted by ESI-MS system.

RESULTS AND DISCUSSION

The 80% ethanoic extract of A. jaluense tubers showed an acute anti-inflammatory effect by suppressing the edema volume in the hind paw of carrageenan-stimulated rats. In addition, A. jaluense tubers exerted an anti-rheumatic activity by reducing the secondary swelling volume from an immunological reaction in the left hind paw of CFA-induced chronic arthritis rats. Additionally, oral treatment with the 80% ethanoic extract -showed potent analgesic effects in the arthritis rats by recovering the paw withdrawal latency stimulated by the thermal hyperalgesia and by reducing the vocalization scores evoked by ankle flexion on both hind paws. Moreover, its treatment also indicated an anti-psychiatric effect by controlling the c-Fos protein expression of the brain hippocampus in CFA-stimulated arthritis rats. These results suggested that these therapeutic effects were exhibited by less toxic mono-esterified diterpenoid alkaloids (MDAs), and nontoxic non-esterified diterpenoid alkaloids (NDAs).

CONCLUSION

A. jaluense tubers may act as viable therapeutic or preventive candidates for acute and chronic arthritis, particularly, for immune-inflammatory rheumatoid arthritis to suppress the pain and psychiatric condition.

Quercetin mitigates rheumatoid arthritis by inhibiting adenosine deaminase in rats

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-1^β, 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.

Quercetin and vitamin E ameliorate cardio-apoptotic risks in diabetic rats

Apoptosis is upregulated in all forms of diabetes, and the mitochondria act as target in diabetes pathophysiology. Quercetin and vitamin E have both shown usefulness in the delay of progression of diabetes-induced complications. However, their effect on the apoptotic process in diabetes mellitus is unknown. We hypothesize that quercetin treatment in diabetes may decrease the propensity for cardiomyocytic death via regulation of the mitochondria permeability transition (mPT) pore opening. Hearts from normal and streptozotocin-induced diabetic rats were used for the study. Low ionic strength heart mitochondria were used for swelling assay and mitochondrial lipid peroxidation (mLPO) activity was spectrophotometrically assessed. Levels of cytochrome c and caspase 3 and 9 were determined by immunohistochemistry, while lesions assessed by histology. Diabetic heart mPT pore showed larger amplitude swelling than control, while mLPO levels were increased in diabetic rats relative to control, this resulted in cytochrome c release. This initiated increased caspase 3 and 9 activity in diabetic rats (p < 0.05). Histology showed hemorrhagic lesions in diabetic rat hearts. Quercetin and vitamin E treatment reversed these effects, suggestive of their anti-apoptotic effect. Quercetin and vitamin E protection in diabetes is mediated by mPT pore inhibition and modulation of mitochondrial-mediated apoptosis.

Low dose of quercetin-loaded pectin/casein microparticles reduces the oxidative stress in arthritic rats

AIMS

Quercetin has been investigated as an agent to treat rheumatoid arthritis. At high doses it improves inflammation and the antioxidant status of arthritic rats, but it also exerts mitochondriotoxic and pro-oxidant activities. Beneficial effects of quercetin have not been found at low doses because of its chemical instability and low bioavailability. In the hope of overcoming these problems this study investigated the effects of long-term administration of quercetin-loaded pectin/casein microparticles on the oxidative status of liver and brain of rats with adjuvant-induced arthritis.

MAIN METHODS

Particle morphology was viewed with transmission electron microscopy and the encapsulation efficiency was measured indirectly by X-ray diffraction. Quercetin microcapsules (10 mg/Kg) were orally administered to rats during 60 days. Inflammation indicators and oxidative stress markers were measured in addition to the respiratory activity and ROS production in isolated mitochondria.

KEY FINDINGS

Quercetin was efficiently encapsulated inside the polymeric matrix, forming a solid amorphous solution. The administration of quercetin microparticles to arthritic rats almost normalized protein carbonylation, lipid peroxidation, the levels of reactive oxygen species as well as the reduced glutathione content in both liver and brain. The paw edema in arthritic rats was not responsive, but the plasmatic activity of ALT and the mitochondrial respiration were not affected by quercetin, indicating absence of mitochondriotoxic or hepatotoxic actions.

SIGNIFICANCE

Quercetin-loaded pectin/casein microcapsules orally administered at a low dose improve oxidative stress of arthritic rats without a strong anti-inflammatory activity. This supports the long-term use of quercetin as an antioxidant agent to treat rheumatoid arthritis.

Micro RNAs 26b, 20a inversely correlate with GSK-3 β/NF-κB/NLRP-3 pathway to highlight the additive promising effects of atorvastatin and quercetin in experimental induced arthritis

Rheumatoid arthritis (RA) is an inflammatory disease with challenging therapeutic potential due to the implication of cross-talking intracellular pathways in the pathogenesis of the disease. This study aimed to evaluate the effects of the combination therapy of atorvastatin and quercetin on glycogen synthase kinase-3 beta/ nuclear factor kappa-B/ nucleotide-binding oligomerization domain-like receptor family pyrin domain containing-3 or inflammasome (GSK-3β/NF-KB/NLRP-3) pathway as well as on microRNAs 26b and 20a (miR-26b, miR-20a) and to investigate the possible beneficial outcomes of the combination to offer a better treatment option than methotrexate (MTX) in adjuvant-induced arthritis (AIA). Assessment of arthritis progression, serum inflammatory, and oxidative parameters were done. The tibiotarsal tissue expression of the inflammatory parameters was evaluated. Western blot analysis was done to assess the expression level of the important members in the GSK-3β/NF-κB/NLRP-3 pathway. Furthermore, the expression level of both microRNAs and serum level of transaminases were determined. All treatments, especially the combination regimen, abated arthritis progression, the elevated serum level of inflammatory and oxidative stress parameters in arthritic rats. Moreover, They down-regulated the gene expression of the important members of the aforementioned signaling pathway, amended the tissue levels of inflammatory parameters and elevated the expression level of miR-26b and miR-20a. Finally, we concluded that the combination therapy modulated miR-26b and miR-20a as well as GSK-3β/NF-κB/NLRP-3 pathway, provided additive anti-inflammatory and anti-oxidant effects and offered an additional hepatoprotective effect as compared to untreated arthritic rats and MTX-treated groups, suggesting its promising role to be used as replacement therapy to MTX in RA.

Majoon Chobchini attenuates arthritis disease severity and RANKL-mediated osteoclastogenesis in rheumatoid arthritis

Majoon Chobchini, a polyherbal Unani compound, has been used holistically in India to treat rheumatoid arthritis. However, the potential mechanism underlying the antiarthritic efficacy of Majoon Chobchini has not been elucidated so far. This study was aimed to explore the underlying molecular mechanism and scientifically validate the therapeutic basis of Majoon Chobchini in rheumatoid arthritis (RA). The anti-arthritic efficacy of Majoon Chobchini was demonstrated in vivo using complete Freund's adjuvant-induced arthritic rat model and adjuvant-induced arthritic fibroblast-like synoviocytes (AA-FLS). The expression of pro-inflammatory mediators and enzymes was evaluated in the serum and synovial tissues of adjuvant-induced arthritis (AIA) rats. In-vitro, AA-FLS, and bone marrow macrophages (BMMs) were co-cultured to evaluate the formation and activity of osteoclasts using TRAP staining analysis and pit formation assay, respectively. RANKL and OPG levels were detected using western blotting and qRT-PCR analysis. Furthermore, the involvement of JAK-STAT-3 signaling in the therapeutic efficacy of Majoon Chobchini was evaluated both in vivo and in vitro. Majoon Chobchini significantly reversed the physical symptoms in AIA rats with reduced expression of pro-inflammatory cytokines and enzymes. Notably, Majoon Chobchini alleviated cartilage degradation and bone erosion in AIA rats via inhibiting the activation of the JAK-STAT-3 signaling pathway in the AIA rats. Consistent with its effect in vivo, Majoon Chobchini decreased osteoclast inducing potential of AA-FLS and thus attenuated osteoclast formation and bone resorption in vitro. Taken together, our findings suggest that the JAK/STAT-3 signaling inhibition may underlie the mechanism through which Majoon Chobchini provides relief against RA symptoms.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-021-02985-4.

Pentahydroxy flavonoid isolated from Madhuca indica ameliorated adjuvant-induced arthritis via modulation of inflammatory pathways

Rheumatoid arthritis (RA) is an autoimmune disease associated with advanced joint dysfunction. Madhuca indica J. F. Gmel, from the family Sapotaceae, is an Indian medicinal plant reported to have an array of pharmacological properties. The aim of present investigation was to determine the anti-arthritic potential of an isolated phytoconstituent from methanolic leaf extract of Madhuca indica (MI-ALC) against FCA-induced experimental arthritis. Polyarthritis was induced in female rats (strain: Wistar) via an intradermal injection of FCA (0.1 mL) into the tail. Polyarthritis developed after 32 days of FCA administration. Then rats were treated orally with an isolated phytoconstituent from MI-ALC at doses of 5, 10, and 20 mg/kg. Findings suggested that High-Performance Thin-Layer Chromatography, Fourier-Transform Infrared Spectroscopy, and Liquid Chromatography-Mass Spectrometry spectral analyses of the phytoconstituent isolated from MI-ALC confirmed the structure as 3,5,7,3′,4′-Pentahydroxy flavone (i.e., QTN). Treatment with QTN (10 and 20 mg/kg) showed significant (p < 0.05) inhibition of increased joint diameter, paw volume, paw withdrawal threshold, and latency. The elevated synovial oxidative stress (Superoxide dismutase, reduced glutathione, and malondialdehyde) and protein levels of Tumor necrosis factor-α (TNF-α) and Interleukin (ILs) were markedly (p < 0.05) reduced by QTN. It also effectively (p < 0.05) ameliorated cyclooxygenase-2 (COX-2), Nuclear factor of kappa light polypeptide gene enhancer in B cells (NF-kβ) and its inhibitor-α (Ikβα), and ATP-activated P2 purinergic receptors (P2X7) protein expressions as determined by western blot analysis. In conclusion, QTN ameliorates FCA-induced hyperalgesia through modulation of elevated inflammatory release (NF-kβ, Ikβα, P2X7, and COX-2), oxido-nitrosative stress, and pro-inflammatory cytokines (ILs and TNF-α) in experimental rats.

Quercetin and vitamin E attenuate diabetes-induced testicular anomaly in Wistar rats via the mitochondrial-mediated apoptotic pathway

The role of quercetin and vitamin E treatment against streptozotocin (STZ)-induced testicular abnormalities in diabetic rats and the possible mechanism of action they use for protection were investigated. Diabetes was induced by STZ (45 mg/kg i.p. once) and blood glucose was determined. Plasmatic insulin, testosterone, luteinising hormone and follicle-stimulating hormone (FSH) were determined by ELISA. Levels of cytochrome c, caspase 3 and caspase 9 were evaluated by immunohistochemistry, while lesions were viewed by histology. Insulin played a role in testicular protection against male infertility through modulation of luteinising hormone (LH). This consequently increased Leydig and Sertoli cells and maturation of germ cells with the attached epididymis having abundant spermatozoa. The study showed a positive correlation in the levels of LH, FSH and testosterone; it was further established that all treatments normalised diabetes-induced alterations. Treatment with quercetin and vitamin E resulted in 34% decrease of apoptogenic cytochrome c release. This protected the testes against excessive apoptosis by decreasing caspase 3 and caspase 9 activation by up to 30 and 28% respectively (p < .05). Histology also showed that treatment prevented testicular cell death. The findings show that quercetin/vitamin E possess free radical scavenging properties that protected against testicular damage in diabetes. This suggests the possibility of pharmaco-therapeutic intervention.

Anti-inflammatory and analgesic properties of Moroccan medicinal plants: Phytochemistry, in vitro and in vivo investigations, mechanism insights, clinical evidences and perspectives

Moroccan medicinal plants exhibit several pharmacological properties such as antimicrobial, anticancer, antidiabetic, analgesic, and anti-inflammatory effects, which are related to the presence of numerous bioactive compounds, including phenolic acids, flavonoids, and terpenoids. In the present review, we systematically evaluate previously published reports on the anti-inflammatory and analgesic effects of Moroccan medicinal plants. The in vitro investigations revealed that Moroccan medicinal plants inhibit several enzymes related to inflammatory processes, whereas in vivo studies noted significant anti-inflammatory and analgesic effects as demonstrated using different experimental models. Various bioactive compounds exhibiting in vitro and in vivo anti-inflammatory and analgesic effects, with diverse mechanisms of action, have been identified. Some plants and their bioactive compounds reveal specific secondary metabolites that possess important anti-inflammatory effects in clinical investigations. Our review proposes the potential applications of Moroccan medicinal plants as sources of anti-inflammatory and analgesic agents.

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Anti-inflammatory and analgesic effects of Moroccan medicinal plants were highlighted.

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Chemical nature of Moroccan medicinal plants with anti-inflammatory and analgesic effects was reported.

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Insights into anti-inflammatory mechanisms of bioactive compounds were highlighted.

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Toxicological investigations of Moroccan medicinal plants were reviewed.

Anti-inflammatory and Hepatoprotective Effects of Quercetin in an Experimental Model of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by inflammation in the joints. Although methotrexate (MX) is the first-line treatment, side effects are common. This study aimed to investigate the effects of quercetin (QT) and/or MX on inflammation and systemic toxicity in a rat model of RA. Male Wistar rats were divided into control (C), RA, QT, MX, and QT + MX groups (n=6). The RA induction consisted of three intra-articular injections of methylated bovine serum albumin (1×/week) in the temporomandibular joint (TMJ). QT (25 mg/kg) and/or MX (0.75 mg) administration occurred by oral gavage daily. We performed mechanical hyperalgesia in TMJ, leukocyte recruitment in synovial fluid, histopathology, and immunohistochemistry (TNF-α, IL-17, and IL-10) in synovial membrane and toxicity parameters. The RA showed a reduction in the nociceptive threshold (p<0.001), increase in leukocyte recruitment in synovial fluid (p<0.001), intense inflammatory infiltrate (p<0.001), and intense immunoexpression of TNF-α, IL-17, and IL-10 in the synovial membrane (p<0.001) compared to C (p<0.001). QT and/or MX therapy reduced inflammatory parameters (p<0.001). However, downregulation of IL-10 was observed only in the groups that received MX (p<0.001). Leukocytosis was seen in RA (p<0.05), but QT and/or MX reversed it (p<0.05). MX was associated with pathological changes in the liver and higher levels of transaminases when compared to the other groups (p<0.05). QT co-administered with MX reversed this hepatotoxicity (p<0.05). There were no alterations in the kidney between the groups (p>0.05). QT has potential to support MX therapy, showing anti-inflammatory and hepatoprotective effects in this model.

Quercetin for COVID-19 and DENGUE co-infection: a potential therapeutic strategy of targeting critical host signal pathways triggered by SARS-CoV-2 and DENV

Background

The clinical consequences of SARS-CoV-2 and DENGUE virus co-infection are not promising. However, their treatment options are currently unavailable. Current studies have shown that quercetin is both resistant to COVID-19 and DENGUE; this study aimed to evaluate the possible functional roles and underlying mechanisms of action of quercetin as a potential molecular candidate against COVID-19 and DENGUE co-infection.

Methods

We used a series of bioinformatics analyses to understand and characterize the biological functions, pharmacological targets and therapeutic mechanisms of quercetin in COVID-19 and DENGUE co-infection.

Results

We revealed the clinical characteristics of COVID-19 and DENGUE, including pathological mechanisms, key inflammatory pathways and possible methods of intervention, 60 overlapping targets related to the co-infection and the drug were identified, the protein–protein interaction (PPI) was constructed and TNFα, CCL-2 and CXCL8 could become potential drug targets. Furthermore, we disclosed the signaling pathways, biological functions and upstream pathway activity of quercetin in COVID-19 and DENGUE. The analysis indicated that quercetin could inhibit cytokines release, alleviate excessive immune responses and eliminate inflammation, through NF-κB, IL-17 and Toll-like receptor signaling pathway.

Conclusions

This study is the first to reveal quercetin as a pharmacological drug for COVID-19 and DENGUE co-infection. COVID-19 and DENGUE co-infection remain a potential threat to the world’s public health system. Therefore, we need innovative thinking to provide admissible evidence for quercetin as a potential molecule drug for the treatment of COVID-19 and DENGUE, but the findings have not been verified in actual patients, so further clinical drug trials are needed.

Phytochemical add-on therapy to DMARDs therapy in rheumatoid arthritis: In vitro and in vivo bases, clinical evidence and future trends

The use of biologically active compounds derived from plants i.e. phytochemicals, have been known for ages for their pharmacological activities in the treatment of autoimmune disorders like rheumatoid arthritis (RA). Besides enormous scientific evidence, the therapeutic potential of phytochemicals is often undervalued. The treatment in RA involves the use of synthetic and biological disease modifying anti-rheumatic drugs (DMARDs). However, the long-term treatment in RA is associated with the risk of gastrointestinal, liver, pulmonary and renal toxicities and serious infections including latent tuberculosis, pneumococcus influenza, herpes zoster and hepatitis. These adverse effects sometimes lead to discontinuation of the therapy. A relatively new vision based on the combination of DMARDs with phytochemicals exhibiting anti-inflammatory, anti-arthritic, anti-oxidant, hepatoprotective and nephroprotective properties for the treatment of RA has achieved substantial importance in the last decade. From this perspective, the present review focuses on the combination of DMARDs (primarily MTX) with phytochemicals that have shown synergistic therapeutic effects while decreasing the toxic repercussions of current RA therapy. The review covers recent evidences of such combination studies that have shown promising results both in experimental arthritic models and clinical arthritis. Few of the combinations including resveratrol, sinomenine, coenzyme Q10 exhibited considerable interest because of their efficacy as an adjuvant to the MTX/standard DMARDs therapy in clinical trials. Besides giving an overview of such combination studies the review also critically discusses the limitations with the use of phytochemicals (e.g. solubility, permeability and bioavailability) compromising their clinical application. Additionally, it stresses upon the need of novel delivery systems and pharmaceutical technologies to increase the therapeutic efficacy of the combination therapy. Overall, the review unveils the potential of phytochemicals in combination with DMARDs with increased tolerability and superior efficacy in further refining the future of the RA therapy.

Quercetin: A Potential Candidate For The Treatment Of Arthritis

Diet plays a significant role in ensuring healthy life and the bioactive compounds present in food and medicinal plants may be developed as drugs that combat various illnesses. A bioactive flavanoid, quercetin which is a dietary component possesses numerous health-promoting effects. In preclinical models of rheumatoid arthritis, gouty arthritis and osteoarthritis, quercetin has shown significant joint protective effects. Taking into account the significance of this compound, the present review discusses its anti-arthritic properties, demonstrating its mechanism of action for the treatment of arthritis with its therapeutic potential.

Mechanism of Modified Danggui Sini Decoction for Knee Osteoarthritis Based on Network Pharmacology and Molecular Docking

Objective

This study aimed to explore the mechanism of Modified Danggui Sini Decoction in the treatment of knee osteoarthritis via a combination of network pharmacology and molecular docking.

Methods

The main chemical components and corresponding targets of Modified Danggui Sini Decoction were searched and screened in TCMSP database. The disease targets of knee osteoarthritis were summarized in GeneCards, OMIM, PharmGkb, TTD, and DrugBank databases. The visual interactive network of “drugs-active components-disease targets” was drawn by Cytoscape 3.8.1 software. The protein-protein interaction network was constructed by STRING database. Then, GO function and KEGG pathway enrichment were analyzed by Bioconductor/R, and the pathway of the highest degree of correlation with knee osteoarthritis was selected for specific analysis. Finally, molecular docking was used to screen and verify core genes by AutoDockTools software.

Results

Seventy-one main components of Modified Danggui Sini Decoction and 116 potential therapeutic targets of knee osteoarthritis were selected. The KEGG pathway and the GO function enrichment analysis showed that the targets of Modified Danggui Sini Decoction in the treatment of knee osteoarthritis were mainly concentrated on PI3K-Akt signaling pathway, TNF signaling pathway, IL-17 signaling pathway, apoptosis signaling pathway, Toll-like receptor signaling pathway, Th17 cell differentiation signaling pathway, HIF-1 signaling pathway, and NF-κB signaling pathway. It mainly involved inflammatory reaction, regulation of apoptotic signaling pathway, cellular response to regulation of inflammatory response, cellular response to oxidative stress, and other biological processes. The molecular docking results showed that ESR1-wogonin, MAPK1-quercetin, RELA-wogonin, RELA-baicalein, TP53-baicalein, TP53-quercetin, and RELA-quercetin have strong docking activities.

Conclusion

Modified Danggui Sini Decoction has the hierarchical network characteristics of “multicomponent, multitarget, multifunction, and multipathway” in the treatment of knee osteoarthritis. It mainly regulates the proliferation and apoptosis of chondrocytes by regulating the PI3K-Akt signaling pathway and establishes cross-talk with many downstream inflammatory-related pathways to reduce the overall inflammatory response. Meanwhile, HIF-1 expression was used to ensure the normal function and metabolism of knee joint under hypoxia condition, and the above processes play a key role in the treatment of knee osteoarthritis.

Quercetin amelioratesAspergillus fumigatuskeratitis by inhibiting fungal growth, toll-like receptors and inflammatory cytokines

PURPOSE

To investigate the antifungal and anti-inflammatory effects of quercetin on Aspergillus fumigatus (A. fumigatus) keratitis.

METHODS

Human corneal epithelial cells (HCECs) and C57BL/6 mice were stimulated by A. fumigatus and treated with quercetin or dimethyl sulfoxide (DMSO) after infection. In HCECs, minimum inhibitory concentration (MIC) and cytotoxicity tests (CCK-8) were used to detect the antifungal effect and cytotoxicity of quercetin. In mice with A. fumigatuskeratitis, clinical score, plate counting and hematoxylin-eosin (HE) staining were performed to evaluate the effects of quercetin in vivo. Myeloperoxidase (MPO) assay and immunofluorescence staining were applied to assess neutrophil recruitment and infiltration. Real time PCR (RT-PCR), enzyme-linked immunosorbent assay (ELISA) and western blot were used to detect the mRNA and protein expressions of inflammatory mediators.

RESULTS

Compared with DMSO control, quercetin (16-64 μM) significantly inhibited the growth of A. fumigatus in a concentration-dependent manner without affecting cell viability in HCECs. In corneas of mice with A. fumigatuskeratitis, quercetin decreased clinical score and fungal load, and reduced neutrophil recruitment and infiltration to the corneal stroma. Moreover, quercetin attenuated the expression of inflammatory mediators including toll-like receptor-4 (TLR-4), TLR-2, interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and high mobility group box 1 (HMGB1) in vitro and in vivo.

CONCLUSIONS

Our study demonstrated that quercetin treatment can ameliorate A. fumigatus keratitis by inhibiting the growth of A. fumigatus, decreasing neutrophil recruitment and infiltration, and downregulating the productions of TLR-4, TLR-2, TNF-α, IL-1β and HMGB1, indicating quercetin is likely to become a potential therapeutic agent in FK treatment.

Quercetin induces autophagy in myelodysplastic bone marrow including hematopoietic stem/progenitor compartment

Myelodysplastic syndrome (MDS) is regarded as a spectrum of bone marrow failure disorders that share hemato-pathological state of cellular dysplasia and cytopenia. The modern treatment of cancers like chemotherapy and radiation therapy sometimes severely pounce on the basic hematopoietic stem/progenitor cellular (HSPC) compartment which gradually disclose the clinical symptoms of MDS. The present study involves flowcytometric protein expression analysis of insulin growth factor receptor (IGFR), PI3K-Akt-mTOR pathway, the autophagy related proteins (ATG's), the status of antioxidative molecules SOD2 and SDF1 and apoptosis profiling in ethyl-nitroso-urea induced myelodysplasia. The redox status that is, reactive oxygen species was estimated with dihydroetidium and the status of mitochondria and lysosomes were checked by Janus green B and neutral red staining respectively, pre and post quercetin treatment in MDS bone marrow. The results revealed the activated IGFR/PI3K/Akt axis in MDS bone marrow but unconventionally both p-mTOR and autophagy (p-ATG1, p-AT6, ATG7, ATG12) was downregulated. Interestingly, post quercetin treatment an upregulation of basal autophagocytosis, reversal of oxidative damage and proper functionality of mitochondria and lysosome was recorded. Taken together, the study hinted that the PI3K-Akt-mTOR pathway does not rule over the process of autophagocytosis in HSPC's of MDS bone marrow and the isoflavanoid quercetin remarkably restored autophagocytosis and hematopoietic oxidative status toward normalcy during the progression of myelodysplasia.

Traditional use, phytochemistry, toxicology, and pharmacology of Origanum majorana L

ETHNOPHARMACOLOGICAL RELEVANCE

Origanum majorana L., is an aromatic and medicinal plant distributed in different parts of Mediterranean countries. This species is widely used in traditional medicine for the treatment of many diseases such as allergies, hypertension, respiratory infections, diabetes, stomach pain, and intestinal antispasmodic.

AIM OF THE REVIEW

This work reports previous studies on O. majorana concerning its taxonomy, botanical description, geographical distribution, traditional use, bioactive compounds, toxicology, and biological effects.

MATERIALS AND METHODS

Different scientific data bases such as Web of Science, Scopus, Wiley Online, SciFinder, Google Scholar, PubMed, ScienceDirect, and SpringerLink were consulted to collect data about O. majorana. The presented data emphasis bioactive compounds, traditional uses, toxicological investigations, and biological activities of O. majorana.

RESULTS

The findings of this work marked an important correlation between the traditional use of O. majorana as an anti-allergic, antihypertensive, anti-diabetic agent, and its biological effects. Indeed, pharmacological investigations showed that essential oils and extracts from O. majorana exhibit different biological properties, particularly; antibacterial, antifungal, antioxidant, antiparasitic, antidiabetic, anticancer, nephrotoxicity protective, anti-inflammatory, analgesic and anti-pyretic, hepatoprotective, and antimutagenic effects. Toxicological evaluation confirmed the safety and innocuity of this species and supported its medicinal uses. Several bioactive compounds belonging to different chemical family such as terpenoids, flavonoids, and phenolic acids were also identified in O. majorana.

CONCLUSIONS

The results suggest that the pharmacological properties of O. majorana confirm its traditional uses. Indeed, O. majorana essential oils showed remarkable antimicrobial, antioxidant, anticancer, anti-inflammatory, antimutagenic, nephroprotective, and hepatoprotective activities. However, further investigations regarding the evaluation of molecular mechanisms of identified compounds against human cancer cell lines, inflammatory process, and microbial infections are needed to validate pharmacodynamic targets. The toxicological investigation of O. Majorana confirmed its safety and therefore encouraged pharmacokinetic evaluation tests to validate its bioavailability.

Anti-rheumatic effect of quercetin and recent developments in nano formulation

Quercetin is a potential anti-rheumatoid drug. Nano formulation strategies could improve its solubility and efficacy.

A mechanistic insight of phytoestrogens used for Rheumatoid arthritis: An evidence-based review

Assessment of the potential therapeutic benefits offered by naturally occurring phytoestrogens necessitate inspection of their potency and sites of action in impeding the chronic, systemic, autoimmune, joint destructing disorder Rheumatoid arthritis (RA). Possessing structural and functional similarity with human estrogen, phytoestrogen promisingly replaces the use of hormone therapy in eradicating RA symptoms with their anti-inflammatory, anti-oxidative, anti-proliferative, anti-angiogenesis, immunomodulatory, joint protection properties abolishing the harmful side effects of synthetic drugs. Scientific evidences revealed that use of phytoestrogens from different chemical categories including flavonoids, alkaloids, stilbenoids derived from different plant species manifest beneficial effects on RA through various cellular mechanisms including suppression of pro-inflammatory cytokines in particular tumor necrosis factor (TNF-α), interleukin(IL-6) and nuclear factor kappa B (NF-κB) and destructive metalloproteinases, inhibition of oxidative stress, suppressing inflammatory signalling pathways, attenuating osteoclastogenesis ameliorating cartilage degradation and bone erosion. This review summarizes the evidences of different phytoestrogen treatment and their pharmacological mechanisms in both in vitro and in vivo studies along with discussing clinical evaluations in RA patients showing phytoestrogen as a promising agent for RA therapy. Further investigations and more clinical trials are mandatory to clarify the utility of these plant derived compounds in RA prevention and in managing oestrogen deficient diseases in patients.

Intra-Articular Delivery of Quercetin Using Thermosensitive Hydrogel Attenuate Cartilage Degradation in an Osteoarthritis Rat Model

OBJECTIVE

Quercetin (Que), a bioflavonoid, is both anti-inflammatory and antioxidative. Que has been used as an oral supplement for osteoarthritis (OA) with inconsistent findings because of its low bioavailability. We encapsulated Que in a mPEG-polypeptide thermogel to prolong its bioactivity. The efficacy of this formulation was evaluated in a posttraumatic OA rat model.

DESIGN

Methoxy-poly(ethylene glycol)-l-poly(alanine) (mPEG-PA) polymer was synthesized and characterized in terms of cytotoxicity and release kinetics in vitro. At 12 weeks old, Sprague-Dawley rats underwent anterior cruciate ligament transection (ACLT). At 24 weeks post-operation, rats received either an intra-articular (IA) injection of saline, hydrogel, or hydrogel with Que (50 or 500 μg). Gait analysis was performed at pre-ACLT, pre-treatment, and at 4, 8, and 12 weeks post-treatment. At 12 weeks post-treatment, knee joints were collected for histopathological evaluation.

RESULTS

In vitro studies showed that chondrocytes were viable after 72 hours of incubation with mPEG-PA, and the release of Que could be sustained for >28 days. Among all OA rats, the limb idleness index (LII) were significantly increased at 24 weeks post-ACLT. Rats that received hydrogel with Que (50 μg) showed the most reduction in LII at both 4 and 8 weeks post-treatment. The Osteoarthritis Research Society International score of rats received hydrogel with Que (50 μg) was significantly lower than the control group. All rats suffered from low-grade synovitis (Krenn score: 2-4).

CONCLUSION

This study suggests that a sustained delivery of Que (50 μg) could provide symptom relief and also delay the progression of OA in the knee.

Quercetin and curcumin effects in experimental pleural inflammation

Background

The inflammatory mechanisms occur with the highest prevalence in pulmonary pathology in addition to oxidative stress and activation of intracellular signaling pathways. The oxidative stress represents the imbalance between pro-oxidants and antioxidants which can lead to the activation of the oxidative mechanisms with noxious potential to the body. Therefore, finding a therapy that would counteract the injurious effects of free radicals and inflammation is highly attractive. Quercetin is the most active flavonoid, with important anti-inflammatory and antioxidant effects, while curcumin has antioxidant effects that are similar to the standard antioxidants and exerts direct anti-inflammatory activity.

Aims

The aim of this study is to evaluate the antioxidant effects of quercetin and curcumin on an experimental model, pleural inflammation induced by carrageenan.

Methods

Eight groups of adult male rats were used: Ia and Ib – control groups, IIa and IIb – with carrageenan administration, IIIa and IIIb – received curcumin and carrageenan, IVa and IVb – quercetin and carrageenan administration. Blood and lung samples were taken at 4 hours (Ia, IIa, IIIa, IVa groups) and at 24 hours (Ib, IIb, IIIb, IVb groups) after carrageenan injection.

Results

At 4 and at 24 hours, curcumin and quercetin have shown protective systemic effects, decreasing significantly the oxidative stress (malondialdehyde level) and stimulating significantly the antioxidant protection (ceruloplasmin and glutathione levels) compared to the group that received only carrageenan. In the lungs, at 4 hours, the redox misbalance was significantly reduced only in animals that were treated with quercetin, modifications that were not observed at 24 hours.

Conclusions

In serum, curcumin presented higher antioxidant effects, compared to quercetin. In lungs, quercetin administration showed superior beneficial effects, but only temporarily.

A glimpse into the efficacy of alternative therapies in the management of benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is a common disease that can cause uncomfortable lower urinary tract symptoms. The occurrence of symptomatic BPH develops after the age of 40 years and increases gradually with age to reach more than 50% at the age of 60 years and severely disturbs the quality of life of the patients. Alpha-blockers and 5‑alpha reductase inhibitors are first-line agents used for the treatment of BPH. Due to the adverse effects of these conventional therapies, many patients turn to phytotherapy and other alternative therapies. This review covers alternative therapies, i.e., phytotherapy (cernilton, eviprostat, quercetin, saw palmetto and pumpkin seed) and physical therapy (acupuncture, aquablation, pulsed electromagnetic field, prostate urethral lift, radial extracorporeal shock wave therapy, thermobalancing therapy, and transurethral needle ablation) commonly used in the management of BPH.

Drug delivery based pharmacological enhancement and current insights of quercetin with therapeutic potential against oral diseases

The heavy burden of oral diseases such as oral cancers, dental caries, periodontitis, etc. and their consequence on the patient's quality of life demonstrated an urgent demand for developing effective therapeutics. Quercetin as a natural derived flavonoid, could be utilized in the therapeutic formulation of various diseases such as diabetes, breast cancer and asthma, owing to its prominent pharmacological values. In the last decade, the applications of quercetin as a natural compound in oral treatment have attracted increasing interest due to its multifunction including antioxidant, antibacterial, anti-inflammatory and antineoplastic activities. Besides, considering the low bioavailability of quercetin, great efforts have been made in its drug delivery systems to address the problem of limited application. Therefore, this review summarized the cutting-edge researches on versatile effects and enhanced bioavailability of quercetin resulting from innovative drug delivery systems, particularly focused on its potential against oral diseases. The application of quercetin would provide novel and promising therapeutic approach for clinical treatment, promoting the development of global dental public health.