Petasites hybridus extracts in vitro inhibit COX-2 and PGE2 release by direct interaction with the enzyme and by preventing p 42/44 MAP kinase activation in rat primary microglial cells. - Fiebich,B.L.; Grozdeva,M.; Hess,S.; Hüll,M.; Danesch,U.; Bodensieck,A.; Bauer,R. (Planta Med, 2005)