Óleo essencial de Piper gaudichaudianum Kunth: rendimento, composição química e atividade fungitóxica in vitro

Abstract

This work describes the seasonal analysis of the yield and chemical composition of the essential oil (EO) for the native species Piper gaudichaudianum Kunth in a population of Santa Maria, in order to determine the best time for collection. The effect of leaves drying on the yield and chemical composition of EO was also verified, in order to evaluate the possible influence of this post-harvest process on the extractive features. The EO oil and its major constituent had their fungitoxicity assessed against phytopathogenic and wood decay fungi. EO from fresh and dried leaves, and reproductive organs (inflorescences and fruits) were extracted separately by hydrodistillation, and then had their yields determined (w/ w %). The chemical composition was analyzed by gas chromatography-mass spectrometry (GC-MS) and gas chromatography with flame ionization detector (GC-FID). Additionally, fungitoxic assays were performed by the agar dilution method using PSA (potato-sucrose-agar). The presence of reproductive organs (RO) did not affect the leaves (L) EO of P. gaudichaudianum on the observed year, with a minimum value of 1.32% and a maximum of 1.61% without significant difference (p > 0.05). Chemical analysis of L and RO EO revealed that these are predominantly formed by phenylpropanoid dilapiolle (59.2 to 87.8%), while myristicin was identified only in the EO of the RO. The chemical composition of EO oils had no influence of seasonality and phenophases, being possible to collect the plant material at any time of year. Drying of the leaves did not affect the yield and composition of EO. The L and RO EO of P. gaudichaudianum presented fungitoxic activity for phytopathogenic fungi (Fusarium moniliforme and Botryosphaeria rhodina) and also for wood decay fungi (Pycnoporus sanguineus and Gloeophyllum trabeum) at concentrations of 0.25-1.0 uL / mL. The results indicated that the major constituent dilapiolle is responsible for the activity.