Taken together, the MHDIs mentioned in this section inhibit Aβ-induced oxidative stress mainly by enhancing the activities of antioxidant enzymes such as SOD, CAT, and GSH-Px and reducing the levels of lipid peroxidation products such as 4-HNE and MDA in the cortex and hippocampus in the early and late phases of AD in animal models (Table 2 and Figure 2). This evidence concerns the gene CAT and Alzheimer disease.