Petasites hybridus Extracts in vitro Inhibit COX-2 and PGE2 Release by Direct Interaction with the Enzyme and by Preventing p42/44 MAP Kinase Activation in Rat Primary Microglial Cells - Fiebich, B L; Grozdeva, M; Hess, S; Hüll, M; Danesch, U; Bodensieck, A; Bauer, R (Planta Medica, 2005)