Journal of Agricultural Research 



Vol. XXII. No. I 



A few preliminary tests of the purple pigment convinced us that it was 

 an anthocyanin of which the nonsugar portion was of the same general 

 group as cyanidin, isolated by Willstatter ^ and his students from several 

 sources, including the cornflower, Centaurea. His proof of the easy 

 chemical transition from the anthocyanin to the flavonol series led us to 

 look for a member of the latter series in the brovvTi maize. In accordance 

 with expectations, we were able to isolate a glucosid of quercetin. This 

 discovery makes it seem exceedingly likely that the anthocyanin of the 

 purple type is a corresponding glucosid of cyanidin. 



The brown color type is a still more unusual one than the purple. 

 It first appeared in Emerson's ^ cultures as a segregate in the second 

 generation of the cross purple X green and is unkno%vn outside this 

 series of cultures. Seedlings and young plants are wholly green. As the 

 flowering period approaches, a brown color appears in the lower sheaths, 

 and at flowering time the culm, sheaths, husks, and staminate inflores- 

 cences are brown. Light is not essential to the development of the 

 color. Our material of the brown type consisted of husks. 



ISOLATION AND IDENTIFICATION OF THE FREE QUERCETIN 



Ground husks were extracted in a large Soxhlet apparatus with redis- 

 tilled 95 per cent alcohol for about 72 hours, and the alcohol was evapo- 

 rated off in vacuo. The thin aqueous sirup was filtered from tarry 

 matter and the filtrate boiled with animal charcoal. By shaking with 

 ether it gave an etherial solution containing a free (nonglucosidal) fla- 

 vone which proved to be quercetin. The ether was evaporated off, and 

 the residue, after being dried in a desiccator, was extracted in a paper 

 thimble, first with benzene, to remove tarry colloids, oils, etc., and 

 finally, for a short time, with ether. The latter solvent dissolved part 

 of the quercetin but left the bulk of it in the thimble. This portion was 

 dried and acetylated for an hour with anhydrous sodium acetate and 

 acetic anhydrid. After purification the acetyl derivative was quanti- 

 tatively hydrolyzed with sulphuric acid in glacial acetic acid. The reac- 

 tion mixture was diluted and the recovered quercetin was washed with 

 cold water. The results are given in Table I. 



Table I. — Data on hydrolysis , by sulphuric acid in glacial acetic-acid solution, of the 

 acetylated free flavone of brown maize husks 



Sample I. Samples. Samples 



Weight of acetyl quercetin (gtn.). . . . 

 Weight of recovered quercetin (gm.) 

 Percentage of recovered quercetin. .. 



0.2521 

 .1484 

 58.86 



0-3165 

 .1866 

 58.95 



0.4908 

 .2902 

 59-13 



1 Willstatter, Richard, and Everest, Arthur E. tjntersuchungen uber die anthocy.vne. i. user 

 DEN FARBSTOFF DER KORNBLUME. /« Licbig's Ann. Chem., Bd. 401, Heft 2, p. 189-232, 4 fig. 1913. 

 ' Emerson, R. A. op. ax. 



