Possible involvement of Nrf2 and PPARγ up-regulation in the protective effect of umbelliferone against cyclophosphamide-induced hepatotoxicity

Abstract

Umbelliferone (UMB) is a coumarin derivative with promising hepatoprotective effects. In this study, we examined the possible protective effects of UMB against cyclophosphamide (CP)-induced hepatotoxicity, addressing the question of the possible role of nuclear factor erythroid 2-related factor 2 (Nrf2) and peroxisome proliferator activated receptor gamma (PPARγ). Wistar rats were orally administered UMB at doses 50 and 100mg/kg two weeks prior to CP injection. Five days after CP administration, the rats were sacrificed and samples were collected for analyses. CP induced a significant increase in circulating liver marker enzymes and pro-inflammatory cytokines. Hepatic lipid peroxidation and nitric oxide levels, and nuclear factor-kappaB (NF-κB) and inducible nitric oxide synthase (iNOS) expression were significantly increased following CP administration. UMB supplementation attenuated CP-induced inflammation and oxidative stress as assessed by restoration of the activity and expression of the antioxidant defenses, and suppression of pro-inflammatory cytokines. Histological examination also showed that UMB could significantly reduce CP-induced alterations. CP-induced rats showed significant down-regulation of Nrf2, HO-1 and PPARγ, an effect that was markedly reversed by UMB. In conclusion, the hepatoprotective effects of UMB appear to depend on co-activation of PPARγ and Nrf2, and subsequent suppression of oxidative stress and inflammation.

Keywords: 7-Hydroxycoumarin; Cyclophosphamide; Hepatotoxicity; Nrf2; Oxidative stress; PPARγ.