Chemical composition and selective BuChE activity of the essential oil of Piper arboreum Aubl. from Ecuador

The aim of this study was to identify the chemical composition of the Piper arboreum Aubl. essential oil (EO), and to evaluate its inhibitory activity in vitro against the enzymes butyrylcholinesterase (BuChE) and acetylcholinesterase (AChE). The EO was obtained by steam distillation of the leaves, which were collected in Pindal canton of the Loja province in southern Ecuador. The chemical composition was analyzed using the gas chromatography technique coupled to a mass spectrometry detector (GC-MS) and gas chromatography coupled to a flame ionization detector (GC-FID). A total of 41 compounds were identified, the major components found in the oil were limonene (31,46%), 0selinene (12,01%), (E)-caryophyllene (7,53%), bicyclogermacrene (6,72%), germacrene D (3,83%) and 0-elemene (3,63%). In in vitro analyzes, the EO showed high selective inhibition for BuChE with an IC50 inhibition value of 29,3 & PLUSMN; 3,3 & mu;g/mL. By contrast, the EO was not active against the AChE enzyme (IC50 was 100,1 & PLUSMN; 15,2 & mu;g/mL).