Product Name: Quercetin
Synonym: Meletin, Sophoretin
Chemical Name: 4H-1-Benzopyran-4-one,
Molecular Formula: C15H10O7
Molecular Weight: 302.23
- Appearance：yellow-needle-crystal (dihydrate in dilute ethanol); dehydrate at 95-97℃.
- Melting Point : 314℃(dissociate)
- Solubility: 1g in 290ml anhydrous ethanol, or 23ml of boiling ethanol, soluble in glacial acetic acid; yellow look in alkaline water solution; practically insoluble in water; very bitter taste in ethanol.
- UV(EtOH, max) nm(log): 258(2.75), 375(2.75) ; 13CNMR(DMSO-d6): 146.9(C2), 135.8(C3), 175.9(C4), 156.2(C5), 98.3(C6), 164.0(C7), 93.5(C8), 160.8(C9), 103.1(C10).
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.