Neuroinflammation inhibition and neuroprotective effects of purpurin, a potential anti-AD compound, screened via network proximity and gene enrichment analyses.

Alzheimer's disease (AD) is a complex neurodegenerative disease without any effective preventive or therapeutic drugs. Natural products with stable structures and pharmacological characteristics are valuable sources for the development of novel drugs for many complex diseases. This study aimed to discover potential natural compounds for the treatment of AD using new technologies and methods and explore the efficacy and mechanism of candidate compounds. AD-related large-scale genetic datasets were collated to construct disease-PPIs and natural products were collected from six databases to construct compound-protein interactions (CPIs). Potential relationships between natural compounds and AD were predicted via network proximity and gene enrichment analyses. Then, five AD-related cell models and d-galactose-induced aging rat model were established to evaluate the neuroprotective effects of candidate compounds in vitro and in vivo. We identified that 267 natural compounds were predicted to have close connections with AD and 19 compounds could exert protective effect in at least one cell model. Notably, purpurin exerted protective effect in three cell models and significantly improved the cognitive learning and memory functions, reduced the oxidative stress injuries and neuroinflammation, and enhanced the synaptic plasticity and neurotrophic effect in the brain of d-galactose-treated rats. In this study, AD-related natural compounds were identified via network proximity and gene enrichment analyses. In vivo and in vitro experiments revealed the therapeutic potential of purpurin for AD treatment, laying the foundation for further in-depth research and providing valuable information for the development of novel anti-AD drugs.