Protective effects of alpinetin on lipopolysaccharide/d-Galactosamine-induced liver injury through inhibiting inflammatory and oxidative responses.

Alpinetin, a type of novel plant flavonoid derived from Alpinia katsumadai Hayata, has been reported to have anti-inflammatory effects. The aim of this investigation was designed to reveal the protective effects of alpinetin on Lipopolysaccharide (LPS)/d-galactosamine (D-Gal)-induced liver injury in mice. Alpinetin (12.5, 25, 50 mg/kg) were given 1 h before LPS and D-Gal treatment. 12 h after LPS and D-Gal treatment, the liver tissues and serum were collected. Our results showed that alpinetin treatment improved liver histology, indicating a marked decrease of inflammatory cell infiltration and restore hepatic lobular architecture. Alpinetin also inhibited liver myeloperoxidase (MPO) activity and malondialdehyde (MDA) level. Furthermore, LPS/D-Gal-induced tumor necrosis factor-α (TNF-α) and Interleukin-1β (IL-1β) production were dose-dependently inhibited by alpinetin. Alpinetin also attenuated LPS/D-Gal-induced expression of phospho-NF-κB p65 and phospho-IκBα. In addition, alpinetin was found to increase the expression of nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1). In conclusion, these findings suggested that alpinetin inhibited liver injury through inhibiting NF-κB and activating the Nrf2 signaling pathway.