Gossypol in the Technology of' Cottonseed Oil XI
13%.
1.I I i ~ i ~ .In., s i ~'The ~ , SI mthern Cotton Oil Company. Savannah,
OSSYI'OI, is :I unique polyliyilroxy lilicmolic wiiipound which apiiareiitly o w i m only in plants of tlic codton faniily (Gossypiuni). Siiiee cottonseed may coiit,aiii ai rriiicli as O.(i per cent of thi r e subrtai;ee, s m i ' of tlii, ing eottoiis(wl oil litive a irregularities encouirtered in definite relationsliip t,o the g content. A iiiajority of tbt: published researeires on io1 lmve l m n roricerrrerl rliicfly xitii its toxic propert,i tlit: work of V'it,liers and ('nrruth (lf), Schwartzc and hIsbi+rg (6, and otliers indicat,a rliat the t,osicitp of free Rossypol is an iinportant fnetor in cottoilseed injury resulting froin the injudieiorrs fceding of cot,toii.;eed meal. In the present paper, however, gossypol litts tieen irirestigntcrl along lines having a direct hcaring oii prdili?~iis of cotkinseed oil milling and refining. The eoniplete striictrire of the gossypol molecule is iiot known. Clark (L) assigns it the molecular formula C'siHs,O*, and elasdies it as a plrenolic substance containing six hyclroxyl groups, t,lie rernnining two oxygen atoms lieing present ns carbonyl groups. Two of tlic hydroxyl groups arr decidedly more ntidic than the other four, aqueous solution, it reacts like a strong pol is insoluble in miter, very slightly ether, soluble in nlcoliol, concentrated sulfuric nckl, ethcr, trichlrromethane, and aqueous alkalies, though in the latter iriecliuin it darkens and osidizcs rapidly. Its hest known derivativcs are t.he acetate, l:sHi.O,.CIf.C:Oi~H, used in isolating gossypol from tlie secd extract,, and the ilianiliiic derivat,ive, Ci2H4JV2Oa,rliich, owing to its crystalline cliameter tiird insolubility, is used for quantitative estiniatioii ( I ) . I )ianiline gossypol is insoluble in alcohol, pet.roleuiriether, et,lii:r, niid vegetable oils. It is soinewliat soluhle in iioiliirg benzene, tricliloromethiinc, arid aniline, and may be recrystallized readily froin any of these solvents. Bltlioiigh ~ o s s y p o lis quite stablc in many respects wlieri i n the pure crystxlline state, it appears to undergo transformat i o n s in the reed during storage) cooking, and pressing. Coldpressed or expellcr oil geiierally cont,aios a considoralrle, :mrount of unchanged gossypol, but. application of the usual aniline precipitation metlwda to hydraulic pressed oil and to t,he etlier extract ofcottonseed Iii k l d oiily traces or none at all. Clark postulates that g jnil condeoses Kith the sniino groups of the seed protei1 :I renatinn analogit,os to the forriiation of dianiline gossypol,arid he trriris the resulting &er-insoluble complex "booix? goossypo." 'Fliis ne.wn!lition is soonorted b r the inct G a t tnainrent ftlie meal with hot asdine will extract the 111 ai o r i t y of hound grwypol as a dianiline gossyjiolwhich isvery siniilar to, if not identical with, diaiiiline nwsypol (3) prepared from pure gossypol. I t has also been wted that mild heating of ether extracts containing gossypol in t.he presence of atinospheric oxygen induces changes in the
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