Role in Preventing Alcoholic Liver Disease Progression: A Comparative Study of Whole-Component Finger Citron Essential Oil and Its Major Component D-Limonene

<b>Background/Objectives</b>: Chronic alcohol overconsumption triggers alcohol liver injury, and therapeutic strategies targeting alcohol-triggered oxidative stress and hepatic inflammatory responses represent potential approaches to ameliorating alcohol-related hepatotoxicity. This study aimed to determine the hepatoprotective activity of finger citron essential oil (FCEO) in alcoholic liver disease (ALD)-afflicted rats and explore its underlying mechanisms. In order to identify the effective components, we compared the effects of FCEO and D-limonene. <b>Methods</b>: The regulatory effects of FCEO on metabolic enzymes were systematically evaluated through in vitro experiments. In vivo studies were conducted to investigate and compare the hepatoprotective effects of FCEO and D-limonene. Staining methods, assay kits, and Western Blot were used to determine the roles of FCEO and D-limonene in the ALD rats. <b>Results</b>: We found that FCEO downregulated phase I metabolic enzymes and upregulated phase II metabolic enzymes in Buffalo Rat Liver-3A (BRL-3A) cells. FCEO and/or D-limonene intervention reduced transaminase levels in ALD rats and effectively alleviated inflammatory cell infiltration and lipid droplet accumulation in their liver tissue. Additionally, FCEO and D-limonene played a regulatory role in oxidative stress and inflammation-related pathways such as the MAPK/Nrf2 and NF-κB/AMPK pathways. FCEO was superior to D-limonene as an antioxidant in alleviating alcoholic liver injury. <b>Conclusions</b>: This study revealed the alleviative effects and mechanisms of FCEO on alcoholic liver injury, demonstrating better efficacy compared to its monomer, thus providing a strategy for the development and utilization of finger citron resources.