Antioxidant effects of pineapple vinegar in reversing of paracetamol-induced liver damage in mice

Background: Pineapple (Ananas comosus) was demonstrated to be hepatoprotective. This study aims to investigate the reversing effects of pineapple vinegar on paracetamol-induced liver damage in murine model. Methods: Pineapple juice was fermented via anaerobic and aerobic fermentation to produce pineapple vinegar. Male BALB/c mice (n = 70) were separated into 7 treatment groups (n = 10). Pineapple vinegar (0.08 and 2 mL/kg BW) and synthetic vinegar were used to treat paracetamol-induced liver damage in mice. The hepatoprotective effects were determined by serum biochemistry profiles (aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and triglyceride (TG)), liver antioxidant levels (ferric-reducing ability plasma (FRAP), superoxide dismutase (SOD), malondialdehyde (MDA), nitric oxide (NO), and reduced glutathione assays (GSH)) and histopathological examination with hematoxylin and eosin (H& E) staining. The effects were further evaluated by the expression levels of iNOS, NF-kappa B, and cytochrome P450 2E1 by quantitative real-time PCR and Western blot analyses. Vinegar samples were also tested for in vitro antioxidant (FRAP, 2,2-diphenyl-2-picrylhydrazyl (DPPH), and total phenolic content (TPC)). Soluble phenolic acid contents in the samples were identified by HPLC. Results: Pineapple vinegar contained 169.67 +/- 0.05 mu g GAE/mL of TPC, with 862.61 +/- 4.38 mu g/mL gallic acid as the main component. Oral administration of pineapple vinegar at 2 mL/kg BW reduced serum enzyme biomarker levels, including AST (P = 0.008), ALT (P = 0.006), ALP (P= 0.002), and TG (P = 0.006) after 7 days of paracetamol treatment. Liver antioxidant levels such as hepatic glutathione (P = 0.003), SOD (P < 0.001), lipid peroxidation (P = 0.002) and FRAP (P < 0.001) were restored after the treatment. Pineapple vinegar reduced the expressions of iNOS (P = 0.003) and NF-kB (P = 0.003) and the level of NO (P = 0.003) significantly. Pineapple vinegar also downregulated liver cytochrome P450 protein expression. Conclusions: Oral administration of pineapple vinegar at 0.08 and 2 mL/kg BW reduced serum enzyme biomarker levels, restored liver antioxidant levels, reduced inflammatory factor expressions, and down regulated liver cytochrome P450 protein expression in paracetamol-induced liver damage in mice.