Abstract
The potential inhibitory effect of 54 Mexican Indian medicinal plants on the activation of transcription factor NF‐κB was studied. Band‐shift experiments identified the ethanolic leaf extracts of Artemisia ludoviciana ssp. mexicana, Calea zacatechichi, and Polymnia maculata (all rich in sesquiterpene lactones) as inhibitors of NF‐κB down to a concentration of 25 μg/ml. The sesquiterpene lactones isohelenin and parthenolide prevented NF‐κB activation completely as low as 5 μM. Treatment of HeLa cells with leaf extract of A. ludoviciana ssp. mexicana, isohelenin and parthenolide prevented the induction of transcription on the IL‐6 promoter. These experiments identify the eudesmanolide and germacranolide type of sesquiterpene lactones as potent non‐antioxidant inhibitors of NF‐κB. All plants active in the NF‐κB assay also showed a delay in the onset of capillary reactions of the allantois membrane in a physiological model for anti‐inflammatory activity — the HET‐CAM assay.