Quercetin

Other Name: Meletin, Sophretin.

Chem. Name: 4H-1-Benzopyran-4-one, 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-

M.F. & M.W.: C15H10O7, 302.23

Physical Property: yellow needle like crystal (dihydrate in dilute ethanol); dehydrate at 95-97; M.P.: 314 (dissociate); solubility: 1g in 290ml anhydrous ethanol, or 23ml of glacial acetic acid; yellow alkaline solution; almost insoluble in water; very bitter taste in ethanol; UV(EtOH, max) nm(log): 258(2.75), 375(2.75)[1] 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), 122.1(C1'), 115.2(C2'), 145.1(C3'), 147.7(C4'), 115.7(C5'), 120.1(C6') [2,3]

Plant Source: Quercus iberica, skin and leaves[4]; Dysosma veitehii(Hemsl.et Vils.) Fu[5]; Hypericum ascyron L., full plant[6]; Apocynum lancifolium Rus., leaves[7].

Functions and applications: fairly good expectorant and antitussive; some antiasthmatic effect; lowering of blood pressure, reducing the brittalness of capillary vessel, lowering blood lipid, dilation of coronary artery, increasing the flow in coronary artery. For the treatment of chronical bronchitis, accessory treatment of coronary heart diseases and hypertension[8-10]. Toxicity: oral dose, mice: LD50 at 160mg/kg[1].