This cluster of papers explores the effects of chronic systemic exposure to D-galactose on aging, neurodegeneration, oxidative damage, and cognitive impairment in animal models. The protective effects of various natural compounds, including R-a-lipoic acid, ursolic acid, melatonin, and troxerutin, are also investigated. The role of Portulaca oleracea (purslane) in ameliorating the detrimental effects of D-galactose is a recurring theme in the research.