Essential oil composition of three Grindelia species

The essential oil of Grindelia humilis Hook ct Am (G.H.), G. robusta Nutt (G.R.) and G. squarrosa Dun F. (G.S.), were analyzed by GC/MS. Sixty-nine components were identified in the oil of G. humilis, representing 89.9% of the oil, while 56 components in the oil of G. robusta, and 68 components in the oil of G. squarrosa were identified representing 78.9% and 81.9% of the oils, respectively. The study revealed that the major components of the oil of G. humilis were polyacetylenes (46.2%) and germacrene D (11.9%). In contrast, the major components of G, robusta were oxygenated terpenoids (57.4%), of which borneol (14.8%) was the largest constituent. The oil of G. squarrosa was characterized by monoterpene hydrocarbons (47.7%), of which limonene (16.8%), alpha-pinene (16.1%) were the major components.