Seasonal Variability of Essential Oils of Eugenia uniflora Leaves

Seasonal influence on the chemical composition of essential oils of Eugenia uniflora leaves with red-orange fruit colour biotype has indicated the presence of two oil clusters in the two seasons of the Brazilian Cerrado. Cluster I included samples collected during dry months (April-September) which were characterized by the highest percentages of spathulenol (10%) and caryophyllene oxide (4.1%). In cluster II, whose samples were collected during wet months (October-March), the major constituent was selina-1,3,7(11)-trien-8-one epoxide (29%). The canonical correlation indicated that spathulenol and caryophyllene oxide revealed a strong relationship with the phenolics and nutrient balance (S, Ca, Fe) in leaves, whereas selina-1,3,7(11)-trien-8-one epoxide was related to K, Cu, Mn, and precipitation during the months of the wet season. Oxygenated sesquiterpenes were predominant in all the sampling months and the oil chemovariation observed might be environmentally determined by a clear seasonal influence.