A Novel Chemical Profile of a Selective In Vitro Cholinergic Essential Oil from Clinopodium taxifolium (Kunth) Govaerts (Lamiaceae), a Native Andean Species of Ecuador

Abstract

A novel chemical profile essential oil, distilled from the aerial parts of Clinopodium taxifolium (Kunth) Govaerts (Lamiaceae), was analysed by Gas Chromatography-Mass Spectrometry (GC-MS, qualitative analysis) and Gas Chromatography with Flame Ionization Detector (GC-FID, quantitative analysis), with both polar and non-polar stationary phase columns. The chemical composition mostly consisted of sesquiterpenes and sesquiterpenoids (>70%), the main ones being (E)-β-caryophyllene (17.8%), α-copaene (10.5%), β-bourbonene (9.9%), δ-cadinene (6.6%), cis-cadina-1(6),4-diene (6.4%) and germacrene D (4.9%), with the non-polar column. The essential oil was then submitted to enantioselective GC analysis, with a diethyl-tert-butyldimethylsilyl-β-cyclodextrin diluted in PS-086 chiral selector, resulting in the following enantiomeric excesses for the chiral components: (1R,5S)-(−)-α-thujene (67.8%), (1R,5R)-(+)-α-pinene (85.5%), (1S,5S)-(−)-β-pinene (90.0%), (1S,5S)-(−)-sabinene (12.3%), (S)-(−)-limonene (88.1%), (S)-(+)-linalool (32.7%), (R)-(−)-terpinen-4-ol (9.3%), (S)-(−)-α-terpineol (71.2%) and (S)-(−)-germacrene D (89.0%). The inhibition activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) of C. taxifolium essential oil was then tested, resulting in selective activity against BChE with an IC50 value of 31.3 ± 3.0 μg/mL (positive control: donepezil, IC50 = 3.6 μg/mL).

Chemical Composition and Anticholinesterase Activity of the Essential Oil of Leaves and Flowers from the Ecuadorian Plant Lepechinia paniculata (Kunth) Epling

“…These results further confirm that chiral secondary metabolites are often present in plants as enantiomeric mixtures. The determination of the enantiomeric purity of a natural or synthetic compound is of great importance for different areas because each enantiomer of a molecule has different properties [ 8 , 18 ].…”

“…Its development has been accelerated by the importance of applying its results to the characterization of volatile mixtures such as EOs. In the case of chiral or optically active components, their fragrance and flavor attributes as well as their ability to act as biological mediators are dependent not only on their chemical structures, but fundamentally on their stereochemical properties [ 8 ]. It is very common to find enantiomers in EOs due to the metabolic response of plants; thus, there may be compounds for which one enantiomer has toxic activities while the other does not.…”

A New Sesquiterpene Essential Oil from the Native Andean Species Jungia rugosa Less (Asteraceae): Chemical Analysis, Enantiomeric Evaluation, and Cholinergic Activity

“…If that is the case, the EO may be considered useless as it is, but suitable to be studied, through a bio-guided fractionation, in search of new sesquiterpene inhibitors. The interest in this aspect resides in that, to the best of the authors' knowledge, the most active EOs are characterised by an important monoterpene fraction (except for the case where the EO is dominated by (E)-β-caryophyllene) [18,22]. However, due to their toxicity, hydrocarbon monoterpenes can hardly be used as pharmaceutical active principles, which cannot be assumed for sesquiterpenes.…”

“…In particular, EOs rich in sesquiterpenes have been presented as promising anti-proliferative agents, whose constituents are able to easily reach certain organs, such as heart, liver, and kidneys [20]. Among all the biological properties of EOs and their constituents, we are particularly interested in the inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), due to the serious implications that neurodegenerative diseases are ever-more producing in western countries [18,[21][22][23].…”

A Rare Dirhamnosyl Flavonoid and Other Radical‐Scavenging Metabolites from Cynophalla mollis (Kunth) J. Presl and Colicodendron scabridum (Kunt) Seem. (Capparaceae) of Ecuador

“…In fact, according to a recent literature, [1] about 75 % of all drugs approved between January 1981 and September 2019 are somehow related to a natural or biological source, including biotechnological drugs, vaccines and naturally inspired synthetic molecules. For these reasons, the search for new natural products and the characterization of major chemical constituents in previously unstudied plants are some of the main research areas of our group [2–10] . In such a context, the determination of important biological activities is, together with the discovery of new molecules and the description of novel metabolic profiles, the main goal in a phytochemical study.…”