Quercitin

At a higher temperature protocatechuic acid is formed. On reduction of quercitin the final product is phloroglucin [28]. 

Amide by action of ammonia at 150°. Is a brown, amorphous compound. Dibromquercitin light yellow needles. Diacetyl-dibromqnercitin yellow needles. Tetrabromquercitin white needles. M.P. 218°. 

Quercitin and quercitrin give beautiful yellow shades on cotton mordanted with alumina. With tin mordants a more orange shade is produced. On a large scale these bodies have an extensive application, and are used in form of a decoction of the bark or as flavin. In dyeing with the extract, it is probable that the quercitrin splits up, and that the shades obtained are due to the formation of quercitin lakes. 

Flavin consists in some cases of nearly pure quercitrin and in 

the glucoside contained in Chinese yellow berries and in the leaves of Ruta graveolens, is closely allied to quercitrin. On boiling with dilute acids it splits up into quercitin and a sugar [29,30,31]. 

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Rhamnetin (3,3 -4, 5-tetrahydroxy-7-methoxy flavone, 7-methyl quercitin) [90-19-7] M 316.3, m >300"(dec), several phenolic pKs -7-10.5. Crystd from EtOH. 

Rao JR, ND Sharma, JTG Hamilton, DR Boyd, JE Cooper (1991) Biotransformation of the pentahydroxy flavone quercitin by Rhizobium loti and Bradyrhizobium strains Lotus. Appl Environ Microbiol 57 1563-1565. 

Krishnamurty HG, FJ Simpson (1970) Degradation of rutin hy Aspergillus flavus. Studies with oxygen 18 on the action of a dioxygenase on quercitin. J Biol Chem 245 1467-1471. 

Steiner RA, KH KaUc, BW Dijkstra (2002) Anaerobic enzyme substrate structures provide insight into the reaction mechanism of the copper-dependent quercitin 2,3-dioxygenase. Proc Natl Acad USA 99 16625-16630. 

Braune A, M Giitschow, W Fngst, M Blaut (2001) Degradation of quercitin and luteolin by Eubacterium ramulus. Appl Environ Microbiol 67 558-5567. 

FIGURE 10.45 Aerobic transformation of (a) quercitin and (b) genistein. (From Neilson, A.H. and Allard, A.-S., The Handbook of Environmental Chemistry, Vol. 3J, pp. 1-80, Springer, Heidelberg, 1998. With permission.)... 

Kochia scoparia, leaves Ferulic acid, myricetin, quercitin 82... 

Luteolin, apigenin, catechin. myricetin, quercitin. kaempferol, morin, macturin, genistein... 

A series of indolizines 281 and azaindolizines 282 were screened as possible inhibitors of 15-lipoxygenase (15-LO) from soybeans and rabbit reticulocytes. Most compounds studied were significantly more active than quercitin (IC50 51 pi) <2003BML5409>. The indolizine and azaindolizine sulfonates were particularly studied and showed high activity <2005BMC5409>. 

The tea plant, Thea sinensis, has provided a desirable beverage for centuries but it is also used as a colorant. Extracts of tea contain a very complex mixture of glycosides of myricetin, quercitin and kaempferol, epicatechin, epigallocatechins, acyl acids and many other polyphenol compounds.33 In black tea, the above compounds may act as precursors to the poorly defined compounds thearubin and theaflavin. 

Delphinidin chloride has a further OH group in the position indicated. The important relations between cyanidin, quercitin, catechin, and luteolin should be studied from the point of view of plant physiology. 

Celosia argentea L. C. margariacea L. Cao Jue Ming (Quail grass) (stem, leaf) Guijaverin, hyperoside, quercitin, isoquercitrin.50 Insecticidal. 

Ficus carica L. Wu Hua Go (Fig) (leaf, fruit) Bergaptin, cerotinic acid, ficusin, glutamine, papain, pepsin, psoralen, guaiaxulene, amyrin, lupeol, retin, octacosane, guaiacol, quercitin, rhamnose, sitosterol, tyrosine, urease.50 55,502 For stomachache, externally for swollen piles, corns, warts. Fruit is laxative, digestive, anthelmintic, hypolipidaemic, and hypotriglyceridaemic acitivities... 

Hippophae rhamnoides L. Sha Ji (Sea buckthorn) (seed, fruit, leaf) Cryptoxanthin, harman, harmol, hemin, isorhamnetin, lycopene, serotonin, isorhamnetin-3-mono-beta-D-glucoside, polyphenols, fatty acids flavonoid, essential oils, tannins, quercitin, vitamin C, vitamin E, beta-carotenoid.50-450 Improve resistance to infection, skin irritation and eruption, treat heart disease, oil for cosmetic use. 

N.A. Carotenoid, flavonoid, essential oil, fatty acids, tannins, quercitin, provitamin A, vitamins , complex, and E.102-139-140141 Improve resistance to infection, skin irritation and eruptions. Treat heart conditions, good source of vitamins C and E. 

N.A. Hypericin, hyperoside, rutin, quercitin, chlorogenic acid, pseudohypericin, flavonoids.99 100 102 Antidepressant, anti-inflammatory, diuretic, antiseptic and astringent properties. 

N.A. Balsaminones, 2-methoxy-l, 4-naphthoquinone, saponins, quercitin, kaempferol derivatives, balsaminasterol, parinaric acid, hosenkosides.302 Remedy for rashes, pain caused by insect bites, anti-inflammation. 

N.A. Stigmast-4-3-one, stigmasterol, beta-sitosterol, polysaccharides, aretylcholine, serotonin, quercitin, histamine, choline, glucoquinone.99,102,176,304 Treat benign prostatic hyperplasia, hair tonic and growth stimulation, use in antidandruff shampoo. 

N.A. Comus canadensis L. Comine, comic acid, quercitin, tannins.102 Decrease inflammation, pain, fever. 

N.A. Crataegus laevigata C. monongyna Jacq. C. oxyacantha L. Flavonoid glycosides, procyanidins, catechins, triterpenoid acid, pectins, amygdalin, proanthocyanidins, emulsin, tartaric acid, tannins, crataegus acid, rutin, coumarins, quercitin, amines 99,100,231,278,279 Therapeutic treatment of heart insufficiency, hypotensive, coronary blood supply, arrhythmia. 

Figure 6.4 Esters of flavonoid mono- or di-glycosides (isoquercitrin 20, quercitin 21, rutin 22, naringin 23) produced by enzyme-catalyzed regioselective acylation.

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