PSEN1 and early-onset autosomal dominant Alzheimer disease: Also, (20S)-Rg3, a triterpene natural compound known as ginsenoside and one compound (SPI-014) isolated from Actaea racemosa reduced Aβ peptide levels in neurons in vitro and in a mouse model of Alzheimer disease, at least in part decreasing the association of presenilin 1 (PS1) fragments with catalytic components of the γ-secretase complex localized in lipid rafts [309].