Researchers have long focused on the accumulation of amyloid beta (Aβ) peptides in the brain as a primary pathological hallmark driving cognitive decline. This study investigated the neuroprotective effects of Rosa rugosa (RR) root extract and its key bioactive constituent, oleamide, against amyloid beta (Aβ)-induced neurotoxicity. Initially, an ethanolic extract of RR root was screened via in vitro assays to assess antioxidant and cytoprotective potential in rat pheochromocytoma cells. Subsequent fractionation, open-column chromatography, and preparatory thin-layer chromatography led to the isolation of oleamide, confirmed by gas chromatography–mass spectrometry and ¹H/¹³C nuclear magnetic resonance analyses. In vivo experiments using intracerebroventricularly injected Aβ in male mice demonstrated that both RR root extract and oleamide significantly improved cognitive performance in the Y-maze and passive avoidance tests. Additionally, oleamide restored acetylcholine levels and reduced malondialdehyde concentrations in brain tissue, indicating mitigation of oxidative stress and support of cholinergic function. No significant toxicity was observed, as evidenced by stable serum transaminase levels and unaltered body or brain weights. These findings highlight oleamide’s potential to protect against Aβ-driven pathology through multiple mechanisms, including reduced lipid peroxidation and improved neurotransmission. Further investigations into oleamide’s molecular targets and synergy with existing therapies may advance its development as a novel candidate for Alzheimer’s disease prevention or adjunct treatment.

Alzheimer's disease (AD) is characterized by multifactorial pathological processes, including cholinergic dysfunction and oxidative stress, highlighting the need for safer, multi‐target interventions beyond current synthetic acetylcholinesterase (AChE) inhibitors. In the present study, we screened ethanolic extracts from various edible and medicinal plants to identify natural sources with cholinesterase‐modulating activity and found that Sparassis crispa ( S. crispa ) extract exhibited robust AChE inhibitory activity. The extract also demonstrated significant antioxidant capacity and protected rat pheochromocytoma cells against oxidative stress–induced cytotoxicity. Chemical characterization using gas chromatography–mass spectrometry identified ergosterol as a major bioactive constituent of S. crispa extract. Ergosterol directly inhibited AChE activity in vitro and was subsequently evaluated in vivo using a trimethyltin chloride (TMT)–induced mouse model of cognitive impairment. Dietary supplementation with S. crispa extract significantly improved spatial working memory and attenuated TMT‐induced elevation of brain AChE activity. Notably, ergosterol supplementation produced dose‐dependent improvements in both spatial working memory and aversive learning, accompanied by restoration of cholinergic function and reduction of lipid peroxidation in brain tissues. No signs of hepatic toxicity were observed following ergosterol administration. Collectively, these findings demonstrate that S. crispa extract exerts cognitive benefits through combined modulation of cholinergic dysfunction and oxidative stress, and identify ergosterol as a key bioactive contributor to these effects. This study provides mechanistic insight into the neuroprotective potential of S. crispa and supports its development, together with ergosterol, as functional food–derived candidates for the prevention or mitigation of cognitive decline.

Spinacia oleracea (spinach) has been proposed as a functional food candidate for cognitive health, yet the active constituent(s) responsible for cholinesterase-modulating effects remain unclear. Here, we screened the acetylcholinesterase (AChE)-inhibitory activity of S. oleracea ethanolic extract and identified a candidate bioactive constituent using bioactivity-guided fractionation coupled with chromatographic and mass spectrometric analyses. An active silica-gel fraction was subjected to high-performance liquid chromatography and gas chromatography–mass spectrometry, and linoleic acid was identified in the active fraction, with its chromatographic identity further supported by coinjection analysis. Linoleic acid also exhibited measurable AChE-inhibitory activity in a tacrine-equivalent calibration assay. Preventive efficacy was evaluated in a trimethyltin chloride (TMT; 2.5 mg/kg, i.p.)-induced neurotoxicity model in male Institute of Cancer Researchmice. Mice received S. oleracea extract (400, 800, or 1200 mg/kg/day) or linoleic acid (10, 20, or 40 mg/kg/day) for 3 weeks prior to TMT challenge. Both the extract and linoleic acid ameliorated TMT-induced deficits in Y-maze spontaneous alternation and passive avoidance latency. The linoleic acid intervention also reduced brain AChE activity and lipid peroxidation, indicating attenuation of cholinergic dysfunction and oxidative stress. Serum AST and ALT activities were not significantly altered, indicating no detectable evidence of hepatocellular injury based on these markers under the tested conditions. Collectively, these findings support the potential of S. oleracea extract as a cognition-oriented functional material and identify linoleic acid as a candidate bioactive constituent warranting further investigation in TMT-induced cognitive impairment.

Pecan (Carya illinoinensis) is an edible nut rich in phytochemicals with potential health-promoting properties; however, the bioactive constituents responsible for its neuroprotective effects remain insufficiently characterized. This study aimed to identify bioactive constituents from pecan through bioactivity-guided fractionation and to evaluate the protective effects of pecan extract and the identified compound against oxidative stress and amyloid beta (Aβ)_1–42-induced cognitive impairment. Pecan ethanolic extract exhibited antioxidant and cytoprotective activities in PC12 cells exposed to hydrogen peroxide-induced oxidative stress. Sequential liquid–liquid fractionation, silica gel open-column chromatography, and preparative thin-layer chromatography, coupled with repeated bioactivity screening, progressively tracked the active fractions and led to the identification of ethyl gallate as a bioactive constituent of pecan extract by high-performance liquid chromatography and gas chromatography–mass spectrometry. The biological relevance of these findings was further evaluated in Aβ_1–42-injected male mice. Dietary administration of pecan extract significantly improved spontaneous alternation performance in the Y-maze test, whereas ethyl gallate improved Y-maze performance and memory retention in the passive avoidance test, without apparent systemic toxicity under the experimental conditions. Although brain malondialdehyde levels showed a numerical decrease following ethyl gallate administration, the differences were not statistically significant. Collectively, these findings demonstrate the bioactivity-guided linkage of ethyl gallate to an active pecan fraction and provide preclinical evidence supporting further investigation of pecan-derived bioactives as food-derived functional ingredients relevant to cognitive health.