tragacanthin

from The Collaborative International Dictionary of English v.0.48

Cerasin \Cer"a*sin\, n. (Chem.)
   A white amorphous substance, the insoluble part of cherry
   gum; -- called also {meta-arabinic acid}.
   [1913 Webster]

   2. (Chem.) A gummy mucilaginous substance; -- called also
      {bassorin}, {tragacanthin}, etc.
      [1913 Webster]