Quercitron is ayellownatural dye obtained from the bark of theEastern Black Oak (Quercus velutina), a foresttree indigenous inNorth America. It was formerly calledDutch pink,English pink, orItalian pink.[1]
The name is a shortened form of quercicitron, fromLatinquercus, oak, andcitron, lemon, and was invented byEdward Bancroft (1744–1821), who by act of Parliament (25 Geo. 3. c. 38) in 1785 was granted special privileges in regard to the importation and use of the substance. Thedyestuff is prepared by grinding the bark inmills after it has been freed from its blackepidermal layer, and sifting the product to separate the fibrous matter, the fine yellow powder which remains forming the quercitron of commerce.
The ruddy-orangedecoction of quercitron containsquercitannic acid, whence its use intanning, and an active dyeing principle,quercitrin, C21H20O11. The latter substance is aglycoside, and in aqueous solution under the influence of mineral acids it yieldsquercetin, C15H10O7, which is precipitated, and the methyl-pentoserhamnose.[2]
Quercetin is a crystalline powder of a brilliant citron yellow color, entirely insoluble in cold water and dissolving only sparingly in hot water, but quite soluble in alcohol. Either by itself or in some form of its glucoside quercitrin, quercetin is found in several vegetable substances, among others incutch, in Persian berries (Rhamnus cathartica),buckwheat leaves (Fagopyrum esculentum), Zante fustic wood (Rhus cotinus), and inrose petals.[2]
Chemically, quercetin is a member of a fairly extensive class of natural coloring matters derived from phenyl benzoyl-pyrone orflavone, the constitution of which followed on the researches ofStanisław Kostanecki,A. G. Perkin,Herzig,Goldschmidt and others. Among the related, coloring matters are:chrysin frompoplar buds,apigenin fromparsley,luteolin fromweld, mignonette anddyer's broom,fisetin from young fustic andyellow cypress,galangin fromgalangal root, andmyricetin fromNageia nagi.[2]
InIowa in the late 1840s and early 1850s, according to the historian Philip Dillon Jordan:
Weld, fustic, and quercitron bark were carried as staple items in drug stores and general merchandise establishments. Sometimes, the physician kept a small supply of dye stuffs. It was not too uncommon, indeed, to find a jar of indigo next to a laudanum bottle and a box of quercitron associating with unrefined quinine.[3]