The Collaborative International Dictionary of English v.0.48:

Dulcamarin \Dul`ca*ma"rin\, n. (Chem.)
   A glucoside extracted from the bittersweet (Solanum
   Dulcamara), as a yellow amorphous substance. It probably
   occasions the compound taste. See Bittersweet, 3
   (a) .
       [1913 Webster]