Essential oils composition of croton species from the Amazon.

The essential oils of leaves and twigs from the Euphorbiaceous Croton draconoides, C. urucurana and Julocroton triqueter were obtained and analyzed by GC and GC-MS. In total, 101 volatile constituents were identified, comprising an average of 90% of the oil, mostly made up of mono- and sesquiterpenes. The monoterpene hydrocarbons varied from 1.2 to 40.2%, the sesquiterpene hydrocarbons from 34.0 to 49.6% and the oxygenated sesquiterpenes from 11.5 to 51.3%. The main compounds found in the oil of C. draconoides were beta-pinene (16.9%), alpha-pinene (16.5%), curzerene (12.8%), germacrene D (9.0%), gamma-elemene (4.7%), and elemol (4.4%). The oil of C. urucurana showed sesquicineole (23.0%), dehydro-sesquicineole (13.8%), beta-caryophyllene (7.9%), beta-bisabolol (5.0%), germacrene D (4.2%) and beta-elemene (4.1%) as the chief compounds. The oil of J. triqueter was dominated by beta-caryophyllene (16.3%), beta-phellandrene (10.2%), spathulenol (5.1%), caryophyllene oxide (5.0%), delta-cadinene (4.3%), (E)-nerolidol (4.3%), and alpha-copaene (4.1%).