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Quercetin Dihydrate


C15H10O7 · 2H2O


Quercetin, 2-(3,4-Dihydroxyphenyl)-3,5,7-trihydroxy-4H-1-benzopyran-4-one dihydrate, 3,3′,4′,5,7-Pentahydroxyflavone dihydrate


Quercetin Dihydrate95%

Quercetin Dihydrate Properties

Quercetin 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.

Pharmacological effects

Quercetin 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.

Chemical Properties

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

Production method

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.

Chemical Properties

Yellow to green yellow crystalline powde

General Description

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

Air & Water Reactions

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

Reactivity Profile

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

Health Hazard

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

Fire Hazard

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

Biological Activity

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.

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