Composition of essential oils and secretory structures of Baccharis anomala, B-megapotamica and B. ochracea

The chemical composition of the essential oils and the anatomical structures of the aerial parts from Baccharis anomala, B. megapotamica and B. ochracea growing in Brazil were studied. The volatile constituents isolated by hydrodistillation were analyzed by gas chromatograph coupled to a mass spectrometer detector (GC-MSD) and gas chromatograph coupled to a flame ionization detector (GC-FID). The botanical material was fixed, sectioned and prepared according to light and scanning microtechniques. The essential oil from B. anomala yielded 0.18% and showed alpha-acorenol (16.0%), spathulenol (13.3%) and caryophyllene oxide (12.1%) as the main components. Spathulenol (28.0% and 37.1%) and caryophyllene oxide (20.4% and 30.8%) represented the major constituents of the essential oils from B. megapotamica (yield = 0.17%) and B. ochracea (yield = 0.18%), respectively. The leaves and stems of these Baccharis species showed non-glandular trichomes and secretory ducts. Glandular trichomes were also found on the vegetative aerial parts of B. megapotamica