Screening for Anti-Inflammatory Activity of 12 Arnica (Asteraceae) Species Assessed by Inhibition of NF-κB and Release of Human Neutrophil Elastase

Several species in the genus Arnica have been used in traditional medicine to treat inflammatory-related disorders. Extracts of twelve Arnica species and two species closely related to Arnica (Layia hieracioides and Madia sativa) were investigated for inhibition of human neutrophil elastase release and inhibition of transcription factor NF-kappa B. Statistical analyses reveal significant differences in inhibitory capacities between extracts. Sesquiterpene lactones of the helenanolide type, of which some are known inhibitors of human neutrophil elastase release and NF-kappa B, are present in large amounts in the very active extracts of A. montana and A. chamissonis. Furthermore, A. longifolia, which has previously not been investigated, shows a high activity similar to that of A. montana and A. chamissonis in both bioassays. Sesquiterpene lactones of the xanthalongin type are present in large amounts in A. longifolia and other active extracts and would be interesting to evaluate further.