AIMS: Oxidative stress and inflammation are always associated. Appropriate management of oxidative mediators may represent a therapeutic strategy to reduce inflammation, and use of antioxidant can be protective against inflammatory diseases. Glycyrrhizin (GL) plays an anti-inflammatory and antioxidant effect by inhibiting high mobility group box 1 (HMGB1) or 11-β-hydroxysteroid dehydrogenase type II (11βHSD2) enzyme. In this study, the potential role of dipotassium glycyrrhizate (DPG), a salt of GL, to reduce oxidative stress in intestinal inflammatory condition was investigated in vivo and the mechanism of action of DPG was studied in vitro. RESULTS: In a colitis mouse model DPG affected oxidative stress reducing iNOS and COX-2 expression, as well as NO and PGE2 levels. By means of LPS-stimulated macrophages we found that DPG inhibited the expression of pro-inflammatory cytokines and reduced iNOS and COX-2 expression in a time dependent manner, through two different ways of signal. DPG reduced, at a later time, both iNOS and COX-2, through a mechanism HMGB1-dependent, and at an earlier time only COX-2, through a mechanism AMP-activated kinase (AMPK)-phosphorylation-mediated. CONCLUSION: DPG has a protective effect on colitis and inflammation through the inhibition of oxidative stress. This study clarifies the two-ways mechanism by which DPG inhibits iNOS and COX-2 during inflammation and demonstrates for the first time that AMPK is a target of DPG. Uncovering this mechanism is significant to clarify the relationship between energy homeostasis and anti-oxidative responses and suggests that DPG could play a relevant role in the development of new therapy against inflammatory diseases associated to oxidative stress.
AIMS: Oxidative stress and inflammation are always associated. Appropriate management of oxidative mediators may represent a therapeutic strategy to reduce inflammation, and use of antioxidant can be protective against inflammatory diseases. Glycyrrhizin (GL) plays an anti-inflammatory and antioxidant effect by inhibiting high mobility group box 1 (HMGB1) or 11-β-hydroxysteroid dehydrogenase type II (11βHSD2) enzyme. In this study, the potential role of dipotassium glycyrrhizate (DPG), a salt of GL, to reduce oxidative stress in intestinal inflammatory condition was investigated in vivo and the mechanism of action of DPG was studied in vitro. RESULTS: In a colitismouse model DPG affected oxidative stress reducing iNOS and COX-2 expression, as well as NO and PGE2 levels. By means of LPS-stimulated macrophages we found that DPG inhibited the expression of pro-inflammatory cytokines and reduced iNOS and COX-2 expression in a time dependent manner, through two different ways of signal. DPG reduced, at a later time, both iNOS and COX-2, through a mechanism HMGB1-dependent, and at an earlier time only COX-2, through a mechanism AMP-activated kinase (AMPK)-phosphorylation-mediated. CONCLUSION:DPG has a protective effect on colitis and inflammation through the inhibition of oxidative stress. This study clarifies the two-ways mechanism by which DPG inhibits iNOS and COX-2 during inflammation and demonstrates for the first time that AMPK is a target of DPG. Uncovering this mechanism is significant to clarify the relationship between energy homeostasis and anti-oxidative responses and suggests that DPG could play a relevant role in the development of new therapy against inflammatory diseases associated to oxidative stress.
Authors: Sandamali A Ekanayaka; Sharon A McClellan; Ronald P Barrett; Linda D Hazlett Journal: J Ocul Pharmacol Ther Date: 2017-12-13 Impact factor: 2.671
Authors: Camila Dos Santos Leite; Gabriel Alves Bonafé; Juliana Carvalho Santos; Carlos Augusto Real Martinez; Manoela Marques Ortega; Marcelo Lima Ribeiro Journal: Int J Mol Sci Date: 2022-04-08 Impact factor: 6.208