Tea catechins’ affinity for human cannabinoid receptors

Korte, G.; Dreiseitel, A.; Schreier, P.; Oehme, A.; Locher, S.; Geiger, S.; Heilmann, J.; Sand, P.G.

doi:10.1016/j.phymed.2009.10.001

« Previous Next »Phytomedicine
Volume 17, Issue 1 , Pages 19-22, January 2010

Tea catechins’ affinity for human cannabinoid receptors

G. Korte
- Department of Psychiatry, University of Regensburg, Franz-Josef-Strauss-Allee 11, H4 R97 93053 Regensburg, Germany
- Corresponding author. Tel.: +499419448955; fax: +499419448956.
A. Dreiseitel
- Department of Psychiatry, University of Regensburg, Franz-Josef-Strauss-Allee 11, H4 R97 93053 Regensburg, Germany
P. Schreier
- Chair of Food Chemistry, University of Wuerzburg, Am Hubland, 97074 Wuerzburg, Germany
A. Oehme
- Chair of Food Chemistry, University of Wuerzburg, Am Hubland, 97074 Wuerzburg, Germany
S. Locher
- Chair of Food Chemistry, University of Wuerzburg, Am Hubland, 97074 Wuerzburg, Germany
S. Geiger
- Chair of Pharmaceutical Biology, Institute of Pharmacy, University of Regensburg, Universitaetsstrasse 31, 93053 Regensburg, Germany
J. Heilmann
- Chair of Pharmaceutical Biology, Institute of Pharmacy, University of Regensburg, Universitaetsstrasse 31, 93053 Regensburg, Germany
P.G. Sand
- Department of Psychiatry, University of Regensburg, Franz-Josef-Strauss-Allee 11, H4 R97 93053 Regensburg, Germany

published online 09 November 2009.

Abstract

Among the many known health benefits of tea catechins count anti-inflammatory and neuroprotective activities, as well as effects on the regulation of food intake. Here we address cannabimimetic bioactivity of catechin derivatives occurring in tea leaves as a possible cellular effector of these functionalities. Competitive radioligand binding assays using recombinant human cannabinoid receptors expressed in Chem-1 and CHO cells identified (–)-epigallocatechin-3-O-gallate, EGCG (K_i=33.6μM), (–)-epigallocatechin, EGC (K_i=35.7μM), and (–)-epicatechin-3-O-gallate, ECG (K_i=47.3μM) as ligands with moderate affinity for type 1 cannabinoid receptors, CB1. Binding to CB2 was weaker with inhibition constants exceeding 50μM for EGC and ECG. The epimers (+)-catechin and (–)-epicatechin exhibited negligible affinities for both CB1 and CB2. It can be concluded that central nervous cannabinoid receptors may be targeted by selected tea catechins but signaling via peripheral type receptors is less likely to play a major role in vivo.

Keywords: Camellia sinensis, Catechins, Epigallocatechin-3-O-gallate, Cannabinoid receptor, Neuroprotection