Chemical Composition and Variability of the Volatile Components of Species Growing in the Amazon Region.

(Myrtaceae) species have been well investigated due to their chemical and biological relevance. The present work aimed to carry out the chemotaxonomic study of essential oils of the species , , and , sampled in the Brazilian Amazon and compare them with the volatile compositions from other species reported to Brazil and Colombia. The leaves of six specimens were collected (PA, Brazil) during the dry season, and their chemical compositions were analyzed by gas chromatography-mass spectrometer (GC-MS) and gas chromatography-flame ionization detector (GC-FID). The main compounds identified in the essential oils were monoterpenes with pinane and menthane skeletons, followed by sesquiterpenes with caryophyllane and cadinane skeletons. Among the sampled specimens, five chemical profiles were reported for the first time: profile I (, α-pinene, 54.0-67.2%); profile II (, terpinolene 23.1%, α-phellandrene 17.7%, and γ-terpinene 8.7%); profile III (, γ-cadinene 17.5%, and an unidentified oxygenated sesquiterpene 15.0%); profile IV (, -caryophyllene 43.2%, and α-humulene 5.3%); and profile V (, -caryophyllene 19.1%, and caryophyllene oxide 41.1%). The chemical profiles showed significant variability in extraction methods, collection sites, plant parts, and genetic aspects.