| Abstract Detail
Membrane Transport Wu, Lankun [1], Leng, Qiang [2], Escalera, Jasmine [3], Jordt, Sven-Eric [3], Hebert, Steven [2], Wurtele, Eve [1]. Echinacea contains metabolite(s) that activate the mammalian TRPV1 transient pain receptor. Originally a Native American medicinal, Echinacea is now commonly used as an herbal immunomodulator. The growing evidence that pain reception and inflammation are closely inter-related led us to hypothesize that Echinacea might mediate inflammatory responses in part via pain receptors. The TRPV1 ligand-gated cation channel is thought to act as a key integrator of inflammatory pain. It is activated by a number of endogenous mammalian ligands, but also by capsaicin (the “hot” component in chili peppers). Here we report for the first time that Echinacea extracts can activate the TRPV1. TRPV1 was transiently expressed in two model systems, Xenopus laevis oocytes and HEK293t cells (human embryonic kidney cells), and ion-channel bioactivity was assayed. Ethanol extracts from roots of 6 species of Echinacea rapidly induce inward ion currents in frog oocytes expressing TRPV1. Specifically, Ca2+ imaging indicates Echinacea induces a rise in Ca2+ in TRPV1-expressing HEK cells. Echinacea extracts were fractionated by semi-preparative HPLC; only a single fraction has bioactivity. Iterative sub-fractionation and bioassays are being used to identify the bioactive constituent(s). E. angustifolia, at a dose of 0.25 mg/ml, evokes a current 10-fold greater than does a saturating dose of capsaicin. We present mutational and kinetic evidence that the mechanism of action of Echinacea on the TRPV1 receptor is distinct from that of capsaicin and endogenous mammalian ligands.
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1 - Iowa State University, Department of Genetics, Development and Cell Biology, Ames, Iowa, 50011, USA
2 - Yale University School of Medicine, Department of Cellular and Molecular Physiology, New Haven, Connecticut, 06520, USA
3 - Yale University School of Medicine, Department of Pharmacology, New Haven, Connecticut, 06520, USA
Keywords:
Echinacea
TRPV1
pain
ion channel.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P10004
Abstract ID:320 |
