Am.  Jour.  Pharm. ) 
September,  1914.  / 
Rhamnus  Purshiana. 
403 
analyzed.  He  considered  that  Wenzell's  crystals,  previously  referred 
to,  were  merely  impure  emodin,  and  could  obtain  no  evidence  of  the 
existence  of  a  glucoside,  nor  could  he  isolate  any  other  crystalline 
substance. 
Dr.  Eccles  reports  in  the  Druggists  Circular  of  March,  1888, 
p.  54,  the  discovery  of  the  presence  of  an  alkaloid  which  he  states  he 
has  separated  from  the  fluidextract  and  precipitated  by  Mayer's 
reagent. 
A.  C.  Zeig  ("  Proc.  of  the  Amer.  Pharm.  Assoc.,"  vol.  37,  1889, 
p.  261 )  further  examined  the  resins  previously  described  by  Prescott, 
but  was  unable  to  isolate  any  definite  principle. 
Le  Prince  (Compt.  rend.,  vol.  115,  1892,  p.  286)  claims  to  have 
obtained  the  active  principle  of  cascara  bark  in  a  crystalline  form  and 
named  it  cascarine.  Le  Prince  suggested  that  cascarine  might  be 
identical  with  rhamnetin. 
A  most  curious  confusion  has  arisen  in  chemical  literature  with 
respect  to  this  substance.  Beilstein  ("  Handbuch,"  3rd  edition,  vol.  3, 
p.  627),  under  cascarine,  states  that  it  is  identical  with  rhamnetin, 
but  Phipson  (Compt.  rend.,  vol.  115,  1892,  474)  considers  that  it  was 
identical  with  xantho-rhamnin,  and  Van  Rijn  ("  Die  Glykoside," 
1900  edition,  p.  299),  without  comment,  accepts  this  latter  statement, 
and  under  xantho-rhamnin  gives  the  details  of  Le  Prince's  prepara- 
tion of  cascarine  from  cascara, 
The  properties  of  cascarine,  as  given  by  Le  Prince,  prove  that  it 
could  not  be  identical  with  either  rhamnetin  or  xantho-rhamnin. 
Le  Prince  presents  no  evidence  of  the  purity  of  cascarine ;  it  agrees, 
however,  in  properties,  with  the  exception  of  the  melting-point,  with 
emodin. 
E.  Cabanes  states  that  the  active  principles  of  cascara  bark  are 
located  in  the  layers  of  bast  immediately  adjoining  the  cambium,  and 
in  the  medullary  rays  traversing  these  layers.  {Pharm.  Jour.,  May  2, 
1896,  p.  343 ;  Rep.  de  Pharm.  (3),  vol.  7,  p.  97 ;  "  Proc.  of  the  Amer. 
Pharm.  Assoc.,"  vol.  44,  1896,  p.  638.) 
A.  R.  L.  Dohme  and  H.  Englehardt  ("  Proc.  of  the  Amer.  Pharm. 
Assoc.,"  vol.  45,  1897,  p.  193)  examined  Rhamnus  Purshiana  and 
claimed  to  have  isolated  the  active  principle  of  the  drug,  which  they 
named  Purshianin.  This  was  stated  to  be  a  glucoside,  yielding,  on 
hydrolysis,  emodin  and  a  sugar  which  was  not  identified.  They  con- 
sider the  fat  to  be  a  mixture  of  dodecyl  palmitate  and  stearate.  They 
also  attempted  to  obtain  the  bitter  principle  in  a  crystalline  form,  but 
were  unsuccessful. 
