Hepatoprotective Activity of Vijaysar Heartwood Extract Against Drug-Induced Liver Injury in Wistar Rats

Background: Hyperthyroidism, whether endogenous or drug induced by L-thyroxine, is characterized by a hypermetabolic state that accelerates oxidative stress and leads to hepatic dysfunction and hepatocellular injury. Pterocarpus marsupium Roxb. (Fabaceae), traditionally known as Vijaysar, is widely used in Indian systems of medicine for the management of metabolic and inflammatory disorders. Objective: The present study aimed to evaluate the hepatoprotective and antioxidant potential of the hydroalcoholic extract of P. marsupium heartwood (HAEBP) against L-thyroxine induced liver injury in Wistar rats. Methods: Adult male Wistar rats were divided into five groups (n = 6). Hyperthyroidism and associated hepatic oxidative stress were induced by oral administration of L-thyroxine (600 µg/kg/day) for 12 consecutive days. After induction, animals were treated with HAEBP at doses of 200 mg/kg and 400 mg/kg, or the standard drug propylthiouracil (PTU, 10 mg/kg) for 15 days. Hepatic injury was assessed by measuring serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Oxidative stress parameters in liver homogenates included lipid peroxidation (MDA), reduced glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT). Results: L-thyroxine administration produced a significant (P < 0.01) elevation in serum AST (205.40 ± 4.25 IU/L) and ALT (128.95 ± 5.75 IU/L) compared with normal controls, indicating marked hepatocellular damage. Liver tissues showed increased MDA levels (4.70 ± 0.90 nM/mg protein) along with depletion of antioxidant defenses (GSH, SOD, CAT). Treatment with HAEBP at 400 mg/kg significantly (P < 0.01) reduced hepatic injury, lowering AST to 135.40 ± 3.30 IU/L and ALT to 88.80 ± 3.95 IU/L. The extract also suppressed lipid peroxidation (MDA: 2.55 ± 0.65 nM/mg protein) and restored antioxidant status, with effects comparable to PTU. Conclusion: The hydroalcoholic extract of Pterocarpus marsupium exhibits strong hepatoprotective activity against L-thyroxine induced liver toxicity. The effect appears to be mediated through free radical scavenging, inhibition of lipid peroxidation, and enhancement of endogenous hepatic antioxidant defenses.