140 
Arbutin  and  Arbutose. 
(  Am.  Jour.  Pharni. 
I     March,  1885. 
tion,  this  reaction  only  occurring  when  some  decomposition  has  taken 
place  ;  neither  does  yeast  set  up  fermentation  with  pure  arbutin. 
Arbutin  is  colored  blue  by  dilute  solution  of  perchloride  of  iron. 
In  testing  for  this  glucoside,  the  substance  to  be  examined  is  moistened 
with  strong  nitric  acid,  then  boiled  with  a  mixture  of  eight  volumes  of 
alcohol  to  one  of  sulphuric  acid ;  finally,  water  and  an  excess  of  pot- 
ash are  added,  when  the  liquid  takes  the  violet  tint  of  the  potash  salt 
and  of  dinitroquinon. 
The  preparation  of  arbutin,  although  very  simple  in  theory,  presents 
considerable  difficulty  in  practice.  The  bearberry  is  especially  rich  in 
tannin  (averaging  35  per  cent.),  and  in  addition  contains  gallic  acid, 
urson,  a  resinous  matter,  gum,  chlorophyll,  pectin,  besides  arbutin,  to 
which  last  it  appears  to  ow^e  the  greater  part  of  its  therapeutic  proper- 
ties. All  these  principles,  with  the  exceptien  of  urson,  are  soluble  in 
boiling  water. 
The  process  given  by  the  author  for  the  preparation  of  arbutin  is 
to  treat  by  successive  decoctions  the  drug  reduced  to  a  coarse  powder, 
then  to  combine  the  products  and  precipitate  the  tannin  and  extractive 
matters  with  subacetateof  lead.  The  decolorized  liquid  is  treated  with 
sulphydric  acid  and  evaporated  rapidly.  The  arbutin  crystallizes  upon 
cooling  in  the  concentrated  liquor;  but  in  consequence  of  the  decom- 
position of  a  certain  quantity  of  arbutin  during  the  operation  a  sticky 
crystalline  mass  is  obtained  which  dries  only  imperfectly.  This  com- 
plex product  is  called  "  arbutose "  by  the  author,  who  says  it  is 
tolerably  uniform  in  composition,  the  proportions  being  about  55  per 
cent,  of  crystalline  arbutin,  35  per  cent,  of  glucose  and  10  per  cent,  of 
water.  In  order  to  obtain  the  crystalline  arbutin  this  arbutose  is  dried 
in  the  air  as  far  as  possible,  treated  with  charcoal  and  then  with  suc- 
cessive quantities  of  alcohol  and  distilled  water. 
But  the  author  is  of  opinion  that,  with  the  exception  of  solutions 
intended  for  hypodermic  injection,  for  which  only  the  crystallized 
arbutin  should  be  used,  arbutose  may  be  used  in  all  pharmaceutical 
preparations.  In  order  to  determine  its  strength  it  is  only  necessary  to 
estimate  the  glucose  by  means  of  cupropotassic  Solution,  and  deduct 
this  and  the  water,  the  remainder  representing  pure  arbutin.  Arbutin 
may  also  be  administered  under  the  form  of  an  elixir  or  in  pills. 
Arbutin  is  non-poisonous,  and  may  be  given  in  doses  of  from  50 
centigrams  to  2  grams  twice  daily.  Under  the  influence  of  this  gluco- 
side  the  urine  will  after  the  second  day  frequently  show  a  o;reen  color, 
