salivary antioxidants and oxidative stress; salivary gland dysfunction; protein glycoxidation and nitrosative stress; salivary; blood and urine redox biomarkers; mitochondrial dysfunction; redox homeostasis; inflammation and apoptosis in metabolic diseases; neurodegeneration; immunodeficiency and cancer; effects of diet on mitochondrial function and oxidative stress; antioxidant activity of drugs and dietary supplements