Oxidative stress biomarkers and flavonoids in Alzheimer's disease: current clinical evidence and therapeutic perspectives.

Alzheimer's disease (AD) is a major global neurodegenerative disorder associated with high morbidity and mortality, yet current treatments remain largely symptomatic and ineffective in halting neurodegeneration. Growing evidence links oxidative stress potentially being an early event in AD progression. Consequently, therapeutic strategies targeting oxidative stress-mediated cellular damage are increasingly attractive. This review summarizes clinical evidence of oxidative stress biomarkers in AD and examines the neuroprotective mechanisms of flavonoids against oxidative stress in vivo, together with current clinical findings. Despite inconsistencies among studies due to variations in detection methods, a consistent trend of elevated oxidative stress in AD is evident, correlating with disease severity. Although in vivo studies have demonstrated that flavonoids restore antioxidant defences and suppress neuroinflammation, convincing clinical evidence of their efficacy in AD patients remains limited. Overall, these findings emphasize oxidative stress as a therapeutic target requiring further validation efforts.