Bioactive Constituents of Phyllanthus amarus Schumach. and Thonn. Mediate Hepatoprotection via Enhanced Antioxidant Defenses and Apoptosis Inhibition in APAP-Challenged LO2 Cells

This study investigated the hepatoprotective potential of Phyllanthus amarus Schumach. & Thonn. ethanolic extract against acetaminophen (APAP)-induced toxicity in human LO2 hepatocytes. Phytochemical analysis revealed high phenolic (58.4 ± 3.2 mg GAE/g) and flavonoid (32.7 ± 2.1 mg QE/g) content, along with bioactive lignans. The extract exhibited excellent safety profile (IC50 >800 μg/mL) with >85% cell viability at 200 μg/mL. Pretreatment with 300 μg/mL extract significantly restored APAP-compromised cell viability to 82.5±4.1% (vs 48.3±3.8% in APAP-only), reduced LDH leakage by 62%, and normalized ALT/AST levels (55-60% reduction). Mechanistic studies demonstrated potent antioxidant activity, increasing SOD (2.3-fold) and CAT (2.4-fold) while elevating GSH (4.8±0.4 vs 1.5±0.2 μM/mg protein) and reducing lipid peroxidation (70% MDA decrease). Notably, the extract dramatically attenuated APAP-induced apoptosis from 45% to 12% (p<0.001), preserving nuclear morphology. These findings validate P. amarus as a multi-target hepatoprotective agent acting through membrane stabilization, oxidative stress mitigation, and apoptosis inhibition, suggesting its potential as a complementary therapy for drug-induced liver injury.