MAPT and Alzheimer disease: For instance, ginseng improved the memory ability and decreased the level of Aβ1–42 and p-tau in AD rats by activating PI3K/AKT signaling pathway [20], ginsenoside Rg1 lowered Aβ contents via suppressing CDΚ5-mediated PPARγ phosphorylation in a neuron model of AD [21], and ginsenoside Rg2 protected against Aβ25–35-induced apoptosis in AD by the enhancement of PI3K/Akt signaling pathway [22].