EFEITO DA SAZONALIDADE SOBRE O RENDIMENTO DO ÓLEO ESSENCIAL DE Piper gaudichaudianum KUNTH

Abstract

Piper gaudichaudianum Kunth (Piperaceae) is widely distributed throughout Brazil. In addition to its ecological importance, it is used in folk medicine and a great number of its biological activities have been already proved. Thus, the aim of this research was to investigate the effect of seasonality on the content of essential oil (EO) in leaves of Piper gaudichaudianum and ascertain the possible influence of the drying process of the plant material in the yield of this extractive. Leaves were randomly collected from individuals of a native population in Santa Maria, RS state, Brazil, along a year. The EO was extracted from fresh and dried leaves by hydrodistillation. When reproductive organs were observed, they were extracted in order to examine their influence on the yield of leaf EO. To determine the moisture content (MC%), 20 g of leaves and 10g of reproductive organs were dried separately in an oven at 50°C until constant weight. The yield of leaf EO (% w/ w) was calculated for the fresh material based on the dry weight considering the MC%, and for the dried material at room temperature. Only small seasonal variations in EO content was detected for the analyzed samples, with no statistical difference between them. The highest yield was observed in the spring for EO from the leaves (1.61 ± 0.09%), and from the reproductive organs (5.17%), while the lowest yields of leaf EO occurred in the summer (1.32 ± 0.14%), the only season which showed no presence of the reproductive organs. The absence of significant difference between the yields indicates no quantitative seasonal variability in production of EO in leaves of this population. However, yields did not differ statistically, indicating no seasonal variability of the EO content of the leaves of this population. Therefore, the collection of this plant organ can be performed at any time of the year in order to obtain this extractive. Since there was no decrease in the content of EO during the drying process at room temperature, this post-harvest processing can be adopted.