Protective effects of E Se tea extracts against alcoholic fatty liver disease induced by high fat/alcohol diet: In vivo biological evaluation and molecular docking study

Abstract

Background: With the development of economy and increased workload, chronic a high-fat/alcohol diet intake may lead to alcoholic fatty liver disease (AFLD), which is considered as a crucial health problem worldwide. E Se tea is produced of the leaves and leaf buds of Malus toringoides (Rehd.) Hughes in Tibet and has human health benefits with anti-hyperglycemia, hypertension, and hyperlipidemia effects.

Purpose: The objective of this work was to investigate the protective effect of aqueous-ethanol and hot-water extracts of E Se tea against chronic high-fat/alcohol diet induced AFLD rats.

Methods: Firstly, to determine the chemical profiling of E Se tea extracts, UHPLC-ESI-HRMS analysis was conducted. Secondly, Sprague-Dawley male rats were used to establish the AFLD animal model by feeding with high-fat/alcohol diet. The animals were treated with E Se tea extracts for 12 weeks. Serum parameters were determined, histologic sections were prepared, and activities of enzymes related to inflammatory response and lipid metabolism imbalance were analyzed. The underlying mechanisms of E Se tea extracts alleviating AFLD were analyzed by immunofluorescence staining and Western blotting analysis. Lastly, key targets of 11-MT against AFLD were verified through molecular docking.

Results: In this study, seven main compounds were confirmed or tentatively identified in E Se tea extracts by UHPLC-ESI-HRMS. The results revealed that both the extracts could reverse histopathological steatotic alternation of the liver and reduced the activity of liver damage markers (ALT, AST). E Se tea extracts mitigated oxidative stress by inhibiting CYP2E1 protein and lipid peroxidation parameters (MDA), but enhancing the endogenous antioxidants (CAT, GSH, SOD). Moreover, E Se tea extracts ameliorated inflammation by restraining the activation of NF-κB, consequently releasing the expression of proinflammatory cytokines (TNF-α, IL-6, IL-1β, COX-2 and iNOS). Subsequently, E Se tea extracts reduced hepatocyte apoptosis by increasing capase-9, caspase-3 and Bax protein expression but decreasing Bcl-2 protein expression. Furthermore, E Se tea extracts improved metabolism imbalance by stimulating AMPK/SREBP1/FAS and PPAR-α/CPT1 signaling pathway by regulating lipid metabolism parameters (TC, TG, HDL-C, LHD-C). Furthermore, molecular docking results indicated that 7 chemical constituents of E Se tea extracts had strong docking affinity with 4 key target proteins (AMPK, PPAR-α, NF-кB and Caspase-9).

Conclusion: E Se tea ameliorated AFLD through ameliorating inflammatory response, apoptosis, and lipid metabolism imbalance.

Keywords: E Se tea; alcoholic fatty liver disease; apoptosis; inflammatory responses; lipid metabolism imbalances.