Study of seasonality and location effects on the chemical composition of essential oils from Eugenia uniflora leaves

The essential oils of Eugenia uniflora leave possess several biological activities but a great variability in their chemical composition is observed. In the present study, gas chromatography and mass spectrometry were applied to examine the essential oil from leaves of four different specimens over the seasons of the year, two of which are located in a habitat of a Brazilian metropolis, and the other two in a natural reserve. The collected data allowed identifying twenty-nine compounds; an aliphatic ketone, sesquiterpenes, fatty acids, hydrocarbons, and phthalate derivatives. Sesquiterpene hydrocarbons and oxygenated sesquiterpenes were the chemical classes prevailing in most samples. The curzerene was observed in higher content (10.5-53.4%) in all samples in which the presence of sesquiterpenes class was confirmed. Phthalate derivatives were identified for the first time in the essential oil of E. uniflora leaves. The occurrence of a common chemical marker for four specimens was not observed. Besides, no compound was observed in the same specimen throughout the seasons, and specimens of the same habitat exhibited different essential oil chemical profiles. According to the multivariate analysis applied to the chemical profile for all individuals in different seasons, four different clusters were identified without dependence on season or location. Key word: Eugenia uniflora, seasonality, location, essential oil, chemical composition.