Cognitive-enhancing effects of a herbal combination on D‑galactose‑induced memory impairment.

Abstract

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline and memory loss, for which effective pharmacological interventions remain limited. This study investigated the cognitive-enhancing effects of an optimized six‑herbal combination (HC) comprising Polygonati Rhizoma (PR), Lycium barbarum polysaccharides (LBPs), Green Tea (GT), Jujube Seeds (JS), Fructus hippophae (FH), and Mori Folium (MF). Using the Ellman method, we evaluated the acetylcholinesterase (AChE) inhibitory activities of individual herbs and HC. An L₂₅(4⁶) orthogonal design was employed to determine the optimal proportions of the six herbs, with AChE inhibition as the evaluation index. The optimal HC composition (PR 9 g, LBPs 6 g, GT 3 g, JS 3 g, FH 3 g, MF 5 g) exhibited 88.11% AChE inhibition at 2000 μg/mL, which was significantly higher than that of any individual herb (p < 0.05). Network pharmacology analysis revealed 682 common targets between HC and AD, with significant enrichment in the PI3K‑Akt signaling pathway, lipid metabolism, and chemical carcinogenesis‑receptor activation pathways, suggesting multi‑target mechanisms of action. In a D‑galactose‑induced subacute aging mouse model (3.5 g·kg⁻¹, 70 days), HC treatment (0.75, 1.5, and 3.0 g·kg⁻¹, 28 days) significantly improved spatial learning and memory in the Morris water maze. Specifically, HC at 1.5 g·kg⁻¹ significantly reduced escape latency (p < 0.01 vs. D‑galactose group), increased superoxide dismutase (SOD) and glutathione (GSH) levels (p < 0.05), and decreased malondialdehyde (MDA) and monoamine oxidase (MAO) levels (p < 0.01), while ameliorating hippocampal neuronal damage, as confirmed by hematoxylin and eosin staining. These findings demonstrate that HC exhibits potent anti‑cholinesterase activity, modulates oxidative stress, and protects against neuronal injury, positioning it as a promising multi‑target botanical candidate for further development in the prevention and management of AD.