Source : Webster's Revised Unabridged Dictionary (1913)

Ligustrin \Li*gus"trin\ (l[-i]*g[u^]s"tr[i^]n), n. (Chem.)
   A bitter principle found in the bark of the privet (Ligustrum
   vulgare), and extracted as a white crystalline substance with
   a warm, bitter taste; -- called also {ligustron}.