Quercetin as an anticancer agent: Focus on esophageal cancer

Quercetin Induces Apoptosis Through Downregulating P4HA2 and Inhibiting the PI3K/Akt/mTOR Axis in Hepatocellular Carcinoma Cells: An In Vitro Study

BACKGROUND

Quercetin is a natural product with multiple activities, which possesses a promising antitumor effect on malignancies. The involvement of proline 4-hydroxylase II (P4HA2) in collagen synthesis is crucial in the growth of tumor cells. Apoptosis is a programmed cell death requisite for the stability of the intracellular environment. However, the relationship between quercetin and cell apoptosis, as well as the impact of P4HA2 in this connection, has not yet been specified in hepatocellular carcinoma(HCC).

AIMS

The present study used HCC cells to investigate how quercetin regulates P4HA2 and influences cell proliferation and apoptosis.

METHODS AND RESULTS

The outcomes reveal that quercetin can impede the viability and growth of HCC cells and generate cell apoptosis in a dose-dependent manner. Additionally, quercetin prompts downregulation of P4HA2, leading to cell apoptosis in HCC cells, and knocking down P4HA2 can enhance this effect. Furthermore, we pretreated HCC cells with inhibitors (Z-VAD-FMK, LY294002) or activators (740Y-P) and found that the PI3K/Akt/mTOR pathway was occupied with quercetin-induced cell apoptosis.

CONCLUSION

This investigation reveals that quercetin compels apoptosis in HCC cells by diminishing P4HA2 and restraining the PI3K/Akt/mTOR axis.

Unlocking the Therapeutic Potential of Natural Polyphenols in Esophageal Cancer

OPINION STATEMENT

Esophageal cancer (EC), one highly malignant upper gastrointestinal cancer, is the eighth most commonly occurring cancer and the sixth leading cause of cancer-related deaths worldwide. Clinically, this malignancy is considered to be one of the most difficult-to-treat cancers, owing to its resistance to common therapies like chemotherapy and radiotherapy, and few targeted therapies are available. There is currently an unmet need for treatment of EC. Polyphenols are naturally occurring plant secondary metabolites in response to environmental threats and injury. Epidemiological evidence suggests that long-term consumption of a polyphenol-rich diet is inversely associated with the risk of cancer. Currently, natural polyphenols have received increased attention for their potential therapeutic effects on EC. In this review, we summarize and discuss recent progress in the therapeutic potential of natural polyphenols in EC, as well as their sources, oral bioavailability, and pharmacokinetics. We review natural polyphenols combined with approved chemotherapy and radiotherapy to overcome challenges faced by either monotherapy. We also discuss the current challenges and future directions to accelerate the clinical application of natural polyphenols in EC. We concluded that natural polyphenols represent promising candidates for the management of EC. Well-designed randomized controlled studies are warranted to verify the efficacy and safety of natural polyphenols for EC. Knowledge gained from this review will outline possible future research directions and should help to develop new therapeutics for this disease.

Quercetin carbon quantum dots: dual-target therapy for intracerebral hemorrhage in mice

Following intracerebral hemorrhage, mitigating oxidative stress and removing excess iron are critical strategies for reducing secondary brain injury and improving neurological outcomes. In vitro, we synthesized quercetin-ethylenediamine carbon quantum dots (QECQDs) with diameters of 2-11 nm and found that QECQDs effectively scavenge ABTS+· and DPPH· free radicals, defending HT22 cells against hemin-induced oxidative stress. In vivo, QECQDs predominantly accumulate in the pia mater, subarachnoid space, and dura mater after intrathecal injection. Compared to the ICH injury group, QECQDs treatment effectively improves cerebral blood flow, inhibits oxidative stress damage, and reduces neuron death. Importantly, QECQDs treatment reduced hemorrhage volume, alleviated edema, and improved neurological function. This lays a foundation for developing multi-target drugs for treating ICH.

Herbal drug‑based nanotherapy for hepatocellular carcinoma: Quercetin‑contained nanocarrier as a multipurpose therapeutic agent against hepatocellular carcinoma (Review)

Cancer remains one of the leading causes of morbidity and mortality worldwide, with hepatocellular carcinoma (HCC) accounting for ~75% of all primary liver cancers and exhibiting a high incidence rate. Unfortunately, the response rate to chemotherapeutic agents for liver cancer is relatively low, primarily due to the development of drug resistance and the lack of targeted therapeutic agents. The present study focused on the anticancer mechanisms of quercetin and the development of innovative nanocarriers designed to enhance its efficacy against HCC while mitigating drug resistance. Quercetin demonstrates a diverse array of biological activities, making it a promising candidate for therapeutic applications. Its mechanisms include inhibition of tumor cell cycle, induction of apoptosis, modulation of reactive oxygen species and inhibition of chemotherapeutic resistance. Given these properties, extensive research has been conducted in pharmaceutical engineering to develop well-designed nanocarriers that incorporate quercetin. These nanocarriers aim to improve the bioavailability and targeting of quercetin, thereby enhancing its therapeutic efficacy against HCC and overcoming the challenges associated with anticancer drug resistance. Through this approach, quercetin could potentially play a pivotal role in the future of HCC treatment, providing a synergistic effect when combined with traditional chemotherapy leading to improved patient outcomes.

Enhanced Bioactivity of Quercetin-Tetrahydroisoquinoline Derivatives: Effect on Lipophilicity, Enzymes Inhibition, Antioxidant Potential, and Cytotoxicity

Quercetin, a well-known flavonoid with significant medicinal potential, was derivatized at the C8 position with a tetrahydroisoquinoline (THIQ) moiety, and physicochemical and pharmacological properties, inhibition potential, antioxidant activity, and cytotoxicity of new compounds were evaluated. Physicochemical and pharmacological properties, including lipophilicity, membrane permeability, and P-glycoprotein substrate affinity, were assessed theoretically using the SwissADME software. The metal-chelating ability of the new compounds was evaluated on metal ions Fe2+, Zn2+, and Cu2+, whose homeostasis disruption is linked to the development of Alzheimer's disease. Inhibition potential was tested on the cholinergic enzymes acetylcholinesterase and butyrylcholinesterase, as well as Na+, K+-ATPase, an enzyme commonly overexpressed in tumours. Antioxidant potential was assessed using the DPPH assay. Cytotoxicity studies were conducted on healthy MRC-5 cells and three cancer cell lines: HeLa, MDA-231, and MDA-468. The results indicated that derivatization of quercetin with THIQ yielded compounds with lower toxicity, preserved chelating ability, improved antioxidant potential, increased selectivity toward the cholinergic enzyme butyrylcholinesterase, and enhanced inhibition potential toward Na+, K+-ATPase and butyrylcholinesterase compared to quercetin alone. Therefore, the synthesized derivatives represent compounds with an improved profile and could be promising candidates for further optimization in developing drugs for neurodegenerative and cancer diseases.

Exploring the immunological mechanism of Houttuynia cordata in the treatment of colorectal cancer through combined network pharmacology and experimental validation

To explore the potential mechanisms of Houttuynia cordata in the treatment of CRC using network pharmacology combined with experimental validation. The major active components of Houttuynia cordata were identified using the TCMSP database, and their related targets were mined. CRC-related target genes were obtained through the Genecards and OMIM databases. The R software Ven Diagram package was used for visualization of the intersection of drug and disease targets. The intersection target genes were subjected to GO function enrichment and KEGG pathway enrichment analysis using the R software clusterProfiler package. A "Drug - active component - target - Disease" network was constructed and analyzed using Cytoscape software. Intersection target genes were uploaded to the STRING database, and the resultant data were imported into Cytoscape software to construct a PPI network and filter core target genes. Expression analysis, diagnostic efficacy, and survival analysis were used to demonstrate the function and clinical value of the core target genes. The correlation between core genes in CRC samples and immune cell infiltration was analyzed using the R software and ssGSVA algorithm. Molecular docking validation of core active components with core target genes was performed using AutodockVina 1.2.2 software. Finally, the effects of quercetin and kaempferol, core active components of Houttuynia cordata, on the growth of HCT116 cells and the regulation of core target genes were validated through CCK8 assay, flow cytometry, and RT-qPCR. Seven effective active components and 147 component-related targets were selected, along with 3806 CRC-related target genes. GO analysis mainly involved biological processes such as epithelial cell proliferation, with KEGG pathway analysis focusing on pathways including AGE-RAGE signaling. Quercetin and kaempferol were identified as two core components, with IL1B, MMP9, CXCL8, and IL6 as four core target genes. Immune infiltration analysis showed that IL1B, MMP9, CXCL8, and IL6 primarily exert anti-CRC effects by promoting neutrophil activity. Molecular docking results indicated stable binding capacities of quercetin and kaempferol with IL1B, MMP9, CXCL8, and IL6. Experimental validation showed that quercetin and kaempferol could inhibit the viability of HCT116 cells in a dose-dependent manner, promote apoptosis, and downregulate the expression of IL1B, MMP9, CXCL8, and IL6 genes. Houttuynia cordata may exert therapeutic effects on CRC by modulating the immune microenvironment and anti-inflammatory responses, providing new research directions and theoretical guidance for the treatment of CRC with Houttuynia cordata.

Molecular Insights on Coffee Components as Chemical Antioxidants

Coffee is not only a delicious beverage but also an important dietary source of natural antioxidants. We live in a world where it is impossible to avoid pollution, stress, food additives, radiation, and other sources of oxidants that eventually lead to severe health disorders. Fortunately, there are chemicals in our diet that counteract the hazards posed by the reactive species that trigger oxidative stress. They are usually referred to as antioxidants; some of them can be versatile compounds that exert such a role in many ways. This review summarizes, from a chemical point of view, the antioxidant effects of relevant molecules found in coffee. Their mechanisms of action, trends in activity, and the influence of media and pH in aqueous solutions, are analyzed. Structure-activity relationships are discussed, and the protective roles of these compounds are examined. A particular section is devoted to derivatives of some coffee components, and another one to their bioactivity. The data used in the analysis come from theoretical and computational protocols, which have been proven to be very useful in this context. Hopefully, the information provided here will pro-mote further investigations into the amazing chemistry contained in our morning coffee cup.   Resumen. El café no solo es una bebida deliciosa, sino también una importante fuente dietética de antioxidantes naturales. Vivimos en un mundo donde es imposible evitar la contaminación, el estrés, los aditivos alimentarios, la radiación y otras fuentes de oxidantes que eventualmente conducen a trastornos de salud graves. Afortunadamente, existen sustancias químicas en nuestra dieta que contrarrestan los peligros planteados por las especies reactivas que desencadenan el estrés oxidativo. Por lo general, se les denomina antioxidantes; algunos de ellos pueden ser compuestos versátiles que ejercen dicho papel de muchas maneras. Este artículo de revisión resume, desde un punto de vista químico, los efectos antioxidantes de moléculas relevantes encontradas en el café. Se analizan sus mecanismos de acción, tendencias en la actividad y la influencia del medio y el pH en soluciones acuosas. Se discuten las relaciones estructura-actividad, y se examinan los roles protectores de estos compuestos. Se dedica una sección particular a los derivados de algunos componentes del café, y otra a su bioactividad. Los datos utilizados en el análisis provienen de protocolos teóricos y computacionales, que han demostrado ser muy útiles en este contexto. Se espera que la información proporcionada aquí promueva investigaciones futuras sobre la química contenida en nuestra taza de café matutina.

The multifaceted role of quercetin derived from its mitochondrial mechanism

Quercetin is a flavonoid with promising therapeutic applications; nonetheless, the phenotype exerted in some diseases is contradictory. For instance, anticancer properties may be explained by a cytotoxic mechanism, whereas antioxidant-related neuroprotection is a pro-survival process. According to the available literature, quercetin exerts a redox interaction with the electron transport chain (ETC) in the mitochondrion, affecting its membrane potential. It also affects ATP generation by oxidative phosphorylation, where ATP deprivation could partly explain its cytotoxic effect. Moreover, quercetin may support the generation of free radicals through redox reactions, causing a prooxidant effect. The nutrimental stress and prooxidant effect induced by quercetin might promote pro-survival properties such as antioxidant processes. Thus, in this review, we discuss the evidence supporting that quercetin redox interaction with the ETC could explain its beneficial and toxic properties.

Phytochemicals in regulating PD-1/PD-L1 and immune checkpoint blockade therapy

Clinical treatment and preclinical studies have highlighted the role of immune checkpoint blockade in cancer treatment. Research has been devoted to developing immune checkpoint inhibitors in combination with other drugs to achieve better efficacy or reduce adverse effects. Phytochemicals sourced from vegetables and fruits have demonstrated antiproliferative, proapoptotic, anti-migratory, and antiangiogenic effects against several cancers. Phytochemicals also modulate the tumor microenvironment such as T cells, regulatory T cells, and cytokines. Recently, several phytochemicals have been reported to modulate immune checkpoint proteins in in vivo or in vitro models. Phytochemicals decreased programmed cell death ligand-1 expression and synergized programmed cell death receptor 1 (PD-1) monoclonal antibody to suppress tumor growth. Combined administration of phytochemicals and PD-1 monoclonal antibody enhanced the tumor growth inhibition as well as CD4+ /CD8+ T-cell infiltration. In this review, we discuss immune checkpoint molecules as potential therapeutic targets of cancers. We further assess the impact of phytochemicals including carotenoids, polyphenols, saponins, and organosulfur compounds on cancer PD-1/programmed cell death ligand-1 immune checkpoint molecules and document their combination effects with immune checkpoint inhibitors on various malignancies.

Microbiota-Gastric Cancer Interactions and the Potential Influence of Nutritional Therapies

Gastric cancer (GC) is one of the most common causes of cancer deaths, and GC treatments represent a large area of research. Although initially regarded as a sterile organ and unsuitable for microbial communities, the discovery of Helicobacter pylori made us realize that some microbes can colonize the stomach. In recent years, growing interest in gastric bacteria has expanded to the gut microbiota and, more recently, to the oral microbiota. Indeed, the oral-gastric-gut microbiota axis may play a crucial role in maintaining homeostasis, while changes in microbiota composition in GC patients can influence clinical outcomes. On the one hand, the microbiota and its metabolites may significantly influence the progression of GC, while anti-GC treatments such as gastrectomy and chemotherapy may significantly impact the oral-gastric-gut microbiota axis of GC patients. In this context, the role of nutritional therapies, including diet, prebiotics, and probiotics, in treating GC should not be underestimated. Wit this review, we aim to highlight the main role of the gastric, oral, and gut microbiota in GC onset and progression, representing potential future biomarkers for early GC detection and a target for efficient nutritional therapies during the course of GC.

Exploring the potential mechanism and molecular targets of Taohong Siwu Decoction against deep vein thrombosis based on network pharmacology and analysis docking

This study aims to investigate the mechanism of Taohong Siwu Decoction (THSWD) against deep vein thrombosis (DVT) using network pharmacology and molecular docking technology. We used the Traditional Chinese Medicine Systems Pharmacology database and reviewed literature to identify the main chemical components of THSWD. To find targets for DVT, we consulted GeneCards, Therapeutic Target Database, and PharmGKB databases. We used Cytoscape 3.8.2 software to construct herb-disease-gene-target networks. Additionally, we integrated drug targets and disease targets on the STRING platform to create a protein-protein interaction network. Then, we conducted Kyoto Encyclopedia of Genes and Genomes and gene ontology analysis. Finally, We employed the molecular docking method to validate our findings. We identified 56 potential targets associated with DVT and found 61 effective components. beta-sitosterol, quercetin, and kaempferol were the most prominent among these components. Our analysis of the protein-protein interaction network revealed that IL6, L1B, and AKT1 had the highest degree of association. Gene ontology analysis showed that THSWD treatment for DVT may involve response to inorganic substances, negative regulation of cell differentiation, plasma membrane protein complex, positive regulation of phosphorylation, and signaling receptor regulator activity. Kyoto Encyclopedia of Genes and Genomes analysis indicated that lipid and atherosclerosis, pathways in cancer, as well as the PI3K-Akt pathway are the main signal pathways involved. Molecular docking results demonstrated strong binding affinity between beta-sitosterol, quercetin, kaempferol, and AKT1 proteins as well as IL1B and IL6 proteins. The main targets for THSWD treatment of DVT may include AKT1, IL1B, and IL6. Beta-sitosterol, quercetin, and kaempferol may be the active ingredients responsible for producing this effect. These compounds may slow down the progression of DVT by regulating the inflammatory response through the PI3K/Akt pathway.

Recent Advances in Biomedical Nanotechnology Related to Natural Products

Natural product processing via nanotechnology has opened the door to innovative and significant applications in medical fields. On one hand, plants-derived bioactive ingredients such as phenols, pentacyclic triterpenes and flavonoids exhibit significant pharmacological activities, on another hand, most of them are hydrophobic in nature, posing challenges to their use. To overcome this issue, nanoencapsulation technology is employed to encapsulate these lipophilic compounds and enhance their bioavailability. In this regard, various nano-sized vehicles, including degradable functional polymer organic compounds, mesoporous silicon or carbon materials, offer superior stability and retention for bioactive ingredients against decomposition and loss during delivery as well as sustained release. On the other hand, some naturally occurring polymers, lipids and even microorganisms, which constitute a significant portion of Earth's biomass, show promising potential for biomedical applications as well. Through nano-processing, these natural products can be developed into nano-delivery systems with desirable characteristics for encapsulation a wide range of bioactive components and therapeutic agents, facilitating in vivo drug transport. Beyond the presentation of the most recent nanoencapsulation and nano-processing advancements with formulations mainly based on natural products, this review emphasizes the importance of their physicochemical properties at the nanoscale and their potential in disease therapy.

Epigenetic regulation by quercetin: a comprehensive review focused on its biological mechanisms

Epigenetics regulates gene expression and play significant roles across diverse disease states. Epigenetics mechanisms, including DNA methylation, histone modifications, microRNAs/lncRNA, and N6-methyladenosine (m6A) RNA methylation, elicit heritable but reversible modifications in gene expression without modifying the DNA sequence. Recent research suggests that certain natural phytochemicals with chemopreventive properties have the potential to function as epigenetic regulators. Quercetin, a derivative of natural flavonoid glycosides and a constituent of the human diet, is linked to a variety of health benefits including anti-inflammatory, anticancer activity, antiapoptotic, antihypertensive, and neuroprotective effects. Recent findings suggest that quercetin possesses the ability to modulate canonical biochemical signaling pathways and exert an impact on epigenetic networks. This review aims to synthesize the most recent research findings that elucidate the potential biological effects of quercetin and its influence on in vitro and in vivo models via epigenetic mechanisms. In light of our findings, it is evident that quercetin possesses the potential to function as an exemplary instance of naturally derived phytochemicals, which can be effectively employed as a pivotal constituent in functional foods and dietary supplements aimed at the amelioration of various ailments. More specifically, its mechanism of action involves the alteration of diverse epigenetic targets.

Therapeutic Strategies for Pancreatic-Cancer-Related Type 2 Diabetes Centered around Natural Products

Pancreatic ductal adenocarcinoma (PDAC), a highly malignant neoplasm, is classified as one of the most severe and devastating types of cancer. PDAC is a notable malignancy that exhibits a discouraging prognosis and a rising occurrence. The interplay between diabetes and pancreatic cancer exhibits a reciprocal causation. The identified metabolic disorder has been observed to possess noteworthy consequences on health outcomes, resulting in elevated rates of morbidity. The principal mechanisms involve the suppression of the immune system, the activation of pancreatic stellate cells (PSCs), and the onset of systemic metabolic disease caused by dysfunction of the islets. From this point forward, it is important to recognize that pancreatic-cancer-related diabetes (PCRD) has the ability to increase the likelihood of developing pancreatic cancer. This highlights the complex relationship that exists between these two physiological states. Therefore, we investigated into the complex domain of PSCs, elucidating their intricate signaling pathways and the profound influence of chemokines on their behavior and final outcome. In order to surmount the obstacle of drug resistance and eliminate PDAC, researchers have undertaken extensive efforts to explore and cultivate novel natural compounds of the next generation. Additional investigation is necessary in order to comprehensively comprehend the effect of PCRD-mediated apoptosis on the progression and onset of PDAC through the utilization of natural compounds. This study aims to examine the potential anticancer properties of natural compounds in individuals with diabetes who are undergoing chemotherapy, targeted therapy, or immunotherapy. It is anticipated that these compounds will exhibit increased potency and possess enhanced pharmacological benefits. According to our research findings, it is indicated that naturally derived chemical compounds hold potential in the development of PDAC therapies that are both safe and efficacious.

Nosip is a potential therapeutic target in hepatocellular carcinoma cells

Nitric oxide synthase-interacting protein (Nosip) interacts with nitric oxide synthase (NOS) and regulates NO synthesis and release, which participates in various critical physiological and pathological processes. However, the role of Nosip in hepatocellular carcinoma (HCC) is unclear. In this study, Nosip expression was found to be elevated in HCC tissues and cells. Nosip siRNA transfection inhibited the proliferation and motility of HCC cells and promoted apoptosis. In contrast, overexpression of Nosip promoted proliferation and migration and invasion, and inhibited apoptosis of HCC cells. As a natural compound, quercetin exerted the effect of inhibiting the proliferation and motility of HCC cells, and this anticancer activity probably via repressing the expression of Nosip. Our results suggest that Nosip could act as an oncogene in the progression of HCC and that quercetin may be a potential natural compound for treating HCC by inhibiting the expression of Nosip.

Flavonoids and gastrointestinal health: single molecule for multiple roles

Diet can be considered as one of the pivotal factors in regulating gastrointestinal health, and polyphenols widely distributed in human daily diet. The polyphenols and their metabolites playing a series of beneficial effects in human gastrointestinal tract that can regulate of the gut microbiota, increase intestinal barrier function, repair gastrointestinal mucosa, reduce oxidative stress, inhibit the secretion of inflammatory factors and regulating immune function, and their absorption and biotransformation mainly depend on the activity of intestinal microflora. However, little is known about the two-way interaction between polyphenols and intestinal microbiota. The objective of this review is to highlight the structure optimization and effect of flavonoids on intestinal flora, and discusses the mechanisms of dietary flavonoids regulating intestinal flora. The multiple effects of single molecule of flavonoids, and inter-dependence between the gut microbiota and polyphenol metabolites. Moreover, the protective effects of polyphenols on intestinal barrier function, and effects of interaction between plant polyphenols and macromolecules on gastrointestinal health. This review provided valuable insight that may be useful for better understanding the mechanism of the gastrointestinal health effects of polyphenols, and provide a scientific basis for their application as functional food.

Salt-Tolerant Plants, Halophytes, as Renewable Natural Resources for Cancer Prevention and Treatment: Roles of Phenolics and Flavonoids in Immunomodulation and Suppression of Oxidative Stress towards Cancer Management

Halophytes and xerophytes, plants with adequate tolerance to high salinity with strong ability to survive in drought ecosystem, have been recognized for their nutritional and medicinal values owing to their comparatively higher productions of secondary metabolites, primarily the phenolics, and the flavonoids, as compared to the normal vegetation in other climatic regions. Given the consistent increases in desertification around the world, which are associated with increasing salinity, high temperature, and water scarcity, the survival of halophytes due to their secondary metabolic contents has prioritized these plant species, which have now become increasingly important for environmental protection, land reclamation, and food and animal-feed security, with their primary utility in traditional societies as sources of drugs. On the medicinal herbs front, because the fight against cancer is still ongoing, there is an urgent need for development of more efficient, safe, and novel chemotherapeutic agents, than those currently available. The current review describes these plants and their secondary-metabolite-based chemical products as promising candidates for developing newer cancer therapeutics. It further discusses the prophylactic roles of these plants, and their constituents in prevention and management of cancers, through an exploration of their phytochemical and pharmacological properties, with a view on immunomodulation. The important roles of various phenolics and structurally diverse flavonoids as major constituents of the halophytes in suppressing oxidative stress, immunomodulation, and anti-cancer effects are the subject matter of this review and these aspects are outlined in details.

Network Pharmacology and in vitro Experimental Verification on Intervention of Quercetin, Present in Chinese Medicine Yishen Qutong Granules, on Esophageal Cancer

OBJECTIVE

To explore the potential mechanism of Yishen Qutong Granules (YSQTG) for the treatment of esophageal cancer using network pharmacology and experimental research.

METHODS

The effective components and molecular mechanism of YSQTG in treating esophageal cancer were expounded based on network pharmacology and molecular docking. The key compound was identified by high-performance liquid chromatography and mass spectrometry (HPLC-MS) to verify the malignant phenotype of the key compounds in the treatment of esophageal cancer. Then, the interaction proteins of key compounds were screened by pull-down assay combined with mass spectrometry. RNA-seq was used to screen the differential genes in the treatment of esophageal cancer by key compounds, and the potential mechanism of key compounds on the main therapeutic targets was verified.

RESULTS

Totally 76 effective compounds of YSQTG were found, as well as 309 related targets, and 102 drug and disease interaction targets. The drug-compound-target network of YSQTG was constructed, suggesting that quercetin, luteolin, wogonin, kaempferol and baicalein may be the most important compounds, while quercetin had higher degree value and degree centrality, which might be the key compound in YSQTG. The HPLC-MS results also showed the stable presence of quercetin in YSQTG. By establishing a protein interaction network, the main therapeutic targets of YSQTG in treating esophageal cancer were Jun proto-oncogene, interleukin-6, tumor necrosis factor, and RELA proto-oncogene. The results of cell function experiments in vitro showed that quercetin could inhibit proliferation, invasion, and clonal formation of esophageal carcinoma cells. Quercetin mainly affected the biological processes of esophageal cancer cells, such as proliferation, cell cycle, and cell metastasis. A total of 357 quercetin interacting proteins were screened, and 531 genes were significantly changed. Further pathway enrichment analysis showed that quercetin mainly affects the metabolic pathway, MAPK signaling pathway, and nuclear factor kappa B (NF- κ B) signaling pathway, etc. Quercetin, the key compound of YSQTG, had stronger binding activity by molecular docking. Pull-down assay confirmed that NF- κ B was a quercetin-specific interaction protein, and quercetin could significantly reduce the protein level of NF- κ B, the main therapeutic target.

CONCLUSION

YSQTG can be multi-component, multi-target, multi-channel treatment of esophageal cancer, it is a potential drug for the treatment of esophageal cancer.

New Insights Into the Anticancer Effects of p-Coumaric Acid: Focus on Colorectal Cancer

Colorectal cancer is considered the second most deadly cancer in the world. Studies have indicated that diet can prevent the risk of developing colorectal cancer. Recently, there has been an increasing interest in polyphenols due to their plausible effect on cancer prevention and treatment. p-Coumaric acid (p-CouA), a phenolic compound, is a cinnamic acid derivative found in several fruits, vegetables, and herbs. A growing body of evidence suggests that p-CouA may be an effective agent for preventing and managing colorectal cancer. In this current review, we briefly highlight the bioavailability of p-CouA. We also provide an up-to-date overview of molecular mechanisms underlying its anticancer effects, focusing on anti-inflammatory and antioxidant potentials, apoptosis induction, and cell cycle blockade. Finally, we discuss the impact of p-CouA on clonogenicity and multidrug resistance of colorectal cancer cells.

Comparative Metabolomic Profiling Reveals Key Secondary Metabolites Associated with High Quality and Nutritional Value in Broad Bean (Vicia faba L.)

High quality and nutritional benefits are ultimately the desirable features that influence the commercial value and market share of broad bean (Vicia faba L.). Different cultivars vary greatly in taste, flavor, and nutrition. However, the molecular basis of these traits remains largely unknown. Here, the grain metabolites of the superior Chinese landrace Cixidabaican (CX) were detected by a widely targeted metabolomics approach and compared with the main cultivar Lingxiyicun (LX) from Japan. The analyses of global metabolic variations revealed a total of 149 differentially abundant metabolites (DAMs) were identified between these two genotypes. Among them, 84 and 65 were up- and down-regulated in CX compared with LX. Most of the DAMs were closely related to healthy eating substances known for their antioxidant and anti-cancer properties, and some others were involved in the taste formation. The KEGG-based classification further revealed that these DAMs were significantly enriched in 21 metabolic pathways, particularly in flavone and flavonol biosynthesis. The differences in key secondary metabolites, including flavonoids, terpenoids, amino acid derivates, and alkaloids, may lead to more nutritional value in a healthy diet and better adaptability for the seed germination of CX. The present results provide important insights into the taste/quality-forming mechanisms and contributes to the conservation and utilization of germplasm resources for breeding broad bean with superior eating quality.

Quercetin improves pancreatic cancer chemo-sensitivity by regulating oxidative-inflammatory networks

Chemotherapy is the main method for controlling pancreatic cancer metastasis but the prevalent chemotherapy resistance limits its utilization. The response of oxidation and inflammation often promotes pancreatic cancer progression and chemo-resistance. It is critical to explore the potential natural products with few side effects to control inflammatory responses and understand the related mechanisms. Quercetin is a flavonoid widely found in numerous vegetables, fruits, and foods and is thought to have antioxidant and anti-inflammatory properties, which may be associated with improvement of chemotherapy sensitivity during pancreatic cancer treatment. Quercetin may sensitize pancreatic cancer cells to the chemotherapeutic agents, including bromodomain and extraterminal domain inhibitors (BETI), daunorubicin, gemcitabine, sulforaphane, doxorubicin, and tumor necrosis factor-related signaling apoptosis-inducing ligand (TRAIL). Meanwhile, during the chemo-resistance therapy, many signaling molecules are involved with toll-like receptor 4 (TLR4)-mediated oxidative and inflammatory pathway. The effects of quercetin on other oxidative and inflammatory pathways were also explored. Quercetin may exert antitumor activity during the prevention of pancreatic cancer progression by regulating oxidative and inflammatory networks, which can promote immune escape of cancer cells by inducing immunosuppressive cytokines. Studying these patterns will help us to better understand the functional role of quercetin in the improvement of pancreatic cancer chemo-sensitivity. PRACTICAL APPLICATIONS: Chemotherapy is the major way for treating pancreatic cancer metastasis but the prevalent chemotherapy resistance caused by oxidative and inflammatory responses limits its utilization. It is necessary to explore the potential natural products with few side effects to prevent the oxidative and inflammatory responses. Quercetin is a flavonoid widely found in numerous vegetables, fruits, and foods and is thought to have antioxidant and anti-inflammatory properties, which may be associated with improvement of chemotherapy sensitivity of pancreatic cancer treatment by sensitizing pancreatic cancer cells to various chemotherapeutic agents via the regulation of oxidative and inflammatory networks. Studying these patterns will help us to better understand the functional role of quercetin in the improvement of pancreatic cancer chemo-sensitivity.

Organically surface engineered mesoporous silica nanoparticles control the release of quercetin by pH stimuli

Controlling the premature release of hydrophobic drugs like quercetin over physiological conditions remains a challenge motivating the development of smart and responsive drug carriers in recent years. This present work reported a surface modification of mesoporous silica nanoparticles (MSN) by a functional compound having both amines (as a positively charged group) and carboxylic (negatively charged group), namely 4-((2-aminoethyl)amino)-4-oxobut-2-enoic acid (AmEA) prepared via simple mechanochemistry approach. The impact of MSN surface modification on physical, textural, and morphological features was evaluated by TGA, N₂ adsorption-desorption, PSA-zeta, SEM, and TEM. The BET surface area of AmEA-modified MSN (MSN-AmEA) was found to be 858.41 m² g^-1 with a pore size of 2.69 nm which could accommodate a high concentration of quercetin 118% higher than MSN. In addition, the colloidal stability of MSN-AmEA was greatly improved as indicated by high zeta potential especially at pH 4 compared to MSN. In contrast to MSN, MSN-AmEA has better in controlling quercetin release triggered by pH, thanks to the presence of the functional groups that have a pose-sensitive interaction hence it may fully control the quercetin release, as elaborated by the DFT study. Therefore, the controlled release of quercetin over MSN-AmEA verified its capability of acting as a smart drug delivery system.

Aptamer-functionalized Quercetin Thermosensitive Liposomes for Targeting Drug Delivery and Antitumor Therapy

Chemo-thermotherapy, as a promising cancer combination therapy strategy, has attracted widespread attention. In this study, a novel aptamer functionalized thermosensitive liposome encapsulating hydrophobic drug quercetin was fabricated as an efficient drug delivery system. This aptamer-functionalized quercetin thermosensitive liposomes (AQTSL) combined the merits of high-loading yield, sustained drug release, long-term circulation in the body of PEGylated liposomes, passive targeting provided by 100-200 nm nanoparticles, active targeting and improved internalization effects offered by AS1411 aptamer, and temperature-responsive of quercetin release. In addition, AQTSL tail vein injection combined with 42℃ water bath heating on tumor site (AQTSL+42℃)treatment inhibited the tumor growth significantly compared with the normal saline administration (p<0.01), and the inhibition rate reached 75%. Furthermore, AQTSL+42℃ treatment also slowed down the tumor growth significantly compared with QTSL combined with 42℃ administration (p<0.05), confirming that AS1411 decoration on QTSL increased the active targeting and internalization effects of the drug delivery system, and AS1411 aptamer itself might also contribute to the tumor inhibition. These data indicate that AQTSL is a potential carrier candidate for different hydrophobic drugs and tumor targeting delivery, and this kind of targeted drug delivery system combined with temperature responsive drug release mode is expected to achieve an ideal tumor therapy effect.

Quercetin as a JAK-STAT inhibitor: a potential role in solid tumors and neurodegenerative diseases

The Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway is involved in many immunological processes, including cell growth, proliferation, differentiation, apoptosis, and inflammatory responses. Some of these processes can contribute to cancer progression and neurodegeneration. Owing to the complexity of this pathway and its potential crosstalk with alternative pathways, monotherapy as targeted therapy has usually limited long-term efficacy. Currently, the majority of JAK-STAT-targeting drugs are still at preclinical stages. Meanwhile, a variety of plant polyphenols, especially quercetin, exert their inhibitory effects on the JAK-STAT pathway through known and unknown mechanisms. Quercetin has shown prominent inhibitory effects on the JAK-STAT pathway in terms of anti-inflammatory and antitumor activity, as well as control of neurodegenerative diseases. This review discusses the pharmacological effects of quercetin on the JAK-STAT signaling pathway in solid tumors and neurodegenerative diseases.

Polyphenols as Plant-Based Nutraceuticals: Health Effects, Encapsulation, Nano-Delivery, and Application

Plant polyphenols have attracted considerable attention because of their key roles in preventing many diseases, including high blood sugar, high cholesterol, and cancer. A variety of functional foods have been designed and developed with plant polyphenols as the main active ingredients. Polyphenols mainly come from vegetables and fruits and can generally be divided according to their structure into flavonoids, astragalus, phenolic acids, and lignans. Polyphenols are a group of plant-derived functional food ingredients with different molecular structures and various biological activities including antioxidant, anti-inflammatory, and anticancer properties. However, many polyphenolic compounds have low oral bioavailability, which limits the application of polyphenols in nutraceuticals. Fortunately, green bio-based nanocarriers are well suited for encapsulating, protecting, and delivering polyphenols, thereby improving their bioavailability. In this paper, the health benefits of plant polyphenols in the prevention of various diseases are summarized, with a review of the research progress into bio-based nanocarriers for the improvement of the oral bioavailability of polyphenols. Polyphenols have great potential for application as key formulations in health and nutrition products. In the future, the development of food-grade delivery carriers for the encapsulation and delivery of polyphenolic compounds could well solve the limitations of poor water solubility and low bioavailability of polyphenols for practical applications.

Exploration of the Molecular Mechanism of Danzhi Xiaoyao Powder in Endometrial Cancer through Network Pharmacology

Endometrial cancer (EC) is a common malignant tumor of the female reproductive system. Current treatments such as surgery and long-term hormone therapy are ineffective and have side effects. Danzhi Xiaoyao powder (DXP) can inhibit the growth of EC cells and induce apoptosis, but the pharmacological and molecular mechanisms of anticancer effects are still unclear. In this study, active components and potential targets of DXP were obtained from public databases. Protein effects and regulatory pathways of common targets were analyzed by protein-protein interaction (PPI), GO and KEGG. The results of network pharmacology showed that there are 87 common targets between EC and DXP. GO enrichment analysis showed that these targets were associated with response to oxidative stress, response to nutrient levels, hormone receptor binding and nuclear hormone receptor binding, etc. The results of KEGG analysis indicated that IL-17, TNF, PI3K/AKT, and RAS/RAF/MEK/ERK (ERK) signaling pathway were enriched in the anti-EC of DXP. Additionally, we cultured HEC-1B and KLE cells for validate experiments. DXP showed an inhibition of proliferation, migration, and cell cycle of both cells. Moreover, the expression of RAS, p-RAF, p-MEK, ERK, and p-ERK related proteins were downregulated. In conclusion, DXP might inhibit the proliferation of EC cells via apoptosis. Furthermore, DXP-induced inhibition of EC development might involve RAS/RAF/MEK/ERK pathway.

A Network Pharmacological Elucidation of the Systematic Treatment Activities and Mechanisms of the Herbal Drug FDY003 Against Esophageal Cancer

Despite accumulating evidence for the value of herbal drugs for cancer treatment, the mechanisms underlying their effects have not been fully elucidated in a systematic manner. In this study, we performed a network pharmacological analysis to elucidate the anti-esophageal cancer (EC) properties of the herbal drug FDY003, a mixture of Artemisia capillaris Thunberg (AcT), Cordyceps militaris (Linnaeus) Link (Cm), and Lonicera japonica Thunberg (LjT). FDY003 reduced human EC cell viability and increased the pharmacological effects of chemotherapeutic drugs. There were 15 active pharmacological chemicals targeting 61 EC-associated genes and proteins in FDY003. The FDY003 targets were key regulators of major oncogenic EC-associated signaling pathways, such as phosphoinositide 3-kinase (PI3K)-Akt, hypoxia-inducible factor (HIF)-1, mitogen-activated protein kinase (MAPK), tumor necrosis factor (TNF), p53, Janus kinase (JAK)-signal transducer and activator of transcription (STAT), erythroblastic leukemia viral oncogene homolog (ErbB), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappa B), and vascular endothelial growth factor (VEGF) cascades. These EC-associated genes, proteins, and pathways targeted by FDY003 determine the malignant behaviors of EC cells, including cell death, survival, division, proliferation, and growth. This network pharmacological analysis provides an integrative view of the mechanisms by which FDY003 contributes to EC treatment.

Traditional Chinese Medicines as Effective Reversals of Epithelial-Mesenchymal Transition Induced-Metastasis of Colorectal Cancer: Molecular Targets and Mechanisms

Colorectal cancer (CRC) is the third most common type of cancer worldwide. Distant metastasis is the major cause of cancer-related mortality in patients with CRC. Epithelial-mesenchymal transition (EMT) is a critical process triggered during tumor metastasis, which is also the main impetus and the essential access within this duration. Therefore, targeting EMT-related molecular pathways has been considered a novel strategy to explore effective therapeutic agents against metastatic CRC. Traditional Chinese medicines (TCMs) with unique properties multi-target and multi-link that exert their therapeutic efficacies holistically, which could inhibit the invasion and metastasis ability of CRC cells via inhibiting the EMT process by down-regulating transforming growth factor-β (TGF-β)/Smads, PI3K/Akt, NF-κB, Wnt/β-catenin, and Notch signaling pathways. The objective of this review is to summarize and assess the anti-metastatic effect of TCM-originated bioactive compounds and Chinese medicine formulas by mediating EMT-associated signaling pathways in CRC therapy, providing a foundation for further research on the exact mechanisms of action through which TCMs affect EMT transform in CRC.

Nanoparticles as phytochemical carriers for cancer treatment: News of the last decade

INTRODUCTION

The development and application of novel therapeutic medicines for the treatment of cancer are of vital importance to improve the disease's outcome and survival rate. One noteworthy treatment approach is the use of biologically active compounds present in natural products. Even though these phytocompounds present anti-inflammatory, antioxidant, and anticancer properties, their use is limited essentially due to poor systemic delivery, low bioavailability, and water solubility concerns. To make full use of the anticancer potential of natural products, these limitations need to be technologically addressed. In this sense, nanotechnology emerges as a promising drug delivery system strategy.

AREAS COVERED

In this review, the benefits and potential of nanodelivery systems for natural products encapsulation as promising therapeutic approaches for cancer, which were developed during the last decade, are highlighted.

EXPERT OPINION

The nanotechnology area has been under extensive research in the medical field given its capacity for improving the therapeutic potential of drugs by increasing their bioavailability and allowing a targeted delivery to the tumor site. Thereby, the nanoencapsulation of phytocompounds can have a direct impact on the recognized therapeutic activity of natural products towards cancer.

Quercetin Impact in Pancreatic Cancer: An Overview on Its Therapeutic Effects

Pancreatic cancer (PC) is a lethal malignancy cancer, and its mortality rates have been increasing worldwide. Diagnosis of this cancer is complicated, as it does not often present symptoms, and most patients present an irremediable tumor having a 5-year survival rate after diagnosis. Regarding treatment, many concerns have also been raised, as most tumors are found at advanced stages. At present, anticancer compounds-rich foods have been utilized to control PC. Among such bioactive molecules, flavonoid compounds have shown excellent anticancer abilities, such as quercetin, which has been used as an adjunctive or alternative drug to PC treatment by inhibitory or stimulatory biological mechanisms including autophagy, apoptosis, cell growth reduction or inhibition, EMT, oxidative stress, and enhancing sensitivity to chemotherapy agents. The recognition that this natural product has beneficial effects on cancer treatment has boosted the researchers' interest towards more extensive studies to use herbal medicine for anticancer purposes. In addition, due to the expensive cost and high rate of side effects of anticancer drugs, attempts have been made to use quercetin but also other flavonoids for preventing and treating PC. Based on related studies, it has been found that the quercetin compound has significant effect on cancerous cell lines as well as animal models. Therefore, it can be used as a supplementary drug to treat a variety of cancers, particularly pancreatic cancer. This review is aimed at discussing the therapeutic effects of quercetin by targeting the molecular signaling pathway and identifying antigrowth, cell proliferation, antioxidative stress, EMT, induction of apoptotic, and autophagic features.

Drug combination studies of PS-1 and quercetin against rhodesain of Trypanosoma brucei rhodesiense

Rhodesain is a cysteine protease crucial for the survival of Trypanosoma brucei rhodesiense, the parasite able to induce the acute lethal form of Human African Trypanosomiasis. PS-1 is a synthetic peptidyl inhibitor of rhodesain, characterised by a picomolar binding affinity (K_i = 1.1 pM). Thus, considering the well-known antiparasitic properties of quercetin, in this study, we decided to carry out drug combination studies of PS-1 and quercetin against rhodesain, according to Chou and Talalay method, which allowed us to obtain for the most relevant f_a values a nearly additive effect for the reduction of rhodesain activity from 40% to 90%, thus considering a promising strategy their use in combination.

Identification of Compounds with Potential Therapeutic Uses from Sweet Pepper (Capsicum annuum L.) Fruits and Their Modulation by Nitric Oxide (NO)

Plant species are precursors of a wide variety of secondary metabolites that, besides being useful for themselves, can also be used by humans for their consumption and economic benefit. Pepper (Capsicum annuum L.) fruit is not only a common food and spice source, it also stands out for containing high amounts of antioxidants (such as vitamins C and A), polyphenols and capsaicinoids. Particular attention has been paid to capsaicin, whose anti-inflammatory, antiproliferative and analgesic activities have been reported in the literature. Due to the potential interest in pepper metabolites for human use, in this project, we carried out an investigation to identify new bioactive compounds of this crop. To achieve this, we applied a metabolomic approach, using an HPLC (high-performance liquid chromatography) separative technique coupled to metabolite identification by high resolution mass spectrometry (HRMS). After chromatographic analysis and data processing against metabolic databases, 12 differential bioactive compounds were identified in sweet pepper fruits, including quercetin and its derivatives, L-tryptophan, phytosphingosin, FAD, gingerglycolipid A, tetrahydropentoxylin, blumenol C glucoside, colnelenic acid and capsoside A. The abundance of these metabolites varied depending on the ripening stage of the fruits, either immature green or ripe red. We also studied the variation of these 12 metabolites upon treatment with exogenous nitric oxide (NO), a free radical gas involved in a good number of physiological processes in higher plants such as germination, growth, flowering, senescence, and fruit ripening, among others. Overall, it was found that the content of the analyzed metabolites depended on the ripening stage and on the presence of NO. The metabolic pattern followed by quercetin and its derivatives, as a consequence of the ripening stage and NO treatment, was also corroborated by transcriptomic analysis of genes involved in the synthesis of these compounds. This opens new research perspectives on the pepper fruit’s bioactive compounds with nutraceutical potentiality, where biotechnological strategies can be applied for optimizing the level of these beneficial compounds.

Gastroprotective Effects of Polyphenols against Various Gastro-Intestinal Disorders: A Mini-Review with Special Focus on Clinical Evidence

Polyphenols are classified as an organic chemical with phenolic units that display an array of biological functions. However, polyphenols have very low bioavailability and stability, which make polyphenols a less bioactive compound. Many researchers have indicated that several factors might affect the efficiency and the metabolism (biotransformation) of various polyphenols, which include the gut microbiota, structure, and physical properties as well as its interactions with other dietary nutrients (macromolecules). Hence, this mini-review covers the two-way interaction between polyphenols and gut microbiota (interplay) and how polyphenols are metabolized (biotransformation) to produce various polyphenolic metabolites. Moreover, the protective effects of numerous polyphenols and their metabolites against various gastrointestinal disorders/diseases including gastritis, gastric cancer, colorectal cancer, inflammatory bowel disease (IBD) like ulcerative colitis (UC), Crohn’s disease (CD), and irritable bowel syndrome (IBS) like celiac disease (CED) are discussed. For this review, the authors chose only a few popular polyphenols (green tea polyphenol, curcumin, resveratrol, quercetin), and a discussion of their proposed mechanism underpinning the gastroprotection was elaborated with a special focus on clinical evidence. Overall, this contribution would help the general population and science community to identify a potent polyphenol with strong antioxidant, anti-inflammatory, anti-cancer, prebiotic, and immunomodulatory properties to combat various gut-related diseases or disorders (complementary therapy) along with modified lifestyle pattern and standard gastroprotective drugs. However, the data from clinical trials are much limited and hence many large-scale clinical trials should be performed (with different form/metabolites and dose) to confirm the gastroprotective activity of the above-mentioned polyphenols and their metabolites before recommendation.

Potential Therapeutic Targets of Quercetin, a Plant Flavonol, and Its Role in the Therapy of Various Types of Cancer through the Modulation of Various Cell Signaling Pathways

Polyphenolic flavonoids are considered natural, non-toxic chemopreventers, which are most commonly derived from plants, fruits, and vegetables. Most of these polyphenolics exhibit remarkable antioxidant, anti-inflammatory, and anticancer properties. Quercetin (Qu) is a chief representative of these polyphenolic compounds, which exhibits excellent antioxidant and anticancer potential, and has attracted the attention of researchers working in the area of cancer biology. Qu can regulate numerous tumor-related activities, such as oxidative stress, angiogenesis, cell cycle, tumor necrosis factor, proliferation, apoptosis, and metastasis. The anticancer properties of Qu mainly occur through the modulation of vascular endothelial growth factor (VEGF), apoptosis, phosphatidyl inositol-3-kinase (P13K)/Akt (proteinase-kinase B)/mTOR (mammalian target of rapamycin), MAPK (mitogen activated protein kinase)/ERK1/2 (extracellular signal-regulated kinase 1/2), and Wnt/β-catenin signaling pathways. The anticancer potential of Qu is documented in numerous in vivo and in vitro studies, involving several animal models and cell lines. Remarkably, this phytochemical possesses toxic activities against cancerous cells only, with limited toxic effects on normal cells. In this review, we present extensive research investigations aimed to discuss the therapeutic potential of Qu in the management of different types of cancers. The anticancer potential of Qu is specifically discussed by focusing its ability to target specific molecular signaling, such as p53, epidermal growth factor receptor (EGFR), VEGF, signal transducer and activator of transcription (STAT), PI3K/Akt, and nuclear factor kappa B (NF-κB) pathways. The anticancer potential of Qu has gained remarkable interest, but the exact mechanism of its action remains unclear. However, this natural compound has great pharmacological potential; it is now believed to be a complementary-or alternative-medicine for the prevention and treatment of different cancers.

Neuroprotective Effects of Quercetin in Pediatric Neurological Diseases

Oxidative stress is a crucial event underlying several pediatric neurological diseases, such as the central nervous system (CNS) tumors, autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD). Neuroprotective therapy with natural compounds used as antioxidants has the potential to delay, ameliorate or prevent several pediatric neurological diseases. The present review provides an overview of the most recent research outcomes following quercetin treatment for CNS tumors, ASD and ADHD as well as describes the potential in vitro and in vivo ameliorative effect on oxidative stress of bioactive natural compounds, which seems like a promising future therapy for these diseases. The neuroprotective effects of quercetin against oxidative stress can also be applied in the management of several neurodegenerative disorders with effects such as anti-cancer, anti-inflammatory, anti-viral, anti-obesity and anti-microbial. Therefore, quercetin appears to be a suitable adjuvant for therapy against pediatric neurological diseases.

Flavonoids as a Natural Enhancer of Neuroplasticity-An Overview of the Mechanism of Neurorestorative Action

Neuroplasticity is a complex physiological process occurring in the brain for its entire life. However, it is of particular importance in the case of central nervous system (CNS) disorders. Neurological recovery largely depends on the ability to reestablish the structural and functional organization of neurovascular networks, which must be pharmacologically supported. For this reason, new forms of therapy are constantly being sought. Including adjuvant therapies in standard treatment may support the enhancement of repair processes and restore impaired brain functions. The common hallmark of nerve tissue damage is increased by oxidative stress and inflammation. Thus, the studies on flavonoids with strong antioxidant and anti-inflammatory properties as a potential application in neuro intervention have been carried out for a long time. However, recent results have revealed another important property of these compounds in CNS therapy. Flavonoids possess neuroprotective activity, and promote synaptogenesis and neurogenesis, by, among other means, inhibiting oxidative stress and neuroinflammation. This paper presents an overview of the latest knowledge on the impact of flavonoids on the plasticity processes of the brain, taking into account the molecular basis of their activity.

Dietary quercetin attenuates depressive-like behaviors by inhibiting astrocyte reactivation in response to stress

The mechanisms underlying the antidepressant activity of quercetin are unknown. We investigated the effect of a quercetin-enriched diet (2 g/kg and 0.5 g/kg doses) on chronic social defeat stress (CSDS)-induced depressive-like behaviors in mice. The 2 g/kg quercetin-enriched diet attenuated depressive-like behaviors when introduced before CSDS (long-term). The long-term 0.5 g/kg quercetin-enriched diet showed a trend toward behavioral improvement. The frequencies of spontaneous excitatory postsynaptic currents (sEPSCs) and spontaneous inhibitory postsynaptic currents (sIPSCs) in the mPFC and hippocampus were significantly higher in mice fed the long-term 2 g/kg quercetin-enriched diet compared with the normal diet; no difference was found in the amygdala. Quercetin-enriched diets administered concurrently and after stress induction failed to trigger these effects. A1-specific astrocyte reactivity was markedly suppressed in the microglia and astrocytes isolated from the mPFC and hippocampus of mice fed the long-term quercetin-enriched diet, but not in those who received quercetin supplementation concurrently or after CSDS. To confirm the role of astrocytes in the neuroprotective effect of quercetin, we activated astrocytes by injecting a chemogenic AAV stimulus into the mPFC and hippocampus and found that astrocyte activation during administration of the long-term quercetin-enriched diet significantly deceased the frequency of sEPSCs and sIPSCs in the mPFC and hippocampus and further attenuated quercetin-induced behavioral improvements. These findings highlight the key role of astrocyte reactivation in the regulation of quercetin neuroprotective activity and suggest that a diet high in quercetin, whether as a fruit- and vegetable-rich diet or food additive may help cope with stress.