Piperine

Piperine is the alkaloid responsible for the pungency of black pepper along with chavicine (an isomer of piperine). It has also been used in some forms of traditional medicine and as an insecticide.

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.

Due to its effects on drug metabolism, piperine should be taken cautiously (if at all) by individuals taking other medications.