Am.  Tour.  Pharm. 
July,  1921. 
Studies  on  Licorice  Root. 
493 
Three  grams  of  the  powdered  root  are  extracted  in  the  Extrac- 
tion Apparatus  of  the  Joint  Rubber  Insulation  Committee  with  50  cc. 
Ether  U.  S.  P.  The  extraction  is  finished  in  about  one  hour  and  will 
remove  from  most  kinds  of  licorice  root,  1.5  to  4.5  per  cent,  resins. 
The  residue  in  the  thimble  is  dried  and  transferred  as  completely 
as  possible  to  a  100  cc.  centrifuge  tube.  The  thimble  is  washed  with 
75  per  cent,  (by  volume)  alcohol  and  the  washings  poured  into  the 
centrifuge  tube.  The  volume  of  75  per  cent,  alcohol  in  the  tube  is 
made  up  to  75  cc.  The  mixture  is  stirred  frequently  and  then  al- 
lowed to  stand  overnight. 
The  ether  extraction  may  also  be  done  in  a  centrifuge  tube  by 
stirring  for  ^5  minutes  each  time  with  three  75  cc.  portions  of  ether, 
centrifuging  and  pouring  off  the  clear  liquor  after  each  treatment.  In 
this  case  there  is  no  thimble  to  dry  and  wash,  the  ether  being  re- 
moved by  placing  the  centrifuge  tube  in  the  oven  for  a  few  minutes ; 
75  cc.  of  75  per  cent,  alcohol  are  then  added  to  the  root  in  the  tube. 
The  subsequent  treatment  follows  that  already  described  for 
licorice  extract — and  comprises  two  further  treatments  with  75  per 
cent,  alcohol,  stirring  for  15  minutes  each  time,  centrifuging  and 
pouring  off  the  clear  liquors,  evaporating  to  dryness,  dissolving  in  10 
cc.  water,  filtering  up  to  20  cc.  (instead  of  30  cc.  prescribed  for  2 
gms.  Licorice  Extract),  precipitating  with  3  cc.  10  per  cent,  sul- 
phuric acid,  etc.,  as  already  described.  Wash  twice  with  ice  cold 
water  saturated  with  ether,  using  5  cc.  each  time.  Precipitate  a  sec- 
ond portion  of  glycyrrhizin  by  evaporating  the  filtrate  and  washings 
from  the  first  portion  to  about  5  cc.  after  neutralizing  with  ammonia, 
subsequently  transferring  to  a  tube  marked  at  10  cc.  and  using  2  cc. 
10  per  cent.  H2S04  for  the  second  precipitation,  and  washing  twice 
with  iced  ether-water  as^  already  described.  The  two  fractions  are 
dissolved  in  30  and  10  cc.  respectively  of  warm  95  per  cent,  alcohol, 
filtered,  and  united.  Two  drops  of  5  per  cent,  ammonia  are  added  to 
fix  any  trace  of  free  sulphuric  acid  and  the  solution  evaporated  to 
dryness,  dried  at  ioo°  C.  and  weighed.  . 
There  is  no  doubt  that  the  figures  given  in  the  literature  for 
glycyrrhizin  in  licorice  root  are  too  low. 
Kraemer  in  his  new  book,  "Scientific  and  Applied  Pharmacog- 
nosy" (1920),  gives  a  figure  of  "about  3  per  cent."  for  glycyrrhizin 
in  Russian  licorice  root.    Tschirch  in  his  "Handbuch  der  Pharma- 
