Am.  jour.  Pharm.  ) 
Sept.,  1885.  t 
Colocynthein,  E  later  i  n ,  Bryonin. 
451 
DETECTION  OF  COLOCYNTHEIN,  ELATERIN, 
AND  BRYONIN. 
By  E.  Johannson. 
Colocynthin  when  heated  with  dilate  sulphuric  acid  yields  colocyn- 
thein,  elaterin  and  bryonin. 
Colocynthin  is  soluble  in  water  and  alcohol ;  it  gives  an  orange  color 
changing  to  red  with  concentrated  sulphuric  acid,  a  cherry-red  colora- 
tion with  sulphuric  acid  containing  niolybdic  acid,  a  blood-red  colora- 
tion turning  blue  at  the  edge  with  sulphuric  and  vanadic  acids,  a  yellow 
coloration  with  alcohol  and  sulphuric  acid,  distinguishing  it  from 
solanine  and  solanidine,  and  a  yellow  coloration  with  sulphuric  and 
selenic  acids;  moistened  with  phenol  and  a  drop  of  sulphuric  acid,  it 
gives  a  blood-red  coloration  changing  to  orange. 
Colocynthein  is  not  as  soluble  in  water  as  colocynthin,  it  is  only 
sparingly  soluble  in  light  petroleum,  but  easily  in  benzene.  Witii 
molybdic  and  sulphuric  acids,  it  remains  at  first  unchanged,  but  finally 
becomes  a  dirty  cherry-red.  With  vanadic  and  sulphuric  acids,  its 
reactions  resemble  those  of  colocynthin.  Colocynthin  and  colocyn- 
thein may  be  separated  by  shaking  the  acid  solution  with  benzene 
which  dissolves  the  colocynthein,  and  afterwards  with  ethyl  acetate 
which  dissolves  the  colocynthin. 
Elaterin  is  insoluble  in  water;  it  is  sparingly  soluble  in  cold,  but 
easily  in  boiling  alcohol ;  it  crystallizes  in  colorless,  shining,  six-sided 
plates.  With  concentrated  sulphuric  acid,  it  gives  a  pale  yellow  colora- 
tion, becoming  red  at  the  edges  after  some  time,  and  finally  cherry- 
red.  Molybdic  and  sulphuric  acids  give  a  fugitive  green  color. 
Phenol  and  sulphuric  acid  give  a  momentary  red  coloration.  Vanadic 
and  sulphuric  acids  give  a  fine  blue,  changing  to  a  bright  green  color. 
Selenic  and  sulphuric  acids  give  a  red  color  not  so  intense  as  that  pro- 
duced by  concentrated  sulphuric  acid  alone.  Alcohol  and  sulphuric 
acid  give  on  warming  only  a  faint  yellow  color.  When  evaporated  on 
the  water-bath,  and  then  treated  with  sulphuric  acid,  a  violet-red 
coloration  is  obtained.  The  elaterin  reactions  are  slow,  and  with  the 
exception  of  the  characteristic  vanadic  and  sulphuric  acids  test,  unsatis- 
factory. 
Bryonin,  in  its  reactions,  resembles  colocynthin  and  elaterin,  and  is 
readily  soluble  in  water  and  alcohol.  Selenic  and  sulphuric  acids 
give  a  dirty  cherry-red, 'and  vanadic  and  sulphuric  acids  a  blue-violet 
color.— Joitr.  Chem.  Soc,  May,  1885,  p.  606  ;  Zeit.  Anal.  C/iem...  vol  24 
154-157.  *  ' 
