Am.  Tour.  Pharm. 
July,  1921. 
Studies  on  Licorice  Root. 
485 
allowed  to  stand  overnight  with  15  cc.  water  at  room  temperature. 
The  mass  is  then  stirred  until  completely  disintegrated,  15  cc.  75  per 
cent,  (  by  volume)  alcohol,  and  53  cc.  95  per  cent,  alcohol  are  added 
from  a  burette  with  stirring,  to  precipitate  the  starch  and  gums.  This 
gives  a  total  mixture  containing  75  per  cent,  (by  volume)  alcohol 
when  the  licorice  extract  contains  25  per  cent,  moisture.  After 
standing  not  less  than  three  hours,  the  tube  is  centrifuged  for  five 
minutes  at  a  speed  of  about  1500  R.  P.  M.  The  clear  solution  is 
poured  off  into  a  flask,  the  sediment  is  stirred  up  with  about  75  cc. 
75  per  cent,  (by  volume)  alcohol,  centrifuged  again  and  the  clear 
solution  is  poured  off.  The  sediment  is  stirred  up  a  second  time  with 
75  cc.  75  per  cent,  alcohol,  centrifuged,  and  the  solution  is  again' 
poured  off.  The  precipitated  starch  and  gums  are  washed  into  a 
tared  dish,  dried  and  weighed.  The  combined  three  liquors  are  evap- 
orated just  to  dryness  from  a  water  bath,  preferably  using  vacuum 
to  finish,  and  recovering  the  alcohol.  The  residue  in  the  flask  is  dis- 
solved in  about"  10  cc.  hot  water,  the  solution  filtered  through  a  small 
filter  paper  into  a  centrifuge  tube  graduated  at  30  cc,  the  flask  and 
paper  are  washed,  and  the  volume  made  to  mark. 
The  filtrate  is  cooled  to  150  C,  and  the  glycyrrhizin  is  precipi- 
tated with  3  cc.  of  10  per  cent,  (by  weight)  sulphuric  acid.  The 
tube  is  allowed  to  stand  in  the  ice  box  overnight,  and  is  then  packed 
in  cracked  ice  for  half  an  hour.  The  tube  is  centrifuged  for  a  half  a 
minute,  and  the  clear  liquid  poured  off.  The  precipitate  is  stirred 
up  with  5  cc.  ice  water  saturated  with  ether,  centrifuged  again  for 
half  a  minute,  and  the  clear  liquid  poured  off.  The  sediment  is 
again  stirred  up  with  5  cc.  iced  ether-water,  centrifuged.  and  the 
clear  liquid  poured  off  as  completely  as  possible.  The  tube  is  kept 
cold  throughout  the  operation  and  all  of  the  glycyrrhizin  is  retained 
in  the  tube.  Thirty  ccvof  warm  95  per  cent,  alcohol  are  added  to 
the  washed  glycyrrhizin  in  the  tube.  This  solution  is  retained  to  be 
united  later  to  the  second  precipitate  of  glycyrrhizin.  To  obtain  this, 
the  combined  filtrate  and  two  washings  obtained  as  above  are  neu- 
tralized with  ammonia,  evaporated  to  about  5  cc,  transferred  to  a 
centrifuge  tube,  made  to  10  cc,  cooled  and  precipitated  with  2  cc. 
10  per  cent,  sulphuric  acid.  After  standing  overnight  the  tube  is 
packed  in  ice  for  half  an  hour,  centrifuged,  and  the  clear  liquor 
poured  off.  The  glycyrrhizin  is  stirred  up  with  5  cc.  iced  ether- water, 
centrifuged  half  a  minute,  and  the  liquor  poured  off.  A  second 
washing  with  ice  cold  ether-water  is  given,  using  3  cc  The  precipi- 
