Nonalcoholic fatty liver disease (NAFLD) is an inflammatory lipotoxic disorder with a prevalence of over 25% worldwide. However, safe and effective therapeutic agents for the management of NAFLD are still lacking. We aimed to investigate the hepatoprotective effect and molecular mechanism of 4-acetylantroquinonol B (4-AAQB), a natural ubiquinone derivative obtained from the mycelia of Antrodia cinnamomea.

RAW264.7 and J774A.1 cells were treated with 4-AAQB and then stimulated with LPS or tunicamycin (TM) for 24 h. Inflammatory responses, markers of endoplasmic reticulum (ER) stress, and NOD-like receptor protein 3 (NLRP3) inflammasome were analyzed in both cell lines. In the applied in vivo model, male C57BL/6J mice were fed with chow or a methionine/choline-deficient (MCD) diet along with vehicle or 4-AAQB (10 mg/kg, i.p. injected, once a day) for 10 consecutive days. Plasma levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were measured. Liver tissues were analyzed using histological techniques; protein levels involved in ER stress, NLRP3 inflammasome, and inflammatory responses were measured.

4-AAQB significantly ameliorated the plasma levels of ALT and AST as well as the NAFLD activity score (NAS) in mice fed the MCD diet. In addition, 4-AAQB suppressed inflammatory responses, ER stress, and NLRP3 inflammasome activation, but increased the nuclear factor erythroid 2-related factor 2 (Nrf2) and Sirtuin 1 (SIRT1) signaling pathways in both in vitro and in vivo models.

We suggest that 4-AAQB treatment might be a tangible therapeutic strategy in the management of NAFLD/NASH.