EXPERIMENT STATION RECORD. 



Vol. 38. Abstract Number. No. 9. 



RECENT WORK IN AGRICULTURAL SCIENCE. 



AGRICTTLTURAL CHEMISTRY— AGROTECimY. 



Contribution to the chemistry of gossypol, the toxic principle of cotton 

 seed, F. E. Cakkuth {Jour. Amer. Chcm. Soc, 40 {1918), Nu. 4, pp. 647-6GS). — 

 Continuing the investigations previously noted (E. S. R., 38, p. GS5), a special 

 study was made of tlie chemical nature of gossypol. 



Analyses of the purified substance prepared by several different methods 

 which are given in detail show an empirical formula for gossypol of CsoHasOg or 

 C30H30O9. It forms a crystalline compound with acetone, amorphous acetyl and 

 benzoyl derivatives, and an insoluble substance with aniline. It readily forms 

 salts with alkalis, and dissolves easily in sodium hydroxid and carbonate and 

 very slowly in bicarbonate and disodium phosphate. Limewater and baryta 

 water and ammonium hydroxid, both strong and dilute, do not dissolve it as 

 readily as do alkali hydroxids. Alkaline solutions of gossypol oxidize readily 

 on exposure to air or by adding hydrogen peroxid with the formation of a 

 complex substance. Strong nitric acid dissolves gossypol with the formation 

 of a substance no longer giving color reactions. 



Three new substances which resemble gossypol more or less have been 

 isolated. One called " B " gossypol is formed by heating gossypol in the air 

 to its decomposition point. " C " gossypol is formed by fusing gossypol with 

 alkalis to a fairly high temperature. " D " gossypol can be isolated from 

 cottonseed meal and is thought to be the substance formed from gossypol in the 

 cooking of cotton seed. The " B " and '* C " forms are less poisonous than the 

 original gossypol, but the " D " variety, although less toxic than the original 

 gossypol, has been shown to give rise to cottonseed meal poisoning of rabbits and 

 swme. If rather dry seed is used in the preparation of cottonseed meal, the 

 gossypol is apparently not so readily converted into the less soluble, less toxic 

 oxidation product but remains in part as such in the meal, causing such a meal 

 to be more toxic than a properly cooked meal. 



" Attempts to get a clue to the constitution of gossypol have failed through 

 inability to split the substance into simpler known substances. 



" The fact that several flavone pigments occur in the cotton plant and the 

 fact that gossypol has 30 carbon atoms suggests that it may be derived by 

 condensation and subsequent reduction of two molecules of a flavone. The 

 acidic properties are thought to be due to carbonyl and hydroyxl groups arranged 

 as in flavonols rather than to carboxyl groups. These substances are suf- 

 ficiently acid to form salts from an alkali acetate. The presence of o-hydroxyl 

 is indicated by the green ferric chlorid reaction and by the formation of lake- 

 like compounds with lead and ferrous salts. The presence of 9 oxygen atoms 



SOI 



