Quercetin

Quercetin(117-39-5) is commonly used as a expectorant drug in clinical medicine in China. This product has various kinds of pharmacological functions such as having a good expectorant, cough effect, also having certain anti-asthma effect, and having further effects of lowering blood pressure, enhancing capillary resistance, reducing capillary fragility, reducing blood fat, expansion of coronary artery, increasing coronary blood flow.
Clinically, quercetin is mainly used for treating clinical bronchitis and phlegmatic inflammation. It also has adjuvant therapy effect on coronary artery disease and high blood pressure. FDA may have some kinds of adverse reactions such as dry mouth, dizziness, and burning sensation in stomach area which may disappear after treatment.
Quercetin is widely distributed in angiosperms such as Threevein Astere, Golden Saxifrage, berchemia lineata, gold, rhododendron dauricum, seguin loquat, purple rhododendron, Rhododendron micranthum, Japanese Ardisia Herb and Apocynum. It is a kind of aglycon which mainly combines with carbohydrate to be in the form of glycosides, such as quercetin, rutin, hyperoside.

Quercetin(117-39-5) can significantly inhibit the effect of cancer-promoting agent, inhibiting the growth of malignant cells in vitro, inhibiting the DNA, RNA, and protein synthesis of Ehrlich ascites tumor cells.
Quercetin has effects of inhibiting the platelet aggregation and the release effect of serotonin (5-HT) as well as inhibiting the platelet aggregation process which is induced by ADP, thrombin and platelet-activating factor (PAF) in which having the strongest inhibition effect on PAF. Moreover, it can also inhibit thrombin-induced the release of platelet 3H-5-HT of rabbit.
(1) Intravenously adding 0.5mmol/L quercetin (10ml/kg) drop wise can significantly shorten the duration of arrhythmia in mice of myocardial ischemia and reperfusion, reduce the incidence of ventricular fibrillation, and reduce the content of MDA as well as the activity of xanthine oxidase inside the ischemic myocardial tissue while having significantly protective effect on SOD. This may be related to the inhibition of the formation process of myocardial oxygen free radical and protection of SOD or directly scavenging of radical free oxygen in myocardial tissue.
(2) Having in vitro assay with quercetin and rutin being together can disperse the platelet and thrombus adhered to the rabbit aorta endothelium with an EC50 of 80 and 500nmol/L, respectivly. In vitro assay of a concentration of quercetin at 50~500μmol/L has shown that it can improve cAMP level inside human platelet, enhance the PGI2-induced improvement of cAMP level of human platelet and inhibit the ADP-induced platelet aggregation. Quercetin at a concentration ranged from 2~50μmol/L has a concentration-dependent enhancement effect. Quercetin, at a concentration of 300 μmol/L in vitro can not only almost completely inhibit the process of platelet aggregation induced by platelet-activating factor (PAF), but also inhibit thrombin and ADP-induced platelet aggregation as well as inhibit the release of rabbit platelet 3H-5HT induced by thrombin; A concentration of 30 μmol/L can significantly reduce the liquidity of platelet membrane.
(3) Quercetin, at a concentration at 4×10-5~1×10-1g/ml, has a inhibitory effect on the release of histamine and SRS-A in the lung of ovalbumin-sensitized guinea pig lung; A concentration of 1 × 10-5g/ml also has inhibitory effect on the for SRS-A induced ileum contraction of guinea pig. Quercetin, at a concentration of 5~50μmol/L, has a concentration-dependent inhibitory effect on the process of histamine release of human basophilic leucocyte. Its inhibitory effect on the ileum contraction of ovalbumin sensitized guinea pig is also concentration-dependent with an IC50 of 10μmol/L. A concentration in the range of 5×10-6~5×10-5mol L can inhibit the proliferation of cytotoxic T lymphocyte (CTL) as well as inhibit ConA-induced DNA synthesis.
The above information is edited by the Chemicalbook of Dai Xiongfeng.

It is yellow needle-like crystalline powder. It has good thermal stability with the decomposition temperature being 314 °C. It can improve the light-tolerance property of food pigment for preventing the change of the flavor of food. Its color will change in case of metal ion. It is slightly soluble in water, soluble in an alkaline aqueous solution. Quercetin and its derivatives is a kind of flavonoid compound which are widely present in a variety of vegetables and fruits such as onions, sea buckthorn, hawthorn, locust, tea. It has effects of anti-free radical, anti-oxidation, anti-bacterial, anti-viral as well as anti-allergic. For application in lard, its various antioxidant indicators are similar with that of BHA or PG.
Because of the double bond between the 2,3 position as well as the two hydroxyl groups in 3 ', 4' , it has application of being used as a metal chelate or being the receptor of the free groups produced during the oxidation process of grease. In this case, it can be used as the antioxidants of ascorbic acid or grease. It also has a diuretic effect.

1. It can be used as a kind of antioxidant which is mainly used for oil, drinks, cold drinks, meat processing products.
2. It has good effects of expectorant, anti-cough, anti-asthma and can be used for treating chronic bronchitis as well as for adjuvant therapy of coronary heart disease and high blood pressure.
3. It can also be used as analytical standards

1. Crash the bark of trees in Fagaceae Quercus (Quercus) into powder, wash with hot brine, extract with dilute ammonia before neutralization with dilute sulfuric acid. Boil the filtrate and separate crystals.
2. It can be obtained by extracting Liliaceae onion (Alliumcepa) with 95% ethanol; it can also be produced from rutin (rutin) extract, quercetin, isoquercitrin, fennel glycosides, hyperoside, quercimeritrin, bloom glycosides through rutin degrading enzyme or hydrolysis with acidic aqueous solution.

The name of quercetin has been used since 1857, which is derived from quercetum (oak forest) after Quercus. Quercetin is widely found in flowers, leaves, and fruits of various plants. Vegetables (such as onions, ginger, celery, etc.), fruits (such as apples, strawberries, etc.), beverages (such as tea, coffee, red wine, fruit juice, etc.), and more than 100 kinds of Chinese herbal medicines (such as Threevein Aster, mountain white chrysanthemum, Huai rice, Apocynum, Ginkgo biloba, etc.) contain this ingredient.
Threevein Aster is a Chinese herbal medicine and used in Jiangxi province, China, for more than 30 years. Its plant name is three veins Mala, Compositae. It is rich in drug sources, which can be found in Southern provinces of China. Clinical practice proved that it has significant anti-inflammatory and expectorant effects, and it is a good prescription for the treatment of elderly chronic bronchitis.

Yellow to green yellow crystalline powde

Appearance: yellow needle-like crystalline powder. Solubility: slightly soluble in water; soluble in ethanol, acetone, pyridine, and acetic acid; easily soluble in ether and methanol. Melting point: 314–317 °C.

In 1936, Szent-Gyorgyi firstly reported the separation and identification of biological activity of quercetin. Usually quercetin is presented in the form of glycosides such as lutin, quercitrin, and mycoside, which can be hydrolyzed to get the quercetin.
Quercetin has a polyphenol hydroxyl structure, which is of weak lipophilicity and poor hydrophilicity, resulting in its low bioavailability and limiting its clinical application. The synthesis of phenolic derivatives improves its bioavailability, which are lipid-soluble quercetin derivatives such as 3-O-methylquercetin, hydrophilic quercetin derivatives such as 3′-ON-carboxymethylformamide quercetin, and quercetin glycosides.
Threevein Aster, having quercetin as one of the main active ingredients, has been used for the domestic clinical treatment for chronic bronchitis in China since 1971.

Medicine, reported formation of epoxy resins on mixing with epichlorohydrin.

ChEBI: Quercetin is a pentahydroxyflavone having the five hydroxy groups placed at the 3-, 3'-, 4'-, 5- and 7-positions. It is one of the most abundant flavonoids in edible vegetables, fruit and wine. It has a role as an antibacterial agent, an antioxidant, a protein kinase inhibitor, an antineoplastic agent, an EC 1.10.99.2 [ribosyldihydronicotinamide dehydrogenase (quinone)] inhibitor, a plant metabolite, a phytoestrogen, a radical scavenger, a chelator, an Aurora kinase inhibitor and a geroprotector. It is a pentahydroxyflavone and a 7-hydroxyflavonol. It is a conjugate acid of a quercetin-7-olate.

It is mainly used for the treatment of chronic bronchitis.

Yellow needles or yellow powder. Converts to anhydrous form at 203-207°F. Alcoholic solutions taste very bitter.

Sensitive to exposure to air and light. Insoluble in water.

3,3',4',5,7-Pentahydroxyflavone is a strong antioxidant and a metal chelator. Promotes the formation of nitrosamines .

Questionable carcinogen.

ACUTE/CHRONIC HAZARDS: When heated to decomposition 3,3',4',5,7-Pentahydroxyflavone emits acrid smoke and irritating fumes.

Flash point data for 3,3',4',5,7-Pentahydroxyflavone are not available; however, 3,3',4',5,7-Pentahydroxyflavone is probably combustible.

Anti-tumor agent; induces apoptosis and inhibits synthesis of heat shock proteins. Inhibits many enzyme systems including tyrosine protein kinase, phospholipase A 2 , phosphodiesterases, mitochondrial ATPase, PI 3-kinase and protein kinase C. Can also activate Ca 2+ and K + channels and behaves as an agonist at estrogen (GPR30) receptors.

Quercetin is a flavonoid with anticancer activity. Quercetin is a mitochondrial ATPase and phosphodiesterase inhibitor. It Inhibits PI3-kinase activity and slightly inhibits PIP kinase activity. Quercetin has antiproliferative effects on cancer cell lines, reduces cancer cell growth via type II estrogen receptors, and arrests human leukemic T cells in late G1 phase of the cell cycle. Quercetin may also inhibit fatty acid synthase activity.

Experimental studies showed that quercetin had antitumor, anti-inflammatory, anti-oxidation, hypoglycemic, anti-obesity, antidepressant, and other effects. In vitro cell experiments and in vivo animal experiments have shown that quercetin could inhibit the growth of various malignant tumor cells such as human ovarian cancer, breast cancer, gastrointestinal tumor cells, and leukemia, and it could induce cancer cell apoptosis and had a reversal of tumor multidrug resistance (MDR) effect, while, combined with other anticancer drugs, it could enhance the effect of anticancer drugs.
Quercetin could alleviate the inflammatory response that was aggravated by the activation of the central granulocytes. In the experimental study on the treatment of non-bacterial prostatitis and acute gouty arthritis, quercetin also showed a good anti-inflammatory effect.
The experimental results showed that quercetin had a good direct scavenging effect on free radicals and exhibited antioxidant activity. In addition, it also had the anti-hepatic fibrosis, pulmonary fibrosis, keloid hyperplasia and glaucoma filtering bubble scarring and other effects, its mechanism involving the inhibition of fibroblast proliferation, inhibition of collagen synthesis, preventing oxidative damage and so on. Moreover, studies have shown that quercetin also had antibacterial, antiaging, antidepressant, antileukemia, antidiabetic, and other pharmacological effects.

Since the first clinical phase I trial of quercetin in 1996 found that it had antitumor activity, quercetin has also been reported in early clinical trials of cardiovascular disease, diabetes, and other diseases. However, there is still insufficient evidence shown that quercetin has a significant effect on the treatment of the disease in clinic.The US FDA has issued a warning, emphasizing that quercetin is not a definite nutrient, unable to determine its content in the diet, nor can it be used as a drug.
China’s Threevein Aster consists of a single Chinese herb, which was released by the Pharmacopoeia of the People’s Republic of China (1977) Part I. One of the main active ingredients obtained following the hydrolysis of Threevein Aster is quercetin, which has the function of relieving cough and eliminating phlegm and can be used for the treatment of chronic bronchitis. The anti-inflammatory effect of Threevein Aster is poor. Side effects after use include stomach discomfort, dizziness, and abdominal pain, while withdrawal can make them disappear.

Poison by ingestion, subcutaneous, and intravenous routes. Experimental teratogenic and reproductive effects. Questionable carcinogen with experimental carcinogenic, neoplastigenic, and tumorigenic data. Human mutation data reported. Used as a pharmaceutical and veterinary drug. When heated to decomposition it emits acrid smoke and irritating fumes

studies showed that administration of quercetin before the initiation stage of carcinogenesis dramatically reduced various chemical agents induced tumor burden in mice models, including benzo(a)pyrene-induced lung tumor burden, azoxymethane-induced preneoplastic lesions in rat colon and n-nitrosodiethylamine-induced hepatocarcinoma etc. [5].

Room temperature

quercetin and cancer chemoprevention. evid based complement alternat med. 2011;2011:591356. doi: 10.1093/ecam/neq053. epub 2011 apr 14.food-derived polyphenols inhibit pancreatic cancer growth through mitochondrial cytochrome c release and apoptosis. int j cancer. 2002 apr 10;98(5):761-9.stabilization of p53 is involved in quercetin-induced cell cycle arrest and apoptosis in hepg2 cells. bioscience, biotechnology and biochemistry. 2008;72(3):797–804.survivin and p53 modulate quercetin-induced cell growth inhibition and apoptosis in human lung carcinoma cells. the journal of biological chemistry. 2004the effects of quercetin on antioxidant status and tumor markers in the lung and serum of mice treated with benzo(a)pyrene. biological and pharmaceutical bulletin. 2007