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BioMed Research International
Volume 2014, Article ID 902735, 8 pages
Research Article

Distinct Action of Flavonoids, Myricetin and Quercetin, on Epithelial Cl Secretion: Useful Tools as Regulators of Cl Secretion

1Department of Molecular Cell Physiology Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
2Japan Institute for Food Education and Health, St. Agnes’ University, Kyoto 602-8013, Japan
3Shin-Koiwa Clinic, Tokyo 124-0023, Japan
4Department of Physiology, School of Medical Sciences, University of Otago, Dunedin 9054, New Zealand
5Department of Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan

Received 25 February 2014; Revised 6 March 2014; Accepted 10 March 2014; Published 10 April 2014

Academic Editor: Akio Tomoda

Copyright © 2014 Hongxin Sun et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Epithelial Cl secretion plays important roles in water secretion preventing bacterial/viral infection and regulation of body fluid. We previously suggested that quercetin would be a useful compound for maintaining epithelial Cl secretion at a moderate level irrespective of cAMP-induced stimulation. However, we need a compound that stimulates epithelial Cl secretion even under cAMP-stimulated conditions, since in some cases epithelial Cl secretion is not large enough even under cAMP-stimulated conditions. We demonstrated that quercetin and myricetin, flavonoids, stimulated epithelial Cl secretion under basal conditions in epithelial A6 cells. We used forskolin, which activates adenylyl cyclase increasing cytosolic cAMP concentrations, to study the effects of quercetin and myricetin on cAMP-stimulated epithelial Cl secretion. In the presence of forskolin, quercetin diminished epithelial Cl secretion to a level similar to that with quercetin alone without forskolin. Conversely, myricetin further stimulated epithelial Cl secretion even under forskolin-stimulated conditions. This suggests that the action of myricetin is via a cAMP-independent pathway. Therefore, myricetin may be a potentially useful compound to increase epithelial Cl secretion under cAMP-stimulated conditions. In conclusion, myricetin would be a useful compound for prevention from bacterial/viral infection even under conditions that the amount of water secretion driven by cAMP-stimulated epithelial Cl secretion is insufficient.