The Collaborative International Dictionary of English v.0.48:

Piperic \Pi*per"ic\ (p[-i]*p[e^]r"[i^]k), a. (Chem.)
   Pertaining to, or derived from, or designating, a complex
   organic acid found in the products of different members of
   the Pepper family, and extracted as a yellowish crystalline
   substance.
   [1913 Webster]