Moreover, it has been shown that the key markers of YZT such as protopine, allocryptopine, tetrahydropalmatine, tetrahydroberberine, corydaline, palmatine, dehydrocorydaline and imperatorin are brain permeable (Tao et al., 2013) , which might explicate the tau-reducing effect of YZT in the central nerveous system of transgenic AD mice; key markers permeable in brain crossing the blood brain barrier namely. Here, MAPT is linked to Alzheimer disease.