26 
Podophyllum  Emodi. 
Am.  Jour.  Pharm. 
Jan.,  1893. 
dry  and  brittle.  (This  substance  is  distinctly  acid,  and  is  described 
by  Thompson  as  podophyllotoxin,  but  corresponds  to  the  inert 
podophyllic  acid  obtained  from  P.  peltatum  by  Podwissotzki.)  The 
ether- chloroform  solution  was  then  filtered  into  a  large  volume  of 
petroleum  ether,  when  the  podophyllotoxin  was  precipitated.  This, 
when  collected,  washed  and  dried  over  sulphuric  acid,  was  found  to 
be  equivalent  to  17-8  per  cent.  It  was  readily  soluble  in  chloroform, 
gave  no  precipitate  with  ether,  indicating  complete  removal  of 
podophyllic  acid,  but  gave  a  deep  green  coloration  with  ferric 
chloride.  This  reaction  pointed  to  the  presence  as  an  impurity  of  a 
body  similar  to  that  described  by  Podwissotzki  and  named  by  him 
podophylloquercetin,  which  will  be  described  subsequently. 
Podophyllotoxin  is  not  soluble  in  solution  of  ammonia,  but  on 
heating  with  it  is  decomposed,  forming  a  gelatinous  precipitate  and 
a  frothy  solution.  The  solution  in  ammonia  when  shaken  with 
ether  and  the  ether  evaporated,  yielded  abundant  groups  of  long 
white  needles  of  picropodophyllin. 
Picropodophyllin. — Ten  grammes  of  the  crude  resin  were  exhausted 
with  cold  chloroform  and  the  solution  evaporated  to  dryness.  This 
was  extracted  with  boiling  petroleum  ether  and  the  residue  dis- 
solved in  rectified  spirit,  mixed  with  lime  and  dried  on  a  water-bath 
and  finally  exhausted  with  boiling  absolute  alcohol.  The  solution 
on  evaporation  and  addition  of  water  yielded  an  abundance  of  silky, 
needle-shaped  crystals.  These  melted  after  re-crystallization  at 
208-2 io°  C,  and  are  undoubtedly  identical  with  the  crystalline 
substance  obtained  by  Podwissotzki  from  P.  peltatum  which  melted 
at  200-2 1  o°  C. 
The  quantity  obtained  was  small,  amounting  to  2-6  per  cent,  of 
the  resin,  although  a  slightly  larger  percentage  was  obtained  by  a 
direct  treatment  of  the  rhizome  as  recommended  by  Podwissotzki. 
Picropodophyllic  acid  was  obtained  by  treatment  of  the  crude 
podophyllotoxin  in  solution  in  alcohol  with  ammonia,  remoying  the 
picropodophyllin  with  ether  and  then  liberating  the  acid  from  its 
ammonium  salt  by  dilute  hydrochloric  acid.  Considerable  difficulty 
was  experienced  in  purifying  the  acid  owing  to  the  readiness  with 
which  it  is  decomposed,  and  the  impossibility  of  freeing  it  entirely 
from  picropodophyllin.  It  is  resinous  in  character  and  agrees 
closely  in  general  properties  with  the  similar  body  obtained  from 
Podophyllum  peltatum. 
