614 
Chemistry  of  Rhubarb. 
Am.  Jonr.  Phiii;rn.» 
Dec.  ,1885. 
CONTKIBUTION  TO  THE  CPIEMISTRY  OF  RHUBARB 
ROOT.i 
By  M.  Kubli. 
Any  one  who  may  have  occupied  himself  with  the  chemical  investi- 
gation of  the  three  vegetable  drugs,  rhubarb,  senna  leaves,  and 
Rhamnus  Frangula  bark,  will  have  made  the  observation  that  there 
is  present  in  them  a  peculiar  body  containing  nitrogen  and  sulphur^ 
which  especially  accompanies  the  active  constituents  of  these  drugs- 
with  great  persistency.  In  resuming  some  interrupted  studies  of 
rhubarb  root  in  the  laboratory  of  the  hospital  pharmacy  at  Diinaburg, 
the  author  sought  first  to  ascertain  what  part  this  peculiar  body  played 
in  these  vegetable  substances,  and  Avhether  it  might  not  be  considered 
as  belonging  to  the  non-organized  ferments,  such  as  emulsin,  myrosin^ 
etc.  The  present  paper  is  a  preliminary  contribution  to  the  solution 
of  this  question. 
After  Schlossberger  and  Dopping  had  first  recognized  the  presence 
of  chrysophanic  acid  in  rhubarb^  the  author  demonstrated  that  the 
acid  occurred  in  the  form  of  a  glucoside^  that  split  upon  being  boiled 
with  acids  into  chrysophanic  acid  and  sugar,  to  which  he  gave  the 
name  "  chrysophan.''  DragendorfF,  subsequently,  in  analyzing  five 
different  commercial  varieties  of  rhubarb,*  confirmed  the  observation 
of  the  author  that  chrysophanic  acid  occurs  ready  formed  only  in  very 
small  quantities  in  the  root.  According  to  this  analysis  it  was  present 
in  appreciable  quantity  (1*01  percent.)  only  in  Rheum sibiricum,  whilst 
in  the  other  four  commercial  varieties  (Rheum  Moscoviticum,.  R^ 
Qmiense,  R.  palmatum  taiigaticum,  and  R.  Angltcum  cultum)  either 
none  or  only  traces  could  be  detected.  The  method  used  by  Dragen- 
dorff  for  the  estimation  of  the  chrysophanic  acid  consisted  in  extract- 
ing powdered  rhubarb  with  light  petroleum  spirit,  the  petroleum  being- 
colored  intensely  yellow  when  the  rhubarb  under  examination 
contained  free  chrysophanic  acid,  whilst  in  the  opposite  case  it 
remained  colorless. 
The  correctness  of  this  method  of  testing  may  be  verified  by  boiling 
powdered  rhubarb  in  which  no  chrysophanic  acid  can  be  detected  by 
^  "  Pliarniaceutische  Zeitschrift  fiir  Russland,"  xxiv,  193, 
"Liebig's  Annalen,"  1844,  i,  215. 
3"  Pharm.  Zeit  f.  Russland,"  vi,  603. 
*"  Pharmaceutical  Journal,"  [3],  viii,  826.. 
