CAT and Alzheimer disease: Consequently, AD is accompanied by elevated levels of oxidative stress biomarkers such as catalase (CAT), superoxide dismutase (SOD), glutathione (GSH) peroxidase and GSH reductase in the brain and inflammatory biomarkers such as cyclooxygenase (COX) and interleukins such as IL-6, IL-1β and TNF-α [4].