Quercetin: A flavonol with multifaceted therapeutic applications?

Recent Advances in Nanoformulations for Quercetin Delivery

Quercetin (QUE) is a flavonol that has recently received great attention from the research community due to its important pharmacological properties. However, QUE's low solubility and extended first-pass metabolism limit its oral administration. This review aims to present the potential of various nanoformulations in the development of QUE dosage forms for bioavailability enhancement. Advanced drug delivery nanosystems can be used for more efficient encapsulation, targeting, and controlled release of QUE. An overview of the primary nanosystem categories, formulation processes, and characterization techniques are described. In particular, lipid-based nanocarriers, such as liposomes, nanostructured-lipid carries, and solid-lipid nanoparticles, are widely used to improve QUE's oral absorption and targeting, increase its antioxidant activity, and ensure sustained release. Moreover, polymer-based nanocarriers exhibit unique properties for the improvement of the Absorption, Distribution, Metabolism, Excretion, and Toxicology (ADME(T)) profile. Namely, micelles and hydrogels composed of natural or synthetic polymers have been applied in QUE formulations. Furthermore, cyclodextrin, niosomes, and nanoemulsions are proposed as formulation alternatives for administration via different routes. This comprehensive review provides insight into the role of advanced drug delivery nanosystems for the formulation and delivery of QUE.

A Descriptive Review of the Action Mechanisms of Berberine, Quercetin and Silymarin on Insulin Resistance/Hyperinsulinemia and Cardiovascular Prevention

Insulin resistance (IR) and the associated hyperinsulinemia are early pathophysiological changes which, if not well treated, can lead to type 2 diabetes, endothelial dysfunction and cardiovascular disease. While diabetes care is fairly well standardized, the prevention and treatment of IR lacks a single pharmaceutical approach and many lifestyle and dietary interventions have been proposed, including a wide range of food supplements. Among the most interesting and well-known natural remedies, alkaloid berberine and the flavonol quercetin have particular relevance in the literature, while silymarin-the active principle of the Silybum marianum thistle-was traditionally used for lipid metabolism disorders and to sustain liver function. This review describes the major defects of insulin signaling leading to IR and the main properties of the three mentioned natural substances, their molecular targets and synergistic action mechanisms. The actions of berberine, quercetin and silymarin are partially superimposable as remedies against reactive oxygen intermediates generated by a high-lipid diet and by NADPH oxidase, which is triggered by phagocyte activation. Furthermore, these compounds inhibit the secretion of a battery of pro-inflammatory cytokines, modulate intestinal microbiota and are especially able to control the various disorders of the insulin receptor and post-receptor signaling systems. Although most of the evidence on the effects of berberine, quercetin and silymarin in modulating insulin resistance and preventing cardiovascular disease derive from experimental studies on animals, the amount of pre-clinical knowledge strongly suggests the need to investigate the therapeutic potential of these substances in human pathology.

Therapeutic Potential of Polyphenols and Other Micronutrients of Marine Origin

Polyphenols are compounds found in various plants and foods, known for their antioxidant and anti-inflammatory properties. Recently, researchers have been exploring the therapeutic potential of marine polyphenols and other minor nutrients that are found in algae, fish and crustaceans. These compounds have unique chemical structures and exhibit diverse biological properties, including anti-inflammatory, antioxidant, antimicrobial and antitumor action. Due to these properties, marine polyphenols are being investigated as possible therapeutic agents for the treatment of a wide variety of conditions, such as cardiovascular disease, diabetes, neurodegenerative diseases and cancer. This review focuses on the therapeutic potential of marine polyphenols and their applications in human health, and also, in marine phenolic classes, the extraction methods, purification techniques and future applications of marine phenolic compounds.

Targeting strategies for bone diseases: signaling pathways and clinical studies

Since the proposal of Paul Ehrlich's magic bullet concept over 100 years ago, tremendous advances have occurred in targeted therapy. From the initial selective antibody, antitoxin to targeted drug delivery that emerged in the past decades, more precise therapeutic efficacy is realized in specific pathological sites of clinical diseases. As a highly pyknotic mineralized tissue with lessened blood flow, bone is characterized by a complex remodeling and homeostatic regulation mechanism, which makes drug therapy for skeletal diseases more challenging than other tissues. Bone-targeted therapy has been considered a promising therapeutic approach for handling such drawbacks. With the deepening understanding of bone biology, improvements in some established bone-targeted drugs and novel therapeutic targets for drugs and deliveries have emerged on the horizon. In this review, we provide a panoramic summary of recent advances in therapeutic strategies based on bone targeting. We highlight targeting strategies based on bone structure and remodeling biology. For bone-targeted therapeutic agents, in addition to improvements of the classic denosumab, romosozumab, and PTH1R ligands, potential regulation of the remodeling process targeting other key membrane expressions, cellular crosstalk, and gene expression, of all bone cells has been exploited. For bone-targeted drug delivery, different delivery strategies targeting bone matrix, bone marrow, and specific bone cells are summarized with a comparison between different targeting ligands. Ultimately, this review will summarize recent advances in the clinical translation of bone-targeted therapies and provide a perspective on the challenges for the application of bone-targeted therapy in the clinic and future trends in this area.

New advances in the research of clinical treatment and novel anticancer agents in tumor angiogenesis

In 1971, Folkman proposed that tumors could be limited to very small sizes by blocking angiogenesis. Angiogenesis is the generation of new blood vessels from pre-existing vessels, considered to be one of the important processes in tumor growth and metastasis. Angiogenesis is a complex process regulated by various factors and involves many secreted factors and signaling pathways. Angiogenesis is important in the transport of oxygen and nutrients to the tumor during tumor development. Therefore, inhibition of angiogenesis has become an important strategy in the clinical management of many solid tumors. Combination therapies of angiogenesis inhibitors with radiotherapy and chemotherapy are often used in clinical practice. In this article, we will review common targets against angiogenesis, the most common and up-to-date anti-angiogenic drugs and clinical treatments in recent years, including active ingredients from chemical and herbal medicines.

New opportunities and advances in quercetin-added functional packaging films for sustainable packaging applications: a mini-review

Recently, research on functional packaging films and their application to food preservation has been actively conducted. This review discusses recent advances and opportunities for using quercetin in developing bio-based packaging films for active food packaging. Quercetin is a plant-based yellow pigment flavonoid with many useful biological properties. Quercetin is also a GRAS food additive approved by the US FDA. Adding quercetin to the packaging system improves the physical performance as well as the functional properties of the film. Therefore, this review focused on quercetin's effect on the various packaging film properties, such as mechanical, barrier, thermal, optical, antioxidant, antimicrobial, and so on. The properties of films containing quercetin depend on the type of polymer and the interaction between the polymer and quercetin. Films functionalized with quercetin are useful in extending shelf life and maintaining the quality of fresh foods. Quercetin-added packaging systems can be very promising for sustainable active packaging applications.

Autophagy and exosomes coordinately mediate quercetin's protective effects on alcoholic liver disease

Alcoholic liver disease (ALD), a spectrum of liver abnormalities induced by chronic alcohol abuse, continues to be the major cause of life-threatening liver disease in developed countries. Autophagy and exosomes were individually confirmed to be involved in the pathogenesis of ALD. Here, we sought to identify the role of autophagy and exosomes in the liver protective effects of quercetin. We observed decreased hepatic LC3II/LC3I and increased p62 level in ethanol-fed mice, and these changes were alleviated by quercetin. Meanwhile, nanoparticle tracking analysis (NTA) showed elevated serum exosomes numbers in ethanol-fed mice, which was combated by quercetin. Ethanol induced elevated LDH, ALT, and AST in HepG2 supernatant, which was alleviated by cytochalasin D (exosomes uptake inhibitor). Moreover, quercetin reduced ethanol-induced LDH and ALT elevation in vitro, and the effects of quercetin were reversed by Rab27a overexpression (induce exosomes release) or wortmannin treatment (autophagy inhibitor). Transcriptomic analysis supported that quercetin reversed the change of lysosome related genes disturbed by ethanol. Meanwhile, western blot analysis exhibited decreased hepatic expression of LAMP2 and ATPA6V1B2, and active Cathepsin B/Cathepsin B by quercetin treatment, indicating quercetin alleviated lysosome dysfunction in ethanol-fed mice. Baf A treatment or transfection of siTFEB offset quercetin's effects in ethanol-induced LDH and ALT elevation, exosomes release, and autophagy inhibition (LC3II/I and p62 accumulation). Taken together, quercetin coordinately activates autophagy and combats exosomes release by restoring lysosome function, and further mitigates ethanol-induced liver damage.

Anti-cervical cancer effects of Compound Yangshe granule through the PI3K/AKT pathway based on network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Compound Yangshe granule is a characteristic Chinese preparation against cervical cancer used at Fudan University Shanghai Cancer Center, and it consists of Hedyotis Diffusae Herba, Solani Lyrati Herba, Rubiae Radix et Rhizoma, Echinopsis Radix, Angelicae Sinensis Radix, Codonopsis Radix and Atractylodis Macrocephalae Rhizoma.

AIM OF THE STUDY

The objective of the current study was to investigate the preclinical efficacy of compound Yangshe granule against cervical cancer and elucidate the underlying mechanisms.

MATERIALS AND METHODS

Antitumor effect of the preparation was investigated in U14 cells in vitro and subcutaneous xenograft mice in vivo. The underlying mechanisms were investigated by through network pharmacological analysis and identified by in vitro study. The components of compound Yangshe granule were collected from the Traditional Chinese Medicine Systems Pharmacology database, and the corresponding targets were predicted by the SwissTargetPrediction database. The targets involved in cervical cancer were collected from the GeneCards, Online Mendelian Inheritance in Man and DrugBank databases. A protein‒protein interaction network was constructed by using the String platform. The drug-disease-target network was plotted by Cytoscape software. Kyoto Encyclopedia of Genes and Genomes and Gene Ontology enrichment analyses were performed to investigate hub targets.

RESULTS

After treatment with 0.5-10 mg/mL compound Yangshe granule, the survival rates of U14 cells gradually declined to 53.32% for 24 h, 23.62% for 48 h, and 12.81% for 72 h. The apoptosis rates of U14 cells gradually increased to 15.52% for 24 h, 23.87% for 48 h, and 65.01% for 72 h after treatment with 2-10 mg/mL compound Yangshe granule. After oral administration of compound Yangshe granule by xenograft mice, the tumor inhibition rates reached 52.27%, 74.62%, and 82.70% in the low, middle, and high dose groups, respectively. According to the network pharmacological analysis, quercetin, luteolin and naringenin were the most bioactive ingredients of the preparation. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that compound Yangshe granule may combat cervical cancer through the PI3K/AKT pathway.

CONCLUSION

In summary, network pharmacology combined with biological experiments demonstrated that the main bioactive components including quercetin, luteolin and naringenin could inhibit the tumor growth by regulating the PI3K/AKT pathway and Bcl-2 family. Thus, compound Yangshe granule may be a promising adjuvant therapy for cervical cancer.

Elucidating the toxicity mechanism of AFM2 and the protective role of quercetin in albino mice

Aflatoxin M2 (AFM2) is a type of mycotoxin detected in milk or dairy products from animals consuming contaminated feed. In this study, the toxicity mechanism of AFM2 and the protective effects of quercetin were investigated in albino mice. For this purpose, the mice were divided into 6 groups and the groups were fed with quercetin and AFM2. The toxic effects of AFM2 and the protective properties of quercetin were investigated using physiological, biochemical and cytogenetic parameters. The genotoxic mechanism of AFM2 and the protective role of quercetin were investigated by molecular docking, which is an in silico model. As a result, 16 mg/kg b.w AFM2 administration caused serious changes in body weight, organ index, kidney and liver weight, and deterioration of antioxidant/oxidant balance in liver and kidney organs. The decrease in glutathione levels along with an increase in malondialdehyde (MDA) levels in the liver and kidney after AFM2 administration indicates that oxidative stress is induced. The increases in alanine transaminase (ALT) and aspartat transaminase (AST) levels, which are indicators of liver damage, and the increases in serum levels of blood urea nitrogen (BUN) and creatinine, which are indicators of kidney damage, confirm the damage in both organs. AFM2 also caused genotoxicity by inducing micronucleus (MN) and chromosomal abnormalities (CAs) in bone marrow tissue. It has been determined that AFM2, which exhibits genotoxicity as a result of its clastogenic and aneugenic effects, causes CAs by interacting with DNA. Quercetin provided significant protection by improving liver and kidney tissues, partial normalization in serum parameter levels, and severe reductions in MN and CAs. The highest protection was determined as 74.1% against dicentric chromosome formations in 50 mg/kg b.w quercetin application. The interaction of quercetin with xanthine oxidase and nitric oxide synthase enzymes was determined in silico with an inhibition constant in the range of 283.71-476.17 nM. These interactions cause changes in the activity of enzymes, reducing the oxidative load in the cell, and in this way, quercetin provides protection. All toxic effects induced by AFM2 were decreased with quercetin administration dose-dependently, and this protective effect was associated with quercetin's reduction of oxidative load by inhibiting the free radical-producing enzyme. All toxic effects caused by AFM2 were decreased with quercetin administration in a dose-dependent manner, and this protective effect was associated with quercetin's reduction of oxidative load by inhibiting the enzyme that produces free radicals.

Quercetin: A Functional Food-Flavonoid Incredibly Attenuates Emerging and Re-Emerging Viral Infections through Immunomodulatory Actions

Many of the medicinally active molecules in the flavonoid class of phytochemicals are being researched for their potential antiviral activity against various DNA and RNA viruses. Quercetin is a flavonoid that can be found in a variety of foods, including fruits and vegetables. It has been reported to be effective against a variety of viruses. This review, therefore, deciphered the mechanistic of how Quercetin works against some of the deadliest viruses, such as influenza A, Hepatitis C, Dengue type 2 and Ebola virus, which cause frequent outbreaks worldwide and result in significant morbidity and mortality in humans through epidemics or pandemics. All those have an alarming impact on both human health and the global and national economies. The review extended computing the Quercetin-contained natural recourse and its modes of action in different experimental approaches leading to antiviral actions. The gap in effective treatment emphasizes the necessity of a search for new effective antiviral compounds. Quercetin shows potential antiviral activity and inhibits it by targeting viral infections at multiple stages. The suppression of viral neuraminidase, proteases and DNA/RNA polymerases and the alteration of many viral proteins as well as their immunomodulation are the main molecular mechanisms of Quercetin's antiviral activities. Nonetheless, the huge potential of Quercetin and its extensive use is inadequately approached as a therapeutic for emerging and re-emerging viral infections. Therefore, this review enumerated the food-functioned Quercetin source, the modes of action of Quercetin for antiviral effects and made insights on the mechanism-based antiviral action of Quercetin.

Heat Shock Protein Response to Stress in Poultry: A Review

Compared to other animal species, production has dramatically increased in the poultry sector. However, in intensive production systems, poultry are subjected to stress conditions that may compromise their well-being. Much like other living organisms, poultry respond to various stressors by synthesising a group of evolutionarily conserved polypeptides named heat shock proteins (HSPs) to maintain homeostasis. These proteins, as chaperones, play a pivotal role in protecting animals against stress by re-establishing normal protein conformation and, thus, cellular homeostasis. In the last few decades, many advances have been made in ascertaining the HSP response to thermal and non-thermal stressors in poultry. The present review focuses on what is currently known about the HSP response to thermal and non-thermal stressors in poultry and discusses the factors that modulate its induction and regulatory mechanisms. The development of practical strategies to alleviate the detrimental effects of environmental stresses on poultry will benefit from detailed studies that describe the mechanisms of stress resilience and enhance our understanding of the nature of heat shock signalling proteins and gene expression.

The Senolytic Drug Fisetin Attenuates Bone Degeneration in the Zmpste24 -/- Progeria Mouse Model

Aging leads to several geriatric conditions including osteoporosis (OP) and associated frailty syndrome. Treatments for these conditions are limited and none target fundamental drivers of pathology, and thus identifying strategies to delay progressive loss of tissue homeostasis and functional reserve will significantly improve quality of life in elderly individuals. A fundamental property of aging is the accumulation of senescent cells. Senescence is a cell state defined by loss of proliferative capacity, resistance to apoptosis, and the release of a proinflammatory and anti-regenerative senescence-associated secretory phenotype (SASP). The accumulation of senescent cells and SASP factors is thought to significantly contribute to systemic aging. Senolytics-compounds which selectively target and kill senescent cells-have been characterized to target and inhibit anti-apoptotic pathways that are upregulated during senescence, which can elicit apoptosis in senescent cells and relieve SASP production. Senescent cells have been linked to several age-related pathologies including bone density loss and osteoarthritis in mice. Previous studies in murine models of OP have demonstrated that targeting senescent cells pharmacologically with senolytic drugs can reduce symptomology of the disease. Here, we demonstrate the efficacy of senolytic drugs (dasatinib, quercetin, and fisetin) to improve age-associated degeneration in bone using the Zmpste24^-/- (Z24^-/-) progeria murine system for Hutchinson-Gilford progeria syndrome (HGPS). We found that the combination of dasatinib plus quercetin could not significantly mitigate trabecular bone loss although fisetin administration could reduce bone density loss in the accelerated aging Z24^-/- model. Furthermore, the overt bone density loss observed in the Z24^-/- model reported herein highlights the Z24 model as a translational model to recapitulate alterations in bone density associated with advanced age. Consistent with the "geroscience hypothesis," these data demonstrate the utility of targeting a fundamental driver of systemic aging (senescent cell accumulation) to alleviate a common condition with age, bone deterioration.

Bioactive compounds in childhood obesity and associated metabolic complications: Current evidence, controversies and perspectives

Obesity represents the most frequent chronic disease among children worldwide, with a significant global burden on society. Metabolically unhealthy obesity (MUO) can affect children since their first years of life, and novel therapeutic strategies to tackle metabolic complications are under investigation. This review focuses on bioactive compounds and their possible beneficial effects on obesity, particularly omega-3, docosahexaenoic acid, vitamin D, biotics, polysaccharide macromolecules, polyphenols, inositols, alpha lipoic acid, and bromelaine. Our aim is to summarize current evidence about bioactive compounds in the treatment of obesity, highlighting recent findings on their use in children and adolescents. Most studied molecules are omega-3 and vitamin D, despite the heterogeneity between the studies. Moreover, given the emerging interest in the gut-brain axis in the link between metabolic health and microbiota, various studies on prebiotics, probiotics, synbiotics, postbiotics and polysaccharide macromolecules have been considered. Some preclinical studies seem to highlight a possible role of the polyphenols, even if their clinical evidence is still discussed. Lastly, we describe possible effects of inositols and alpha-lipoic acid. Despite some dietary supplements seem to be promising in overweight subjects, only in a few of them a dose/response efficacy has been found in the pediatric age. Innovative, well-designed and targeted clinical trials are then needed to prove the beneficial effects of these compounds that could support the standard behavioral therapy for obesity.

Quercetin and polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a reproductive endocrine disease, and results to opsomenorrhea or amenorrhea, hairy, acne, acanthosis, infertility, abortion. In the long term, PCOS may also increase the risk of endometrial cancer, diabetes, hypertension, dyslipidemia and other diseases. Till now there is no specific drug for PCOS due to the unclearness of the cause and pathogenesis, as current treatments for PCOS only target certain symptoms. Quercetin (QUR) is a flavonoid drug widely found in Chinese herbal medicines, fruits, leaves, vegetables, seeds and plants roots. Studies on other diseases have found that QUR has anti-oxidant, anti-inflammatory, anti-insulin resistance, anti-cancer and other effects. Some studies have shown that serum testosterone (T), luteinizing hormone (LH), the LH/follicule-stimulating hormone (FSH) ratio, fasting glucose, fasting insulin, HOMA-IR and lipid levels are reduced in PCOS patients with QUR treatment. However, the mechanisms of QUR in PCOS patients have not been completely elucidated. In this review, we retrospect the basic characteristics of QUR, and in vitro studies, animal experiments and clinical trials of QUR and plant extracts containing QUR in the treatment of PCOS. We also summarized the effects and mechanism of QUR in ovarian cells in vitro and PCOS model rats, the changes in relevant parameters after QUR administration in PCOS patients, and its potentially therapeutic applications.

Quercetin inhibits the progression of endometrial HEC-1-A cells by regulating ferroptosis-a preliminary study

BACKGROUND

Endometrial carcinoma (EC) is one of the most common female reproductive system tumors, which seriously threatens women's health. This preliminary study aimed to investigate the effects of quercetin on the EC cells and explore the potential mechanism.

METHODS

In this study, the effects of quercetin on endometrial cancer HEC-1-A cells were studied by a series of cell biological methods, including CCK-8 detection of cell activity, Western blotting of ferroptosis-related proteins, apoptosis detection, reactive oxygen species (ROS) detection and other detections.

RESULTS

Our results showed that quercetin inhibited the proliferation and migration of EC cells, induced cell apoptosis, and affected the cell cycle. Furthermore, the anti-tumor effect of quercetin was related to the induction of ferroptosis in the EC cells.

CONCLUSIONS

Our study shows quercetin may exert anti-tumor effects, which may be related to the regulation of ferroptosis. Our study provides evidence for the future treatment of EC with small molecule drugs.

Particle Size Tailoring of Quercetin Nanosuspensions by Wet Media Milling Technique: A Study on Processing and Formulation Parameters

Background

A large number of new substances have insufficient biopharmaceutical properties for oral administration caused by their slow dissolution rate and poor solubility.

Objective

The purpose of our experiment was to improve the physicochemical properties of a hydrophobic drug, quercetin, by the nanomilling approach.

Methods

Quercetin nanosuspensions were prepared using a wet-milling method followed by lyophilization. Stabilizer type and ratio, drug content, milling time, and bead size were identified as critical variables, and their impacts on quercetin particle size were assessed. The optimized nanocrystal was characterized by its morphology, crystallinity, molecular interactions, saturation solubility, and dissolution properties.

Results

At optimized process conditions of milling at 500 rpm for 18 cycles of grinding with 0.3 - 0.4 mm zirconium oxide beads, minimum particle size, and PDI values were 281.21 nm and 0.22, respectively. Nanocrystals showed rod-like nanostructures, and XRD scans confirmed a decrease in drug crystallinity. The optimized formulation showed increased solubility and dissolution rate, as well as good physical stability.

Conclusions

Particle size reduction by media milling technique was an efficient method for the solubility enhancement of hydrophobic drugs.

Biochemical Characterization of Rare and Threatened Local Populations of Peas (Pisum sativum L.) Cultivated in the Arid Region of Southern Tunisia

Pea (Pisum sativum L.) is an important legume for human and animal consumption, cultivated in many temperate regions of the world. In the present investigation, the seeds of twelve pea accessions collected from the arid regions of southern Tunisia, characterized by different colors of flowers and seed coats, were evaluated for their proteins, phenolic compounds and antioxidant activities. The protein content determined by the Bradford method ranged from 46.91 to 151.08 mg/g DW. The content of total phenol, total flavonoid and condensed tannin, ranging from 36.85 to 102.52 mg GAE/100 g DW, 6.95 to 48.11 mg QE/100 g DW, and 12.37 to 70.43 mg CE/100 g DW, respectively. These parameters were characterized respectively by the following three methods, the Folin-Ciocalteu reagent, the aluminum chloride and the vanillin assay. The LC-ESI/MS analysis identified the presence of 8 phenolic acids and 9 flavonoids which quinic acid, protocatechuic acid, hyperoside, and quercetin-3-O-rhamnosidewere detected as the most abundant compounds. Moreover, the antioxidant activity of pea seeds was evaluated by the ABTS+and DPPH tests. Indeed, DPPH and ABTS anti-free radical activity values ranged from 1.92 to 14.11 μmoL TEAC/g DW and 2.3 to 14.95 μmoL TEAC/g DW, respectively. The variability across the assessed traits revealed significant differences as computed by ANOVA tests. Else, the results showed significant correlations between seed coat color, seed shape, flower color and phenolic compounds. Therefore, genotypes characterized by a purple flower, brown seed coat, and wrinkled form had the highest levels of phenolic compounds and antioxidant activity. Correlation analysis revealed that phenolic compounds presented a strong positive correlation with antioxidant activities, while being negatively correlated with protein content. UPGMA cluster and Principal component analysis (PCA) revealed two main groups. This work highlights the nutritional value of P. sativum seeds as a good source of natural antioxidant compounds that may be useful in the food and pharmaceutical industries.

Dual role of quercetin in enhancing the efficacy of cisplatin in chemotherapy and protection against its side effects: a review

Chemotherapy has opened a new window in cancer therapy. However, the resistance of cancer cells has dramatically reduced the efficacy of chemotherapy. Cisplatin is a chemotherapeutic agent and its potential in cancer therapy has been restricted by resistance of cancer cells. As a consequence, the scientists have attempted to find new strategies in elevating chemotherapy efficacy. Due to great anti-tumour activity, naturally occurring compounds are of interest in polychemotherapy. Quercetin is a flavonoid with high anti-tumour activity against different cancers that can be used with cisplatin to enhance its efficacy and also are seen to sensitise cancer cells into chemotherapy. Furthermore, cisplatin has side effects such as nephrotoxicity and ototoxicity. Administration of quercetin is advantageous in reducing the adverse effects of cisplatin without compromising its anti-tumour activity. In this review, we investigate the dual role of quercetin in enhancing anti-tumour activity of cisplatin and simultaneous reduction in its adverse effects.

Quercetin as a cancer chemopreventive or chemotherapeutic agent: Where we stand

Quercetin has a wide range of potential health benefits, working as a direct or indirect agent or an adjuvant following different principles. It may be used as a generally useful or exclusive supplement, but also specifically used to treat an acute or chronic condition. Quercetin may work as a cancer chemopreventive and chemotherapeutic agent, because this versatile substance, which owns antioxidant and anti-inflammatory properties, may also kill cancer cells and also holds senolytic properties. While both the specific chemo-preventive or chemotherapeutic uses as a drug need clinical trials, it may be used without any contraindication as a general chemo-preventive supplement.

Role of potential bioactive metabolites from traditional Chinese medicine for type 2 diabetes mellitus: An overview

Type 2 diabetes mellitus (T2DM) is a metabolic disease with persistent hyperglycemia primarily caused by insulin resistance (IR). The number of diabetic patients globally has been rising over the past decades. Although significant progress has been made in treating diabetes mellitus (DM), existing clinical drugs for diabetes can no longer fully meet patients when they face complex and huge clinical treatment needs. As a traditional and effective medical system, traditional Chinese medicine (TCM) has a unique understanding of diabetes treatment and has developed many classic and practical prescriptions targeting DM. With modern medicine and pharmacy advancements, researchers have discovered that various bioactive metabolites isolated from TCM show therapeutic on DM. Compared with existing clinical drugs, these bioactive metabolites demonstrate promising prospects for treating DM due to their excellent biocompatibility and fewer adverse reactions. Accordingly, these valuable metabolites have attracted the interest of researchers worldwide. Despite the abundance of research works and specialized-topic reviews published over the past years, there is a lack of updated and systematic reviews concerning this fast-growing field. Therefore, in this review, we summarized the bioactive metabolites derived from TCM with the potential treatment of T2DM by searching several authoritative databases such as PubMed, Web of Science, Wiley Online Library, and Springer Link. For the convenience of readers, the content is divided into four parts according to the structural characteristics of these valuable compounds (flavonoids, terpenoids, alkaloids, and others). Meanwhile, the detailed mechanism and future directions of these promising compounds curing DM are also summarized in the related sections. We hope this review inspires increasingly valuable and significant research focusing on potential bioactive metabolites from TCM to treat DM in the future.

Quercetin Attenuates Nitroglycerin-Induced Migraine Headaches by Inhibiting Oxidative Stress and Inflammatory Mediators

This study aimed to investigate the antimigraine potential of quercetin in migraine pain induced by nitroglycerin (NTG), 10 mg/kg, intraperitoneal injection in rats. Quercetin was administered orally for 1 week, and behavioral parameters associated with pain were assessed 30 min after NTG injection. At the end of the study, the rats were killed so that immunohistochemical examination of their brains could be performed. The time and frequency of rearing and sniffing in the category of exploratory behavior, walking in the category of locomotor behavior, and total time spent in the light chamber were reduced in the disease control group compared with the normal group during the assessment of behavioral parameters. Pathologic migraine criteria, such as increased levels of calcitonin gene-related peptide and increased release of c-fos cells, were more prominent in the caudal nucleus triceminalis of the NTG control group. In the treatment groups, behavioral and pathological measures were less severe after pretreatment with quercetin at doses of 250 and 500 mg/kg. Therefore, it was concluded that quercetin improved the pain behavior of migraine patients in the NTG-induced migraine rat model. Quercetin is thought to have antimigraine effects due to its antioxidant and anti-inflammatory potential. Quercetin may therefore be a novel agent that can treat or prevent migraine pain and associated avoidance behaviors.

Phytochemicals in the Prevention and Treatment of SARS-CoV-2-Clinical Evidence

The first case of SARS-CoV-2 infection was reported in December 2019. Due to the rapid spread of the disease and the lack of adequate therapy, the use of plants that have a long history in the treatment of viral infections has often been considered. The aim of this paper is to provide a brief review of the literature on the use of phytochemicals during the new pandemic. An extensive search of published works was performed through platforms Google Scholar, PubMed, Science Direct, Web of Science and Clinicaltrials.gov. Numerous preclinical studies on the use of phytochemicals (quercetin, curcumin, baicalin, kaempferol, resveratrol, glycyrrhizin, lycorine, colchicine) against SARS-CoV-2 have shown that these components can be effective in the prevention and treatment of this infection. Clinical research has proven that the use of black cumin and green propolis as well as quercetin has positive effects. As for other phytochemicals, in addition to preclinical testing which has already been carried out, it would be necessary to conduct clinical tests in order to assert their effectiveness. For those phytochemicals whose clinical efficacy has been proven, it would be necessary to conduct research on a larger number of patients, so that the conclusions are more representative.

Investigation on Characterization of Novel Anti-bacterial Chitosan/Gelatin Composite Membranes Loaded with Quercetin via Electrophoretic Deposition

Peri-implantitis is characterized by inflammation resulting from bacterial infections in peri-implant connective tissue. The purpose of this study was to prepare and characterize chitosan/gelatin (CSG)-based membranes with antibacterial agents to functionalize the surface of titanium (Ti) implants. CSG membranes were prepared on Ti substrates via electrophoretic deposition (EPD). Quercetin, an active flavonoid responsible for fulfilling various plant functions, was introduced as an antibacterial agent to be loaded into the membrane during preparation. The fabrication of quercetin-loaded CSG membranes via EPD was also investigated. Fluorescent microscope, Attenuated Total Reflection Fourier transform infrared spectroscopy, and X-ray diffraction results verified the entrapment of quercetin. The membranes swelled by 150% of mass after rehydration. The antibacterial effects of quercetin on Gram-positive bacteria, such as Staphylococcus aureus and methicillin-resistant Staphylococcus aureus, were verified by spread-plate, scanning electron microscopy, and live/dead staining. Cytological experiments showed that the biocompatibility of rat bone marrow mesenchymal stromal cells was promoted by quercetin-loaded membranes, exclusively in the group with the highest content of quercetin. The quercetin-loaded groups also enhanced the antineoplastic activity of MG-63 cells. These results suggested that quercetin-loaded CSG membranes were successfully fabricated via EPD. Thus, biocompatible and antibacterial membranes could be a potential strategy to functionalize Ti implants.

Effect of Telmisartan and Quercetin in 5 Fluorouracil-Induced Renal Toxicity in Rats

Purpose

The present study was designed to evaluate the possible synergistic effects of telmisartan and quercetin in 5 fluorouracil (5-FU) induced nephrotoxicity in rats.

Methodology

Forty male rats were randomly divided into five groups: The negative control group, the positive control group that received 5-FU, the telmisartan group, receiving 10 mg/kg, the quercetin group, receiving 80 mg/kg, and the combination of telmisartan and quercetin group. All the treatments were given orally for 14 days. A single intraperitoneal injection of 5-FU (150 mg/kg) on day 13 of the experiment was given except for the negative control group. On the 15th day after scarification, approximately 5 mL of blood was collected and used for measurement of CBC, urea, creatinine, and uric acid. The kidneys were used for histopathological examination and for the measurement of kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), Cystatin C (Cys-C), and total antioxidant capacity (TAOC).

Results

The combination therapy significantly attenuated the levels of tissue KIM-1, NGAL, Cys-C, and serum uric acid as well as blood inflammatory markers, Neutrophil/Lymphocyte (NLR), Monocyte/Lymphocyte (MLR), and Platelets/Lymphocyte ratios (PLR), and restored the TAOC. The histopathological findings greatly support the biochemical tests.

Conclusion

The results strongly suggest the renoprotective effects of telmisartan and quercetin in combination against the nephrotoxic effect of 5-FU through decreasing the levels of KIM-1, NGAL, and cys-C, and the novel inflammatory markers of kidney injury like NLP, MLR, and PLR, as well as decreasing uric acid and restoring the TAOC. The proposed mechanism could be the additive inhibitory effect on RAS provided by both telmisartan and quercetin.

Quercetin ameliorated insulin resistance via regulating METTL3-mediated N6-methyladenosine modification of PRKD2 mRNA in skeletal muscle and C2C12 myocyte cell line

BACKGROUND AND AIMS

N6-Methyladenosine (m6A) modification is involved in many pathological processes, including insulin resistance (IR). Quercetin (Que), a bioactive compound with strong antioxidant activity, has potential therapeutic effects on IR-related metabolic diseases. The aim of this study is to investigate the roles of m6A and Que in hyperinsulinemia.

METHODS AND RESULTS

Male C57Bl/6 mice received a high-fat diet (HFD) for 8 weeks to establish an IR model. Que treatment reduced the body weight, blood glucose, plasma triglycerides (TG) and serum insulin, ameliorated IR, and decreased oxidative stress in HFD-fed mice. Cellular IR model was established in C2C12 cells by palmitic acid (PA) stimulation, and a noncytotoxic dose of Que was found to promote glucose uptake and inhibit oxidative stress. Moreover, methyltransferase-like 3 (METTL3) and serine-threonine kinase protein kinase D2 (PRKD2) was downregulated in skeletal muscle of HFD-fed mouse and in PA-induced C2C12 cells. The online bioinformatic tool SRAMP revealed that there were multiple m6A modification sites in the PRKD2 mRNA sequence. Downregulation of METTL3 enhanced PRKD2 expression by reducing m6A level and promoting mRNA stability in PRKD2 mRNA transcript. Que decreased m6A, METTL3, and phosphorylated insulin receptor substrate 1 (p-IRS1) levels, increased the protein expression of PRKD2, glucose transporter type 4 (GLUT4) and p-AKT, promoted glucose uptake, and reduced oxidative stress in PA-induced C2C12 cells. Moreover, METTL3 overexpression or PRKD2 silence reversed the inhibitory effects of Que on the levels of MDA and p-IRS1 and the promotive effects on glucose uptake, superoxide dismutase (SOD), GSH and GLUT4 and p-AKT levels.

CONCLUSION

Que promoted glucose uptake, repressed oxidative stress and improved IR through METTL3-mediated m6A of PRKD2 mRNA.

Protective role of Codiaeum variegatum against genotoxicity induced by carmustine in somatic and germ cells of male mice

BACKGROUND

Carmustine (Cr) is an important chemotherapeutic drug, widely used in the treatment of brain tumors. Herein, the protective role of Codiaeum variegatum leaves ethyl acetate fraction was determined against genotoxicity of Cr. The technique HPLC-qTOF-MS/MS was used to identify the constituents in C. variegatum.

MATERIALS

90 male mice were used to evaluate micronuclei (MPCEs) in bone marrow, chromosomal aberration (CAs) in bone marrow and mouse spermatocytes, sperm abnormalities, and gene expression (qRT-PCR). The following groups were included, I: Negative control (ethanol 30%), II: Positive control (i.p injected once with 30 mg/kg Cr), III: Control orally treated with C. variegatum at 500 mg/kg, four days. IV-VI: treated with 100, 300, and 500 mg/kg of the plant (4 days) plus a single dose of Cr.

RESULTS

In bone marrow, Cr induced significant increase in MPCEs and CAs by 3 and 7-folds respectively over the control. Cr also induced a significant percentage of CAs in spermatocytes in meiosis in the form of univalent (X-Y and autosomal univalent) and also a significant percentage of morphological sperm abnormalities was recorded. A large number of coiled tail abnormalities were detected indicating the effect of Cr in sperm motility. Cr induced an overexpression of p53 gene. C. variegatum mitigated all deleterious genotoxic effects of Cr. Chemical analysis showed that flavones (35.21%) and phenolic acids (17.62%) constitute the main components.

CONCLUSIONS

The results indicated that Cr is genotoxic in both somatic and germ cells. The active components in C. variegatum together participate in the obtained protective role.

Quercetin alleviates kainic acid-induced seizure by inhibiting the Nrf2-mediated ferroptosis pathway

BACKGROUND

Epilepsy is one of the most common neurological disorders in childhood. However, classical antiepileptic drugs are linked with drug toxicity and cognitive function impairment in children. Hence, it is essential to develop a novel therapy to solve this problem. Currently, studies indicate regulating the nuclear factor-erythroid 2-related factor 2 (Nrf2)-mediated ferroptosis pathway represents a potential advanced therapy for seizures. Hence, the present study aimed to explore whether quercetin, a natural polyphenol, could alleviate seizure-induced neuron death and preserve cognitive function by inhibiting Nrf2-mediated ferroptosis.

METHODS

Kainic acid-induced epileptic mice model, morris water maze (MWM) test, cell counting kit-8 (CCK-8) assays, western blotting analysis, enzyme-linked immunosorbent assay, flow cytometry, quantitative real-time reverse transcription PCR (qRT-PCR), immunofluorescence staining, and RNA sequencing analysis were employed to explore the potential mechanisms by which quercetin exerts protective effects on seizure-induced neuron death in kainic acid-induced epileptic mice model and glutamate-induced HT22 neuronal cell death.

RESULTS

Our findings suggested the association between the Nrf2-mediated ferroptosis pathway and seizures in a clinical setting. Quercetin pretreatment alleviates seizure-like behaviors and cognitive impairment in KA-induced epileptic mice. Additionally, in vitro, co-treatment with quercetin effectively exerts neuroprotective effects in glutamate-induced HT22 neuronal cell death. These protective effects were also closely linked to regulating the Nrf2-mediated ferroptosis pathway. Furthermore, bioinformatic profiling revealed that the SIRT1/Nrf2/SLC7A11/GPX4 pathway plays a crucial role in the Glu-induced HT22 cell death pretreated with quercetin.

CONCLUSIONS

These findings indicated that quercetin effectively protects against seizure-induced neuron death in vivo and in vitro and alleviates cognitive function impairment via the SIRT1/Nrf2/SLC7A11/GPX4 pathway.

Participation of the Serotonergic System and Brain-Derived Neurotrophic Factor in the Antidepressant-like Effect of Flavonoids

Depressive disorders are among the most disabling diseases experienced around the world, and their incidence has significantly increased over the last few decades due to multiple environmental, social, and biological factors. The search for new pharmacological alternatives to treat depression is a global priority. In preclinical research, molecules obtained from plants, such as flavonoids, have shown promising antidepressant-like properties through several mechanisms of action that have not been fully elucidated, including crossing of the blood brain barrier (BBB). This review will focus on discussing the main findings related to the participation of the serotonergic system and brain-derived neurotrophic factor (BDNF) on the antidepressant-like effect of some flavonoids reported by behavioral, neurochemical, and molecular studies. In this sense, evidence shows that depressive individuals have low levels of serotonin and BDNF, while flavonoids can reverse it. Finally, the elucidation of the mechanism used by flavonoids to modulate serotonin and BDNF will contribute to our understanding of the neurobiological bases underlying the antidepressant-like effects produced by these natural compounds.

Preparation of Fluorescently Labeled Chitosan-Quercetin Drug-Loaded Nanoparticles with Excellent Antibacterial Properties

In recent years, quercetin plays an increasingly important role in the medical field. However, the absorption and effect of quercetin as a drug in vivo are limited due to its extremely poor solubility in water. In addition, chitosan nanoparticles can deliver poorly soluble drugs as drug delivery carriers. Herein, chitosan nanoparticles were prepared by oxidative degradation and ionic cross-linking technology to study the drug loading properties of quercetin. On the other hand, the application of chitosan for fluorescent materials can improve the biocompatibility of fluorescent materials and increase the adsorption of fluorescent materials. Fluorescently labeled chitosan nanoparticles, especially chitosan microsphere fluorescent probes prepared using the abundant amino groups on chitosan chains to react with fluorescein isothiocyanate (FTIC), have been widely used as fluorescent probes in biomarkers and medical diagnostics. Therefore, chitosan–quercetin (CS–QT) drug-loaded nanoparticles are labeled with FITC, and the drug-loaded rate, encapsulation efficiency, and antioxidant properties were investigated. The drug-loaded rate of the sample reaches 8.39%, the encapsulation rate reaches 83.65%, and exhibits good antioxidant capacity. The fluorescence aperture of the obtained sample was consistent with the inhibition zone, which could realize the visualization of the antibacterial performance of the sample. The fluorescent-labeled nano-system exhibit superior antibacterial properties, which provide a strategy for observing the release and function of drugs.

Recent insights into oxidative metabolism of quercetin: catabolic profiles, degradation pathways, catalyzing metalloenzymes and molecular mechanisms

Quercetin is the most abundant polyphenolic flavonoid (flavonol subclass) in vegetal foods and medicinal plants. This dietary chemopreventive agent has drawn significant interest for its multiple beneficial health effects ("polypharmacology") largely associated with the well-documented antioxidant properties. However, controversies exist in the literature due to its dual anti-/pro-oxidant character, poor stability/bioavailability but multifaceted bioactivities, leaving much confusion as to its exact roles in vivo. Increasing evidence indicates that a prior oxidation of quercetin to generate an array of chemical diverse products with redox-active/electrophilic moieties is emerging as a new linkage to its versatile actions. The present review aims to provide a comprehensive overview of the oxidative conversion of quercetin by systematically analyzing the current quercetin-related knowledge, with a particular focus on the complete spectrum of metabolite products, the enzymes involved in the catabolism and the underlying molecular mechanisms. Herein we review and compare the oxidation pathways, protein structures and catalytic patterns of the related metalloenzymes (phenol oxidases, heme enzymes and specially quercetinases), aiming for a deeper mechanistic understanding of the unusual biotransformation behaviors of quercetin and its seemingly controversial biological functions.

Flavonoids regulate tumor-associated macrophages - From structure-activity relationship to clinical potential (Review)

In recent years, the strategy for tumor therapy has changed from focusing on the direct killing effect of different types of therapeutic agents on cancer cells to the new mainstream of multi-mode and -pathway combined interventions in the microenvironment of the developing tumor. Flavonoids, with unique tricyclic structures, have diverse and extensive immunomodulatory and anti-cancer activities in the tumor microenvironment (TME). Tumor-associated macrophages (TAMs) are the most abundant immunosuppressive cells in the TME. The regulation of macrophages to fight cancer is a promising immunotherapeutic strategy. This study covers the most comprehensive cognition of flavonoids in regulating TAMs so far. Far more than a simple list of studies, we try to dig out evidence of crosstalk at the molecular level between flavonoids and TAMs from literature, in order to discuss the most relevant chemical structure and its possible relationship with the multimodal pharmacological activity, as well as systematically build a structure-activity relationship between flavonoids and TAMs. Additionally, we point out the advantages of the macro-control of flavonoids in the TME and discuss the potential clinical implications as well as areas for future research of flavonoids in regulating TAMs. These results will provide hopeful directions for the research of antitumor drugs, while providing new ideas for the pharmaceutical industry to develop more effective forms of flavonoids.

Quercetin positively affects gene expression profiles and metabolic pathway of antibiotic-treated mouse gut microbiota

Quercetin has a wide range of biological properties that can be used to prevent or decrease particular inflammatory diseases. In this study, we aimed to investigate the gene expression profile and metabolic pathway of the gut microbiota of an antibiotic-treated mouse model administered quercetin. Blood, feces, and intestinal tissue samples were collected and metagenomic sequencing, enzyme-linked immunosorbent assay, and western blot analysis were used to detect variations. The results showed that the quercetin-treated group exhibited increased levels of health beneficial bacterial species, including Faecalibaculum rodentium (103.13%), Enterorhabdus caecimuris (4.13%), Eggerthella lenta (4%), Roseburia hominis (1.33%), and Enterorhabdus mucosicola (1.79%), compared with the model group. These bacterial species were positively related to butyrate, propionate, and intestinal tight junction proteins (zonula occludens-1 and occludin) expression, but negatively related to serum lipopolysaccharide and tumor necrosis factor-α level. In addition, the metabolic pathway analysis showed that dietary quercetin significantly enhanced spliceosomes (111.11%), tight junctions (62.96%), the citrate cycle (10.41%), pyruvate metabolism (6.95%), and lysine biosynthesis (5.06%), but decreasing fatty acid biosynthesis (23.91%) and N-glycan (7.37%) biosynthesis. Furthermore, these metabolic pathway changes were related to relative changes in the abundance of 10 Kyoto Encyclopedia of Genes and Genomes genes (K00244, K00341, K02946, K03737, K01885, k10352, k11717, k10532, K02078, K01191). In conclusion, dietary quercetin increased butyrate-producing bacterial species, and the acetyl-CoA-mediated increased butyrate accelerated carbohydrate, energy metabolism, reduced cell motility and endotoxemia, and increased the gut barrier function, thereby leading to healthy colonic conditions for the host.

Quercetin ameliorates XIAP deficiency-associated hyperinflammation

XIAP (X-linked inhibitor of apoptosis) deficiency is a rare inborn error of immunity. XIAP deficiency causes hyperinflammatory disease manifestations due to dysregulated TNF (tumor necrosis factor)-receptor signaling and NLRP3 (NOD- [nucleotide-binding oligomerization domain], LRR- [leucine-rich repeat] and pyrin domain-containing protein 3) inflammasome function. Safe and effective long-term treatments are needed and are especially important to help prevent the need for high-risk allogeneic hematopoietic cell transplantation. Here we evaluated inflammasome inhibitors as potential therapeutics with a focus on the natural flavonoid antioxidant quercetin. Bone marrow (BM)-derived macrophages were derived from XIAP-deficient or wild-type (WT) mice. Human monocytes were obtained from control or XIAP-deficient patients. Cells were stimulated with TLR (Toll-like receptor) agonists or TNF-α ± inhibitors or quercetin. For in vivo lipopolysaccharide (LPS) challenge experiments, XIAP-deficient or WT mice were fed mouse chow ± supplemental quercetin (50 mg/kg per day exposure) for 7 days followed by a challenge with 10 ng/kg LPS. IL-1β (interleukin-1β) and IL-18 were measured by ELISA (enzyme-linked immunosorbent assay). In murine studies, quercetin prevented IL-1β secretion from XIAP knockout cells following TLR agonists or TNF-α stimulation (P < .05) and strongly reduced constitutive production of IL-18 by both WT and XIAP-deficient cells (P < .05). At 4 hours after in vivo LPS challenge, blood levels of IL-1β and IL-18 were significantly decreased in mice that had received quercetin-supplemented chow (P < .05). In experiments using human cells, quercetin greatly reduced IL-1β secretion by monocytes following TNF-α stimulation (P < .05). Our data suggest that quercetin may be an effective natural therapeutic for the prevention of XIAP deficiency-associated hyperinflammation. Clinical trials, including careful pharmacokinetic and pharmacodynamic studies to ensure that effective levels of quercetin can be obtained, are warranted.

Development of flavonoid probes and the binding mode of the target protein and quercetin derivatives

This study investigated the mechanism underlying anti-cancer cell migration activity of quercetin derivatives by investigating the binding mode of the target protein. Five flavonoid probes were newly synthesized, and pull down assay using synthesized flavonoid probes indicated matrix metalloproteinase-1 (MMP-1) as the target protein of quercetin derivatives. Quercetin and 3-O-methylquercetin (3MQ) inhibited MMP-1. SPR analysis demonstrated dose dependent interaction between quercetin derivatives and recombinant MMP-1 catalytic domain. And ¹H-¹⁵N heteronuclear single quantum coherence (HSQC) NMR analysis using ¹⁵N-labeled MMP-1 catalytic domain indicated that 3MQ interacted around metal ions in the MMP-1. The development of flavonoid probes can broaden the possibility to discover the new target proteins and elucidate the core mechanisms of the multi bioactivity of flavonoids.

Nrf2-mediated anti-inflammatory polarization of macrophages as therapeutic targets for osteoarthritis

Macrophages are the most abundant immune cells within the synovial joints, and also the main innate immune effector cells triggering the initial inflammatory responses in the pathological process of osteoarthritis (OA). The transition of synovial macrophages between pro-inflammatory and anti-inflammatory phenotypes can play a key role in building the intra-articular microenvironment. The pro-inflammatory cascade induced by TNF-α, IL-1β, and IL-6 is closely related to M1 macrophages, resulting in the production of pro-chondrolytic mediators. However, IL-10, IL1RA, CCL-18, IGF, and TGF are closely related to M2 macrophages, leading to the protection of cartilage and the promoted regeneration. The inhibition of NF-κB signaling pathway is central in OA treatment via controlling inflammatory responses in macrophages, while the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway appears not to attract widespread attention in the field. Nrf2 is a transcription factor encoding a large number of antioxidant enzymes. The activation of Nrf2 can have antioxidant and anti-inflammatory effects, which can also have complex crosstalk with NF-κB signaling pathway. The activation of Nrf2 can inhibit the M1 polarization and promote the M2 polarization through potential signaling transductions including TGF-β/SMAD, TLR/NF-κB, and JAK/STAT signaling pathways, with the regulation or cooperation of Notch, NLRP3, PI3K/Akt, and MAPK signaling. And the expression of heme oxygenase-1 (HO-1) and the negative regulation of Nrf2 for NF-κB can be the main mechanisms for promotion. Furthermore, the candidates of OA treatment by activating Nrf2 to promote M2 phenotype macrophages in OA are also reviewed in this work, such as itaconate and fumarate derivatives, curcumin, quercetin, melatonin, mesenchymal stem cells, and low-intensity pulsed ultrasound.

Fabrication of multifunctional alginate microspheres containing hydroxyapatite powder for simultaneous cell and drug delivery

Novel alginate-hydroxyapatite hybrid microspheres were developed for simultaneous delivery of drugs and cells as a multifunctional bone substitute for osteoporotic bone tissue regeneration. The microspheres were used to enhance osteogenesis and to carry and deliver quercetin, a representative phytoestrogen that controls bone tissue regeneration metabolism in osteoporosis patients, through sustained release over a long period. To overcome quercetin’s hydrophobicity and low solubility in aqueous environments, we added it to the surface of hydroxyapatite (HAp) nanoparticles before mixing them with an alginate solution. The homogeneous distribution of the HAp nanoparticles in the alginate solution was essential for preventing nozzle clogging and achieving successfully fabricated hybrid microspheres. To this end, a 3D ultrasonic treatment was applied. Electrostatic microencapsulation was then used to fabricate hybrid alginate-HAp microspheres containing quercetin and cells. The microspheres were approximately 290.7 ± 42.5 μm (aspect ratio of 1). The sustained release of quercetin was confirmed during a test period of 20 weeks. The cells in the hybrid microspheres maintained good cell viability during the entire testing period, and their osteogenic differentiation behavior was boosted by the presence of HAp. Thus, osteogenic differentiation could be greatly improved by adding quercetin. These novel multi-biofunctional hybrid microspheres have great potential for the regeneration of osteoporotic bone tissue at indeterminate defect sites.

Therapeutic Potential of Quercetin in the Management of Type-2 Diabetes Mellitus

Diabetes Mellitus (DM) is a metabolic disorder that is spreading alarmingly around the globe. Type-2 DM (T2DM) is characterized by low-grade inflammation and insulin resistance and is closely linked to obesity. T2DM is mainly controlled by lifestyle/dietary changes and oral antidiabetic drugs but requires insulin in severe cases. Many of the drugs that are currently used to treat DM are costly and present adverse side effects. Several cellular, animal, and clinical studies have provided compelling evidence that flavonoids have therapeutic potential in the management of diabetes and its complications. Quercetin is a flavonoid, present in various natural sources, which has demonstrated in vitro and in vivo antidiabetic properties. It improves oral glucose tolerance, as well as pancreatic β-cell function to secrete insulin. It inhibits the α-glucosidase and DPP-IV enzymes, which prolong the half-life of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). Quercetin also suppresses the release of pro-inflammatory markers such as IL-1β, IL-4, IL-6, and TNF-α. Further studies are warranted to elucidate the mode(s) of action of quercetin at the molecular level. This review demonstrates the therapeutic potential of quercetin in the management of T2DM.

Molecular mechanisms of Biyu decoction as treatment for psoriasis: A network pharmacology and molecular docking study

BACKGROUND

The therapeutic effects of a combination of Chinese medicines called Biyu decoction have been clinically verified, although its molecular targets in psoriasis remain unknown.

AIM

To explore the molecular mechanisms of Biyu decoction for psoriasis treatment.

METHODS

In this network pharmacology and molecular docking study, the Traditional Chinese Medicine Systems Pharmacology database was searched for Biyu decoction active ingredients. GeneCards, Online Mendelian Inheritance in Man, PharmGkb, Therapeutic Target Database, and DrugBank databases were searched for psoriasis-related genes. The genes targeted by the decoction’s active ingredient and disease genes were intersected to obtain predictive targets of the drug during psoriasis treatment. Cytoscape 3.8.0 was used to construct a drug component/ target disease network. The The functional protein association networks database and Cytoscape were used to construct a protein-protein interaction network and streamline the core network. The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes were used for pathway enrichment analysis. Molecular docking technology was used to verify the drug component/target disease network.

RESULTS

We screened 117 major active ingredients, including quercetin, kaempferol, naringenin, and acetyl-shikonin, and identified 213 gene targets, such as MAPK3, JUN, FOS, MYC, MAPK8, STAT3, and NFKBIA. Using a molecular docking analysis, the main active ingredients demonstrated good binding to the core targets. The Gene Ontology analysis showed that these ingredients were significantly associated with biological activities, such as transcription factor DNA binding, RNA polymerase II-specific DNA binding of transcription factors, and cytokine receptor binding; responses to lipopolysaccharides, molecules of bacterial origin, and oxidative stress; and were mainly distributed in membrane rafts, microdomains, and regions. The Kyoto Encyclopedia of Genes and Genomes analysis showed that decoction ingredients act on Th17 cell differentiation, tumor necrosis factor and mitogen-activated protein signaling pathways, the interleukin-17 signaling pathway, and the PI3K-Akt signaling pathway.

CONCLUSION

Biyu decoction may be effective against psoriasis through multi-component, multi-target, and multi-channel synergy.

Profile of free and conjugated quercetin content in different Italian wines

Quercetin and its structural derivatives are natural compounds belonging to the flavonoid class, widely distributed in plants. Beneficial physiological activities have been attributed to them, but some require deeper investigation. In this paper the content of quercetin and five analogues (quercetin-3-glucoside, quercetin-3-rutinoside, quercetin-3-ramnoside, quercetin-3-arabinoglucoside, 4'-O-methylquercetin) were determined by HPLC-ESI-MS/MS in wines made of different varieties of red and white vines. The aim was a comparative study focusing on quercetin and on the contribution of related compounds in twenty wines coming from different part of Italy. Wines produced from Sangiovese and Nero d'Avola, monovarietal grapes, were richest in quercetin compounds and our results were compared to our previous study and to other investigations. The proposed method resulted simple, fast, economical, and suitable for the analysis of quercetin analogues without the need of hydrolysis and falls in the optic of a 360° characterization of active wine compounds, with nutraceutical properties.

Pharmacological action of quercetin against testicular dysfunction: A mini review

The testis is an immune-privileged organ susceptible to oxidative stress and inflammation, two major factors implicated in male infertility. A reduction in the concentration and activities of testicular function biomarkers has been shown to correlate with impaired hypothalamic-pituitary-testicular axis and oxidative stress. However, the use of natural products to ameliorate these oxidative stress-induced changes may be essential to improving male reproductive function. Quercetin possesses several pharmacological activities that may help to combat cellular reproduction-related assaults, such as altered sperm function and reproductive hormone dysfunction, and dysregulated testicular apoptosis, oxidative stress, and inflammation. Studies have shown that quercetin ameliorates testicular toxicity, largely by inhibiting the generation of reactive oxygen species, with the aid of the two antioxidant pharmacophores present in its ring structure. The radical-scavenging property of quercetin may alter signal transduction of oxidative stress-induced apoptosis, prevent inflammation, and increase sperm quality in relation to the hormonal concentration. In this review, the therapeutic potential of quercetin in mediating male reproductive health is discussed.

Effects of lime and oxalic acid on antioxidant enzymes and active components of Panax notoginseng under cadmium stress

Cadmium (Cd) pollution poses potential safety risks for Panax notoginseng cultivation, a medicinal plant in Yunnan. Under exogenous Cd stress, field experiments were conducted to understand the effects of lime (0, 750, 2250 and 3750 kg hm⁻²) applied and oxalic acid (0, 0.1 and 0.2 mol L⁻¹) leaves sprayed on Cd accumulation, antioxidant system and medicinal components of P. notoginseng. The results showed that Lime and foliar spray of oxalic acid were able to elevate Ca²⁺ and alleviate Cd²⁺ toxicity in P. notoginseng under Cd stress. The addition of lime and oxalic acid increased the activities of antioxidant enzymes and alters osmoregulator metabolism. The most significant increase in CAT activities increased by 2.77 folds. And the highest increase of SOD activities was 1.78 folds under the application of oxalic acid. While MDA content decreased by 58.38%. There were very significant correlation with soluble sugar, free amino acid, proline and soluble protein. Lime and oxalic acid were able to increase calcium ions (Ca²⁺), decrease Cd content and improve the stress resistance of P. notoginseng, while increasing the production of total saponins and flavonoids. Cd content were the lowest, 68.57% lower than controls, and met the standard value (Cd ≤ 0.5 mg kg⁻¹, GB/T 19086-2008). The proportion of SPN was 7.73%, which reached the highest level of all treatments, the flavonoids content increased significantly by 21.74%, which reached the medicinal standard value and optimal yield.

Quercetin ameliorates oxidative stress‑induced cell apoptosis of seminal vesicles via activating Nrf2 in type 1 diabetic rats

It was known that diabetes may affect the male reproductive function by inhibiting the secretion of male accessory glands including seminal vesicles. Increased cell apoptosis induced by oxidative stress is thought to be an important pathological change in the seminal vesicles in diabetic patients. Quercetin is a potent anti-oxidative bioflavonoid. In this study, we explore the effect of quercetin on cell apoptosis of seminal vesicles and its underlying mechanism. The STZ-induced type 1 diabetic rat model was established. Three doses (low, medium and high) of quercetin were administrated to the STZ-induced type 1 diabetic rats for 4 months. Fasting blood glucose, the fructose in seminal plasma, total antioxidant capacity (T-AOC) and malondialdehyde (MDA) in seminal vesicles were determined by colorimetric method. Nuclear transcription factor- Nrf2 was observed by immunofluorescent staining. Biomarkers related to cell apoptosis, such as Bcl-2, Bax and cleaved -Caspase3 were measured by Western blotting and immumohistochemical staining. The body weight and seminal vesicle weight indexes were also determined. The results showed that T-AOC and Nrf2 were decreased, the levels of MDA were increased, the cleaved Caspase-3 was increased and the ratio of Bax to BCL-2 was decreased in seminal vesicles of diabetic rats, along with the severe hyperglycemia. When diabetic rats were treated by quercetin for 4 months, all the indexes were reversed at different degree except the fasting blood glucose. Our results suggested that quercetin could ameliorate oxidative stress‑induced cell apoptosis of seminal vesicles via inhibiting Nrf2 in type 1 diabetic rats, which indicated that quercetin could be used for preventing lesions of seminal vesicles in type 1 diabetes.