Title | Abstract | Num Citations | Date | Authors | Link |
Overviews of Biological Importance of Quercetin: A Bioactive Flavonoid | Quercetin (Que) and its derivatives are naturally occurring phytochemicals with promising bioactive effects. The antidiabetic, anti-inflammatory, antioxidant, antimicrobial, anti-Alzheimer’s, antiarthritic, cardiovascular, and wound-healing effects of Que have been extensively investigated, as well as its anticancer activity against different cancer cell lines has been recently reported. Que and its derivatives are found predominantly in the Western diet, and people might benefit from their protective effect just by taking them via diets or as a food supplement. Bioavailability-related drug-delivery systems of Que have also been markedly exploited, and Que nanoparticles appear as a promising platform to enhance their bioavailability. The present review aims to provide a brief overview of the therapeutic effects, new insights, and upcoming perspectives of Que. | 89 | 2016 Jul-Dec | Alexander Victor Anand David, Radhakrishnan Arulmoli, and Subramani Parasuraman | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5214562/ |
Anti-inflammatory potential of Quercetin in COVID-19 treatment | SARS-CoV-2 is a betacoronavirus causing severe inflammatory pneumonia, so that excessive inflammation is considered a risk factor for the disease. According to reports, cytokine storm is strongly responsible for death in such patients. Some of the consequences of severe inflammation and cytokine storms include acute respiratory distress syndrome, acute lung injury, and multiple organ dysfunction syndromes. Phylogenetic findings show more similarity of the SARS-CoV-2 virus with bat coronaviruses, and less with SARS-CoV. Quercetin is a carbohydrate-free flavonoid that is the most abundant flavonoid in vegetables and fruits and has been the most studied to determine the biological effects of flavonoids. Inflammasomes are cytosolic multi-protein complexes assembling in response to cytosolic PAMP and DAMPs, whose function is to generate active forms of cytokines IL-1β and IL-18. Activation or inhibition of the NLRP3 inflammasome is affected by regulators such as TXNIP, SIRT1 and NRF2. Quercetin suppresses the NLRP3 inflammasome by affecting these regulators. Quercetin, as an anti-inflammatory, antioxidant, analgesic and inflammatory compound, is probably a potential treatment for severe inflammation and one of the main life-threatening conditions in patients with COVID-19. | 27 | 28 January 2021 | Ali Saeedi-Boroujeni & Mohammad-Reza Mahmoudian-Sani | https://journal-inflammation.biomedcentral.com/articles/10.1186/s12950-021-00268-6 |
Interactions between polyphenolic antioxidants quercetin and naringenin dictate the distinctive redox-related chemical and biological behaviour of their mixtures | Food synergy concept is suggested to explain observations that isolated antioxidants are less bioactive than real foods containing them. However, mechanisms behind this discrepancy were hardly studied. Here, we demonstrate the profound impact of interactions between two common food flavonoids (individual: aglycones quercetin—Q and naringenin—N− or their glycosides rutin—R and naringin—N+ vs. mixed: QN− and RN+) on their electrochemical properties and redox-related bioactivities. N− and N+ seemed weak antioxidants individually, yet in both chemical and cellular tests (DPPH and CAA, respectively), they increased reducing activity of mixtures synergistically. In-depth measurements (differential pulse voltammetry) pointed to kinetics of oxidation reaction as decisive factor for antioxidant power. In cellular (HT29 cells) tests, the mixtures exhibited properties of a new substance rather than those of components. Pure flavonoids did not influence proliferation; mixtures stimulated cell growth. Individual flavonoids tended to decrease global DNA methylation with growing concentration; this effect was more pronounced for mixtures, but not concentration-dependent. In nutrigenomic studies, expression of gene set affected by QN− differed entirely from common genes modulated by individual components. These results question the current approach of predicting bioactivity of mixtures based on research with isolated antioxidants. | 3 | 10 June 2021 | Monika Baranowska, Zuzanna Koziara, Klaudia Suliborska, Wojciech Chrzanowski, Michael Wormstone, Jacek Namieśnik & Agnieszka Bartoszek | https://www.nature.com/articles/s41598-021-89314-0 |
Therapeutic Potential of Quercetin: New Insights and Perspectives for Human Health | Quercetin (Que) and its derivatives are naturally occurring phytochemicals with promising bioactive effects. The antidiabetic, anti-inflammatory, antioxidant, antimicrobial, anti-Alzheimer’s, antiarthritic, cardiovascular, and wound-healing effects of Que have been extensively investigated, as well as its anticancer activity against different cancer cell lines has been recently reported. Que and its derivatives are found predominantly in the Western diet, and people might benefit from their protective effect just by taking them via diets or as a food supplement. Bioavailability-related drug-delivery systems of Que have also been markedly exploited, and Que nanoparticles appear as a promising platform to enhance their bioavailability. The present review aims to provide a brief overview of the therapeutic effects, new insights, and upcoming perspectives of Que. | 70 | May 14, 2020 | Bahare Salehi,Laura Machin,Lianet Monzote, Javad Sharifi-Rad, Shahira M. Ezzat,Mohamed A. Salem,Rana M.Merghany,Nihal M.El Mahdy,Ceyda Sibel Kılıç,Oksana Sytar,Mehdi Sharifi-Rad, Farukh Sharopov,Natália Martins,Miquel Martorell and William C. Cho. | https://pubs.acs.org/doi/10.1021/acsomega.0c01818# |
Quercetin: Its Main Pharmacological Activity and Potential Application in Clinical Medicine | Quercetin is a flavonoid compound widely present in plants and exhibits a variety of biological activities. Research on quercetin has shown its potential for medical application. In this research, we elucidate its antioxidant mechanism and the broad-spectrum antibacterial and antiparasite properties; summarise its potential application in antioncology and cardiovascular protection and anti-immunosuppression treatment; and demonstrate its ability to alleviate the toxicity of mycotoxins. This research is expected to offer some insights and inspirations for the further study of quercetin, its properties, and the scientific basis for its better application in clinical practice. | 31 | 31 Dec 2020 | Dengyu Yang,Tiancheng Wang,Miao Long and Peng Li. | https://www.hindawi.com/journals/omcl/2020/8825387/ |
Therapeutic charm of quercetin and its derivatives: a review of research and patents | Bioactive polyphenolic compounds derived from plants are being utilized for prevention of various chronic diseases including cancer and cardiovascular disorders. Quercetin, a potential poly-phenolic flavonol, found in onions, apples and berries, has been implicated against cancer proliferation, chronic inflammation and various other oxidative manifestations. Evidences suggested that quercetin negatively regulates the numerous crucial signaling pathways associated with life-threatening diseases. Major signaling pathways including NF-κB, MAPK, PI3K-AKT and mTOR are found to be regulated by quercetin. In addition, several patents have reported recently on quercetin derivatives describing wide therapeutic applications such as anticancer/antiproliferatory, antioxidative/antiaging, antiviral, anti-inflammatory, cardioprotective. Present review emphasizes the chemistry and sources of quercetin followed by description of its broad-spectrum therapeutic potential along with proposed mechanisms of action. Furthermore, this review also highlights the important modifications in the basic chemical structure of quercetin in terms of published patents. Insolubility of the bioactive compounds restricts their medicinal importance which could be overcome by modifications in the chemical structure of so-called derivatives. Most of the patents deal with the modifications in chemical structure of quercetin mainly at hydroxyl groups and C-6 and C-7 positions. | 66 | January 2018 | Ajay Sharma,Dharambir Kashyap,Katrin Sak,Hardeep Singh Tuli | https://www.researchgate.net/publication/321733465_Therapeutic_charm_of_quercetin_and_its_derivatives_a_review_of_research_and_patents |
Quercetin: A Versatile Flavonoid | Associative evidence from observational and intervention studies in human subjects shows that a diet including plant foods (particularly fruit and vegetables rich in antioxidants) conveys health benefits. There is no evidence that any particular nutrient or class of bioactive substances makes a special contribution to these benefits. Flavonoids occur naturally in fruits, vegetables and beverages such as tea and wine. Quercetin is the major flavonoid which belongs to the class called flavonols. Quercetin is found in many common foods including apples, tea, onions, nuts, berries, cauliflower, cabbage and many other foods. Quercetin provides many health promoting benefits, including improvement of cardiovascular health, eye diseases, allergic disorders, arthritis, reducing risk for cancers and many more. The main aim of this review is to obtain a further understanding of the reported beneficial health effects of Quercetin, its pharmacological effects, clinical application and also to evaluate its safety. | 255 | November 2007 | Parul Lakhanpal & Dr. Deepak Kumar Rai | https://www.researchgate.net/publication/26502595_Quercetin_A_Versatile_Flavonoid |
Possible Therapeutic Effects of Adjuvant Quercetin Supplementation Against Early-Stage COVID-19 Infection: A Prospective, Randomized, Controlled, and Open-Label Study | Quercetin, a well-known naturally occurring polyphenol, has recently been shown by molecular docking, in vitro and in vivo studies to be a possible anti-COVID-19 candidate. Quercetin has strong antioxidant, anti-inflammatory, immunomodulatory, and antiviral properties, and it is characterized by a very high safety profile, exerted in animals and in humans. Like most other polyphenols, quercetin shows a very low rate of oral absorption and its clinical use is considered by most of modest utility. Quercetin in a delivery-food grade system with sunflower phospholipids (Quercetin Phytosome®, QP) increases its oral absorption up to 20-fold. | 3 | 8 June 2021 | Di Pierro F , Derosa G , Maffioli P, Bertuccioli A , Togni S, Riva A , Allegrini P , Khan A, Khan S, Khan BA, Altaf N, Zahid M, Ujjan ID, Nigar R, Khushk MI, Phulpoto M, Lail A, Devrajani BR, Ahmed S | https://www.dovepress.com/possible-therapeutic-effects-of-adjuvant-quercetin-supplementation-aga-peer-reviewed-fulltext-article-IJGM |
A Review of Quercetin: Chemistry, Antioxidant Properties, and Bioavailability | Flavonoids are natural antioxidants derived from plants and commonly found in foods, such as fruits and vegetables, with the ability to sequester free radicals. Quercetin, part of a subclass of flavonoids called flavonols, has received considerable attention because of its overwhelming presence in foods. Quercetin is believed to protect against several degenerative diseases by preventing lipid peroxidation. However, the degree and method of quercetin's absorption in vivo has yet to be absolutely determined. It is thought that the predominant glucoside form is converted to the aglycone, which is then converted to one of several quercetin metabolites. Synthesis and study of quercetin metabolites is key to understanding how quercetin acts as an antioxidant. This review provides a survey of the literature regarding flavonoids in general, and more specifically, quercetin. The structure and corresponding antioxidant properties are discussed to emphasize the importance of flavonoids. However, the antioxidant capability of flavonoids expressed in vitro may prove to be a moot point as their degree of absorption is controversial. Several of the studies performed in vivo have offered the alternative view that better absorbed antioxidants, like vitamin C, are exerting the antioxidant effect witnessed after consumption of certain food, such as apples. This review addresses this issue by providing a survey of in vitro and in vivostudies regarding the absorption, bioavailability, and antioxidant properties of flavonoids, specifically quercetin and its metabolites. | 10 | April 1, 2009 | Alexandra B. Bentz | https://www.jyi.org/2009-april/2017/10/15/a-review-of-quercetin-chemistry-antioxidant-properties-and-bioavailability |
Promising Effects of 3-Month Period of Quercetin Phytosome® Supplementation in the Prevention of Symptomatic COVID-19 Disease in Healthcare Workers: A Pilot Study | Quercetin, for its crucial properties, fulfills the need for a multifactor action that is useful for the potential counterbalance of a COVID-19 infection. Given this background, the aim of the study was to evaluate the potential effect of 3 months’ supplementation with Quercetin Phytosome® (250 mg twice a day) as prevention against symptomatic COVID-19. In total, 120 subjects were enrolled (males, 63; females, 57; age 49 ± 12), with 60 in the supplementation group and 60 in the placebo group. No significant differences were detected between groups in terms of gender, smoking, and chronic disease. Subjects underwent rapid COVID-19 diagnostic tests every 3 weeks. During our study, 5 subjects had COVID-19, 1 out of 60 subjects in the quercetin group and 4 out of 60 in the control group. Complete clinical remission was recorded at 7 and 15 days in the quercetin and placebo groups, respectively. Analysis showed that, at 5 months, the COVID free survival function (risk of infection) was 99.8% in subjects under quercetin supplementation and 96.5% in control group. As shown by the value of EXP(B), those who had taken the supplement had a protection factor of 14% more to not contract the COVID-19 infection than that of those who had taken a placebo. Obtained results are encouraging, but further studies are required to add quercetin as regular prophylaxis. | 24 | 4 January 2022 | Mariangela Rondanelli,Simone Perna,Clara Gasparri,Giovanna Petrangolini,Alessandro Cavioni,Milena Anna Faliva,Francesca Mansueto,Zaira Patelli,Gabriella Peroni,Alice Tartara and Antonella Riva. | https://www.mdpi.com/2075-1729/12/1/66 |
Effect of Quercetin on Injury to Indomethacin-Treated Human Embryonic Kidney 293 Cells | Nonsteroidal anti-inflammatory drugs (NSAIDs) are used to treat inflammation and pain and even to prevent the progression of cardiovascular disease. They have become widely used because of their effectiveness, especially among athletes performing high-intensity training. Indomethacin is used for pain management in sports medicine and is highly effective and versatile. However, several clinical studies have reported that indomethacin induces acute renal damage. In the present study, we determined that indomethacin reduced human embryonic kidney 293 (HEK293) cell viability in a concentration-dependent manner by triggering apoptosis. In addition, we demonstrated the effect of quercetin on indomethacin-treated HEK293 cells by inactivating the caspase-3 and caspase-9 signals. Furthermore, quercetin reduced ROS production and increased mitochondrial membrane potential (ΔΨm) in indomethacin-treated HEK293 cells. Our results indicate that quercetin can interrupt the activated caspase and mitochondrial pathway induced by indomethacin in HEK293 cells and affect apoptotic mRNA expression. Quercetin can protect against indomethacin-induced HEK293 cell apoptosis by regulating abnormal ΔΨm and apoptotic mRNA expression. | 11 | 25 October 2021 | Chun Chen,Jai-Sing Yang,Chi-Cheng Lu,Yu-Tse Wu and Fu-An Chen | https://www.mdpi.com/2075-1729/11/11/1134 |
Quercetin: Antiviral Significance and Possible COVID-19 Integrative Considerations | Quercetin, a naturally occurring dietary flavonoid, is well known to ameliorate chronic diseases and aging processes in humans, and its antiviral properties have been investigated in numerous studies. In silico and in vitro studies demonstrated that quercetin can interfere with various stages of the coronavirus entry and replication cycle such as PLpro, 3CLpro, and NTPase/helicase. Due to its pleiotropic activities and lack of systemic toxicity, quercetin and its derivatives may represent target compounds to be tested in future clinical trials to enrich the drug arsenal against coronavirus infections. There is evidence that quercetin in combination with, for example, vitamins C and D, may exert a synergistic antiviral action that may provide either an alternative or additional therapeutic/preventive option due to overlapping antiviral and immunomodulatory properties. This review summarizes the antiviral significance of quercetin and proposes a possible strategy for the effective utilization of natural polyphenols in our daily diet for the prevention of viral infection. | 173 | December 3, 2020 | Pawan K. Agrawal, Chandan Agrawal, Gerald Blunden | https://journals.sagepub.com/doi/full/10.1177/1934578X20976293 |
Quercetin and its derivates as antiviral potentials: A comprehensive review | Quercetin, widely distributed in fruits and vegetables, is a flavonoid known for its antioxidant, antiviral, antimicrobial, and antiinflammatory properties. Several studies highlight the potential use of quercetin as an antiviral, due to its ability to inhibit the initial stages of virus infection, to be able to interact with proteases important for viral replication, and to reduce inflammation caused by infection. Quercetin could also be useful in combination with other drugs to potentially enhance the effects or synergistically interact with them, in order to reduce their side effects and related toxicity. Since there is no comprehensive compilation about antiviral activities of quercetin and derivates, the aim of this review is providing a summary of their antiviral activities on a set of human viral infections along with mechanisms of action. Thus, the following family of viruses are examined: Flaviviridae, Herpesviridae, Orthomyxoviridae, Coronaviridae, Hepadnaviridae, Retroviridae, Picornaviridae, Pneumoviridae, and Filoviridae. | 1 | 28 October 2021 | Amalia Di Petrillo, Germano Orrù, Antonella Fais, Massimo C. Fantini | https://onlinelibrary.wiley.com/doi/full/10.1002/ptr.7309 |
Antioxidant and cytotoxic studies for kaempferol, quercetin and isoquercitrin | The aim of the present study was to investigate a cytotoxic oxidative cell stress related and the antioxidant profile of kaempferol, quercetin, and isoquercitrin. The flavonol compounds were able to act as scavengers of superoxide anion (but not hydrogen peroxide), hypochlorous acid, chloramine and nitric oxide. Although flavonoids are widely described as antioxidants and this activity is generally related to beneficial effects on human health, here we show important cytotoxic actions of three well known flavonoids. They were able to promote hemolysis which one was exacerbated on the presence of hypochlorous acid but not by AAPH radical. Therefore, despite they expected scavenger action over free radicals an oxidants, these compounds could be very lesive to living organisms by acting over erythrocytes and maybe other cellular types.cytotoxicity; oxidative damage; free radical; flavonoids | 36 | 09 Mar 2012 | José Carlos Rebuglio Vellosa Luis O. Regasini Najeh Maissar Khalil Vanderlan da Silva Bolzani Omar A. K. Khalil Francine Alessandra Manente Harli Pasquini Netto Olga M. M. de Faria Oliveira | https://www.scielo.br/j/eq/a/hqDVYFgRchM6Y8zk5dRZNvp/?lang=en |
Quercetin as a potential treatment for COVID-19-induced acute kidney injury: Based on network pharmacology and molecular docking study | Kidneys are one of the targets for SARS-CoV-2, it is reported that up to 36% of patients with SARS-CoV-2 infection would develop into acute kidney injury (AKI). AKI is associated with high mortality in the clinical setting and contributes to the transition of AKI to chronic kidney disease (CKD). Up to date, the underlying mechanisms are obscure and there is no effective and specific treatment for COVID-19-induced AKI. In the present study, we investigated the mechanisms and interactions between Quercetin and SARS-CoV-2 targets proteins by using network pharmacology and molecular docking. The renal protective effects of Quercetin on COVID-19-induced AKI may be associated with the blockade of the activation of inflammatory, cell apoptosis-related signaling pathways. Quercetin may also serve as SARS-CoV-2 inhibitor by binding with the active sites of SARS-CoV-2 main protease 3CL and ACE2, therefore suppressing the functions of the proteins to cut the viral life cycle. In conclusion, Quercetin may be a novel therapeutic agent for COVID-19-induced AKI. Inhibition of inflammatory, cell apoptosis-related signaling pathways may be the critical mechanisms by which Quercetin protects kidney from SARS-CoV-2 injury. | 13 | January 14, 2021 | Yue-Yu Gu,Min Zhang,Huan Cen,Yi-Fan Wu,Zhaoyu Lu,Fuhua Lu,Xu-Sheng Liu,Hui-Yao Lan | https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0245209 |
Pharmacological Applications of Quercetin and its Derivatives: A Short Review | Quercetin (3,3ʹ,4ʹ,5,7-pentahydroxyl-flavone) is a flavonol, and it belongs to a class of plant secondary metabolites known as flavonoids. It is present in man’s daily diet and is known for biological activities such as antioxidant, antiviral, anticancer, antimicrobial, anti-inflammatory and many more. Quercetin has been reported for its antioxidant and antiviral applications, hence, it is not only used as such but also its various derivatized forms have potentials for development into drugs for the treatment of diseases caused by oxidative stress and lethal viruses. | 5 | September 2014 | Aneela Maalik,Farhan A. Khan,Amara Mumtaz,Adeem Mehmood,Saira Azhar,Muhammad Atif,Sabiha Karim,Yasir Altaf and Imran Tariq | http://www.bioline.org.br/pdf?pr14215 |
Novel quercetin and apigenin-acetamide derivatives: design, synthesis, characterization, biological evaluation and molecular docking studies | Flavonoids exhibit essential but limited biological properties which can be enhanced through chemical modifications. In this study, we designed, synthesized, and characterized two novel flavonoid derivatives, quercetin penta-acetamide (1S3) and apigenin tri-acetamide (2S3). These compounds were confirmed using (1H, 13C) NMR, UV-Vis, and FT-IR characterizations. Their interaction with fish sperm DNA (FS-DNA) at physiological pH was investigated by UV-Vis and fluorescence spectrophotometry. The binding constant (Kb) for the UV-Vis experiment was found to be 1.43 ± 0.3 × 104 M−1 for 1S3 and 2.08 ± 0.2 × 104 M−1 for 2S3. The binding constants (KSV) for the fluorescence quenching experiment were 1.83 × 104 M−1 and 1.96 × 104 M−1 for 1S3 and 2S3, respectively. Based on molecular modeling and docking studies, the binding affinities were found to be −7.9 and −9.1 kcal mol−1, for 1S3 and 2S3, respectively. The compound–DNA docked model correlated with our experimental results, and they are groove binders. Furthermore, mutagenicity potential was examined. 1S3 and its metabolites showed no mutagenic activity for both TA98 and TA100 strains. 2S3 did not show any mutagenic activity for the strain TA 98, while its metabolites were only active at high doses. Both 2S3 and its metabolites showed mutagenic activity in the TA100 strain. | 3 | 2020 | Daniel Isika,Mustafa Çeşme,Francis J. Osongaa and Omowunmi A. Sadik | https://pubs.rsc.org/en/content/articlelanding/2020/ra/d0ra04559d#!divCitation |
Quercetin: A Promising Flavonoid with a Dynamic Ability to Treat Various Diseases, Infections, and Cancers | Quercetin is a multifaceted dietary flavonoid with a multitude of biologic activities that can be used to treat various ailments. These include cancer, bacterial and viral infections, cardiovascular disease, and diabetes. A greater emphasis on cancer is discussed within this paper by highlighting some of the beneficial qualities of quercetin without including other related dietary flavonoids and quercetin analogs. In vitro and in vivo analysis are evaluated without making recommendations on dosage, dosing regiments, or administration since quercetin has not been subjected to rigorous clinical trials despite the significant amount of research that has been conducted with quercetin. | 6034 | February 2016 | Aaron J. Smith, John Oertle, Dan Warren, Dino Prato. | https://www.scirp.org/journal/paperinformation.aspx?paperid=63623 |
Therapeutic Potential of Quercetin Based on Nanotechnology: A Review | Quercetin, a natural flavonoid, has attracted considerable interest in its numerous health benefits; nevertheless, some limitations restrict its oral use. Therefore, to improve its bioavailability, investigators are applying nanotechnology, specifically nanocarriers, to direct quercetin to specific sites of action. Studies indicate that cancer is the most investigated disease due to high mortality and poor prognosis around the world, and the antiproliferative and apoptotic effects in different types of neoplasia, including breast cancer, have been reported. The greatest interest has also been focused on inflammatory and cardiovascular diseases. Thus, this review outlines the most relevant development scenarios, highlighting studies using the delivery mechanisms, showing that the studies present promising results. | 18 | 2 Sep 2019 | da Silva, T. A.;* Gomes, J. H. R.; de Bulhões, L. C. G.; Neto, R. M. S.; Júnior, I. D. B.; de Moura, M. A. B. F.; do Nascimento, T. G.; Grillo, L. A. M.; Dornelas, C .B | http://static.sites.sbq.org.br/rvq.sbq.org.br/pdf/v11n4a24.pdf |
Quercetin feeding protects plants against oxidative stress [version 1; peer review: 1 approved, 1 approved with reservations] | Background: Flavonoids are a complex group of plant-made phenolic compounds that are considered of high nutraceutical value. Their beneficial impacts on human health relate predominantly to their capacity to serve as antioxidants, thus protecting cells against the damaging impact of reactive oxygen species. Recent studies have also pointed at an essential role for flavonoids as antioxidants in plants. Results: Here we show that the flavonoid quercetin, which is known to protect human cells from oxidative stress, has the same effect on plant cells. Under oxidative stress conditions, Arabidopsis plants grown on quercetin-supplemented media grew better than controls and contained less oxidized proteins. This protection was also observed in the dicot Nicotiana tabacum and the aquatic monocot Lemna gibba. Conclusion: Quercetin can be used as a general antioxidant stress protectant for plants. | 302 | 03 Oct 16 | Jasmina Kurepa, Timothy E. Shull, Jan A. Smalle | https://f1000research.com/articles/5-2430 |
Quercetin: A Versatile Flavonoid | Associative evidence from observational and intervention studies in human subjects shows that a diet including plant foods (particularly fruit and vegetables rich in antioxidants) conveyshealth benefits. There is no evidence that any particular nutrient or class of bioactive substances makes a special contribution to these benefits. Flavonoids occur naturally in fruits, vegetables and beverages such as tea and wine. Quercetin is the major flavonoid which belongs to the class called flavonols. Quercetin is found in many common foods including apples, tea, onions, nuts, berries, cauliflower, cabbage and many other foods. Quercetin provides many health promoting benefits, including improvement of cardiovascular health, eye diseases, allergic disorders, arthritis, reducing risk for cancers and many more. The main aim of this review is to obtain a further understanding of the reported beneficial health effect s of Quercetin, its pharmacological effects, clinical application and also to evaluate its safety | 4 | Jul-Dec 2007 | Dr. Parul Lakhanpal, MD and Dr. Deepak Kumar Rai, MD | https://gjmpbu.org/ijmu/Paper05_Jul-Dec2007_.pdf |
Quercetin as a potential nutraceutic against coronavirus disease 2019 (COVID-19) | Introduction: The coronavirus disease 2019 (COVID-19) is a viral disease that affects several human organs and sys- tems. Preventive or prophylactic treatments are specifically useful in emerging infectious diseases such as COVID-19 because they reduce the need for hospitalization and public health spending. Although the SARS-CoV-2 preventive effect of several therapeutic agents (e.g., hydroxychloroquine/chloroquine, remdesivir, lopinavir, and ritonavir) has been extensively evaluated, none of them have demonstrated significant clinical efficacy. Method: We aim to address and discuss the recently published studies on the chemoprophylactic potential of quer- cetin against SARS-CoV-2. A literature search was carried out on different databases, such as PubMed/MEDLINE, Scielo, Scopus, Web of Science, Cochrane Library, and Clinical Trials.gov. Studies that report the effect of quercetin against SARS-CoV-2 or other types of coronaviruses were included and critically evaluated. Results: Studies have shown that quercetin, an FDA-approved flavonoid used as an antioxidant and anti-inflamma- tory agent, inhibits the entry of coronavirus (SARS-CoV) into the host cell. Moreover, an in silico study showed that quercetin is a potent inhibitor of the SARS-CoV-2 main protease (Mpro), suggesting that this flavonoid is also active against COVID-19. Conclusions: Because quercetin might prevent and lessen the duration of SARS-CoV-2 infections, it is plausible to assume that the prophylactic use of this flavonoid produces several clinical benefits. However, this preliminary evidence needs to be confirmed by in vitro assays and, posteriorly, in randomized clinical trials. | 20.12.2020 | Júlio César Moreira Brito,William Gustavo Lima,Waleska Stephanie da Cruz Nizer | https://scielo.isciii.es/pdf/ars/v62n1/2340-9894-ars-62-01-85.pdf | |
Quercetin in prostate cancer: Chemotherapeutic and chemopreventive effects, mechanisms and clinical application potential (Review) | The morbidity and mortality of prostate cancer have been increasing recently, and the comprehensive treatment for prostate cancer is unable to achieve satisfactory outcomes. Quercetin is a natural flavonoid compound that has attracted increased interest and attention due to its anticancer activity. In vitro and in vivo studies have verified that quercetin effectively inhibits prostate cancer via various mechanisms. Clinical trails concerning the pharmacokinetics and application of quercetin in humans have also obtained promising results. Meanwhile, epidemiologic studies have demonstrated a negative association between quercetin intake and prostate cancer incidence and have suggested a chemopreventive effect of quercetin on prostate cancer that has been exhibited in animal experiments. The main issue concerning quercetin utilization is its low bioavailability. Therefore, solutions to the issues concerning its use such as alteration of the molecular structure and combination therapy are in the exploratory stage. In the present review, the most important aspects of chemotherapeutic and chemopreventive effects, mechanisms and clinical application potential of quercetin in prostate cancer are summarized. | 67 | March 31, 2015 | Feiya Yang Liming Song Huiping Wang Jun Wang Zhiqing Xu Nianzeng Xing | https://www.spandidos-publications.com/10.3892/or.2015.3886 |
Quercetin and Epigallocatechin Gallate in the Prevention and Treatment of Obesity: From Molecular to Clinical Studies | Obesity is a worldwide epidemic, which is characterized by the excess accumulation of adipose tissue and to an extent that impairs both the physical and psychosocial health and well-being. There are several weight-loss strategies available, including dietary modification, pharmacotherapy, and bariatric surgery, but many are ineffective or not a long-term solution. Bioactive compounds present in medicinal plants and plant extracts, like polyphenols, constitute the oldest and most extensive form of alternative treatments for the prevention and management of obesity. Their consumption is currently increasing in the population due to the high cost, potential adverse effects, and limited benefits of the currently available pharmaceutical drugs. A great number of studies has explored how dietary polyphenols can interfere with the different mechanisms associated with obesity development. They suggest that these compounds can decrease energy and food intake, lipogenesis, and preadipocyte differentiation and proliferation, while increasing energy expenditure, lipolysis, and fat oxidation. Both quercetin, one of the most common dietary flavonols in the western diet, and epigallocatechin gallate (EGCG), the most abundant polyphenol in green tea, exhibit antiobesity effects in adipocyte cultures and animal models. However, the extrapolation of these potential benefits to obese humans remains unclear. Although quercetin supplementation does not seem to exert any beneficial effects on body weight, this polyphenol could prevent the obesity-associated mortality by reducing cardiovascular disease risk. An important consideration for the design of further trials is the occurrence of gene polymorphisms in key enzymes involved in flavanol metabolism, which determines a subject's sensitivity to catechins and seems, therefore, crucial for the success of the antiobesity intervention. Although the evidence supporting antiobesity effects is more consistent in EGCG than with quercetin studies, they could still be beneficial by reducing the cardiovascular risk of obese subjects, rather than inducing body weight loss. | 8 | 6 Aug 2019 | Catalina Carrasco-Pozo,María Jose Cires and Martin Gotteland | https://www.liebertpub.com/doi/10.1089/jmf.2018.0193 |
QUERCETIN, ENCAPSULATED QUERCETIN AND ITS APPLICATION- A REVIEW | Flavonoids are plant secondary metabolite shows a wide range of pharmacological and biological functions. Among the flavonoids, quercetin gained special attention for its potential therapeutic activities. The aim of this work was to summarize the medicinal property of quercetin, role of quercetin in synthesizing the silver and gold nanoparticles, pros and cons of quercetin, nanoencapsulation of quercetin and its advantages. This review article summarizes the published experimental research and scientific literature from the databases including PubMed, Google and local library searches. The results of these studies provide a complete understanding of the biological action of quercetin. Pharmaceutical effects of quercetin such as anti-oxidant, anti-inflammatory, anti-cancer, anti-toxic and immunomodulatory effects prove that quercetin has potential therapeutic value, though it has several beneficial effects on human health, it possesses some disadvantages like poor solubility, low bioavailability, the hydrophobic nature and poor permeability. To overcome the disadvantages of quercetin, it is encapsulated in the polymers to enhance its bioavailability and to increase its solubility. In this paper, a brief description about the encapsulation of quercetin and its application were focused. | 08 Aug 2014 | NATHIYA S, DURGA M, DEVASENA T | https://innovareacademics.in/journals/index.php/ijpps/article/view/1470/9355 | |
Effect of quercetin nanoparticles on the kidney of the streptozotocin-induced diabetes in male rats: A histological study and serum biochemical alterations | Diabetes is directly involved in oxidative stress production. Therefore, this study was conducted to investigate the morphological and functional alterations caused by oxidative stress and to evaluate the antioxidant effect of quercetin nanoparticles (QUNPs) in streptozotocin (STZ)-induced diabetic (type II) rats. Seventy two male albino adult rats were randomly distributed in 6 different experimental groups, with 12 animals per group: Normal Control (NC) group, Positive Control (PC) group received one dose of STZ (60 mg/kg body weight [bw]); QUNPs 10 mg/kg bw/day alone group; QUNPs 10 mg/kg bw/day + one dose of STZ (60 mg/kg bw) group; QUNPs 20 mg/kg bw/day alone group; and QUNPs 20 mg/kg bw/day + one dose of STZ (60 mg/kg bw) group. STZ-diabetic rats were treated with QUNPs (10 and 20 mg/kg bw/day) for 7 weeks to analyze their effects on markers of renal enzymes antioxidant [malondialdehyde (MDA), catalase (CAT), glutathione reductase (GR), and glutathione peroxidase (GPx)], total protein and albumin, and also on kidney tissues. The results showed that the particle size of QUNPs is 16.13 nm at flow rate 10 ml/min. QUNPs especially at the dosage of 20 mg/kg bw/day gave results close to normal values observed in NC compared to PC. Also, histopathology of kidney sections for QUNPs 20 mg/kg bw/day + STZ and QUNPs (10 and 20 mg/kg bw/day) alone, appeared similar to NC. It can be concluded that QUNPs could become a promising adjuvant in the treatment of diabetes mellitus and can act as an antioxidant agent. | 2 | September 2017 | Suhailah S. Al-Jameel & Soheir N. Abd El-Rahman | https://academicjournals.org/journal/AJB/article-abstract/5B8A9E966131 |
Bioavailability of Quercetin | Quercetin is generally present as quercetin glycoside in nature and involves quercetin aglycone conjugated to sugar moieties such as glucose or rutinose. Quercetin has been reported to exhibit antioxidative, anti-carcinogenic, anti-inflammatory, anti-aggregatory and vasodilating effects. Unfortunately, quercetin bioavailability is generally poor and several factors affect its bioavailability. Quercetin bioavailability varies widely between individuals. Gender may affect quercetin bioavailability, but there is no clear evidence. There has been little research looking for the effects of age and vitamin C status on bioavailability of quercetin supplements, but there is no research seeking out the effects of age and vitamin C status on bioavailability of food-derived quercetin. Presence of sugar moieties increases bioavailability and differences in quercetin-conjugated glycosides affect bioavailability. For instance, onion-derived quercetin, which is mainly quercetin glucoside, is more bioavailable than apple-derived quercetin, which contains quercetin rhamnoside and quercetin galactoside. Quercetin is lipophilic compound, thus dietary fat enhances its bioavailability. Nondigestible fiber may also improve quercetin bioavailability. Quercetin bioavailability is greater when it is consumed as an integral food component. This study reviews and discusses factors affecting quercetin bioavailability. | 07-10-2016 | Müzeyyen Berkel Kaşıkcı and Neriman Bağdatlıoğlu | https://www.foodandnutritionjournal.org/vol04nospl-issue-conf-october-2016/bioavailability-of-quercetin/ | |
Evaluation of the Effect of Zinc, Quercetin, Bromelain and Vitamin C on COVID-19 Patients | Coronavirus disease 2019 (COVID-19) is an infectious disease caused by a new strain of coronavirus. There are three phases of COVID-19: early infection stage, pulmonary stage and hyper-inflammation stage respectively. It is important to prevent lung or other organs injuries by preventing phase-II and phase-III via pharmacological or non-pharmacological treatments. This was a case series study done on twenty-two patients confirmed to be infected with SARS-CoV-2 and diagnosed with COVID-19. Patients in this study have been used quercetin 800 mg, bromelain 165 mg, zinc acetate 50 mg and ascorbic acid 1 g once daily as supplements for 3 to 5 days during SARS-CoV-2 infection. The aim of this study is to evaluate the safety and efficacy of quercetin, bromelain, zinc and ascorbic acid combination supplements on patients with COVID-19. The mean levels of WBC, ANC, ALC, AMC and AST were normal among all included patients before and after taking quercetin, bromelain, zinc and ascorbic acid supplements (P-value > 0.05). Quercetin 800 mg, bromelain 165 mg, zinc acetate 50 mg and ascorbic acid 1 g once daily supplements were safe for patients infected with SARS-CoV-2 and may prevent poor prognosis. Randomized clinical trials needed in the future to ensure the efficacy of quercetin, bromelain, zinc and vitamin c combination. | 3 | December 24, 2020 | Amr Kamel, Heba Abdelseed, Yousef Albalawi, Eman Aslsalameen, Yousef Almutairi, Abdullah Alkattan | https://www.medrxiv.org/content/10.1101/2020.12.22.20245993v1 |
Bioavailability of Quercetin in Humans with a Focus on Interindividual Variation | After consumption of plant-derived foods or beverages, dietary polyphenols such as quercetin are absorbed in the small intestine and metabolized by the body, or they are subject to catabolism by the gut microbiota followed by absorption of the resulting products by the colon. The resulting compounds are bioavailable, circulate in the blood as conjugates with glucuronide, methyl, or sulfate groups attached, and they are eventually excreted in the urine. In this review, the various conjugates from different intervention studies are summarized and discussed. In addition, the substantial variation between different individuals in the measured quercetin bioavailability parameters is assessed in detail by examining published human intervention studies where sources of quercetin have been consumed in the form of food, beverages, or supplements. It is apparent that most reported studies have examined quercetin and/or metabolites in urine and plasma from a relatively small number of volunteers. Despite this limitation, it is evident that there is less interindividual variation in metabolites which are derived from absorption in the small intestine compared to catabolites derived from the action of microbiota in the colon. There is also some evidence that a high absorber of intact quercetin conjugates could be a low absorber of microbiota-catalyzed phenolics, and vice versa. From the studies reported so far, the reasons or causes of the interindividual differences are not clear, but, based on the known metabolic pathways, it is predicted that dietary history, genetic polymorphisms, and variations in gut microbiota metabolism would play significant roles. In conclusion, quercetin bioavailability is subject to substantial variation between individuals, and further work is required to establish if this contributes to interindividual differences in biological responses. | 7 | 2018 | A. Filipa Almeida ,Grethe Iren A. Borge,Mariusz Piskula ,Adriana Tudose,Liliana Tudoreanu,Kateˇrina Valentov ́a ,Gary Williamson, and Cl ́audia N. Santos | https://researchmgt.monash.edu/ws/portalfiles/portal/256521175/256521066_oa.pdf |
Effects of Quercetin on Blood Pressure: A Systematic Review and Meta‐Analysis of Randomized Controlled Trials | Quercetin, the most abundant dietary flavonol, has antioxidant effects in cardiovascular disease, but the evidence regarding its effects on blood pressure (BP) has not been conclusive. We assessed the impact of quercetin on BP through a systematic review and meta‐analysis of available randomized controlled trials. | 12 Jul 2016 | Maria‐Corina Serban,Amirhossein Sahebkar,Alberto Zanchetti,Dimitri P. Mikhailidis,George Howard,Diana Antal,Florina Andrica,Ali Ahmed,Wilbert S. Aronow,Paul Muntner,Gregory Y. H. Lip,Ian Graham,Nathan Wong,Jacek Rysz,Maciej Banach and for the Lipid and Blood Pressure Meta‐analysis Collaboration (LBPMC) Group | https://www.ahajournals.org/doi/10.1161/jaha.115.002713 | |
The Influence of Quercetin on Exercise Performance and Muscle Mitochondria | This is a review of recent human clinical trials evaluating quercetin supplementation at doses of 1,000 mg/day. A recent study suggests supplementation with quercetin combined with fish oil and green tea extracts yields greater effect than quercetin alone. Some studies on athletic performance suggest moderate effect in trained athletes and more significant effect in untrained individuals. Both animal and human data suggest quercetin stimulates mitochondrial biogenesis. The scientific literature provides compelling clinical information about this interesting flavonol. | May 2010 | Jacob Schor, ND, FABNO | https://www.naturalmedicinejournal.com/journal/2010-05/influence-quercetin-exercise-performance-and-muscle-mitochondria | |
Dry matter yield, feeding value, and antioxidant activity in Mediterranean chicory (Cichorium intybus L.) germplasm | Knowledge about the forage yield potential and bioactive compound contents of Mediterranean natural populations of chicory is still scarce, even though it could be very helpful in view of the exploitation of the feeding value of local chicory germplasm for ruminants. Dry matter yield, chemical composition, antioxidant capacity, total polyphenols, flavonoids, and condensed tannins content were determined in 7 natural populations of Mediterranean wild chicory and, as a comparison, in the chicory commercial variety Spadona. Original seed was collected in different pastureland areas of Sardinia (Italy) and plants were grown in North Sardinia. Statistically significant differences were found in the leaf dry matter yield, ranging from 1.3 to 3.8 t ha –1,and were not found in protein and fiber contents. The local populations were comparable to the commercial variety; however, the antioxidant activities, detected by means of 2 in vitro assays, significantly differed between populations. Among bioactive compounds, total flavonoids ranged from 27 to 37 g catechin equivalent kg –1 dry weight and statistically significant differences were also found in total polyphenol content and nontannic polyphenols; condensed tannins were not detected. Considering the importance of some bioactive compounds for the enhancement of animal nutrition and welfare, the exploitation of variability in bioactive compound content and antioxidant capacity of the chicory natural populations can be important for a more complete valorization of its Mediterranean germplasm. | 10 | 27.05.2014 | Giovanna PILUZZA, Leonardo SULAS, Simonetta BULLITTA | https://dergipark.org.tr/tr/download/article-file/120826 |
A Comparative Study between Topical 5% Minoxidil and Topical “Redensyl, Capixyl, and Procapil”Combination in Men with Androgenetic Alopecia | Objective: Androgenetic Alopecia (AGA) is one of the three most common forms of noncicatricial alopecia characterized by hair loss in both men and women. It occurs in 50% of men above in their sixth decade. Currently, two effective treatments for AGA are used in men: topical minoxidil and oral finasteride. However, although clinical studies have shown that minoxidil and finasteride have positive therapeutic outcomes, their use can have certain side-effects. In this study, we aimed to compare the safety and effectiveness of an alternative treatment, Redensyl, Capixyl, and Procapil (RCP), and 5% minoxidil solution in adult male patients suffering from AGA. Methods: This randomized controlled study was conducted on patients who used either RCP or 5% minoxidil for 24 weeks. The patients applied 1 mL of each solution to their head skin twice each day, in the morning and evening. Results: The comparison between RCP and minoxidil groups revealed that patients treated with RCP had a significantly higher researcher score (minoxidil group 25.5% vs. RCP group 64.7%), higher global photographic evaluation score (minoxidil: 60% vs. RCP: 88.9%), and higher self-evaluation score. Conclusion: The RCP group showed a significantly better clinical recovery in terms of hair growth. | 5 | March 14, 2019 | Nezih Karaca and Nebahat Demet Akpolat | https://www.hilarispublisher.com/open-access/a-comparative-study-between-topical-5-minoxidil-and-topical-redensyl-capixyl-and-procapil-combination-in-men-with-androg.pdf |
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