Sanshools are major active ingredients of Zanthoxylum piperitum and are used as food additives in East Asia. Sanshools cause irritant, tingling and sometimes paresthetic sensations on the tongue. However, the molecular mechanism underlying the pungent or tingling sensation induced by sanshools is not known. Because many transient receptor potential (TRP) channels are responsible for the sensations induced by various spices and food additives, we expressed 17 TRP channels in human embryonic kidney (HEK) cells and investigated their activation by hydroxy-alpha-sanshool (HalphaSS) or hydroxy-beta-sanshool (HbetaSS) isolated from Zanthoxylum piperitum. It was found that HalphaSS, but not HbetaSS, depolarized sensory neurons with concomitant firing of action potentials and evoked inward currents. Among 17 TRP channels expressed in HEK cells, HalphaSS caused Ca(2+) influx in cells transfected with TRPV1 or TRPA1, and evoked robust inward currents in cells transfected with TRPV1 or TRPA1. In primary cultured sensory neurons, HalphaSS induced inward currents and Ca(2+) influx in a capsazepine-dependent manner. Moreover, HalphaSS-induced currents and Ca(2+) influx were greatly diminished in TRPV1(-/-) mice. HalphaSS evoked licking behavior when injected into a single hind paw of wild-type mice, but this was much reduced in TRPV1-deficient mice. These results indicate that TRPV1 and TRPA1 are molecular targets of HalphaSS in sensory neurons. We conclude that the activations of TRPV1 and TRPA1 by HalphaSS explain its unique pungent, tingling sensation.

Five linear fatty acid amides (1-5) of the sandshool class, including two new compounds, were isolated from Zanthoxylum piperitum seeds. Based on combined spectral analyses, the structures of new compounds 4 and 5 were determined to be 2',3'-dihydroxy-alpha-sanshool and 2',3'-dihydroxy-beta-sanshool, respectively. These compounds exhibited weak cytotoxicity in the A-549 (human lung cancer) cell line.

Five new dihydroxystyrene metabolites and six known compounds of the same structural class were isolated from an association of the sponges Poecillatra wondoensis and Jaspis sp., collected from Keomun Island, Korea. The structures of novel compounds were determined to be the sodium or N, N-dimethyl guanidinium salts of a dihydroxystyrene dimer (5) and two trimers (6, 7). Two dimers (10, 11) containing imidazole moieties were also identified on the basis of the results of combined spectroscopic analyses. Several compounds exhibited weak to moderate inhibitory effects against isocitrate lyase and sortase A enzymes derived from microorganisms.