Echinacea purpurea significantly induces cytochrome P450 3 A activity but does not alter Lopinavir-Ritonavir exposure in healthy subjects - Penzak, S R; Robertson, S M; Hunt, J D; Chairez, C L; Malati, C Y; Alfaro, R M; Stevenson, J G; Kovacs, J A (Pharmacotherapy, 2010)