650 
Chemistry  of  Gossypol. 
Am.  Jour.  Pharm. 
Sept.,  1918. 
Crude  cottonseed  oil  is  of  an  intense  ruby,  nearly  black  color  due  to  its 
holding  in  solution  a  powerful  vegetable  coloring  principle.  This  latter,  ac- 
cording to  the  results  obtained  by  the  author,  amounts  to  10  to  15  pounds 
per  ton  of  oil.  .  .  . 
This  coloring  matter  has  now  been  isolated  by  the  author  with  the  result 
of  throwing  some  light  on  its  nature.  In  the  dry  state  it  is  a  light  powder  of 
pungent  odor,  of  a  brown  earthy  color  and  possesses  powerful  dyeing  proper- 
ties. A  small  proportion  of  it  is  soluble  in  water,  but  the  principal  bulk  dis- 
solves only  in  alcohol  or  alkalies.   It  is  quite  insoluble  in  acids. 
Longmore  employed  strong  alkalies  to  salt  out  the  soap  in  the 
foots  and  to  keep  the  gossypol  in  solution.  He  isolated  the  gossy- 
pol by  adding  acid  to  the  alkaline  solution.  He  mentions  no  further 
purification  and  it  is  evident  that  his  product  was  very  impure. 
Finally  Marchlewski6  isolated  a  crystalline  product  from  the 
"  foots  "  of  cottonseed  oil  by  means  of  a  tedious  purification  process. 
He  named  the  crystalline  substance  gossypol  from  gossyp(ium- 
phen)ol.  His  method  of  preparation  is  given  in  the  following 
translation : 
The  crude  product  which  was  obtained  from  an  English  oil  manufac- 
turer had  already  undergone  a  purification  process  consisting  of  the  removal 
of  the  greater  part  of  accompanying  fatty  acids  in  the  form  of  their  calcium 
salts. 
It  was  extracted  with  ether  which  dissolved  the  gossypol,  its  oxidation 
products  (which  give  the  solution  a  dark  brown,  almost  black  color)  and  also 
considerable  amounts  of  impurities.  This  solution  is  concentrated.  There 
remains  a  viscous  mass  which  is  added  in  portions  to  boiling  acetic  acid. 
When  solution  takes  place  it  is  filtered  from  a  small  residue  and  allowed  to 
cool.  After  some  standing  a  dark  brown  amorphous  mass  separates  which 
is  again  dissolved  in  acetic  acid.  After  4  or  5  repetitions  one  finally  obtains 
microscopic  crystals  which  are  dark  brown  in  color,  and  which  represent  the 
still  very  impure  gossypol. 
Further  purification  is  best  secured  as  follows  :  Dissolve  the  crystalline 
mass  in  boiling  alcohol  and  add  to  the  dark  brown  solution  50  per  cent,  acetic 
acid  until  clouding  is  noticeable.  Then  the  solution  is  heated  to  boiling  and 
filtered.  After  some  standing  crystals  appear  which  are  considerably  lighter 
than  the  first  product.  Repeating  this  process  5  or  6  times  finally  3rields  a 
beautifully  crystallized  3<ellow  product.  Attempts  to  obtain  the  gossypol  en- 
tirely colorless  failed.  It  seems  then  that  the  yellow  color  is  inherent 
athough  this  is  not  considered  as  established. 
Marchlewski's  " gossypol"  was,  no  doubt,  a  substance  contain- 
ing one  molecule  of  acetic  acid  in  loose  combination  with  the  phe- 
nolic body.  This  compound  with  acetic  acid  will  be  called  for  con- 
venience gossypol  "acetate,"  and  the  phenolic  body  itself  gossypol. 
6 /.  prakt.  Chem.,  60,  84-90  (1899). 
