Piperine is commercially available. If desired, it may be extracted
from black pepper using dichloromethane. The amount of piperine
varies from 1-2% in long pepper, to 5-9% in the white and the black
peppers of commerce. Further, it may be prepared by treating the
solvent-free residue from an alcoholic extract of black pepper,
with a solution of sodium hydroxide to remove resin (said to
contain chavicine, an isomer of piperine) and solution of the
washed, insoluble residue in warm alcohol, from which the alkaloid
crystallises on cooling.
The pungency caused by capsaicin and piperine is caused by
activation of the heat and acidity sensing TRPV ion channel TRPV1
on nociceptors (pain sensing nerve cells).
Piperine has also been found to inhibit human CYP3A4 and
P-glycoprotein, enzymes important for the metabolism and transport
of xenobiotics and metabolites. In animal studies, piperine also
inhibited other enzymes important in drug metabolism. By inhibiting
drug metabolism, piperine may increase the bioavailability of
various compounds. Notably, piperine may enhance bioavailability of
curcumin by 2000% in humans.