Enantiomeric Distribution Research Articles

Occurrence, elimination, enantiomeric distribution and intra-day variations of chiral pharmaceuticals in major wastewater treatment plants in Beijing, China

The occurrence, eliminations, enantiomeric distribution and intra-day variations of five chiral pharmaceuticals (three beta-blockers and two antidepressants) were investigated in eight major WWTPs in Beijing, China. The results revealed that metoprolol (MTP) and venlafaxine (VFX) were of the highest concentrations among the five determined pharmaceuticals with mean concentrations of 803 ng L−1 and 408 ng L−1, respectively in influents, and 354 ng L−1 and 165 ng L−1 in effluents, respectively. Their removal efficiencies, intra-day concentration changes and enantiomeric profiles during wastewater treatment were further analyzed. Loads of these two chiral pharmaceuticals were also studied to reveal drug use pattern. A/A/O+MBR (anaerobic/anoxic/oxic + membrane bio-reactor) followed by joint disinfection treatment process exhibited the high removal efficiencies. No or weak enantioselectivity was observed in most WWTPs. However, obvious enantiomeric fraction (EF) changing of MTP was observed in WWTP3 employing A/A/O+MBR. Intra-day concentration fluctuations of MTP were smaller than VFX. A quick response to sudden rise influent concentration of MTP was observed in WWTP1 effluent but EF response lagged behind. Similar bihourly EF variations in influents and effluents were also observed in most WWTPs for MTP and VFX in consideration of hydraulic residence time (HRT).

Ethyl 2-hydroxy-3-methylbutanoate enantiomers: quantitation and sensory evaluation in wine

Aim: To investigate chemical and sensory characteristics of ethyl 2-hydroxy-3-methylbutanoate in wines.Methods and results: Ethyl 2-hydroxy-3-methylbutanoate has been recently identified as a potential marker of lactic acid bacteria esterase activity. Enantiomers of this fruity ester were quantitated in 99 wines from various vintages and French regions using chiral gas chromatography (γ-cyclodextrin phase). Analyses revealed the predominant presence of the R enantiomer in red and white wines, with a maximum R/S enantiomeric ratio of 94/6 in a 1993 red wine. Results also highlighted greater levels of the ester in red than white wines, depending on grape origin. The detection thresholds of the R- and S-form were estimated at 4 µg/L and 1.5 µg/L in water and 51 mg/L and 21 mg/L in red wine, respectively. Moreover, ranking tests made with levels found in wines did not show significant sensory differences.Conclusion: The concentrations found in wines were considerably below the detection threshold, indicating no direct effect of these compounds on fruity aroma modulation. The absence of significant difference in sensory tests demonstrates that ethyl 2-hydroxy-3-methylbutanoate does not contribute significantly to the fruity aroma of red wine.Significance and impact of the study: To our knowledge, no previous research had determined the enantiomeric distribution and the sensory characteristics of this compound in wine.

Relationship between the terpene enantiomeric distribution and the growth cycle of lemon fruit and comparison of two extraction methods

Lemon essential oil is one of the most widely used natural flavours in the food and beverage industries. Knowledge of the enantiomeric ratio in flavours has gained relevance because they may indicate differences in their organoleptic characteristics or their authenticity. The study was carried out during the growth of the lemon fruit to evaluate the possible variations of the enantiomeric ratio of four characteristic terpenes: α-pinene, β-pinene, linalool and limonene. Two extraction methods were applied to extract the terpenes: simultaneous distillation–extraction at reduced pressure (V-SDE) and solid-phase microextraction; the results were equivalent whatever the method applied. In both cases, the target compounds were obtained from the lemon peel. Enantiomeric profiles were obtained by enantioselective multi-dimensional gas chromatography–mass spectrometry (enantio-MDGC-MS). Consistent enantiomeric ratios of α-pinene, β-pinene and limonene were observed; however, the enantiomeric ratio of linalool varied significantly according to the growth stage of the lemons in a spontaneous and natural way.

1,5-Dimethylhexylamine (octodrine) in sports and weight loss supplements: Natural constituent or synthetic chemical?

In the past years, there has been a mounting trend toward the addition of sympathomimetic stimulants in sports and weight loss supplements sold in the US and claimed to be from natural constituents. The latest among those pharmaceutical stimulants is 1,5-dimethylhexylamine (1,5-DMHA or octodrine), an ingredient in newly introduced sports and weight loss supplements with its ‘natural’ origin being cited from Aconitum or Kigelia plants. In order to validate the natural existence of 1,5-DMHA, two GC/MS methods were developed. One method involved using thick film megabore capillary columns to analyze the underivatized 1,5-DMHA. The second method was to determine enantiomeric distribution of 1,5-DMHA. Fifteen Aconitum or Kigelia plant samples originating from various locations were analyzed, and none of them contained 1,5-DMHA within the limit of detection (25 ng/mL) of the method. In contrast, although 1,5-DMHA was listed on the labels or website for all the 13 dietary supplements, only four products were found to contain this compound, with the highest quantity being reported as 112 mg per serving size. This is equivalent to more than three times the highest pharmaceutical dose established in Europe. The enantiomeric ratios of 1,5-DMHA in these products were determined to be between 0.9–1.0 (expressed as peak area ratio of one enantiomer over another), suggesting racemic nature. Interestingly, two byproducts from 1,5-DMHA synthesis were identified in commercial supplements containing 1,5-DMHA, indicating that 1,5-DMHA indeed originated from a poor quality source. Overall, the significant amount of 1,5-DMHA observed in the supplements, the enantiomeric distribution and the presence of the synthetic byproducts all suggested the synthetic origin of 1,5-DMHA in the commercial products.

Combination of separation and spectroscopic analytical techniques: application to compositional analysis of a minor citrus species

The composition of juice and essential oil of Citrus limetta Risso was investigated. Multidimensional and enantio-gas chromatography were used for the elucidation of the volatile profile and the assessment of enantiomeric distribution. Predominant compounds were linalyl acetate (13.06 g/100 g), β-pinene (6.79 g/100 g), myrcene (1.40 g/100 g) and sabinene (1.05 g/100 g). Through a β-cyclodextrin column eight chiral pairs were separated, equally distributed between laevorotatory and dextrorotatory enantiomers. Liquid chromatography with triple quadrupole ESI-MS and PDA detection showed the presence of flavonoids and phenolic compounds (791.34 ± 36.83 and 32.97 ± 1.92 mg L−1, respectively) in the juice. Sugars (i.e. glucose 202.23 ± 26.81 and fructose 146.73 ± 3.17 mM, respectively), aminoacids (i.e. proline 29.40 ± 3.78 and GABA 8.90 ± 0.95 mM) and organic acids (i.e. citrate 4.68 ± 0.81 mM) were determined in juice by means of 1H NMR spectroscopy.

Phytochemical Investigation of Male and Female Hedyosmum scabrum (Ruiz & Pav.) Solms Leaves from Ecuador.

This article reports the chemical composition of the essential oils obtained by hydrodistillation of male and female H.scabrum fresh leaves. The essential oils, HSMO and HSFO, respectively, were analyzed by GC/MS and GC-FID. A total of 93 components were detected, accounting for 94.8% and 95.3% of HSMO and HSFO, respectively. The prevalent constituents of HSMO were pinocarvone (13.1%), d-germacren-4-ol (12.6%), 1,8-cineole (10.8%), α-pinene (6.4%), and β-pinene (4.8%), whereas the major components of HSFO were 1,8-cineole (20.5%), linalool (16.5%), α-pinene (15.0%), β-pinene (6.4%), and sabinene (6.3%). The different enantiomeric distribution of β-pinene, sabinene, limonene, linalool in the two oils, was determined. The non-volatile esters of p-coumaric and ferulic acids with borneol (1 and 4), cis-chrysanthenol (2 and 5), and cis-pinocarveol (3 and 6) were identified in the leaves after basic hydrolysis and analysis of the NMR spectra of the free acids, and GC/MS spectra of the monoterpene alcohols, respectively. Compounds 2, 3, 5, and 6 have been found in nature for the first time. These findings demonstrated that, from a chemical point of view, male and female individuals of H.scabrum collected in Ecuador seem quite differentiated between each other and from samples of the same species growing in Bolivia and in Peru.

Acorenone B: AChE and BChE Inhibitor as a Major Compound of the Essential Oil Distilled from the Ecuadorian Species Niphogeton dissecta (Benth.) J.F. Macbr.

This study investigated the chemical composition, physical proprieties, biological activity, and enantiomeric analysis of the essential oil from the aerial parts of Niphogeton dissecta (culantrillo del cerro) from Ecuador, obtained by steam distillation. The qualitative and quantitative analysis of the essential oil was realized by gas chromatographic and spectroscopic techniques (GC-MS and GC-FID). Acorenone B was identified by GC-MS and NMR experiments. The enantiomeric distribution of some constituents has been assessed by enantio-GC through the use of a chiral cyclodextrin-based capillary column. We identified 41 components that accounted for 96.46% of the total analyzed, the major components were acorenone B (41.01%) and (E)-β-ocimene (29.64%). The enantiomeric ratio of (+)/(−)-β-pinene was 86.9:13.1, while the one of (+)/(−)-sabinene was 80.9:19.1. The essential oil showed a weak inhibitory activity, expressed as Minimal Inhibitory Concentration (MIC), against Enterococcus faecalis (MIC 10 mg/mL) and Staphylococcus aureus (MIC 5 mg/mL). Furthermore, it inhibited butyrylcholinesterase with an IC50 value of 11.5 μg/mL. Pure acorenone B showed inhibitory activity against both acetylcholinesterase and butyrylcholinesterase, with IC50 values of 40.8 μg/mL and 10.9 μg/mL, respectively.

Quali-quantitative characterization of the volatile constituents in Cordia verbenacea D.C. essential oil exploiting advanced chromatographic approaches and nuclear magnetic resonance analysis

Cordia verbenacea D.C. (Boraginaceae, Varronia curassavica Jacq. synonym) is a medicinal plant, native from Brazil, especially the leaves are used in folk medicine. The aim of this study was to extend the characterization of the volatile fraction of the essential oil obtained from this plant, by using GC-FID, GC–MS, and chiral GC. Moreover, to further clarify the composition of the volatile fraction, preparative multidimensional-GC (prep-MDGC) was used to collect unknown compounds, followed by NMR characterization. Specifically, the chemical characterization, both qualitative and quantitative, of the volatile fraction of the essential oil obtained from Cordia verbenacea cultivated in the Minas Gerais area (central area of Brazil) was investigated for the first time. The principal components from a quantitative point of view were α-pinene (25.32%; 24.48g/100g) and α-santalene (17.90%; 17.30g/100g), belonging to the terpenes family. Chiral-GC data are reported for the enantiomeric distribution of 7 different components. Last, to obtain the complete characterization of the essential oil constituents, prep-MDGC analysis was used to attain the isolation of two compounds, not present in the principal MS databases, which were unambiguously identified by NMR investigation as (E)-α-santalal and (E)-α-bergamotenal, reported for the first time in Cordia verbenacea essential oil.

Chemical Composition, Enantiomeric Distribution, and Antifungal Activity of the Oleoresin Essential Oil of Protium amazonicum from Ecuador.

Background: Protium species (Burseraceae) have been used in the treatment of various diseases and conditions such as ulcers and wounds. Methods: The essential oil from the oleoresin of Protium amazonicum was obtained by hydrodistillation and analyzed by GC-MS, GC-FID, and chiral GC-MS. P. amazonicum oleoresin oil was screened for antifungal activity against Candida albicans, Aspergillus niger, and Cryptococcus neoformans. Results: A total of 54 components representing 99.6% of the composition were identified in the oil. The essential oil was dominated by δ-3-carene (47.9%) with lesser quantities of other monoterpenoids α-pinene (4.0%), p-cymene (4.1%), limonene (5.1%), α-terpineol (5.5%) and p-cymen-8-ol (4.8%). Chiral GC-MS revealed most of the monoterpenoids to have a majority of levo enantiomers present with the exceptions of limonene and α-terpineol, which showed a dextro majority. P. amazonicum oleoresin oil showed promising activity against Cryptococcus neoformans, with MIC = 156 μg/mL. Conclusions: This account is the first reporting of both the chemical composition and enantiomeric distribution of the oleoresin essential oil of P. amazonicum from Ecuador. The oil was dominated by (−)-δ-3-carene, and this compound, along with other monoterpenoids, likely accounts for the observed antifungal activity of the oil.

Chemical Composition and Monoterpenoid Enantiomeric Distribution of the Essential Oils from Apharsemon (Commiphora gileadensis).

Background: Commiphora gileadensis (Hebrew: apharsemon) has been used since Biblical times to treat various ailments, and is used today in the traditional medicine of some Middle Eastern cultures. Methods: The essential oils from the stem bark, leaves, and fruits of Commiphora gileadensis—collected at the Ein Gedi Botanical Garden, Israel—were obtained by hydrodistillation and analyzed by gas chromatography–mass spectrometry. In addition, the enantiomeric distributions of the monoterpenoids in the essential oils have been determined by chiral gas chromatography. Results: The essential oils were dominated by monoterpene hydrocarbons, followed by oxygenated monoterpenoids. The major components in C. gileadensis oils were the monoterpenes α-pinene (11.1–18.4%), sabinene (15.8–35.9%), β-pinene (5.8–18.0%), p-cymene (4.8–8.4%), limonene (1.3–6.2%), γ-terpinene (0.7–8.1%), and terpinen-4-ol (5.3–18.5%). The (–)-enantiomers predominated for α-pinene, sabinene, β-pinene, limonene, and terpinen-4-ol. Conclusions: The chemical compositions of the C. gileadensis essential oils from Israel are markedly different from previously reported samples, which were rich in sesquiterpenoids. Likewise, the enantiomeric distribution of monoterpenoids is very different from Boswellia spp. essential oils.

Enantiomeric differentiation of three key volatile compounds in three different palm wines (Elaeis guineensis, Borassus flabellifer and Nypa fruticans)

ABSTRACTThe contents and enantiomeric distributions of three chiral compounds, linalool, phenylethanol and acetoin, were investigated in three different palm wines (i.e. Elaeis guineensis, Borassus flabellifer, and Nypa fruticans). While N. fruticans and B. flabellifer wines were predominated with the (S)-enantiomers of linalool, phenylethanol and acetoin, respectively, E. guineensis wine contained acetoin primarily as (R)-enantiomers in addition to the (S)-forms of linalool and phenylethanol. Interestingly, results revealed a high level of acetoin in all wines with concentrations ranging from 2437 to 6611 µg/L and an average ratio of S/R of 4:96–100:0. Moreover, noticeable differences occurred in the enantiomeric ratios and concentrations of enantiomers of the chiral compounds during storage. In all the wines, concentration of the (S)-form decreased during storage, whereas those of the (R)-form increased.

2-Methylbutyl acetate in wines: Enantiomeric distribution and sensory impact on red wine fruity aroma

Enantiomers of 2-methylbutyl acetate were assayed in red and white commercial wines from various vintages and origins, using chiral gas chromatography (γ-cyclodextrin), revealing the exclusive presence of the S-enantiomeric form. Results also confirmed that (S)-2-methylbutyl acetate levels were generally higher in red than white wines of the same age, and that acetate levels increased gradually during ageing. Olfactory threshold of (S)-2-methylbutyl acetate was evaluated at 313µg/L in dilute alcohol solution (12% v/v) and 1083µg/L in a fruity aromatic reconstitution, reflecting its presence in wines at subthreshold concentrations. At concentrations considerably lower than its olfactory threshold, 2-methylbutyl acetate was associated with blackberry-fruit and banana notes. It was also revealed that, even at subthreshold concentrations, this compound had a modification on the perception of fruity aromas in the matrices studied. Sensory profiles highlighted, for the first time, its specific contribution to black-, fresh-, and jammy-fruit notes, despite its subthreshold concentrations.

Tissue distribution and metabolism of triadimefon and triadimenol enantiomers in Chinese lizards (Eremias argus)

Triadimefon (TF, S-(+)-TF, R-(-)-TF) and its metabolite triadimenol (TN, TN-A1, A2 and TN-B1, B2) are two systemic fungicides and both of them are chiral pharmaceuticals which are widely used in agricultural industry. Many researches focused on the toxicity effects of triadimefon on mammals, while the ecotoxicological data of tiradimefon on reptiles is limited. In order to understand the toxicity mechanism of triadimefon in reptiles, the current study administrated S-(+)-TF or R-(-)-TF traidimefon (50mg/kgbw) to Chinese lizards (Eremias argus) respectively, the absorption, distribution of triadimefon and the formation of triadimenol were analysed at different sampling times. The metabolic pathways were demonstrated through relative gene expression using quantitative real-time PCR reaction. During the experiment time, triadimefon was quickly peaked to the maximum concentration within 12h in liver, brain, kidney, and plasma, eliminated slowly. The biotransformation in kidney was the lowest and fat possessed the worst degradation ability among others. The metabolite, triadimenol was detected in blood in 2h and reached to a plateau at about 12h in most organs (fat excepted), while the process of metabolism is stereoselective. The mainly metabolite in R-(-)-TF treated group was TN-B1, and TN-A2 in S-(+)-TF group which showed the selective metabolism to other species caused by environmental conditions, differences in the animal models and concentration of TF. The related gene expression of cyp1a1, cyp3a1 and hsd11β mRNA level in lizards showed different metabolic pathways in the liver and brain. Both P450s enzymes and 11β-hydroxysteroid dehydrogenase participated in metabolic reaction in liver, while no 11β-hydroxysteroid dehydrogenase pathway observed in brain. This diversity in liver and brain may cause different degradation rate and ecotoxicological effect in different organs.

Distribution of enantiomers of volatile organic compounds in selected fruit distillates.

The enantiomer ratios of chiral volatile organic compounds in fruit distillates were determined by multidimensional gas chromatography using solid-phase microextraction (SPME) as a sample treatment procedure. Linalool and its oxides, limonene, α-terpineol, and nerolidol, were present at the highest concentration levels, while significantly lower amounts of β-citronellol and lactones were found in the studied samples. However, almost all terpenoids mainly occur as a racemic or near-racemic mixture; enantiomer distribution of some chiral organic compounds in fruit distillates correlated to a botanical origin. In particular, a significant enantiomeric excess of (R)-linalool and (S)-α-terpineol was found only for pear brandy, and likewise the dominance (R)-limonene and the second eluted enantiomer of nerolidol for Sorbus domestica and strawberry, respectively. The distribution of γ-lactones stereoisomers was more nonspecific, with a general excess of the R-enantiomer.

Chemical Composition, Enantiomeric Distribution, and Biological Activities of Rhododendron anthopogon Leaf Essential Oil from Nepal

Rhododendron anthopogon D. Don., A small compact Himalayan shrub growing in Nepal, is a known medicinal plant used to treat sore throat, colds, blood disorders, bone disease, potato allergies, and vomiting, and to relieve liver disorders, headaches and back pain. The present study investigated the chemical composition and bioactivities of the leaf essential oil from R. anthopogon from Dhankuta, Nepal. The essential oil from leaves was obtained by hydrodistillation and a detailed chemical analysis was conducted by gas chromatography - mass spectrometry.(GC-MS). The enantiomeric distribution of monoterpenoid components was determined using chiral gas chromatography and represents the first chiral examination of R. anthopogon essential oil. The essential oil was screened for antimicrobial activity using the microbroth dilution test, and for cytotoxic activity against MCF-7, MDA-MB-231, and 5637 using the MTT assay. A total of 70 volatile componeits were identified from the essential oil. The major components were α-pinene (21.5%), δ-cadinene (13.8%), β-pinene (9.5%), limoiene (5.9%), δ-amorphene (4.6%), α-muurolene (4.5%), and (E)-daryophyllene (3.2%) with other minor constituents (< 3%). The essential oil showed marginal antibacterial and.cytotoxic activities, but no antifungal effects.

Critical evaluation of monitoring strategy for the multi-residue determination of 90 chiral and achiral micropollutants in effluent wastewater.

It is essential to monitor the release of organic micropollutants from wastewater treatment plants (WWTPs) for developing environmental risk assessment and assessing compliance with legislative regulation. In this study the impact of sampling strategy on the quantitative determination of micropollutants in effluent wastewater was investigated. An extended list of 90 chiral and achiral micropollutants representing a broad range of biological and physico-chemical properties were studied simultaneously for the first time. During composite sample collection micropollutants can degrade resulting in the under-estimation of concentration. Cooling collected sub-samples to 4°C stabilised ≥81 of 90 micropollutants to acceptable levels (±20% of the initial concentration) in the studied effluents. However, achieving stability for all micropollutants will require an integrated approach to sample collection (i.e., multi-bottle sampling with more than one stabilisation method applied). Full-scale monitoring of effluent revealed time-paced composites attained similar information to volume-paced composites (influent wastewater requires a sampling mode responsive to flow variation). The option of monitoring effluent using time-paced composite samplers is advantageous as not all WWTPs have flow controlled samplers or suitable sites for deploying portable flow meters. There has been little research to date on the impact of monitoring strategy on the determination of chiral micropollutants at the enantiomeric level. Variability in wastewater flow results in a dynamic hydraulic retention time within the WWTP (and upstream sewerage system). Despite chiral micropollutants being susceptible to stereo-selective degradation, no diurnal variability in their enantiomeric distribution was observed. However, unused medication can be directly disposed into the sewer network creating short-term (e.g., daily) changes to their enantiomeric distribution. As enantio-specific toxicity is observed in the environment, similar resolution of enantio-selective analysis to more routinely applied achiral methods is needed throughout the monitoring period for accurate risk assessment.

Piperitone Profiling in Fine Red Bordeaux Wines: Geographical Influences in the Bordeaux Region and Enantiomeric Distribution.

Piperitone was recently identified in red Bordeaux wines, and this study was designed to further explore its contribution to wine aroma. Firstly, a geographical origin effect was detected within the Bordeaux region (left versus right banks of the Gironde estuary), with significantly higher mint aroma intensities and piperitone levels in wines from the left bank (Medoc appellations). Statistical analysis of chemical and sensory data highlighted a correlation with the proportion of Cabernet Sauvignon in the wine blends. Accordingly, it was suggested that these sensory and chemical differences may be of varietal origin. Secondly, the contribution of piperitone to minty aromas in the aging bouquet was confirmed by combining both sensory and chemical data from a wide range of red Bordeaux wines. Subsequent investigation of the enantiomeric distribution of piperitone found a significantly higher proportion of the (+)-(6S) enantiomeric form in wines displaying a strong aging bouquet.

In Situ Calibration of a New Chemcatcher Configuration for the Determination of Polar Organic Micropollutants in Wastewater Effluent.

Passive sampling is proposed as an alternative to traditional grab- and composite-sampling modes. Investigated here is a novel passive sampler configuration, the Chemcatcher containing an Atlantic HLB disk covered by a 0.2 μm poly(ether sulfone) membrane, for monitoring polar organic micropollutants (personal care products, pharmaceuticals, and illicit drugs) in wastewater effluent. In situ calibration showed linear uptake for the majority of detected micropollutants over 9 days of deployment. Sampling rates (RS) were determined for 59 compounds and were generally in the range of 0.01-0.10 L day(-1). The Chemcatcher was also suitable for collecting chiral micropollutants and maintaining their enantiomeric distribution during deployment. This is essential for their future use in developing more accurate environmental risk assessments at the enantiomeric level. Application of calibration data in a subsequent monitoring study showed that the concentration estimated for 92% of micropollutants was within a factor of 2 of the known concentration. However, their application in a legislative context will require further understanding of the properties and mechanisms controlling micropollutant uptake to improve the accuracy of reported concentrations.

Identifying Chiral Molecules and their Enantiomeric Excesses in Extraterrestrial Samples: An Experimental Journey

AbstractExtraterrestrial materials have showered the Earth since it formed and may be as diverse as small presolar grains of stellar origins, larger bodies made of dust and water, such as km‐sized comets, and stony meteorites of various sizes and composition broken off asteroids. Between these, carbonaceous chondrites have the distinction of containing up to 30 % carbon, most of which is present as organic material. This review follows studies over nearly half a century, and in particular, chronicles the progress toward understanding the enantiomeric distributions in some of their chiral organic molecules through innovative methodologies, from the seminal design of chiral stationary phases for GC columns by Gil‐Av to the optimization of their use through compound‐specific isolation and derivatization techniques developed for meteorite samples.

Artemisiaarborescens Essential Oil Composition, Enantiomeric Distribution, and Antimicrobial Activity from Different Wild Populations from the Mediterranean Area.

Aerial parts of Artemisiaarborescens were collected from different sites of the Mediterranean area (southwestern Algeria and southern Italy) and the chemical composition of their essential oil (EO) extracted by hydrodistillation was studied by both gas chromatography (GC) equipped with an enantioselective capillary column and GC/mass spectrometry (GC/MS). The EOs obtained were tested against several Listeriamonocytogenes strains. Using GC and GC/MS, 41 compounds were identified, accounting for 96.0-98.8% of the total EO. All EOs showed a similar terpene profile, which was rich in chamazulene, β-thujone, and camphor. However, the concentration of such compounds varied among the EOs. A.arborescens EO inhibited up to 83.3% of the L.monocytogenes strains, but the inhibitory spectrum varied among the EOs, with those from Algeria showing a higher inhibition degree than the Italian EOs. Such effect likely depended on the ketone (β-thujone+camphor) content of the EO. The differences in the EO composition support the hypothesis that A.arborescens has at least two different chemotypes: a β-thujone and a chamazulene type. The EO inhibitory spectrum indicates the A.arborescens EO as a valuable option in the control of the food-borne pathogens.