Chemical Composition of Essential Oils from Leaves and Fruits of Schinus molle Obtained by Different Extraction Methods (Hydrodistillation, Fractional Hydrodistillation and Steam Distillation) and Seasonal Variations

Abstract

The Schinus molle species produces high yields of volatile oils that can be obtained from leaves and fruits. It has been reported that S. molle oils have a variable chemical composition and biological activities, besides, they can be a source of bioactive compounds. In this work, studies were performed on the influence of extraction methods (hydrodistillation, steam distillation and fractional hydrodistillation) and seasonal variation, on the chemical composition (GC/MS and GC/FID analysis) of volatile oils (fruits and leaves) of this species. The comparison between the methods of hydrodistillation and steam distillation demonstrated that higher yields are obtained with hydrodistillation (1.2 % ± 0.2 % leaves, 1.8 % ± 0.3 % fruits). Increases in the concentrations of monoterpenes (50.7 % leaves and 70 % fruits) and sesquiterpenes (73.2 % leaves and 45.9 % fruits) are favored by the use of hydrodistillation and steam distillation techniques, respectively. Fractional hydrodistillation, using fractions collected at different extraction times (120 and 240 minutes), presented variations in the composition of oils from leaves and fruits. The 120 minutes fraction displayed the balanced distribution of monoterpenes and sesquiterpenes (46.8 % and 48.7 %, respectively), while 240 minutes fraction exhibited a high concentration of sesquiterpenes (80.5 %), with a predominance of epi-α-cadinol (40 %). The 240-minutes fraction was subjected to purification by preparative thin-layer chromatography and enabled isolation of the epi-α-cadinol (characterized by NMR). In the statistical analysis referring to the seasonal study of oil from leaves, 3 groups of compounds were characterized. Group I, corresponding to autumn, was characterized by the highest content of sesquiterpenes. Group II, corresponding to spring, was characterized by a higher percentage of monoterpenes. And group III, referring to summer and winter, was characterized by concentrations close to all the compounds identified.