A revision of Eupatorium (Compositae: Eupatorieae) from Michoacan Una revisión de Eupatorium (Compositae: Eupatorieae) de Michoacán

An important study in species of the genus Eupato- rium, that inhabits other parts of the world, was conducted in the search for new molecules with pharmacological activities, thus show- ing that it is a potential source of novel secondary metabolites. We reviewed the number of Eupatorium species that have been described in the State of Michoacan, and that can be available for harvesting, to make a phytochemical screening. It was found that 69 Eupato- rium spp are growing in 69% of the Michoacan territory. Within this group there are ten species used in Mexican traditional medicine. It was evident the difficulty in taxonomic classifying these species since several Eupatorium spp have synonyms. It appeared that the number of native members should be reduced in the genus. A preliminary chemical analysis was conducted on the flowers of nine native Eupa- torium spp by nuclear magnetic resonance of hexane extracts. It was determined that the major secondary metabolites belonged to the chemical families of terpenes and chromenes.