ANALYSIS OF THE SEASONALITY EFFECT ON THE ESSENTIAL OIL YIELD OF LEAVES OF Nectandra grandiflora Nees

This study aimed to evaluate the effect of seasonal variability on the yield of essential oil (EO) present in leaves of Nectandra grandiflora Nees and as well as to determine whether the drying process at room temperature of the plant material influences the yield of this EO. Plant material was collected from 12 individuals over a year and EO was extracted by hydrodestillation separately from fresh and dried leaves. Simultaneously, 20 g of fresh leaves was taken to stove at 40 degrees C to constant weight for determination of moisture content. This procedure was performed for each collection individually. The yield of EO in leaves (% w/w) was calculated for fresh plant material based on dry matter, determined by considering the moisture content, as well as for the material dried at room temperature. The yields were analyzed by Tukey test (P< 0.05). Results showed that the content of EO in the leaves showed seasonal variability with the highest production detected in spring (0.75 +/- 0.06%) and the lowest yield in winter (0.39 +/- 0.02%). Thereby, it is recommended that the leaves of N. grandiflora be collected in spring, aiming to increase EO yield. Additionally, no loss of EO content during the drying process at room temperature occurred thus this postharvest procedure could be adopted without compromising the extractive yield.