PPARGC1A and Alzheimer disease: The previous finding on the advantage of Cinn in AD suggested that the trans-cinnamaldehyde improves AD pathology by reducing β-secretase levels, the first rate-limiting enzyme in Aβ production, through activation of the silent information regulator 1, peroxisome proliferator-activated receptor γ coactivator 1α (PGC)-1α, and PPARγ pathway (16).