Geroprotective effects of Salvianolic acid A through redox and detoxification pathway activation in an aging Drosophila Alzheimer’s model

Alzheimer's disease (AD) is characterized by the accumulation of amyloid-β42 (Aβ42) neurotoxic peptides that cause oxidative stress and neurodegeneration. The current study examined the neuroprotective properties of salvianolic acid A (SalA), an antioxidant polyphenol, in a Drosophila melanogaster model of AD. Transgenic flies expressing human Aβ42 were assayed for eye morphology, life span, and locomotor function after SalA diet supplementation. RNA-seq and RT-qPCR were used to quantify transcriptional regulation with SalA treatment. Aβ42 expression resulted in classic AD phenotypes, including retinal degeneration, shortened lifespan, and compromised climbing ability. Partial rescue of the rough-eye phenotype, significant prolongation of lifespan, and improved locomotor function in aging flies were induced by SalA treatment. Transcriptome profiling showed the upregulation of glutathione metabolism-associated, cytochrome P450 activity-associated, and antioxidant defence-associated genes, while muscle development-associated, cell adhesion-associated, and apoptosis-associated genes were downregulated. Network analysis identified a SalA-responsive gene module enriched in detoxification and immune pathways that was conducive to enhanced cellular resistance to Aβ42 toxicity. These findings identify a redox-regulated aging mechanism whereby SalA maintains neuronal and systemic homeostasis during aging. SalA inhibits Aβ42-induced neurotoxicity in Drosophila via promoting redox equilibrium and detoxification. These findings present SalA as a potential multi-target lead drug for AD and other age-related neurodegenerative diseases.