Auto-oxidation products of epigallocatechin gallate activate TRPA1 and TRPV1 in sensory neurons.

2014 Fiscal Year Final Research Report

• Project/Area Number: 24570170
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Functional biochemistry
• Research Institution: Nagahama Institute of Bio-Science and Technology
• Principal Investigator: SAITOH Osamu 長浜バイオ大学, バイオサイエンス学部, 教授 (60241262)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 味覚 / TRPチャネル

Outline of Final Research Achievements

We examined how mammalian TRPV1 and TRPA1, which are nociceptive sensors are activated by green tea catechins during the auto-oxidation process. Neither TRPV1 nor TRPA1 could be activated by any of the freshly prepared catechin. When EGCG was pre-incubated for 3h in salt solution, it significantly activated both TRP channels expressed in HEK293 cells. Even after incubation other catechins showed much less effects, suggesting that only oxidative products of EGCG activate both TRPV1 and TRPA1. Dorsal root ganglion (DRG) sensory neurons were also activated by the incubated EGCG through TRPV1 and TRPA1 channels. Liquid chromatography/mass spectrometry revealed that theasinensin (TS) A and D are formed during incubation of EGCG. We found that purified TS-A activates both TRPV1 and TRPA1, and that it stimulates DRG neurons through TRPV1 and TRPA1 channels. Results suggested a possibility that TRPV1 and TRPA1 channels are involved in the sense of astringent taste of green tea.

Free Research Field

分子神経生物学