Essential oil variability in Baccharis uncinella DC and Baccharis dracunculifolia DC growing wild in southern Brazil, Bolivia and Uruguay

Essential oils of Baccharis uncinella DC and B. dracunculifolia DC collected from different wild populations growing in Bolivia, southern Brazil and Uruguay were analysed using gas chromatography and gas chromatography-mass spectrometry techniques, to check for chemical variability. Cluster analysis led to the identification of two chemotypes for B. dracunculifolia, related to aromadendrane- or cadinane-derived components. As the timing of sampling of the plant material may have an influence on the composition of the essential oil isolated, the seasonal influence at the moment of harvesting was studied for two populations of each species. The results suggested that the flowering season was optimal both species and this supported the practice of harvesting at the full bloom stage. Copyright (C) 2008 John Wiley & Sons, Ltd.