Antioxidant and Anti‐Inflammatory Activities of <i>Ulva lactuca</i> Aqueous Extract: An In Vitro and In Vivo Study Supported With Phytochemical Profiling

Abstract

Ulva lactuca, a green marine macroalga, is a promising natural resource for use in food, medicine, and environmental biotechnology. The primary aim of the current research was to examine its phytochemical profile, along with its antioxidant and anti-inflammatory activity. The phytochemical characterization of the U. lactuca extract was achieved by gas chromatography-mass spectrometry (GC-MS) and HPLC analyses. The anti-inflammatory effect of the U. lactuca extract was investigated using acute lung injury (ALI) induced by LPS. According to GC-MS analysis, the aqueous extract of U. lactuca includes a number of fatty acids, esters, and essential oils with antibacterial, anti-inflammatory, and antioxidant characteristics. HPLC resolved five phenolic compounds, of which ferulic acid was most prevalent, followed by catechol, gallic acid, caffeic acid, and ellagic acid. Four flavonoids were found, including catechin, rutin, apigenin, and luteolin. ABTS and DPPH assays found that the extract suppressed radical scavenging activity by 75.2% and 80.3%, respectively. Histological study of lung tissues showed dose-dependent recovery. The treated group (300 mg/kg) showed restoration of almost normal architecture and a lowering of inflammation and fibrosis. Immunohistochemical analysis revealed that the extract effectively decreased the levels of key inflammatory markers, including COX-2, NF-κB, and TNF-α, with the most notable effect at higher doses.