Hormophysa cuneiformis protects against methamphetamine-induced hepatotoxicity via antioxidant, anti-inflammatory, and autophagy-regulatory mechanisms: histological and biochemical studies.

INTRODUCTION: Methamphetamine (METH) abuse is linked to significant hepatic injury, driven by oxidative stress, inflammatory pathway activation, autophagic dysregulation, and apoptosis induction. This study explored the hepatoprotective and anti-inflammatory potential of the brown seaweed Hormophysa cuneiformis extract against METH-induced liver damage in adult male Wistar rats.

METHODS: Extracts prepared using methanol, ethanol, hexane, and water were screened for antioxidant activity. The methanolic extract, selected for further investigation, was characterized by phytochemical analysis and GC-MS profiling. Molecular docking was performed to evaluate the interactions of the identified bioactive compounds with TNF-α and LC3B-II. The cytotoxicity and selectivity of the methanolic extract were assessed using HepG-2 hepatocellular carcinoma and WI-38 normal cells. Its hepatoprotective effects were further evaluated in vivo in METH-treated adult male Wistar rats using biochemical, Western blot, immunohistochemical, and histopathological analyses.

RESULTS: The methanolic extract showed the greatest antioxidant activity, achieving 57.16% ± 1.96% DPPH radical scavenging and 54.71% ± 0.84% ferric-reducing antioxidant power. Although these values were lower than those of ascorbic acid (97.23 ± 0.48%), the methanolic extract exhibited higher antioxidant potential than the other extracts. Secondary metabolites, including alkaloids, saponins, tannins, and total phenolic compounds, were detected in notable amounts. GC-MS analysis identified oleic acid, palmitic acid, linoleic acid, and arachidonic acid as the major constituents. The extract exhibited dose-dependent cytotoxicity against HepG-2 cells, with an IC50 of 77.14 ± 1.63 µg mL-1, while showing lower toxicity toward WI-38 cells (CC50 = 141.99 ± 3.54 µg mL-1), indicating selective antiproliferative activity and a favorable safety margin. In vivo, METH administration significantly elevated serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) levels. Oral co-treatment with the H. cuneiformis methanolic extract (15 mg kg-1) significantly attenuated METH-induced hepatocellular injury, lowering serum ALT from 89.33 to 54.33 U L-1, AST from 294.33 to 57.33 U L-1, and ALP from 264.67 to 189.00 U L-1. Western blot analysis showed that METH markedly increased LC3B-II and Beclin-1 expression, whereas co-administration of the extract significantly reduced both proteins. Immunohistochemical analysis also demonstrated increased caspase-3- and NF-κB-positive cells in the METH-treated group, which were significantly reduced following H. cuneiformis treatment.

DISCUSSION: Collectively, these findings suggest that H. cuneiformis exerts hepatoprotective effects against METH-induced liver injury through antioxidant, anti-inflammatory, anti-apoptotic, and autophagy-modulating mechanisms.