Lemon Juice-Assisted Green Extraction of Strawberry Enhances Neuroprotective Phytochemicals: Insights into Alzheimer’s-Related Pathways

Abstract

Background/Objective: Alzheimer’s disease (AD) is a neurodegenerative condition characterized by oxidative stress, neuroinflammation, amyloidogenesis, and tau-related pathology. This study investigated the macronutrient and phytochemical composition of strawberry (S), lemon (L), and lemon juice-assisted strawberry (S/L) extracts and evaluated their neuroprotective efficacy relative to selenium (Se) in an aluminum chloride (AlCl3)-induced rat model of AD. Methods: Macronutrients and phenolics were quantified in S, L, and S/L, and the extracts were profiled using high-performance liquid chromatography and electrospray ionization tandem mass-spectrometry. Male Sprague–Dawley rats received AlCl3 with or without S, L, S/L, or Se, and their cognitive performance was assessed using the Morris water maze, Y-maze, and conditioned avoidance tests. Markers of oxidative status, inflammation, cholinergic function, apoptotic signaling, and Wnt3/β-catenin pathway activity were quantified in the brain tissue, and cortico-hippocampal morphology was examined. Results: The S/L extract showed the highest carbohydrate, protein, and lipid content. The total phenolic content was highest in S/L (60.46 mg gallic acid equivalents/g), followed by L (55.08) and S (44.75), with S/L also being the richest in gallic, ellagic, and chlorogenic acids. S/L attenuated AlCl3-induced cognitive deficits, restored antioxidant status, suppressed neuroinflammation, improved cholinergic indices, modulated apoptotic signaling, and downregulated amyloidogenic and NLRP3 inflammasome markers, consistent with histological evidence of neuronal preservation. Conclusions: Lemon juice-assisted extraction enhanced the macronutrient and phenolic richness and multitarget neuroprotection of strawberries. S/L co-extracts represent promising functional food–derived adjuvants for AD management and support integrative compositional–mechanistic profiling to optimize natural product–based interventions.