Vinpocetine (Fig. 7) is a PDE1 inhibitor.88 In Europe, it has been approved for the treatment of dementia.89 Its preclinical data indicated some significant effects, such as repairing cognitive impairment in a rodent AD model,90 downregulating BACE1,90 decreasing oxidative stress,91,92 and reducing mitochondrial dysfunction.93 Despite the significant preclinical findings, the results of clinical studies were disappointing with regard to the improvement of AD patients.94 Here, BACE1 is linked to Alzheimer disease.