Chemical composition of essential oils of Grindelia squarrosa and G. hirsutula

The essential oils of Grindelia squarrosa (Pursh) Dunal and G. hirsutula Hook. & Am. cultivated in Romania were isolated by hydrodistillation. The essential oils were analyzed by a combination of GC-FID and GC-MS. The identification of the constituents was achieved from their retention indices and comparison of their MS data with computer library database and literature data. The fifty-six identified constituents accounted for 72.1-81.3% of the oils. The oils were found to contain a-pinene, beta-pinene, limonene, borneol, bornyl acetate and germacrene D as main constituents. The oils obtained from the two species showed small differences in chemical composition. However, menthol, menthone and pulegone were detected only in the essential oil of G. hirsutula.