SYNERGISTIC HEPATOPROTECTION BY POMEGRANATE AND ORANGE PEELS AGAINST PARACETAMOL-INDUCED LIVER INJURY IN RATS

Abstract

Background: Drug-induced liver injury (DILI) remains one of the leading causes of acute liver failure worldwide, yet effective and widely accessible hepatoprotective therapies are scarce. Pomegranate (Punica granatum) and orange (Citrus sinensis) peels are rich in complementary polyphenolic phytoconstituents with documented antioxidant and anti-inflammatory properties, but their comparative and combined hepatoprotective efficacy has not been systematically evaluated.

Objective: To characterise the phytochemical profiles and antioxidant activity of ethanolic extracts of pomegranate peel (PPE), orange peel (OPE), and their 1:1 combination (CPE), and to evaluate their hepatoprotective efficacy against paracetamol-induced liver injury in Wistar rats.

Methods: Ethanolic (70% v/v) peel extracts were prepared by maceration-Soxhlet extraction and characterised by HPLC, FTIR spectroscopy, Folin Ciocalteu total phenolic content (TPC), AlCl₃ total flavonoid content (TFC), DPPH radical scavenging, and FRAP assays. Thirty male Wistar rats (180–220 g) were allocated into five groups (n = 6): normal control, hepatotoxic control (paracetamol 3 g/kg, single oral dose), PPE (200 mg/kg/day × 14 days), OPE (200 mg/kg/day × 14 days), and CPE (200 mg/kg/day × 14 days). Serum AST and ALT were measured at baseline, post-toxicity, and post-treatment. Liver sections were evaluated histopathologically using a semiquantitative H&E scoring system.

Results: PPE demonstrated higher TPC (284.6 ± 12.3 mg GAE/g DW), TFC (142.3 ± 7.8 mg QE/g DW), and antioxidant potency (DPPH IC₅₀: 38.4 ± 1.9 µg/mL; FRAP: 312.4 ± 14.7 µmol Fe²⁺/g DW) than OPE (TPC: 189.4 ± 9.7; TFC: 98.7 ± 5.4; IC₅₀: 52.7 ± 2.6 µg/mL; FRAP: 218.9 ± 10.3), while CPE exhibited synergistic radical scavenging (IC₅₀: 29.6 ± 1.4 µg/mL). In vivo, paracetamol elevated serum AST and ALT approximately 4.5-fold. After 14 days of treatment, PPE reduced AST and ALT by ~55–57%, OPE by ~43%, and CPE by ~68–69% approaching normal control values. Histopathologically, CPE achieved near-complete resolution of centrilobular necrosis and inflammation with prominent hepatocyte regeneration (overall score: 1/12 vs. 11/12 in the toxic control). A strong positive correlation (r = 0.94) was observed between TPC and percentage transaminase reduction.

Conclusion: The combination of pomegranate and orange peel ethanolic extracts provides synergistic hepatoprotection and hepatorestorative activity exceeding either extract alone, mediated by complementary modulation of Nrf2-dependent antioxidant defence and NF-κB-driven inflammatory signalling. These findings support development of a standardised pomegranate–orange peel nutraceutical formulation for DILI prevention and management