Am.  .lour.  Pharm. 
May,  1884. 
Alkaloids  in  Belladonna  Root. 
279 
THE  ESTIMATION  OF  THE  ALKALOIDS  IN  THE  ROOT 
OF  ATROPA  BELADONNA. 
By  Wyndham  R.  Dunstan, 
Assistant  Lecturer  in  Chemistry  and  Physics  to  the  Pharmaceutical  Society 
and  Demonstrator  of  Practical  Chemistry  in  the  School  of  Pharmacy  •  and 
F.  Ransom. 
Many  methods  have  been  proposed  for  the  estimation  of  the  alka- 
loids which  exist  in  Atropa  Belladonna.  The  majority  of  these 
methods  involve  the  use  of  solvents  which  extract  large  quantities  of 
non-alkaloidal  organic  substances,  and  thus  necessitate  the  subsequent 
use  of  other  solvents  and  precipitants  to  purify  and  isolate  the  alka- 
loid. A  great  advance  was  made  by  Pesci  (Gazzetta  di  Chimica 
Italiana,  x,  425),  when  he  showed  that  the  alkaloid  could  be  extracted 
in  a  comparatively  pure  state  by  benzene  from  an  aqueous  extract  of 
belladonna  after  the  addition  of  an  alkali.  The  benzene  was  then 
agitated  with  dilute  sulphuric  acid,  which  was  subsequently  rendered 
alkaline  with  ammonia  and  the  alkaloid  removed  by  chloroform. 
Pesci's  method  of  extraction,  although  a  great  improvement  upon  older 
methods,  was  still  far  from  perfect,  and  obviously  could  not  be  easily 
applied  for  the  estimation  of  the  alkaloid.  In  a  previous  paper1  one 
of  us  has  proposed  a  new  method  in  plant  analysis  where  a  body 
soluble  in  chloroform  has  to  be  isolated.  This  method  was  based  upon 
the  general  principle  that  in  plant  analysis  that  solvent  should  be 
selected  for  the  estimation  of  the  active  constituent  which  extracts  this 
•constituent  with  the  smallest  quantity  of  the  other  constituents,  thus 
rendering  unnecessary  long  processes  of  subsequent  purification. 
There  are  many  solvents  which  can  be  used  for  this  purpose,  solvents 
which  easily  dissolve  alkaloids,  glucosides,  etc.,  but  less  readily  dissolve 
coloring  matter,  acids,  sugars,  etc.  Chloroform  is  one  which  often 
admits  of  use,  but  it  was  pointed  out  in  the  paper  referred  to  that 
chloroform  alone  was  ill-suited  for  completely  extracting  the  plant 
tissues,  owing  to  its  weak,  penetrating  power.  It  was  also  proved  in 
the  special  instance  of  nux  vomica  that  this  difficulty  could  be  over- 
come by  the  admixture  of  alcohol  with  the  chloroform  ;  that  is  to  say, 
while  chloroform  alone  was  incapable  of  extracting  the  whole  of  the 
'Dunstan  and  Short,  "The  Assay  of  Nux  Vomica"  "Pharm.  Jour.," 
[3],  xiii,  665 ;  "Amer.  Jour.  Phar.,"  1883,  p.  268. 
