PGP and Alzheimer disease: Continuous intake of SJW extracts with a high dose of hyperforin ([80]; 5% hyperforin per 300 mg of dried extract, Dr. Wilmar Schwabe Pharmaceuticals, Karlsruhe, Germany and [81]; 0.61% hyperforin and 0.3% hypericin per 300 mg of dried extract, Finzelberg GmbH and Co. KG, Andernach, Germany) can upregulate P-gp, BCRP, and MRP2 by activating pregnane-X-receptor (PXR) in the rat hippocampus and the BBB in transgenic mice with AD [54,80,81].