Quercetin modulates Nrf2 and glutathione-related defenses in HepG2 cells: Involvement of p38

Dietary flavonoid quercetin has been suggested as a cancer chemopreventive agent, but the mechanisms of action remain unclear. This study investigated the influence of quercetin on p38-MAPK and the potential regulation of the nuclear transcription factor erythroid-2p45-related factor (Nrf2) and the cellular antioxidant/detoxifying defense system related to glutathione (GSH) by p38 in HepG2 cells. Incubation of HepG2 cells with quercetin at a range of concentrations (5-50 οM) for 4 or 18 h induced a differential effect on the modulation of p38 and Nrf2 in HepG2 cells, 50 οM quercetin showed the highest activation of p38 at 4h of treatment and values of p38 similar to those of control cells after 18 h of incubation, together with the inhibition of Nrf2 at both incubation times. Quercetin (50 οM) induced a time-dependent activation of p38, which was in concert with a transient stimulation of Nrf2 to provoke its inhibition afterward. Quercetin also increased GSH content, mRNA levels of glutamylcysteine-synthetase (GCS) and expression and/or activity of glutathione-peroxidase, glutathione-reductase and GCS after 4 h of incubation, and glutathione-S-transferase after 18 h of exposure. Further studies with the p38 specific inhibitor SB203580 showed that the p38 blockage restored the inhibited Nrf2 transcription factor and the enzymatic expression and activity of antioxidant/detoxificant enzymes after 4 h exposure. In conclusion, p38-MAPK is involved in the mechanisms of the cell response to quercetin through the modulation of Nrf2 and glutathione-related enzymes in HepG2 cells. © 2011 Elsevier Ireland Ltd. All rights reserved.

Bibliographic Details

Main Authors:	Granado-Serrano, Ana B., Martín, M. Ángeles, Bravo, Laura, Goya, Luis, Ramos, Sonia
Other Authors:	Ministerio de Ciencia e Innovación (España)
Format:	artículo biblioteca
Language:	English
Published:	Elsevier 2012
Online Access:	http://hdl.handle.net/10261/60709 http://dx.doi.org/10.13039/501100004837
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