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Nutrients Mar 2016In vitro and some animal models have shown that quercetin, a polyphenol derived from plants, has a wide range of biological actions including anti-carcinogenic,... (Review)
Review
In vitro and some animal models have shown that quercetin, a polyphenol derived from plants, has a wide range of biological actions including anti-carcinogenic, anti-inflammatory and antiviral activities; as well as attenuating lipid peroxidation, platelet aggregation and capillary permeability. This review focuses on the physicochemical properties, dietary sources, absorption, bioavailability and metabolism of quercetin, especially main effects of quercetin on inflammation and immune function. According to the results obtained both in vitro and in vivo, good perspectives have been opened for quercetin. Nevertheless, further studies are needed to better characterize the mechanisms of action underlying the beneficial effects of quercetin on inflammation and immunity.
Topics: Administration, Oral; Animals; Anti-Inflammatory Agents; Biological Availability; Diet; Dietary Supplements; Humans; Immune System; Inflammation; Intestinal Absorption; Quercetin; Recommended Dietary Allowances; Treatment Outcome
PubMed: 26999194
DOI: 10.3390/nu8030167 -
Molecules (Basel, Switzerland) Apr 2022Polyphenols are the known group of phytochemicals that essentially consists of phenolic rings. These are the plant product present in varied fruits and vegetables. These... (Review)
Review
Polyphenols are the known group of phytochemicals that essentially consists of phenolic rings. These are the plant product present in varied fruits and vegetables. These secondary metabolites perform a protective function in plants from environmental and biological stress. When consumed as a human diet these are also known to prevent various age-associated diseases. Polyphenols are known to possess antioxidant properties and protect against oxidative stress. The literature survey was carried out using databases such as PubMed, Science direct and Springer. The research articles from last 10-12 years were selected for this review based on its relevancy with the topic. The articles selected was mainly focused on quercetin and its health benefits. The present review highlights the main functions of a flavonoid, quercetin. Quercetin is among the widely occurring polyphenol, found abundantly in nature. It is commonly present in different plant products. Onion is known to have the highest quantity of quercetin. This plant compound is possessed antioxidant properties and is considered to have a protective function against aging. It is known to be present in both free and conjugated forms. Quercetin has anti-oxidative, anti-inflammatory, anti-proliferative, anti-carcinogenic, anti-diabetic, and anti-viral properties. The molecule is lipophilic and can easily cross the BBB (Blood-Brain Barrier) and hence protects from neurodegenerative diseases. Various in vivo and in vitro studies have demonstrated the role of quercetin and here a detailed review of quercetin as a curative agent in neurodegeneration, diabetes, cancer, and inflammation has been carried out. Studies have proved that quercetin plays a crucial role in the prevention of age-related disorders. Quercetin is a potent antioxidant which is currently being used in various pharmaceuticals. Properties of quercetin can be further explored in various other disorders. Nanoformulations and liposomal formulations of quercetin can be made to treat other age associated diseases.
Topics: Aging; Antioxidants; Flavonoids; Humans; Polyphenols; Quercetin
PubMed: 35458696
DOI: 10.3390/molecules27082498 -
Phytotherapy Research : PTR Jan 2022Quercetin, widely distributed in fruits and vegetables, is a flavonoid known for its antioxidant, antiviral, antimicrobial, and antiinflammatory properties. Several... (Review)
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.
Topics: Antiviral Agents; Flavonoids; Humans; Quercetin; Virus Diseases; Virus Replication
PubMed: 34709675
DOI: 10.1002/ptr.7309 -
Molecules (Basel, Switzerland) Mar 2019Quercetin is a bioactive compound that is widely used in botanical medicine and traditional Chinese medicine due to its potent antioxidant activity. In recent years,... (Review)
Review
Quercetin is a bioactive compound that is widely used in botanical medicine and traditional Chinese medicine due to its potent antioxidant activity. In recent years, antioxidant activities of quercetin have been studied extensively, including its effects on glutathione (GSH), enzymatic activity, signal transduction pathways, and reactive oxygen species (ROS) caused by environmental and toxicological factors. Chemical studies on quercetin have mainly focused on the antioxidant activity of its metal ion complexes and complex ions. In this review, we highlight the recent advances in the antioxidant activities, chemical research, and medicinal application of quercetin.
Topics: Antioxidants; Catalase; Glutathione; Oxidative Stress; Quercetin; Reactive Oxygen Species; Signal Transduction; Structure-Activity Relationship; Superoxide Dismutase
PubMed: 30901869
DOI: 10.3390/molecules24061123 -
Nutrients Sep 2019Fruit and vegetable intake has been associated with a reduced risk of cardiovascular disease. Quercetin and kaempferol are among the most ubiquitous polyphenols in fruit... (Review)
Review
Fruit and vegetable intake has been associated with a reduced risk of cardiovascular disease. Quercetin and kaempferol are among the most ubiquitous polyphenols in fruit and vegetables. Most of the quercetin and kaempferol in plants is attached to sugar moieties rather than in the free form. The types and attachments of sugars impact bioavailability, and thus bioactivity. This article aims to review the current literature on the bioavailability of quercetin and kaempferol from food sources and evaluate the potential cardiovascular effects in humans. Foods with the highest concentrations of quercetin and kaempferol in plants are not necessarily the most bioavailable sources. Glucoside conjugates which are found in onions appear to have the highest bioavailability in humans. The absorbed quercetin and kaempferol are rapidly metabolized in the liver and circulate as methyl, glucuronide, and sulfate metabolites. These metabolites can be measured in the blood and urine to assess bioactivity in human trials. The optimal effective dose of quercetin reported to have beneficial effect of lowering blood pressure and inflammation is 500 mg of the aglycone form. Few clinical studies have examined the potential cardiovascular effects of high intakes of quercetin- and kaempferol-rich plants. However, it is possible that a lower dosage from plant sources could be effective due to of its higher bioavailability compared to the aglycone form. Studies are needed to evaluate the potential cardiovascular benefits of plants rich in quercetin and kaempferol glycoside conjugates.
Topics: Biological Availability; Cardiovascular Diseases; Humans; Kaempferols; Quercetin
PubMed: 31557798
DOI: 10.3390/nu11102288 -
Biomolecules May 2019Despite advancements in healthcare facilities for diagnosis and treatment, cancer remains the leading cause of death worldwide. As prevention is always better than cure,... (Review)
Review
Despite advancements in healthcare facilities for diagnosis and treatment, cancer remains the leading cause of death worldwide. As prevention is always better than cure, efficient strategies are needed in order to deal with the menace of cancer. The use of phytochemicals as adjuvant chemotherapeutic agents in heterogeneous human carcinomas like breast, colon, lung, ovary, and prostate cancers has shown an upward trend during the last decade or so. Flavonoids are well-known products of plant derivatives that are reportedly documented to be therapeutically active phytochemicals against many diseases encompassing malignancies, inflammatory disorders (cardiovascular disease, neurodegenerative disorder), and oxidative stress. The current review focuses on two key flavonols, fisetin and quercetin, known for their potential pharmacological relevance. Also, efforts have been made to bring together most of the concrete studies pertaining to the bioactive potential of fisetin and quercetin, especially in the modulation of a range of cancer signaling pathways. Further emphasis has also been made to highlight the molecular action of quercetin and fisetin so that one could explore cancer initiation pathways and progression, which could be helpful in designing effective treatment strategies.
Topics: Animals; Apoptosis; Chemoprevention; Flavonoids; Flavonols; Humans; Neoplasms; Quercetin; Signal Transduction
PubMed: 31064104
DOI: 10.3390/biom9050174 -
Molecules (Basel, Switzerland) Oct 2022Quercetin, as a flavonol compound found in plants, has a variety of biological activities. It is widely present in nature and the human diet, with powerful oxidative... (Review)
Review
Quercetin, as a flavonol compound found in plants, has a variety of biological activities. It is widely present in nature and the human diet, with powerful oxidative properties and biological activities. In this review, the antioxidant mechanism and broad-spectrum antibacterial properties of quercetin are revealed; the intervention effects of quercetin on pesticide poisoning and the pathway of action are investigated; the toxic effects of main mycotoxins on the collection and the detoxification process of quercetin are summarized; whether it is able to reduce the toxicity of mycotoxins is proved; and the harmful effects of heavy metal poisoning on the collection, the prevention, and control of quercetin are evaluated. This review is expected to enrich the understanding of the properties of quercetin and promote its better application in clinical practice.
Topics: Anti-Bacterial Agents; Antioxidants; Humans; Mycotoxins; Pesticides; Quercetin
PubMed: 36235082
DOI: 10.3390/molecules27196545 -
Frontiers in Immunology 2021Autoimmune diseases are a worldwide health problem with growing rates of morbidity, and are characterized by breakdown and dysregulation of the immune system. Although... (Review)
Review
Autoimmune diseases are a worldwide health problem with growing rates of morbidity, and are characterized by breakdown and dysregulation of the immune system. Although their etiology and pathogenesis remain unclear, the application of dietary supplements is gradually increasing in patients with autoimmune diseases, mainly due to their positive effects, relatively safety, and low cost. Quercetin is a natural flavonoid that is widely present in fruits, herbs, and vegetables. It has been shown to have a wide range of beneficial effects and biological activities, including anti-inflammation, anti-oxidation, and neuroprotection. In several recent studies quercetin has reportedly attenuated rheumatoid arthritis, inflammatory bowel disease, multiple sclerosis, and systemic lupus erythematosus in humans or animal models. This review summarizes the evidence for the pharmacological application of quercetin for autoimmune diseases, which supports the view that quercetin may be useful for their prevention and treatment.
Topics: Animals; Anti-Inflammatory Agents; Antirheumatic Agents; Autoimmune Diseases; Humans; Quercetin
PubMed: 34248976
DOI: 10.3389/fimmu.2021.689044 -
Biomedicine & Pharmacotherapy =... Aug 2020Isorhamnetin is one of the most important active ingredients in the fruits of Hippophae rhamnoides L. and the leaves of Ginkgo biloba L., which possesses extensive... (Review)
Review
Isorhamnetin is one of the most important active ingredients in the fruits of Hippophae rhamnoides L. and the leaves of Ginkgo biloba L., which possesses extensive pharmacological activities. At present, there have been numerous investigations on isorhamnetin, which has the effects of cardiovascular and cerebrovascular protection, anti-tumor, anti-inflammatory, anti-oxidation, organ protection, prevention of obesity, etc. The related mechanisms involve the regulation of PI3K/AKT/PKB, NF-κB, MAPK and other signaling pathways as well as the expression of related cytokines and kinases. Isorhamnetin has a high value of development and application. However, the investigations on its mechanism of action are limited and lack of detailed scientific validation. The manuscript reviewed the pharmacological effects of isorhamnetin and related mechanisms of action for the development of its medicinal properties further.
Topics: Animals; Fruit; Gene Expression Regulation; Ginkgo biloba; Hippophae; Humans; Plant Extracts; Plant Leaves; Plants, Medicinal; Quercetin; Signal Transduction
PubMed: 32502837
DOI: 10.1016/j.biopha.2020.110301 -
Biomedicine & Pharmacotherapy =... Jan 2020Quercetin is a kind of flavonoid compounds that comes from nature and is widely existed in the daily diet. Previous studies have found that quercetin has many effects... (Review)
Review
Quercetin is a kind of flavonoid compounds that comes from nature and is widely existed in the daily diet. Previous studies have found that quercetin has many effects such as anti-inflammatory, anti-oxidation and anti-cancer. Both in vivo and in vitro experiments have demonstrated that quercetin can exert anti-tumor effects by altering cell cycle progression, inhibiting cell proliferation, promoting apoptosis, inhibiting angiogenesis and metastasis progression, and affecting autophagy. This review summarizes the evidence for the pharmacological potential and inhibition of quercetin on cancers, supporting the viewpoint that quercetin should be adequately considered as a therapeutic agent against various cancers.
Topics: Animals; Antineoplastic Agents; Antioxidants; Apoptosis; Cell Line, Tumor; Cell Proliferation; DNA Methylation; Humans; Neoplasms; Quercetin
PubMed: 31733570
DOI: 10.1016/j.biopha.2019.109604