Pungent qualities of sanshool-related compounds evaluated by a sensory test and activation of rat TRPV1

The detection threshold and taste characteristics of sanshools were examined by sensory evaluation, after isolating four sanshools (alpha-, gamma-, and delta-), and two hydroxy sanshools alpha- and from the pericarp of Japanese pepper. The Scoville unit (SU) values of the four sanshools were in the range of 80,000-110,000, while those of hydroxy sanshools were 3-5 fold lower than corresponding sanshools. The pungent qualities of each sanshool were different. Burning and tingling were predominantly perceived and lasted for the longest time with alpha-sanshool. Burning and fresh for gamma-sanshool, and tingling and numbing for hydroxy a-sanshool were perceived. Tests on the activation of rat TRPV1 were also performed. All of them were weak agonists. Among them, gamma-sanshool was the most potent agonist, although its EC50 value of 5.3 mu m was 230 fold higher than that of capsaicin. These results indicate that it would be difficult to explain the pungent quality of each sanshool simply in terms of TRPV1 activation.