286    Chemical  Examination  of  Ipomcea  Purpurea.  {^mj^ifosarm' 
various  extracts  were  finally  subjected  to  treatment  with  5  per  cent, 
aqueous  sulphuric  acid.  The  portions  extracted  by  ether  and  chloro- 
form yielded,  for  the  most  part,  identical  products,  namely,  formic 
and  butyric  acids,  together  with  a  readily  soluble,  non-volatile  acid, 
and  apparently  a  little  glucose.  The  portion  extracted  by  ethyl 
acetate  yielded,  in  addition  to  the  products  just  mentioned,  a  very 
small  amount  of  ipurolic  acid.  The  portion  which  was  soluble 
only  in  alcohol  was  considerable  in  amount.  After  further  purifica- 
tion with  animal  charcoal,  it  was  obtained  in  the  form  of  a  nearly 
white  powder.  It  melted  at  105-110°  C,  and  was  optically  active, 
having  in  aqueous  solution  [a]D  —  67-58°.  When  treated  with 
5  per  cent,  aqueous  sulphuric  acid,  it  yield  ed,  besides  formic  and 
butyric  acids,  a  hydroxy  I  auric  acid  (m.  p.  69-700  C.)  and  ipurolic 
acid,  together  with  a  readily  soluble  organic  acid  and  glucose. 
The  physiological  action  of  the  above-described  extracts  of  the 
original  resin  was  kindly  determined  for  us  by  Dr.  H.  H.  Dale, 
Director  of  the  Wellcome  Physiological  Research  Laboratories,  and 
our  thanks  are  due  to  him  for  the  assistance  which  he  has  thus 
rendered  us. 
One  gramme  of  each  of  the  extracts  was  administered  at  inter- 
vals of  several  days  to  a  dog,  with  the  following  results.  The 
petroleum  extract  produced  no  definite  effect.  The  ether,  ethyl 
acetate  and  alcohol  extracts  had  a  very  marked  purgative  action 
two  hours  after  ingestion,  which  lasted  for  about  twenty-four  hours, 
after  which  the  animal  became  quite  normal.  There  was  no  notice- 
able difference  in  the  action  of  these  three  extracts.  The  chloroform 
extract,  on  the  other  hand,  had  a  rather  less  pronounced  aperient 
effect,  and  caused  slight  vomiting. 
The  alcohol  extract  of  the  resin  which  had  been  hydrolyzed  by 
means  of  baryta,  consisting  of  a  product  which  was  readily  soluble 
in  water,  had  no  perceptible  physiological  action  when  administered 
to  a  dog  in  doses  of  one  gramme.  This  result  is  in  accordance 
with  the  observations  previously  recorded  respecting  the  action  of 
an  analogous,  but  less  completely  purified  product  from  jalap  resin, 
which  has  been  designated  "  convolvulic  acid"  (compare  Husemann, 
"  Die  PflanzenstofTe,"  second  edition,  1882,  p.  1141). 
It  will  be  seen  from  this  investigation  that  Ipomcea  purpurea, 
Roth,  like  many  other  species  of  the  same  genus,  contains  resins 
which  possess  purgative  properties,  and  is  thus  capable  of  being 
utilized  medicinally. 
