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

Abstract

A potential source of new inhibitors of cholinesterase enzymes are certain compounds of natural plant origin; therefore, in the study described herein we have determined the chemical composition and the acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activities of the essential oil (EO) steam distilled from aerial parts of Hypericum aciculare, which was collected in southern Ecuador. The oil qualitative and quantitative composition was determined by GC-FID and GC-MS using a non-polar and a polar chromatographic column. A total of fifty-three constituents were identified, that accounted for about 98% of the EO content. The hydrocarbon n-nonane (16.4–28.7%) and the aldehyde n-decanal (20.7–23.1%) were the predominant oil constituents. In addition, the EO showed significant inhibition of BuChE (IC50 = 28.3 ± 2.7 μg/mL) and moderate activity towards AChE (IC50 = 82.1 ± 12.1 µg/mL). Thus, the EO from H. aciculare aerial parts is an interesting candidate to investigate the mechanism of selective ChE inhibition by the two ChE enzymes with the aim to discover potential targets to control the progression of the Alzheimer’s disease (AD).

Composition and Anti-Acetylcholinesterase Properties of the Essential Oil of the Ecuadorian Endemic Species Eugenia valvata McVaugh

“…For example, E. egensis, E. flavescens, E. polystachya and E. patrisii presented values of 2.5%, 1.0%, 1.0% and 0.7%, respectively [29]; it is important to note that these plants were air-dried, and the yield was similar to that of E. uniflora L. (0.13%) [30]. According to the literature, the yield may be related to the influence of variables such as genetic factors, the developmental stage and phenological cycle of seasonal changes, the type of plant material, and other conditions such as geographical distribution [31].…”

“…The essential oil was obtained from 2.09 kg of fresh leaves, which were chopped manually and subjected immediately to steam distillation for 3 h at atmospheric pressure, in a Clevenger apparatus. The essential oil obtained was dried over anhydrous sodium sulfate and refrigerated (below −4 • C) until the GC analysis; this process was carried out in triplicate [31].…”