Chemical Characterization and Biological Activity of the Essential Oil from Araucaria brasiliensis Collected in Ecuador

Abstract

The purpose of this study was to determine the chemical composition, physical properties, enantiomeric composition and cholinesterase inhibitory activity of the essential oil (EO) steam-distilled from the leaves of the plant Araucaria brasiliensis Loud. collected in Ecuador. The chemical composition was determined by gas chromatography coupled to mass spectrometry (GC-MS) analysis on two capillary GC columns (DB5-ms and HP-INNOWax). Thirty-three compounds were identified in the EO; the main compounds were beyerene (26.08%), kaurene (24.86%), myrcene (11.02%), α-pinene (9.99%) and 5,15-rosadiene (5.87%). Diterpene hydrocarbons (65.41%), followed by monoterpene hydrocarbons (21.11%), were the most representative components of the EO. Enantioselective analysis of the EO showed four pairs of enantiomeric compounds, α-pinene, camphene, γ-muurolene and δ-cadinene. In an in vitro assay, the EO showed moderate inhibitory activity towards the enzyme butyrylcholinesterase (BuChE) (95.7 µg/mL), while it was inactive towards acetylcholinesterase (AChE) (225.3 µg/mL). Further in vivo studies are needed to confirm the anticholinesterase potential of the EO.

Chemical and Biological Activity Profiling of Hedyosmum strigosum Todzia Essential Oil, an Aromatic Native Shrub from Southern Ecuador

“…The homologous series of n-alkanes (C9–C25) was also injected, in order to calculate the linear retention indices. The enantiomers were identified determined by injection of enantiomerically pure standards [ 30 ].…”

Constituents and Selective BuChE Inhibitory Activity of the Essential Oil from Hypericum aciculare Kunth

“…Finally, the temperature was increased at 15 °C/min to 250 °C and held for 5 minutes. Ultrapure helium at a flow rate of 1 mL/min was used as a carrier gas and 1 μL of the EO solution in CH 2 Cl 2 (1% v/v ) was injected (split 40:1) [ 20 , 46 , 49 ].…”

“…The cholinesterase inhibitory activity of the H. aciculare EO was determined against acetylcholinesterase (AChE, from Electrophorus electricus , Sigma-Aldrich, C3389, St. Louis, MO, USA) and butyrylcholinesterase (BuChE, from equine serum, Sigma-Aldrich, SRE020, St Louis., MO, USA) [ 49 ]. AChE and BuChE inhibitory effects of the oil were measured in vitro in accordance with the procedure initially designed by Ellman [ 50 ], which we subsequently adapted to essential oils, as described in [ 46 , 49 , 51 ]. Measurements were made in triplicate.…”

“…Donepezil was used as the reference ChE inhibitor. False positive results, due high concentration (>100 µg/mL) of amines or aldehydes, were not excluded [ 20 , 46 , 49 ]. Used as a control, the horseradish peroxidase activity versus its substrate, 2,2′-azino-di-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), was determined using the increase in the absorbance at 405 nm (see Figure 4 ), in the equipment described for cholinesterase assays.…”

“…The column temperature was programmed from an initial temperature of 60 • C for 5 min, followed by a gradient of 2 • C/min to 100 • C, followed by a gradient of 3 • C/min to 150 • C, followed by a gradient of 5 • C/min to 200 • C. Finally, the temperature was increased at 15 • C/min to 250 • C and held for 5 minutes. Ultrapure helium at a flow rate of 1 mL/min was used as a carrier gas and 1 µL of the EO solution in CH 2 Cl 2 (1% v/v) was injected (split 40:1) [20,46,49].…”