LAUSR

ABSTRACT This study describes a comparative analysis of the essential oil (EO) chemical composition of leaves and reproductive organs (inflorescences and fruits) of Piper gaudichaudianum during the seasons of a year in order to determine the best collection time and the most suitable plant organ to obtain this extractive. The chemical composition of EO obtained from fresh leaves was compared to the dried ones, to verify if the drying process interferes in the extractive quality. The leaves were collected from a native population of Santa Maria, RS, Brazil, twice in each season, in triplicate, while inflorescences and fruits were sampled when they were present. The EO was obtained by hydrodistillation of the different plant organs for 3 h. The 20 EO samples were analyzed by gas chromatography (GC) coupled to mass spectrometry and GC with flame ionization detector, in triplicate. Hierarchical cluster analysis (HCA) and principal components analysis (PCA) were performed to verify a possible formation of chemical groups (CG) and the cohesion among them. The phenylpropanoid dillapiole was the major constituent of the EO in all seasons and in all plant organs, and myristicin was observed only in reproductive organs. The EO samples of this population were divided into two CG by HCA and PCA, showing the variability in chemical composition between different plant organs, however there was no chemical variability due to seasonality and phenophases. Since the drying of the leaves did not alter the EO chemical composition, this post-harvest procedure can be used without compromising the extrative quality.