Enantiomeric Distribution Research Articles

Chemical Composition, Enantiomeric Distribution, and Physical Properties of the Fruit Essential Oil from Zanthoxylum lepidopteriphilum (Reynel) Rutaceae from Ecuador

Chemical Composition, Enantiomeric Distribution, and Physical Properties of the Fruit Essential Oil from Zanthoxylum lepidopteriphilum (Reynel) Rutaceae from Ecuador

Effect of cultivation and geographical location on chemical composition and enantiomeric distribution in linalool-rich Origanum dubium Boiss. essential oils obtained at different growth stages

ABSTRACT The current study is objected to investigate the essential oil yields, chemical compositions, and enantiomeric distribution of wild and cultivated linalool rich Origanum dubium Boiss. essential oils obtained at pre-flowering, initial flowering, and post-flowering growth stages. Wild plant materials are collected from Mediterranean region of Turkey. Samples were also cultivated in Mediterranean and Aegean coastlines of Turkey in the experimental fields of Ministry of Agriculture and Forestry of Turkey. O. dubium samples yielded between 6.7 and 9.7% (mL/100 g) of essential oils. The compositions were dominated by oxygenated monoterpenes (98.2–98.9%). Linalool was detected as the major compound in all essential oils (97.0–97.6%). The dominant enantiomer was discovered as (R)-(-)-linalool with a 99.3–99.4% enantiomeric purity. The essential oil yields, chemical compositions and enantiomeric distributions were found to be constant regardless of cultivation, geographical locations or different growth stages. The result of this manuscript indicates that by culturing linalool chemotype of O. dubium, the industrial need for (R)-(-)-linalool could be met at more affordable costs.

Analysis of the Volatile and Enantiomeric Compounds Emitted by Plumeria rubra L. Flowers Using HS-SPME-GC.

The volatile components emitted by fresh aromatic flowers of Plumeria rubra L., harvested in southern Ecuador during three different months were determined to evaluate the fluctuation of secondary metabolites. The volatile compounds were analyzed using headspace solid-phase microextraction (HS-SPME) followed by gas chromatography coupled to mass spectrometry (GC-MS) and a flame ionization detector (GC-FID) using two types of columns: a non-polar (DB-5ms) and polar column (HP-INNOWax). The principal chemical groups were hydrocarbon sesquiterpenes (43.5%; 40.0%), oxygenated sesquiterpenes (23.4%; 26.4%), oxygenated monoterpenes (14.0%; 11.2%), and hydrocarbon monoterpenes (12.7%; 9.3%). The most representative constituents were (E,E)-α-Farnesene (40.9-41.2%; 38.5-50.6%), (E)-nerolidol (21.4-32.6%; 23.2-33.0%), (E)-β-ocimene (4.2-12.5%; 4.5-9.1%), (Z)-dihydro-apofarnesol (6.5-9.9%; 7.6-8.6%), linalool (5.6-8.3%; 3.3-7.8%), and perillene (3.1-5.9%; 3.0-3.2%) in DB-5ms and HP-INNOWax, respectively. Finally, we reported for the first time the enantiomeric distribution of P. rubra flowers, where the enantiomers (1R,5R)-(+)-α-pinene, (S)-(-)-limonene, (S)-(+)-Linalool, and (1S,2R,6R,7R,8R)-(+)-α-copaene were present as enantiomerically pure substances, whereas (S)-(+)-(E)-Nerolidol and (R)-(+)-(E)-Nerolidol were observed as scalemic mixtures. This study provides the first comprehensive and comparative aroma profile of Plumeria rubra cultivated in southern Ecuador and gave us a clue to the variability of P. rubra chemotypes depending on the harvesting time, which could be used for future quality control or applications in phytopharmaceutical and food industries.

Gas chromatographic techniques and spectroscopic approaches for a deep characterization of Piper gaudichaudianum Kunth essential oil from Brazil

Piper gaudichaudianum Kunth essential oil (EO) is a natural source of bioactive components, having multiple therapeutic applications. Its chemical composition is highly variable, and strictly depends on abiotic factors, resulting in various biological activities. The present study details the utilization of multiple gas chromatographic techniques alongside nuclear magnetic resonance (NMR) spectroscopy to characterize the essential oil of Piper gaudichaudianum Kunth from Brazil. Seventy-six components were identified using GC–MS analysis, while enantio‑selective multidimensional gas chromatography elucidated the enantiomeric distribution of eight chiral components, for the first time in the literature. Following GC–MS analysis, an unidentified component, constituting approximately 27 % of the total oil, prompted an isolation step through preparative gas chromatography. Through the combined use of nuclear magnetic resonance, GC-Fourier transform infrared spectroscopy (FTIR), and mass spectrometry (MS), the unknown molecule was structurally identified as 4-[(3E)‑dec-3-en-1-yl]phenol. Remarkably, it was identified as a known molecule, gibbilimbol B, and not previously listed in any MS database. Subsequently, the spectrum was included in a commercial library, specifically the FFNSC 4.0 MS database, for the first time.

From grape to wine: A thorough compound specific isotopic, enantiomeric and quali-quantitative investigation by means of gas chromatographic analysis

In this study, multiple analytical approaches, including simultaneous enantiomeric and isotopic analysis, were employed to thoroughly investigate the volatile fraction in Moscato giallo grape berries and wines. For the qualitative and quantitative profiling, a fast GC-QqQ/MS approach was successfully utilized. However, prior to isotopic analysis, the extracts underwent an additional concentration step, necessitating an assessment of isotopic fractionation during the concentration process. Once the absence of carbon isotopic fractionation was confirmed, this research aimed to develop a suitable gas chromatographic method for the simultaneous detection of both enantiomeric and isotopic ratios of target monoterpenoids in Moscato giallo samples. To address the limitations associated with a one-dimensional approach, multidimensional gas chromatography was employed to enhance separation before IRMS and qMS detections. Utilizing a Deans switch transfer device, the coupling of an apolar column in the first dimension and a chiral cyclodextrin-based stationary phase in the second dimension proved effective for this purpose. The data obtained from the analysis of Moscato giallo samples allowed for the assessment of natural isotopic and enantiomeric distributions in grapes and wines for the first time in the literature. Significant enantiomeric excesses were observed for the target terpenoids investigated. Regarding isotopic distribution, a consistent trend was observed for all detected target terpenols, including the linalool enantiomers. To date, this study represents the first investigation of simultaneous δ13C and chiral investigation of the main terpenoids in oenological products in the literature.

Chemical Profiling of Drimys granadensis (Winteraceae) Essential Oil, and Their Antimicrobial, Antioxidant, and Anticholinesterase Properties.

A complete and comprehensive chemical and biological study of Drimys granadensis, a native Ecuadorian aromatic plant, was conducted. By conventional steam distillation from dried leaves, a yellowish, translucent essential oil (EO) with a density of 0.95 and a refractive index of 1.5090 was obtained. The EO was analyzed by gas chromatography coupled to a mass spectrometer (GC/MS) and an FID detector (GC/FID), respectively. Enantiomeric distribution was also carried out by GC/MS using a chiral selective column (diethyl tert-butylsilyl-BETA-cyclodextrin). The microdilution broth method was employed to assess the antibacterial and antifungal activity of the EO against a panel of opportunistic microorganisms. Antioxidant capacity was measured using diphenyl picryl hydrazyl (DPPH) and azino-bis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals. Finally, the inhibitory potential of the EO against acetylcholinesterase was also valued. Sixty-four chemical compounds, constituting 93.27% of the total composition, were identified, with major components including γ-muurolene (10.63%), spathulenol (10.13%), sabinene (5.52%), and δ-cadinene (4.22%). The characteristic taxonomic marker of the Drimys genus, Drimenol, was detected at very low percentages (<2%). Two pairs of enantiomers ((1S,5R)-(+)-α-pinene/(1S,5S)-(-)-α-pinene; (1S,5R)-(+)-β-pinene/(1S,5S)-(-)-β-pinene) and one pure enantiomer (1R,4S)-(-)-camphene were identified. Regarding antimicrobial potency, the EO exhibited a significant moderate effect on Listeria monocytogenes with a minimal inhibitory concentration (MIC) value of 250 µg/mL, while with the remaining microorganisms, it exerted less potency, ranging from 500 to 2000 µg/mL. The EO displayed moderate effects against the ABTS radical with a half scavenging capacity of 210.48 µg/mL and no effect against the DPPH radical. The most notable effect was noticed for acetylcholinesterase, with a half inhibition concentration (IC50) of 63.88 ± 1.03 µg/mL. These antiradical and anticholinesterase effects hint at potential pharmacological applications in Alzheimer's disease treatment, although the presence of safrole, albeit in low content (ca. 2%), could limit this opportunity. Further in vivo studies are necessary to fully understand their potential applications.

New Essential Oils from Ecuadorian Gynoxys cuicochensis Cuatrec. and Gynoxys sancti-antonii Cuatrec. Chemical Compositions and Enantioselective Analyses.

The present study belonged to an unfunded project, dealing on the systematic description of unprecedented essential oils (EOs), distilled from 12 species of genus Gynoxys Cuatrec. In this very case, the aim was the first chemical and enantiomeric analyses of two volatile fractions, obtained from the leaves of Gynoxys cuicochensis Cuatrec. and Gynoxys sancti-antonii Cuatrec. These EOs were analyzed by GC-MS (qualitatively) and GC-FID (quantitatively), detecting 89 and 60 components from G. cuicochensis and G. sancti-antonii, respectively. Major components for G. cuicochensis EO, on a nonpolar and polar stationary phase, were α-pinene (29.4-29.6%), p-vinylguaiacol (3.3-3.6%), and germacrene D (20.8-19.9%). In G. sancti-antonii EO, the main compounds were α-pinene (3.0-2.9%), β-pinene (12.9-12.1%), γ-curcumene (19.7-18.3%), germacrene D (9.0% on the polar phase), ar-curcumene (5.3% on the polar phase), δ-cadinene (4.1-4.6%), α-muurolol (3.3-2.4%), α-cadinol (3.0% on both columns), and an undetermined compound, of molecular weight 220. In addition to chemical composition, the enantioselective analysis of the main chiral compounds was carried out on two different chiral selectors. In G. cuicochensis EO, (1R,5R)-(+)-α-pinene, (S)-(+)-β-phellandrene, (R)-(-)-piperitone, and (S)-(-)-germacrene D were enantiomerically pure, whereas β-pinene, sabinene, α-phellandrene, limonene, linalool, and terpinen-4-ol were observed as scalemic mixtures. On the other hand, in G. sancti-antonii EO, the pure enantiomers were (1S,5S)-(-)-α-pinene, (1R,5R)-(+)-sabinene, (R)-(-)-β-phellandrene, (S)-(-)-limonene, (1S,2R,6R,7R,8R)-(+)-α-copaene, (R)-(-)-terpinen-4-ol, and (S)-(-)-germacrene D, whereas β-pinene, linalool, and α-terpineol were present as scalemic mixtures. The principal component analysis demonstrated that G. cuicochensis volatile fraction was quite similar to many of the other EOs of the same genus, whereas G. sancti-antonii produced the most dissimilar EO. Furthermore, the enantioselective analyses showed the usual variable enantiomeric distribution, with a greater presence of enantiomerically pure compounds in G. sancti-antonii EO.

Chemical Variability, Antioxidant and Larvicidal Efficacy of EOs from Citrus sinensis (L.) Osbeck Peel, Leaf, and Flower

Essential oils (EOs) from Citrus sinensis (Rutaceae) possess diverse biological activities. However, a comprehensive comparison of their chemical composition and bioactivity across different plant parts has not been studied yet. The current research comparatively assesses the yield, chemical composition, chiral distribution, antioxidant properties, and larvicidal activity of EOs extracted from the peels, leaves, and flowers of C. sinensis. EOs extracted via hydro-distillation (HD) and steam distillation (SD) were analyzed by gas chromatography–mass spectrometry (GC-MS) and chiral GC-MS to explore their chemical composition and enantiomeric distribution. In addition, their larvicidal and antioxidant potentials were evaluated following standard protocols. Peels of C. sinensis exhibited significantly higher oil content (1.75–2.25%) compared to its leaves (0.75–0.78%) and flowers (0.20–0.25%). The GC-MS analysis identified around 60 compounds, including terpenoids, sesquiterpenoids, and oxygenated terpenoids in the HD and SD extractions. Higher concentrations of sabinene were found in flower extract (38.05–39.89%) and leaf extract (32.30–36.91%), while peel extract contained more than 90% limonene. The larvicidal activity of peel oil was primarily attributed to limonene, with an LC50 value of 0.0031 µL/mL. The current study reports the first chiral (GC-MS) analysis in the essential oil of the leaves and flowers of C. sinensis, paving the way for authenticity and purity. Furthermore, the chemical profiling of citrus EOs, particularly from the peel, demonstrates a safe and promising candidate for diverse biological applications.

Unraveling the Enantiomeric Distribution of Glycosidically Bound Linalool in Teas (Camellia sinensis) and Their Acidolysis Characteristics and Pyrolysis Mechanism.

Glycosidically bound linalool plays important roles in the formation of excellent tea flavor, while their enantiomeric distribution in teas and the actual transformations with free linalool are still unclear. In this study, a novel chiral ultrahigh performance liquid chromatography-mass spectrometry/mass spectrometry approach to directly analyze linalyl-β-primeveroside and linalyl-β-d-glucopyranoside enantiomers in teas was established and then applied in 30 tea samples. A close transformation relationship existed between the two states of linalool for their consistent dominant configurations (most S-form) and corresponding distribution trend in most teas (r up to 0.81). The acidolysis characterization indicated that free linalool might be slowly released from linalyl-β-primeveroside with stable enantiomeric ratios during long-term withering of white tea in a weakly acidic environment, along with other isomerized products, e.g., geraniol, nerol, α-terpineol, etc. Furthermore, a novel online thermal desorption-gas chromatography-mass spectrometry approach was established to simulate the pyrolysis releasing of linalyl-β-primeveroside during tea processing. Interestingly, free linalool was not the selected pyrolysis product of linalyl-β-primeveroside but rather trans/cis-2,6-dimethyl-2,6-octadiene during the high-fire roasting or baking step of oolong and green teas. The identification of above high-fire chemical marks presented great potential to scientifically evaluate the proper thermal conditions in the practical production of tea.

The Essential Oils of Wyethia Species: Wyethia Amplexicaulis (Nutt.) Nutt. and Wyethia Helianthoides Nutt.

Background/Objective: Wyethia amplexicaulis (shiny mule's ears) and Wyethia helianthoides (white-head mule's ears) are conspicuous forbs growing in open hillsides and prairies at mid to upper elevations in the Intermountain West region of the United States. There have been no previous reports on the essential oil compositions of any Wyethia species, so the objective of this study is to examine the chemical compositions, including enantiomeric distribution of chiral terpenoids, of W. amplexicaulis and W. helianthoides from southern Idaho. Methods: Three individual samples of W. amplexicaulis and W. helianthoides were collected, and the essential oils were obtained by hydrodistillation using a Likens-Nickerson apparatus and analyzed by gas chromatography coupled with mass spectrometry (GC-MS), gas chromatography with flame ionization detection, and enantioselective GC-MS. Results: The essential oils were obtained in yields of 0.090% to 0.136% and 1.489% to 1.771% for W. amplexicaulis and W. helianthoides, respectively. The three W. helianthoides samples showed high similarity with (−)-germacrene D (16.5%-21.5%), ( E)-β-ocimene (10.0%-14.3%), myrcene (8.6%-12.4%), α-pinene (6.3%-7.3%, ≥ 95% (+)-α-pinene), 15-copaenol (4.3%-6.0%), and carotol (3.5%-5.9%) as the major components. The W. amplexicaulis essential oils, on the other hand, showed variation. Two samples were rich in monoterpene hydrocarbons, mostly myrcene (22.4% and 32.2%), while the third sample was dominated by oxygenated sesquiterpenoids, 15-copaenol (11.4%), carotol (10.0%), silphiperolan-7β-ol (8.2%), and caryophyllene oxide (5.8%). This is the first investigation of Wyethia essential oils. Conclusions: There are 11 recognized Wyethia species, so additional research is needed to understand the volatile phytochemicals present in this genus.

The Essential Oil Compositions of Ambrosia acanthicarpa Hook., Artemisia ludoviciana Nutt., and Gutierrezia sarothrae (Pursh) Britton & Rusby (Asteraceae) from the Owyhee Mountains of Idaho.

As part of our interest in the volatile phytoconstituents of aromatic plants of the Great Basin, we have obtained essential oils of Ambrosia acanthicarpa (three samples), Artemisia ludoviciana (12 samples), and Gutierrezia sarothrae (six samples) from the Owyhee Mountains of southwestern Idaho. Gas chromatographic analyses (GC-MS, GC-FID, and chiral GC-MS) were carried out on each essential oil sample. The essential oils of A. acanthicarpa were dominated by monoterpene hydrocarbons, including α-pinene (36.7-45.1%), myrcene (21.6-25.5%), and β-phellandrene (4.9-7.0%). Monoterpene hydrocarbons also dominated the essential oils of G. sarothrae, with β-pinene (0.5-18.4%), α-phellandrene (2.2-11.8%), limonene (1.4-25.4%), and (Z)-β-ocimene (18.8-39.4%) as major components. The essential oils of A. ludoviciana showed wide variation in composition, but the relatively abundant compounds were camphor (0.1-61.9%, average 14.1%), 1,8-cineole (0.1-50.8%, average 11.1%), (E)-nerolidol (0.0-41.0%, average 6.8%), and artemisia ketone (0.0-46.1%, average 5.1%). This is the first report on the essential oil composition of A. acanthicarpa and the first report on the enantiomeric distribution in an Ambrosia species. The essential oil compositions of A. ludoviciana and G. sarothrae showed wide variation in composition in this study and compared with previous studies, likely due to subspecies variation.

The pinyon pines of Utah: Leaf essential oils of Pinus edulis and Pinus monophyla

The pinyon pines, Pinus edulis (two-needle pinyon pine) and Pinus monophylla (single-leaf pinyon pine) are conspicuous trees in the pinyon-juniper woodlands of the Great Basin. The purpose of this study is to examine the volatile phytochemicals in the leaf essential oils of P. edulis and P. monophylla, including enantiomeric distribution of the chiral monoterpenoids. Leaves (needles) of P. edulis and P. monophylla were collected in Utah and the essential oils were obtained by hydrodistillation. Gas chromatographic analysis revealed the major components to be α-pinene (13.1-36.5% and 27.8-29.0%, respectively), β-pinene (6.2-34.8% and 11.2-23.4%), β-phellandrene (9.5-20.2% and 11.9-14.7%), and α-terpineol (3.8-6.8% and 6.2-9.2%). Enantioselective gas chromatography showed (–)-β-pinene (> 95%), (–)-β-phellandrene (> 98%), and (–)-α-terpineol (53.6-93.0%) to be the dominant enantiomers while α-pinene showed some variability (39.5-88.9% (+)-α-pinene). The enantiomeric distributions of chiral terpenoids are presented for these essential oils for the first time and adds to our understanding of Pinus essential oils. However, additional research is needed to investigate the enantiomeric distributions of chiral terpenoids of Pinus essential oils more fully.

Optimization of enantioselective high-performance liquid chromatography-tandem mass spectrometry method for the quantitative determination of 3,4-methylenedioxy-methamphetamine (MDMA) and its phase-1 metabolites in human biological fluids

Recently we published in this journal an enantioselective high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantitative determination of 3,4-methylenedioxymethamphetamine (MDMA) and its major phase-1 metabolites, 4-hydroxy-3-methoxyamphetamine (HMA), 4-hydroxy-3-methoxymethamphetamine (HMMA) and 3,4-methylenedioxyamphetamine (MDA) in human plasma, sweat, oral fluid and urine. Since we did not achieve simultaneous enantioseparation of all 4 compounds with a single chiral column, two amylose-based chiral columns were used alternatively. Further optimization of the mobile phase in the present study enabled baseline separation of all four pairs of enantiomers on a single Lux AMP column. In addition, by optimization of the column dimension and applied flow-rate it became possible to complete the separation within 6 minutes. These new methods were applied to the analysis of human plasma, oral fluid and urine. While results on the concentration of MDMA and its metabolites in various biological fluids were reported in our recent publication, in the present study an attempt was made to hydrolyze glucuronides in urine samples by using alternatively, hydrochloric acid or glucuronidase and to evaluate the effect of hydrolysis on the concentration and enantiomeric distribution of hydroxy metabolites of MDMA such as HMA and HMMA.

Spatial variation in constituents of essential oils from fruit pericarp of Zanthoxylum armatum DC of Nepali origin and their antibacterial activity

The fruit pericarp of Zanthoxylum armatum DC is used in spices and to manage different diseases like toothaches, inflamed gums, arthritis, swollen joints, insect bites, diarrhea, common flu, and respiratory difficulties by local people. In this study, the essential oil was extracted from the fruit pericarp of Z. armatum DC collected from different commercial sites in Nepal using the hydro-distillation method. The chiral gas chromatography-mass spectrometry (GC/MS) was used to identify the chemical compounds present in the essential oil with their stereochemistry. Major constituents identified in all samples included linalool, limonene, and methyl trans-cinnamate. Linalool, a monoterpene alcohol, exhibited the highest percentages in all three samples, recording 58.31%, 58.45%, and 80.37% in Salyan, Surkhet, and Myagdi respectively. Notably, twenty-five enantiomeric components were identified using chiral GC/MS among its sixty constituents. The enantiomeric component distribution of linalool and limonene was in their (+) dextrorotatory form, while others were dominant in the levorotatory form. This research underscores that Z. armatum from the Myagdi district of Nepal, is a prominent source of the medicinally and industrially important compound linalool, along with exhibiting higher antimicrobial activity. To the best of our knowledge, this represents the first report of a chiral GC/MS study conducted on this plant.

Vitex agnus-castus L.: Chemical characterization, enantiomeric distribution, and antibacterial efficacy of the essential oil from north-central Nigeria

Vitex agnus-castus L.: Chemical characterization, enantiomeric distribution, and antibacterial efficacy of the essential oil from north-central Nigeria

Aromatic profiles and enantiomeric distributions of volatile compounds during the ripening of Dendropanax dentiger honey

Dendropanax dentiger honey (DDH) is a specialty herbal honey from China. Previous research on DDH has mostly focused on its composition and potential chemical markers, no studies have been conducted on the changes in aroma characteristics and chiral odorants during its maturation. Therefore, the present study aims to address the missing parts. The proportions and total concentrations of 185 volatile compounds identified in different classes varied with DDHs ripening. Fourteen common odor-active compounds were identified by odor activity values (OAVs) and GC-olfactometry (GC-O) analysis. The aroma profiles of DDHs were observed to vary at different ripening stages, although the dominant aroma characteristic was “fruity” aroma, which became more pronounced with increasing maturity. The enantiomeric contents and distributions of 7 volatile enantiomers were related to specific physicochemical indicators and the maturity of DDHs, among which the enantiomers of linalool oxide A may be a potential indicator to identify its maturity. Furthermore, precise quantification and OAVs calculation showed that the enantiomer (2S, 5S)-linalool oxide A presented the highest concentration (8.83–27.39 ng/mL) and only the enantiomer R-linalool (OAVs: 5.56–6.14) was an important contributor to the aroma profiles of DDHs at different stages of maturity. These results provided a new research idea for quality control and identification of DDHs at different maturity stages.

A New Essential Oil from the Native Andean Species Nectandra laurel Klotzsch ex Nees of Southern Ecuador: Chemical and Enantioselective Analyses.

The leaves of Nectandra laurel Klotzsch ex Nees, belonging to the family, Lauraceae, were collected in the province of Loja (Ecuador), dried, and analytically steam-distilled. An unprecedented essential oil was obtained, with a 0.03% yield by weight of dry plant material. The volatile fraction was submitted to qualitative (GC-MS) and quantitative (GC-FID) chemical analysis, on two orthogonal stationary phases. Seventy-eight compounds were detected and quantified on at least one column. The essential oil was dominated by sesquiterpene hydrocarbons (53.0-53.8% on the non-polar and polar stationary phase, respectively), followed by oxygenated sesquiterpenoids (18.9-19.0%). A third group was constituted by metabolites of other origins, mainly aliphatic compounds, apparently derived from the acetate pathway (11.7-8.5%). The major components of the EO (≥3.0% with at least one column) were δ-selinene (30.5-28.8%), δ-cadinene (5.4-6.4%), epi-α-cadinol (4.9-5.2%), an undetermined compound with a molecular weight of 204 (3.4-4.2%), α-pinene (3.3-2.9%), and α-cadinol (2.9-3.0%). Finally, the essential oil was submitted to enantioselective analysis, on two β-cyclodextrin-based chiral selectors, determining the enantiomeric distribution of seven chiral terpenes. Among them, (1R,5R)-(+)-α-pinene, (1R,5R)-(+)-β-pinene, and (R)-(-)-α-phellandrene were enantiomerically pure, whereas camphene, borneol, α-copaene, and α-terpineol were present as scalemic mixtures.

A Study of the Essential Oil Isolated from Ageratina dendroides (Spreng.) R.M. King & H. Rob.: Chemical Composition, Enantiomeric Distribution, and Antimicrobial, Antioxidant, and Anticholinesterase Activities.

Ageratina dendroides is an aromatic species native to Ecuador. In this study, the chemical composition, enantiomeric distribution, and antifungal, antibacterial, antioxidant, and anticholinesterase activities of the essential oil isolated from aerial parts of Ageratina dendroides were determined. The quantitative chemical composition was determined using gas chromatography equipped with a flame ionization detector. The qualitative chemical composition was determined using gas chromatography coupled with mass spectrometry. The enantiomeric distribution was determined using an enantioselective chromatographic column. A broth microdilution method was used to determine the antibacterial activity. This antibacterial activity was tested against three Gram-negative bacilli bacteria and three Gram-positive cocci bacteria. The antifungal activity was tested against two fungi, a fungus, and a yeast. The antioxidant activity was determined using the ABTS (2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)) method and DPPH (2,2-diphenyl-1-picrylhydrazyl) method. The anticholinesterase activity was analyzed using the spectrophotometric method. Sixty-eight volatile compounds were identified in the essential oil. These compounds represent 99.49% of the total composition. In terms of the number of compounds and their relative abundance, the most representative group was sesquiterpene hydrocarbons, with thirty-four compounds and an abundance of 49.22%. The main constituents were found to be andro encecalinol (14.41 ± 1.26%), germacrene D (8.86 ± 1.06%), amorpha-4,9-dien-14-al (7.68 ± 0.70%), β-sesquiphellandrene (7.01 ± 1.49%), α-muurolol (5.89 ± 0.93%), and 7-epi-α-selinene (5.68 ± 0.53%). Five pairs of enantiomers were identified in the essential oil of Ageratina dendroides. The essential oil did not report antimicrobial activity at the maximum concentration tested (MIC > 4000 µg/mL) against any of the microorganisms tested. The antioxidant activity of the essential oil was strong in the ABTS method, with an SC50 of 33.2 ± 1.4 µg/mL. Additionally, the Ageratina dendroides essential oil reported moderate anticholinesterase activity, with an IC50 of 297.8 ± 1.03 µg/mL.

Chemical-Enantiomeric Characterization and In-Vitro Biological Evaluation of the Essential Oils from Elsholtzia strobilifera (Benth.) Benth. and E. blanda (Benth.) Benth. from Nepal

Background: Essential oils (EOs) are one of the most important groups of plant secondary metabolites responsible for their various biological activities. They also have wide applications as natural ingredients in many fields like the food, cosmetic, and medicine industries. This study was conducted to determine the chemical composition, enantiomeric distribution, and in-vitro biological activities of Elsholtzia strobilifera (Benth.) Benth. and E. blanda (Benth.) Benth. essential oils of Lamiaceae from Nepal. Methods: Essential oils obtained from hydro-distillation were analyzed by gas-chromatography mass-spectrometry (GC–MS) for their chemical constituents and the enantiomeric distribution of chiral terpenoids were determined by chiral GC–MS. Microbroth dilution was used to investigate the in-vitro antimicrobial activity, while cytotoxic activities were determined by cell viability using a Cell Counting Kit assay. The DPPH (2,2-diphenyl-1-picrylhydrazyl) radical-scavenging and FRAP (ferric-reducing antioxidant power) assays were used to evaluate the antioxidant activities. Results: A total of 55 compounds were identified in E. strobilifera with pinocarvone (40.7%), β-pinene (10%) and cis-pinocamphone (7.9%) as predominant constituents. While, 41 compounds were identified in the E. blanda EOs, including dihydrotagetone (49.1%), ( Z)-tagetone (15.6%) and ( E)-tagetone (8%) as major components; both essential oils were dominated by oxygenated monoterpenoids. The chiral separation and analyses of 12, E. strobilifera and 7, E. blanda essential oil components were performed, respectively, where (–)-β-caryophyllene and (–)-germacrene D were detected as enantiomerically pure in both oils. Elsholtzia EOs exhibited strong antifungal activity with MIC value of 156.3 µg/mL against Aspergillus niger, whereas, E. strobilifera EO against Staphylococcus epidermidis and E. blanda EO against Staphylococcus aureus showed inhibitory effects with MIC values of 156.3 µg/mL. E. strobilifera EO showed very active in-vitro cytotoxicity against the NIH-3T3 cell line with IC50 of 20.2 µg/mL, whereas E. blanda EO displayed effective cytotoxicity against MCF-7 cell line with IC50 of 33.1 µg/mL. The antioxidant activity of E. strobilifera EO was relatively good with IC50 of 188.8 ± 0.7 µg/mL in DPPH and EC50 value of 348.0 ± 0.1 µg/mL in FRAP, as compared to that of E. blanda EO. Conclusion: Elsholtzia EOs showed prominent biological activities emphasizing their importance as natural ingredients.

The Essential Oil Composition of Anthriscus caucalis M. Bieb. (Apiaceae) Growing Wild in Southwestern Idaho

Background Anthriscus caucalis is a non-native plant in North America with invasive potential. As part of our interests in essential oils of the Great Basin, a wild-growing sample of A. caucalis was collected in southwestern Idaho. Methods The essential of A. caucalis was obtained by hydrodistillation and analyzed by gas chromatographic methods (GC–MS, GC–FID, and chiral GC–MS). Results The major components in the essential oil were cis-chrysanthenyl acetate (42.3%), myrcene (20.4%), cis-chrysanthenol (6.7%), α-pinene (4.2%), and ( E)-β-farnesene (4.2%). (+)-α-Thujene, (+)-α-pinene, (+)-sabinene, (+)-limonene, (−)-β-phellandrene, (−)-bornyl acetate, (−)-( E)-β-caryophyllene, and (−)-germacrene D were the predominant enantiomers in the essential oil. Conclusion The essential oil composition of A. caucalis from Idaho is similar to those from Europe, but markedly different from A. caucalis from China. The enantiomeric distributions are comparable to those reported in other essential oils of the Apiaceae.