The Collaborative International Dictionary of English v.0.48:

Columbin \Co*lum"bin\, n. (Chem.)
   A white, crystalline, bitter substance. See Calumbin.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Calumbin \Ca*lum"bin\, n. (Chem.)
   A bitter principle extracted as a white crystalline substance
   from the calumba root. [Written also colombin, and
   columbin]
   [1913 Webster]