Molecular and cellular mechanisms of the pungent and tingling impression of black pepper ( Piper nigrum L . )

Sensory-directed fractionation of an ethanol extract prepared from black pepper corns (Piper nigrum L.) followed by LC-TOF-MS, LC-MS/MS, and 1D/2D-NMR experiments as well as synthesis revealed in sum 25 key tingling and/or pungent stimuli, which belong to two chemical classes of non-volatiles: the piperine-type analoges and unsaturated, long-chain fatty acid amides. While sensory evaluation of human recognition threshold concentrations by means of a modified half tongue test demonstrated the structural features causing the tingling and/or pungent impression of these pepper amides, the data obtained did not correlate with those reported for heterologously expressed TRP channels TRPV1 and TRPA1 in literature. Screening experiments with two-pore domain (KCNK, K2P) K channels suggest that pungent/tingling chemosensates from pepper exhibit a marked effect on three KCNK channels, namely TASK-1 (KCNK3, K2P 3.1), TASK-3 (KCNK9, K2P 9.1) and TRESK (KCNK18, K2P 18.1), respectively, which are likely to play a complementary role to TRP channels in the complex orosensory impression elicited by black pepper corns.