Brunodelphinine A alleviates non-alcoholic fatty liver disease by inhibiting oxidative stress and regulating lipid metabolism via NOX4/SIRT1/PPARs axis

Background Nonalcoholic fatty liver disease (NAFLD), which is characterized by the accumulation of fat in the liver, has emerged as a leading cause of chronic liver diseases and malignancies. However, there remains a scarcity of approved therapeutic interventions. Brunodelphinine A (BruA) is a diterpenoid alkaloid isolated from Delphinium brunonianum Royle. in our previous study. It was evaluated with strong activity of lipid-lowering. Nevertheless, its precise effects and mechanisms in the treatment of NAFLD remain unexplored. Purpose The present study aims to elucidate the effects of BruA against NAFLD and to investigate its potential pharmacological mechanism. Methods The lipid-lowering and anti-NAFLD effects of BruA were evaluated in the free fatty acid (FFA)-induced cell model and high-fat diet (HFD)-induced mice. Network pharology analysis combined with Non-targeted metabolomics study was used to explore the key mechanism of BruA. Furthermore, molecular docking and cellular thermal shift assay (CETSA) were used to simulate and verify the targeting activation of BruA on the NADPH oxidase 4 (NOX4). The core role of NOX4 in BruA in regulating nicotinamide adenine dinucleotide (NAD + )/Sirtuin 1 (SIRT1) and peroxisome proliferators-activated receptors (PPARs) signaling pathway to improve oxidative stress and lipid metabolic disorders was further focused, and such mechanism was evaluated in WT and NOX4 knockout mice or HepG2 cells. Results BruA dose-dependently reduced FFA-induced lipid accumulation and cell damage in vitro , and mitigated HFD-induced NAFLD in mice. At the metabolite level, BruA improved metabolic disorder in NAFLD mice focusing on the metabolism of arachidonic acid and linolenic acid, which has been considered as signs of oxidative stress, that positively correlated with NAFLD. BruA targeting inhibited NOX4 to mitigate reactive oxygen species (ROS)-mediated oxidative stress and prevent abnormal redox levels, thereby regulating NAD + /SIRT1 in protecting the liver from oxidative damage, and further affected downstream PPARs-related lipid metabolism regulation processes, thus alleviating hepatic lipid accumulation. Furthermore, NOX4 deficiency suppressed the protective effect of BruA in vitro and in vivo . Conclusion BruA improved oxidative stress and lipid metabolic disorders of NAFLD by regulating the NOX4-SIRT1-PPARs signaling axis in vivo and in vitro , and this regulation is targeting dependent on NOX4. For its mechanisms of antioxidant stress and lipid-lowering, there is great therapeutic potential for BruA in the treatment of period with elevated lipids and inflammation production in NAFLD.