Protective effects of <i>Boehmeria nivea</i> leaf extracts against amyloid beta-induced cognitive impairment

Amyloid beta (A) accumulation is a key pathological factor associated with cognitive impairment in neurodegenerative disorders.Boehmeria nivea (ramie) leaves have long been used as food and traditional materials and are known to contain various bioactive compounds.In this study, the protective effects of Boehmeria nivea leaf extracts on A25-35-induced cognitive impairment were evaluated using an ICR mouse model.Two methanolic extracts prepared from ramie leaves with different cultivation origins were orally administered at a dose of 200 mg/kg/day.Cognitive performance was assessed using the T-maze, novel object recognition, and water maze tests.In addition, lipid peroxidation, nitric oxide (NO) production, and the protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were analyzed in brain tissues.Administration of Boehmeria nivea leaf extracts significantly improved A-induced deficits in spatial working memory, object recognition memory, and spatial learning.The extracts also reduced lipid peroxidation and NO levels in mouse brains.Furthermore, A-induced increases in iNOS and COX-2 protein expression were markedly suppressed following extract treatment.These results indicate that Boehmeria nivea leaf extracts exert protective effects against A-induced cognitive impairment and suggest their potential applicability as functional materials for cognitive health.