Composición química y actividad Butirilcolinesterasa selectiva del aceite esencial de Piper arboreum Aubl. de Ecuador / 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%), ß-selinene (12,01%), (E)-caryophyllene (7,53%), bicyclogermacrene (6,72%), germacrene D (3,83%) and ß-elemene (3,63%). In in vitro analyzes, the EO showed high selective inhibition for BuChE with an IC50 inhibition value of 29,3±3,3 µg/mL. By contrast, the EO was not active against the AChE enzyme (IC50was 100,1±15,2 µg/mL).

El objetivo del presente estudio consistió en identificar la composición química del aceite esencial de la especie Piper arboreum Aubl. y evaluar su actividad inhibitoria in vitro frente a las enzimas butirilcolinesterasa (BuChE) y acetilcolinesterasa (AChE). El aceite esencial (AE) se obtuvo mediante destilación por arrastre de vapor de las hojas de la planta, que se colectaron en el cantón Pindal de la provincia de Loja al sur de Ecuador. La composición química se analizó mediante la técnica de cromatografía de gases acoplado a un detector de espectrometría de masas (GC-MS) y cromatografía de gases acoplado a un detector de ionización de llama (GC-FID). Se identificaron en total 41 compuestos, siendo los mayoritarios, el limoneno (31,46%), ß-selineno (12,01%), (E)-cariofileno (7,53%), biciclogermacreno (6,72%), germacreno D (3,83%) y ß-elemeno (3,63%). En los análisis in vitro, el AE mostró una alta inhibición selectiva para BuChE con un valor de inhibición CI50 de 29,3±3,3 µg/mL. Por el contrario,el AE no resultó activo frente a la enzima AChE con un valor de inhibión CI50= 100,1±15,2 µg/mL.

Composición química y actividad AChE-BuChE del aceite esencial de palo santo Bursera graveolens (Kunth) Triana & Planch de Jipijapa, Ecuador / Chemical composition and AChE-BuChE activities of the essential oil of palo santo Bursera graveolens (Kunth) Tr iana & Planch from Jipijapa, Ecuador

Abstract: This article describes the chemical composition, physical properties and acetylcholinesterase (A ChE) and butyrylcholinesterase (BuChE) activity of stem - distilled essential oil (E O ) from Bursera graveolens wood chips, Burseraceae. The plant material was acquired in Quimis (Bosque de Sancán), city of Jipijapa in the province of Manabí, coastal region o f Ecuador. Thirty - six components were identified by CG - MS, which represented 98.54% of the volatile oil. The main components were limonene (68.52%) and mentofuran (20.37%). The hydrocarbon monoterpenes constituted the most abundant fractions. The average y ield of the E O was 1.26%. Regarding the physical properties of E O , the following values were obtained: relative density (1,029 g/mL), refractive index (1,477) and specific rotation (+4,567). The E O presented IC 50 inhibition values of 47.2 and 51.9 µg/mL fo r the enzymes AChE and BuChE, respectively.

Resumen: Este artículo describe la composición química, propiedades físicas y actividad acetilcolinesterasa (AChE) y butirilcolinesterasa (BuChE) del aceite esencial (AE) destilado a vapor de astillas de madera de Bursera graveolens , Burseraceae. La materia vegetal fue adquirida en Quimis (Bosque de Sancán), ciudad de Jipijapa en la provincia de Manabí, región costera d e Ecuador. Treinta y seis componentes fueron identificados por CG - MS, que representaron al 98.54 % del aceite volátil. Los componentes principales fueron limoneno (68.52%) y mentofurano (20.37%). Los monoterpenos hidrocarburos constituyeron las fracciones m ás abundantes. El rendimiento medio del AE fue de 1.26%. Con respecto a las propiedades físicas del AE se obtuvo los siguientes valores, densidad relativa (1.029 g/mL), índice de refracción (1.477) y rotación específica (+4.567). El AE presentó valores de inhibición IC 50 de 47.2 y 51.9 µg/mL para las enzimas AChE y BuChE, respectivamente.

Selective BuChE inhibitory activity, chemical composition, and enantiomer content of the volatile oil from the Ecuadorian plant Clinopodium brownei

ABSTRACT This paper describes the chemical composition and the enantiomer content of the volatile oil hydrodistilled from Clinopodium brownei (Sw.) Kuntze, Lamiaceae. The plant was collected in the South of Ecuador. Thirty one components were identified by GC-MS, which accounted for the 96.15% of the volatile oil. The major components were pulegone (48.44%), menthone (34.55%) and β-acorenol (3.41%). Oxygenated monoterpenes (86.06%), followed by oxygenated sesquiterpenes (5.36%) constituted the most abundant fractions. The enantiomeric compositions of β-pinene, sabinene, 3-octanol, menthone, pulegone and menthyl acetate were determined by enantioselective GC-MS. (-)-Menthone showed the highest enantiomeric excess (ee = 83.4%). In in vitro tests, the volatile oil showed high selective inhibitory activity for butyrylcholinesterase with an IC50, 13.4 ± 1.8 µg/ml. In contrast, it was weakly active against acetylcholinesterase with an IC50 >250 µg/ml.

Carnosol from Lepechinia mutica and tiliroside from Vallea stipularis: Two promising inhibitors of BuChE

Abstract Lepechinia mutica (Benth.) Epling, Lamiaceae, and Vallea stipularis L.f., Elaeocarpaceae, are the object of the present study. These plants are endemic to the Andean region and have attracted our attention on the basis of interesting results obtained in a preliminary anticholinesterase screening. Actually, carnosol and tiliroside, isolated from L. mutica and V. stipularis, respectively, have shown a promising selective inhibitory activity against butyrylcholinesterase. Specifically, the anti-butyrylcholinesterase activity of carnosol was 5.15 µM and that of tiliroside was 52.9 µM, compared to 8.568 ± 0.570 µM of the positive control Donepezil. Carnosol and tiliroside were purified chromatographically from the ethyl acetate extract of L. mutica and V. stipularis, respectively. Spectrophotometric methods were used for enzymatic studies.