Oct. 1, 1921 Quercetin in Emerson s Brown-Husked Type of Maize 3 



The mean of the three determinations is 58.98 per cent — in exact 

 accord with theory. 



The entire yield of approximately i gm. of acetyl derivative was 

 divided to make the above determinations. The quercetin obtained 

 (0.6254 gin.) was again acetylated, yielding 0.8352 gm. of penta-acetyl- 

 quercetin. The acetyl derivative melted at 190° to 192° C. The recov- 

 ered flavone melted at about 305° to 306° with darkening. When 

 mixed with quercetin from Bscholtzia (melting point approximately 

 305° to 310°) the mixture melted at 306° to 307°. In other charac- 

 teristics the quercetin from maize was identical with a sample obtained 

 by the writers ^ from rutin, a glucosid of quercetin found in Escholtzia 

 petals. 



Combustions of the free quercetin and of its acetyl derivative were 

 made, with the results shown in Table II. 



Table II. — Combustions of the free quercetin of brown maize husks and of its acetyl 



derivative 



Quercetin. 



Penta-acetylquercetin. 



Sample i. Sample 2 



Weight of sample (gm.) 



Weight of carbon dioxid (gm.) 



Weight of water (gm.) 



Percentage of carbon 



Percentage of hydrogen 



0-1353 

 .2951 

 .0404 

 59-47 

 3-34 



o. 1126 

 .2430 

 .0403 

 58-85 



4.00 



0.2026 



•4338 

 .0691 



58.39 

 3.82 



Theory requires: For quercetin, carbon 59.59 per cent, hydrogen 3.34 per cent; for penta-acetylquercetin, 

 carbon 58.59 per cent, hydrogen 3.90 per cent. 



PREPARATION OF THE GLUCOSID 



After partition of the alcoholic extract of the brown husks between 

 ether and water, the aqueous solution, containing as one of its chief con- 

 stituents a quercetin glucosid, was treated with four successive portions 

 of lead acetate. The first fraction of the lead precipitate was discarded. 

 The second consisted largely of tarry matter and was therefore not used 

 for the preparation of pure glucosid but yielded quercetin on hydrolysis 

 after decomposition with hydrogen sulphid. The third and fourth frac- 

 tions were combined, suspended in hot alcohol, decomposed with hydrogen 

 sulphid, filtered, and evaporated to small bulk. A small quantit}' of 

 impure glucosid separated out on standing, but the greater part was got 

 by shaking the solution with ethyl acetate. 



The glucosid was purified only with great difficulty, by fractional solu- 

 tion of the dry impure product in ethyl acetate and successive crystalli- 

 zation of the purer fractions from water. The yield of pure glucosid 



' Sando, Charles E., and Bartlett, H. H. rutin, the flavone pigment of escholtzia californica 

 CHAM. /« Jour. Biol. Chem., V. 41, no. 4, p. 495-501, pi. 6-7. 1920. 



