Alkamides from echinacea angustifolia interact with P-glycoprotein of primary brain capillary endothelial cells isolated from porcine brain blood vessels: authors: Anne Mahringer, Karin Ardjomand-Woelkart, Rudolf Bauer, Gert Fricker, Thomas Efferth - Mahringer, Anne; Fricker, Gert (Planta medica, 2013)