352  Constituents  of  Andrographis  Paniculata.  {KmjJ™'  Jnf* 
Examination  of  the  Bitter  Principle  (A). 
This  was  purified  by  dissolution  in  alcohol  and  fractional  precipi- 
tation ;  the  process  was  repeated  three  times.  It  had  a  pale  yellow 
color.  When  a  little  of  the  substance  was  heated  in  a  test-tube  it 
diffused  a  very  fragrant  odor.   It  had  melting-point  of  2060  C. 
Strong  sulphuric  acid  produced  a  yellowish-brown  color.  With 
potassium  dichromate  and  sulphuric  acid  the  substance  at  first  gave 
a  deep  brown  (almost  black)  color,  attended  with  brisk  effervescence. 
After  a  time  the  effervescence  ceased  and  the  color  passed  to  grass- 
green. 
Strong  sulphuric  acid  containing  a  trace  of  nitric  acid  produced 
a  reddish-brown  color. 
Strong  sulphuric  acid  containing  ammonium  vanadate  produced 
brownish-red  color,  changing  to  green. 
In  strong  nitric  acid  the  substance  dissolved  readily,  the  solution 
acquiring  a  yellow  color. 
The  substance  is  very  soluble  in  ethyl  and  methyl  alcohol,  though 
not  to  the  above  extent  in  amyl  alcohol.  It  is  very  slightly  soluble 
in  chloroform  and  ether.  Benzene  and  petroleum  ether  do  not  dis- 
solve it  even  on  boiling. 
It  is  neither  an  alkaloid  nor  a  glucoside,  as  it  neither  contains 
nitrogen  nor  produces  a  reducing  sugar  after  hydrolysis.  It  can  be 
acetylated, — i.e.,  it  contains  hydroxyl  groups;  the  acetyl  derivative 
is  white  and  insoluble  in  water.    Its  melting-point  is  95  °  C. 
When  the  substance  was  added  to  a  solution  of  bromine  in 
chloroform  a  dark-colored  oil  separated  out;  on  washing  the  latter 
with  a  dilute  solution  of  potassium  carbonate  a  white  solid  substance 
was  left  behind.  This  was  the  bromo  derivative  of  the  bitter; 
the  direct  absorption  of  bromine  proves  the  presence  of  at  least  one 
double  bond.  The  melting-point  of  the  bromo  derivatives  would  not 
be  determined,  as  it  began  to  decompose  at  1200  C.  before  melting; 
at  1600  C.  it  was  a  liquid,  but  began  to  give  off  a  quantity  of  gas. 
0.0498  Gm.  of  the  bromo  derivative  gave  0.0160  Gm.  of  AgBr 
or  13.7  per  cent,  of  bromine.  Since  there  must  be  at  least  two 
atoms  of  bromine  in  the  molecule,  the  molecular  weight  is  1175  or 
some  multiple  of  it. 
0.1008  Gm.  of  the  bitter  analysis  gave  0.2521  Gm.  of  CO'2  and 
0.0763  Gm.  of  H20. 
Hence  C  68.2,  H  8.4. 
