The Collaborative International Dictionary of English v.0.48:

Piperine \Pip"er*ine\, n. [L. piper pepper: cf. F. piperin,
   piperine.] (Chem.)
   A white crystalline compound of piperidine and piperic acid.
   It is obtained from the black pepper (Piper nigrum) and
   other species.
   [1913 Webster]

WordNet (r) 3.0 (2006):

piperine
    n 1: derived from pepper (especially black pepper); source of
         the hotness of black and white pepper [syn: piperin,
         piperine]