Protective Effect of Dihydrokaempferol on Acetaminophen-Induced Liver Injury by Activating the SIRT1 Pathway

Acetaminophen (APAP) overdose is the leading cause of acute liver failure (ALF) in the Western world, with limited treatment opportunities. 3,5,7,4 ′ -Tetrahydroxyflavanone (Dihydrokaempferol, DHK, Aromadendrin) is a flavonoid isolated from Chinese herbs and displays high anti-oxidant and anti-inflammatory capacities. In this study, we investigated the protective effect by DHK against APAP-induced liver injury in vitro and in vivo and the potential mechanism of action. Cell viability assays were used to determine the effects of DHK against APAP-induced liver injury. The levels of reactive oxygen species (ROS), serum alanine/aspartate aminotransferases (ALT/AST), liver myeloperoxidase (MPO), and malondialdehyde (MDA) were measured and analyzed to evaluate the effects of DHK on APAP-induced liver injury. Western blotting, immunofluorescence staining, RT-PCR, and Transmission Electron Microscope were carried out to detect the signaling pathways affected by DHK. Here, we found that DHK owned a protective effect on APAP-induced liver injury with a dose-dependent manner. Meanwhile, Western blotting showed that DHK promoted SIRT1 expression and autophagy, activated the NRF2 pathway, and inhibited the translocation of nuclear p65 (NF- κ B) in the presence of APAP. Furthermore, SIRT1 inhibitor EX-527 aggravated APAP-induced hepatotoxicity when treating with DHK. Molecular docking results suggested potential interaction between DHK and SIRT1. Taken together, our study demonstrates that DHK protects against APAP-induced liver injury by activating the SIRT1 pathway, thereby promoting autophagy, reducing oxidative stress injury, and inhibiting inflammatory responses.