112  Active  Constituents  of  Podophyllin.        { ^"MarTiSr™' 
The  poAvder  is  allowed  to  completely  deposit,  for  which  a  repose  of 
24  hours  is  sufficient,  and,  after  carefully  removing  the  water,  it  is 
brought  upon  a  filter,  the  petroleum  ether  allowed  to  drain  off,  and  the 
residue  dried  at  the  above  mentioned  moderate  temperature.  By 
proper  treatment  there  is  obtained  upon  drying  an  almost  completely 
white  or  slightly  yellowish-white  powder  of  podophyllotoxin.  The 
latter  is  not  decomposed  by  light  and  can  therefore  be  preserved  in 
ordinary  glass  vessels. 
Podophyllotoxin  can  also  be  obtained  from  the  officinal  podophyllin, 
although  it  must  hereby  be  considered  that  the  latter  contains  not  only 
considerable  amounts  of  podophyllinic  acid  and  podophylloquercetin, 
but  also  many  products  of  decomposition  which  are  formed  by  the 
extraction  of  the  rhizome  with  boiling  alcohol  and  subsequent  evapo- 
ration of  the  solutions.  These  decomposition  products  are  readily 
taken  up  by  chloroform  and  it  is  afterwards  difficult  to  separate  them 
from  the  podophyllotoxin ;  the  latter  prepared  from  the  officinal  podo- 
phyllin  is  always  of  a  more  yellow  color  than  that  obtained  from  the 
rhizome;  the  methotl  of  obtaining  it  is  the  same  as  that  above 
described. 
Pure  podophyllotoxin  must  dissolve  readily  in  chloroform,  and  this 
solution  should  give  no  precipitate  on  the  addition  of  ether.  Ferric 
chloride  should  not  color  it  green  and  on  the  addition  of  petroleumi 
ether  to  the  chloroform  solution  it  must  be  precipitated  as  a  white 
powder.  In  ammonia  water  it  should  not  be  completely  soluble; 
ammonia  should  dissolve  simply  the  picropodophyllinic  acid  from  the 
podophyllotoxin,  which  solution  on  standing  for  some  time  becomes- 
somewhat  colored  ;  the  picropodophyllin  must  hereby  separate  out,  in 
consequence  of  which,  if  the  amount  of  ammonia  is  not  too  large,  a. 
thick  gelatinous  mass  is  obtained.  If  to  this  mass  or  to  a  mixture  of" 
podophyllotoxin  and  ammonia  ether  be  added,  gently  warmed  and 
agitated,  the  picropodophyllin  should  dissolve  in  the  ether,  and,  after- 
cooling  and  volatilization  of  the  latter,  it  should  crystallize  out  in  the 
form  of  delicate,  colorless  crystals.^ 
The  preparation  of  pure  crystallized  picropodophyllin  can  be  effected 
as  easily  from  the  officinal  podophyllin  as  from  the  podophyllum  rhi- 
1  The  method  here  described  for  obtaining  podophyllotoxin,  by  means  of 
whicli  the  podophyllinic  acid  is  completely  removed,  is  an  improvement 
and  addition  to  that  previously  published  by  the  author  in  "Archiv  fiir 
exper.  Pathologic  und  Pharmacologic." 
