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

PH-sensitive BSA-modified resveratrol micelles targeting macrophages alleviate symptoms of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease, leading to severe inflammatory infiltration and joint damage, accompanied by a decrease in pH of joint microenvironment. Macrophages play an important role in the pathogenesis of RA, with high expression of bovine serum albumin (BSA) receptors on the surface of macrophages. Resveratrol (Res) has strong anti-inflammatory effects, but its application is limited due to its poor water solubility and low bioavailability. Therefore, we constructed pH-sensitive micelles by encapsulating Res and modifying BSA on the surface of the micelles (BSA-Res@Ms), thereby greatly improving the therapeutic effect of RA. Our research results indicated that BSA-Res@Ms had a smooth and uniform appearance, small particle size, high drug encapsulation efficiency, good stability, and pH-sensitive properties. In vitro, BSA-Res@Ms increased the uptake of Res by RAW264.7 cells, reduced the levels of pro-inflammatory cytokines and cleared excess ROS produced by activated RAW264.7 cells, and inhibited the generation of osteoclasts. In vivo, BSA-Res@Ms could target inflamed joint sites, significantly alleviate joint inflammation symptoms, inhibit activated macrophages, improve synovial hyperplasia and inflammatory cell infiltration, and protect cartilage. BSA-Res@Ms provide a very promising method for the treatment of RA, which can effectively improve the inflammatory manifestations of RA.

Therapeutic effects and molecular mechanisms of quercetin in gynecological disorders

Quercetin is a representative flavonoid that is widely present in fruits, herbs, and vegetables. It is also an important active core component in traditional Chinese medicines. As an important flavonoid, quercetin has various properties and exerts antioxidant, anti-inflammatory, and cardioprotective effects. The public interest in quercetin is increasing, and quercetin has been used to prevent or treat numerous of diseases, such as polycystic ovary syndrome (PCOS), cancer, autoimmune diseases and chronic cardiovascular diseases, in clinical experiments and animal studies due to its powerful antioxidant properties and minimal side effects. Quercetin exerts marked pharmacological effects on gynecological disorders; however, there have been no reviews about the potential health benefits of quercetin in the context of gynecological disorders, including PCOS, premature ovary failure (POF), endometriosis (EM), ovarian cancer (OC), cervical cancer (CC) and endometrial carcinoma (EC). Thus, this review aimed to summarize the biological effects of quercetin on gynecological disorders and its mechanisms.

Quercetin's antibiofilm effectiveness against drug resistant Staphylococcus aureus and its validation by in silico modeling

Staphylococcus aureus is typically treated with antibiotics, however, due to its widespread and unselective usage, resistant strains of S. aureus have increased to a great extent. Treatment failure and recurring staphylococcal infections are also brought on by biofilm development, which boosts an organism's ability to withstand antibiotics and is thought to be a virulence factor in patients. The present study investigates the antibiofilm activity of naturally available polyphenol Quercetin against drug-resistant S. aureus. Micro dilution plating and tube adhesion methods were performed to evaluate the antibiofilm activity of quercetin against S. aureus. Quercetin treatment resulted in remarkably reduction of biofilm in S. aureus cells. Further we performed a study to investigate binding efficacies of quercetin with genes icaB and icaC from ica locus involved in biofilm formation. 3D structure of icaB, icaC and quercetin were retrieved from Protein data bank and PubChem chemical compound database, respectively. All computational simulation were carried out using AutoDock Vina and AutoDockTools (ADT) v 1.5.4. In silico study demonstrated a strong complex formation, large binding constants (Kb) and low free binding energy (ΔG) between quercetin and icaB (Kb = 1.63 × 10-5, ΔG = -7.2 k cal/mol) and icaC (Kb = 1.98 × 10-6, ΔG = -8.7 kcal/mol). This in silico analysis indicates that quercetin is capable of targeting icaB and icaC proteins which are essential for biofilm formation in S. aureus. Our study highlighted the antibiofilm activity of quercetin against drug resistant pathogen S.aureus.

Levofloxacin and Ciprofloxacin Co-Crystals with Flavonoids: Solid-State Investigation for a Multitarget Strategy against Helicobacter pylori

In this paper, we address the problem of antimicrobial resistance in the case of Helicobacter pylori with a crystal engineering approach. Two antibiotics of the fluoroquinolone class, namely, levofloxacin (LEV) and ciprofloxacin (CIP), have been co-crystallized with the flavonoids quercetin (QUE), myricetin (MYR), and hesperetin (HES), resulting in the formation of four co-crystals, namely, LEV∙QUE, LEV∙MYR, LEV2∙HES, and CIP∙QUE. The co-crystals were obtained from solution, slurry, or mechanochemical mixing of the reactants. LEV∙QUE and LEV∙MYR were initially obtained as the ethanol solvates LEV∙QUE∙xEtOH and LEV∙MYR∙xEtOH, respectively, which upon thermal treatment yielded the unsolvated forms. All co-crystals were characterized by powder X-ray diffraction and thermal gravimetric analysis. The antibacterial performance of the four co-crystals LEV∙QUE, LEV∙MYR, LEV2∙HES, and CIP∙QUE in comparison with that of the physical mixtures of the separate components was tested via evaluation of the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). The results obtained indicate that the association with the co-formers, whether co-crystallized or forming a physical mixture with the active pharmaceutical ingredients (API), enhances the antimicrobial activity of the fluoroquinolones, allowing them to significantly reduce the amount of API otherwise required to display the same activity against H. pylori.

Nanoformulations of quercetin for controlled delivery: a review of preclinical anticancer studies

One of the well-studied older molecules, quercetin, is found in large quantities in many fruits and vegetables. Natural anti-oxidant quercetin has demonstrated numerous pharmacological properties in preclinical and clinical research, including anti-inflammatory and anti-cancer effects. Due to its ability to control cell signaling pathways, including NF-κB, p53, activated protein-1 (AP-1), STAT3, and epidermal growth response-1 (Egr-1), which is essential in the initiation and proliferation of cancer, it has gained a lot of fame as an anticancer molecule. Recent research suggests that using nanoformulations can help quercetin to overcome its hydrophobicity while also enhancing its stability and cellular bioavailability both in vitro and in vivo. The main aim of this review is to focus on the comprehensive insights of several nanoformulations, including liposomes, nano gels, micelles, solid lipid nanoparticles (SLN), polymer nanoparticles, gold nanoparticles, and cyclodextrin complexes, to transport quercetin for application in cancer.

Nanostructured Lipid Carriers Enriched Hydrogels for Skin Topical Administration of Quercetin and Omega-3 Fatty Acid

Chronic skin exposure to external hostile agents (e.g., UV radiation, microorganisms, and oxidizing chemicals) may increase oxidative stress, causing skin damage and aging. Because of their well-known skincare and protective benefits, quercetin (Q) and omega-3 fatty acids (ω3) have attracted the attention of the dermocosmetic and pharmaceutical sectors. However, both bioactives have inherent properties that limit their efficient skin delivery. Therefore, nanostructured lipid carriers (NLCs) and enriched PFC® hydrogels (HGs) have been developed as a dual-approach vehicle for Q and/or ω3 skin topical administration to improve bioactives' stability and skin permeation. Two NLC formulations were prepared with the same lipid composition but differing in surfactant composition (NLC1-soy lecithin and poloxamer 407; NLC2-Tween® 80 and dioctyl sodium sulfosuccinate (DOSS)), which have an impact on physicochemical properties and pharmaceutical and therapeutic performance. Despite both NLCs presenting high Q loading capacity, NLC2's physicochemical properties make them more suitable for topical skin administration and ensure longer colloidal stability. Additionally, NLC2 demonstrated a more sustained Q release, indicating higher bioactive storage while improving permeability. The occlusive effect of NLCs-enriched HGs also has a positive impact on skin permeability. Q-loaded NLC2, with or without ω3, -enriched HGs demonstrated efficacy as antioxidant and photoprotective formulations as well as effective reduction in S. aureus growth, indicating that they constitute a promising approach for topical skin administration to prevent skin aging and other damaging cutaneous processes.

Quercetin-loaded chitosan nanoparticles ameliorate adjuvant-induced arthritis in rats by regulating anti-oxidant enzymes and downregulating pro- and inflammatory cytokines

Rheumatoid arthritis (RA) is an inflammatory condition and associated with the symmetrical synovitis of the joints and cause joint pain. The use of anti-rheumatic drugs is associated with many adverse effects. Quercetin, an important polyphenolic flavonoid, possess anti-inflammatory and anti-rheumatic effects. Quercetin use is limited due to poor absorption and bioavailability. Nanomedicines are used for the targeted drug delivery, hence it reduces the adverse effects of the drug. Based upon these factors, quercetin-loaded chitosan nanoparticles (Q-NPs) were prepared by solvent evaporation method, characterized and their better anti-rheumatic effect with mechanistic insights was validated in Freund's complete adjuvant (FCA)-induced arthritic rats along with safety studies. The animals were divided into five groups, each containing 5 animals. Group I was normal control, group II was arthritic control, while groups III, IV and V were administered with quercetin (15 mg/Kg) and Q-NPs (10 and 20 mg/Kg), respectively. The reduction in ankle diameter, serum oxidative stress markers as well as pro- and inflammatory cytokines, e.g., tumor necrosis factor (TNFα), interleukin (IL-6) were determined. The prepared Q-NPs showed hydrodynamic size of 83.9 nm, polydispersity index of 0.687, entrapment efficiency 90.5% as well as no interaction between quercetin and chitosan in Fourier transform infrared spectroscopy (FTIR). A significant reduction (p < 0.001) in ankle diameter was observed after administration of high-dose Q-NPs (4.32 ± 0.14 cm to 5.13 ± 0.62 cm). There was also reduction (p < 0.001) in levels of TNFα and IL-6 following high-dose Q-NPs (72.56 ± 2.30 and 308.19 ± 11.5 pg). The effect on biochemical tests, hematological parameters and oxidative stress parameters was also found to be significant. Histopathological changes of kidney, liver and ankle also confirmed the anti-rheumatic effect of high-dose Q-NPs. The study concludes that administration of Q-NPs (20 mg/Kg) may be used for the treatment of FCA-induced RA in rats.

Gallium-modified gelatin nanoparticles loaded with quercetin promote skin wound healing via the regulation of bacterial proliferation and macrophage polarization

Background: Wound healing is a complicated process involving multiple cell components and can help the re-establishment of the skin's barrier function. Previous studies have pointed out that bacterial infection and sustained inflammatory reactions are the main causes of the delay of wound closure and scar formation during wound healing. The effect of current approaches for scar-free wound repair still faces many challenges, and alternative therapeutic methods are urgently needed to be established. Methods: The basic characteristics of the new-designed nanoparticles were clarified through the characterization of the material. The biocompatibility of the nanoparticles, as well as its effect on fibroblast function, anti-bacterial capacity, inflammation suppressive role, and the underlying mechanism were further verified by a panel of biochemical assays in vitro. Ultimately, pre-clinical rat model was employed to testify its role in wound healing and scar formation in vivo. Results: Firstly, gallium-modified gelatin nanoparticles loaded with quercetin was successfully established, displaying good biocompatibility and facilitative effect on fibroblast function. In addition, the nanoparticles showed prominent anti-bacterial and inflammation-suppressive effects. What's more important, the nanoparticles could also induce the polarization of macrophages from M1 to M2 phenotype to exert its inflammatory inhibitory role through TGF-β/Smad signaling pathway. Ultimately, in vivo experiment showed that the nanoparticles could effectively promote wound repair and inhibit scar formation during the process of wound healing. Conclusion: Taken together, the new nanoparticles have good anti-bacterial and anti-scar formation effects and great potential in the field of skin wound repair, which provides a promising therapeutic strategy for wound treatment.

An insight into anticancer, antioxidant, antimicrobial, antidiabetic and anti-inflammatory effects of quercetin: a review

Flavonoids are present naturally in many fruits and vegetables including onions, apples, tea, cabbage, cauliflower, berries and nuts which provide us with quercetin, a powerful natural antioxidant and cytotoxic compound. Due to antioxidant property, many nutraceuticals and cosmeceuticals products contain quercetin as a major ingredient nowadays. Current review enlightened sources and quercetin's role as an antioxidant, antimicrobial, antidiabetic, anticancerous and anti-inflammatory agent in medical field during last 5 to 6 years. Literature search was systematically done using scientific for the published articles of quercetin. A total of 345 articles were reviewed, and it was observed that more than 40% of articles were about quercetin's use as an antioxidant agent, more than 25% of studies were about its use as an anticancer agent, and articles on antimicrobial activity were more than 15%. 10% of the articles showed anti-inflamamatory effects of quercetin. Literature search also revealed that quercetin alone and its complexes with chitosan, metal ions and polymers possessed good antidiabetic properties. Thus, the review focuses on new therapeutic interventions and drug delivery system of quercetin in medical field for the benefit of mankind.

Flavonoid-Conjugated Gadolinium Complexes as Anti-Inflammatory Theranostic Agents

In this study, we designed, synthesized, and evaluated gadolinium compounds conjugated with flavonoids as potential theranostic agents for the treatment of inflammation. These novel theranostic agents combine a molecular imaging agent and one of three flavonoids (galangin, chrysin, and 7-hydroxyflavone) as anti-inflammatory drugs as a single integrated platform. Using these agents, MR imaging showed contrast enhancement (>10 in CNR) at inflamed sites in an animal inflammation model, and subsequent MR imaging used to monitor the therapeutic efficacy of these integrated agents revealed changes in inflamed regions. The anti-inflammatory effects of these agents were demonstrated both in vitro and in vivo. Furthermore, the antioxidant efficacy of the agents was evaluated by measuring their reactive oxygen species scavenging properties. For example, Gd-galangin at 30 μM showed a three-fold higher ROS scavenging of DPPH. Taken together, our findings provide convincing evidence to indicate that flavonoid-conjugated gadolinium compounds can be used as potentially efficient theranostic agents for the treatment of inflammation.

The bone-protective mechanisms of active components from TCM drugs in rheumatoid arthritis treatment

Rheumatoid arthritis (RA) is an autoimmune disease whose hallmarks are synovial inflammation and irreversible bone destruction. Bone resorption resulting from osteoclasts involves the whole immune and bone systems. Breakdown of bone remodeling is attributed to overactive immune cells that produce large quantities of cytokines, upregulated differentiation of osteoclasts with enhanced resorptive activities, suppressed differentiation of osteoblasts, invading fibroblasts and microbiota dysbiosis. Despite the mitigation of inflammation, the existing treatment in Western medicine fails to prevent bone loss during disease progression. Traditional Chinese medicine (TCM) has been used for thousands of years in RA treatment, showing great efficacy in bone preservation. The complex components from the decoctions and prescriptions exhibit various pharmacological activities. This review summarizes the research progress that has been made in terms of the bone-protective effect of some representative compounds from TCM drugs and proposes the substantial mechanisms involved in bone metabolism to provide some clues for future studies. These active components systemically suppress bone destruction via inhibiting joint inflammation, osteoclast differentiation, and fibroblast proliferation. Neutrophil, gut microenvironment and microRNA has been proposed as future focus.

Benefits of Applying Nanotechnologies to Hydrogels in Efficacy Tests in Osteoarthritis Models-A Systematic Review of Preclinical Studies

Osteoarthritis (OA) is a severe musculoskeletal disease with an increasing incidence in the worldwide population. Recent research has focused on the development of innovative strategies to prevent articular cartilage damage and slow down OA progression, and nanotechnologies applied to hydrogels have gained particular interest. The aim of this systematic review is to investigate the state of the art on preclinical in vitro and in vivo efficacy studies applying nanotechnologies to hydrogels in OA models to elucidate the benefits of their applications. Three databases were consulted for eligible papers. The inclusion criteria were in vitro and in vivo preclinical studies, using OA cells or OA animal models, and testing hydrogels and nanoparticles (NPs) over the last ten years. Data extraction and quality assessment were performed. Eleven papers were included. In vitro studies evidenced that NP-gels do not impact on cell viability and do not cause inflammation in OA cell phenotypes. In vivo research on rodents showed that these treatments could increase drug retention in joints, reducing inflammation and preventing articular cartilage damage. Nanotechnologies in preclinical efficacy tests are still new and require extensive studies and technical hits to determine the efficacy, safety, fate, and localization of NPs for translation into an effective therapy for OA patients.

Dose-dependent effects of oleuropein administration on regulatory T-cells in patients with rheumatoid arthritis: An in vitro approach

Introduction:

Rheumatoid arthritis (RA) is an autoimmune disease that is identified with chronic inflammation and progressive destruction of the joints. The defective activity of regulatory T cells (Tregs) plays a crucial role in RA development. Oleuropein (OLEU) is the most common polyphenolic compound in olive leaf extracts with numerous pharmacological activities. In this study, the potential effects of OLEU in shifting CD4⁺ T cells toward Tregs are evaluated in patients with RA.

Methods

32 healthy controls (HC) and 45 RA patients were included in two groups. The immunoturbidometric technique was used to measure serum levels of c-reactive protein (CRP) and rheumatoid factor (RF). Isolated CD4⁺ T cells from peripheral blood mononuclear cells (PBMCs) of HC and RA patients were cultured with appropriate concentrations of OLEU. The cytotoxicity effects of OLEU were determined using the MTT assay at 24, 48, and 72 h. The percentage of CD4⁺CD25 + FoxP3 regulatory T lymphocytes (Tregs) and the expressions of IL-10 and TGF-β were evaluated by flow cytometry and immunoassay techniques after treatment of cells with different concentrations of OLEU for 24 h. The serum levels of RF and CRP in patients with RA were 11.8 ± 5.32 IU/ml and 6.36 ± 5.82 mg/l, respectively.

Results

OLEU had a dose-dependent effect on the CD4⁺ T cells via increasing the frequency of CD4⁺CD25 + FoxP3 Tregs (p = 0.0001). Moreover, it induced the production of IL-10 (p = 0.0001) and TGF-β (p < 0.01) in both HC and RA patients.

Conclusion

The findings of this study suggest that OLEU may have immunomodulatory effects by inducing Tregs, and it might help in developing a novel nutrition strategy for management of autoimmune diseases such as RA.

Quercetin and its role in modulating endoplasmic reticulum stress: A review

The endoplasmic reticulum (ER) is the place where proteins and lipids are biosynthesized and where transmembrane proteins are folded. Both pathological and physiological situations may disturb the function of the ER, resulting in ER stress. Under stress conditions, the cells initiate a defensive procedure known as the unfolded protein response (UPR). Cases of severe stress lead to autophagy and/or the induction of cell apoptosis. Many studies implicate ER stress as a major factor contributing to many diseases. Therefore, the modulation of ER stress pathways has become an attractive therapeutic target. Quercetin is a plant-derived metabolite belonging to the flavonoids class which presents a range of beneficial effects including anti-inflammatory, cardioprotective, anti-oxidant, anti-obesity, anti-carcinogenic, anti-atherosclerotic, anti-diabetic, anti-hypercholesterolemic, and anti-apoptotic activities. Quercetin also has anti-cancer activity, and can be used as an adjuvant to decrease resistance to cancer chemotherapy. Furthermore, the effect of quercetin can be increased with the help of nanotechnology. This review discusses the role of quercetin in the modulation of ER stress (and related diseases) and provides novel evidence for the beneficial use of quercetin in therapy.

On the Development of a Cutaneous Flavonoid Delivery System: Advances and Limitations

Flavonoids are one of the vital classes of natural polyphenolic compounds abundantly found in plants. Due to their wide range of therapeutic properties, which include antioxidant, anti-inflammatory, photoprotective, and depigmentation effects, flavonoids have been demonstrated to be promising agents in the treatment of several skin disorders. However, their lipophilic nature and poor water solubility invariably lead to limited oral bioavailability. In addition, they are rapidly degraded and metabolized in the human body, hindering their potential contribution to the prevention and treatment of many disorders. Thus, to overcome these challenges, several cutaneous delivery systems have been extensively studied. Topical drug delivery besides offering an alternative administration route also ensures a sustained release of the active compound at the desired site of action. Incorporation into lipid or polymer-based nanoparticles appears to be a highly effective approach for cutaneous delivery of flavonoids with good encapsulation potential and reduced toxicity. This review focuses on currently available formulations used to administer either topically or systemically different classes of flavonoids in the skin, highlighting their potential application as therapeutic and preventive agents.