Protective Effects of the Ethyl Acetate Fraction of Distylium racemosum Against Metabolic Dysfunction-Associated Steatohepatitis

Metabolic dysfunction-associated steatohepatitis (MASH), previously referred to as non-alcoholic steatohepatitis (NASH), which is a progressive non-alcoholic fatty liver disease, is accompanied by hepatic steatosis, inflammation, and fibrosis. Despite its increasing prevalence, available treatment options for MASH are limited. Here, we investigated the protective effects of the Distylium racemosum ethyl acetate fraction (DRE) using MASH models and explored its key physiologically active components. Palmitic acid (PA)-induced AML12 hepatocytes and high-fat methionine- and choline-deficient-fed C57BL/6 mice were used as MASH models. Lipid accumulation was evaluated via triglyceride measurement, oil red O staining, and histological analysis. Lipid accumulation, inflammation, and fibrosis-associated gene expression were evaluated via real-time polymerase chain reaction. The physiologically active components of DRE were identified via high-performance liquid chromatography. Lipid accumulation and triglyceride levels were significantly reduced in PA-treated AML12 cells following DRE treatment. Additionally, DRE inhibited the expression of genes involved in lipogenesis (FAS and SREBP1c), inflammation (CD68, IL-6, and MCP-1), and fibrosis (COL1A1, COL1A2, and TIMP1). DRE reduced the liver weight, liver-to-body weight ratio, and hepatic steatosis in MASH model mice. It increased carnitine palmitoyltransferase-1 levels and decreased CD36 and transforming growth factor-β levels in the MASH mouse liver. High-performance liquid chromatography revealed that the extract contained rutin flavonoid family members. Overall, DRE was involved in lipid metabolism, inflammation, and fibrosis regulation, exerting potent hepatoprotective effects partly attributed to rutin and serving as a potential preventive candidate for MASH.