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Dirk W Lachenmeier - One of the best experts on this subject based on the ideXlab platform.
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the choice of Thujone as drug for diabetes
Natural Product Research, 2011Co-Authors: Dirk W Lachenmeier, Stephan G WalchAbstract:The use of Thujone, a monoterpene ketone often present in sage (Salvia officinalis L.) or wormwood (Artemisia absinthium L.), for the treatment of diabetes mellitus was recently suggested in a study published in this journal. Evidence was based on the findings obtained in a diabetic rat model. After oral treatment with Thujone (5 mg/kg bodyweight (bw)/day for 28 days), the cholesterol and triglyceride levels were significantly adjusted to normal levels when compared to diabetic, untreated rats. While these results sound promising and worthy of further investigation, the well-defined profile of the adverse properties of Thujone demands a cautious interpretation of these results. The therapeutic margin of Thujone appears to be small, as a dose-related incidence of seizures was noted in 2-year National Toxicology Program studies in rats and mice. The dose level in the diabetic rat study is also considerably higher than a daily intake that is acceptable for humans (0.1 mg/kg bw/day).
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rapid determination of total Thujone in absinthe using 1h nmr spectroscopy
International Journal of Spectroscopy, 2011Co-Authors: Yulia B Monakhova, Thomas Kuballa, Dirk W LachenmeierAbstract:1H NMR spectroscopy is utilized to quantify total Thujone (sum of - and -isomers) in absinthe. For sample preparation, a simple dilution with buffer is required. Thujone produces a distinct peak of the CH2 group in the cyclopentanone moiety in the 2.13–2.11 ppm range. No overlap with other typical constituents such as anethole or fenchone occurs. The detection limit of 0.3 mg/L is adequate to control the EU maximum limit. The relative standard deviation was 6%, and linearity was observed from 1 to 100 mg/L. Applicability was proven by analysis of 69 authentic absinthes. The correlation between NMR and our previous method consisting of liquid-liquid extraction followed by GC/MS was significant (). The simple and cheap NMR method can be used for rapid screening of absinthes for total Thujone content while chromatographic techniques are recommended for more specific (- and -Thujone isomers) analysis if required.
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determination of the biologically active flavour substances Thujone and camphor in foods and medicines containing sage salvia officinalis l
Chemistry Central Journal, 2011Co-Authors: Stephan G Walch, Thomas Kuballa, Wolf Stuhlinger, Dirk W LachenmeierAbstract:The sage plant Salvia officinalis L. is used as ingredient in foods and beverages as well as in herbal medicinal products. A major use is in the form of aqueous infusions as sage tea, which is legal to be sold as either food or medicine. Sage may contain two health relevant substances, Thujone and camphor. The aim of this study was to develop and validate an analytical methodology to determine these active principles of sage and give a first overview of their concentrations in a wide variety of sage foods and medicines. A GC/MS procedure was applied for the analysis of α- and β-Thujone and camphor with cyclodecanone as internal standard. The precision was between 0.8 and 12.6%, linearity was obtained from 0.1 - 80 mg/L. The recoveries of spiked samples were between 93.7 and 104.0% (average 99.1%). The time of infusion had a considerable influence on the content of analytes found in the teas. During the brewing time, Thujone and camphor show an increase up to about 5 min, after which saturation is reached. No effect was found for preparation with or without a lid on the pot used for brewing the infusion. Compared to extracts with ethanol (60% vol), which provide a maximum yield, an average of 30% Thujone are recovered in the aqueous tea preparations. The average Thujone and camphor contents were 4.4 mg/L and 16.7 mg/L in food tea infusions and 11.3 mg/L and 25.4 mg/L in medicinal tea infusions. The developed methodology allows the efficient determination of Thujone and camphor in a wide variety of sage food and medicine matrices and can be applied to conduct surveys for exposure assessment. The current results suggest that on average between 3 and 6 cups of sage tea could be daily consumed without reaching toxicological thresholds.
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letter to the editor the choice of Thujone as drug for diabetes
2011Co-Authors: Dirk W Lachenmeier, Stephan G Walch, Weissenburger StrasseAbstract:The use of Thujone, a monoterpene ketone often present in sage (Salvia officinalis L.) or wormwood (Artemisia absinthium L.), for the treatment of diabetes mellitus was recently suggested in a study published in this journal. Evidence was based on the findings obtained in a diabetic rat model. After oral treatment with Thujone (5 mg/kg bodyweight (bw)/day for 28 days), the cholesterol and triglyceride levels were significantly adjusted to normal levels when compared to diabetic, untreated rats. While these results sound promising and worthy of further investigation, the well-defined profile of the adverse properties of Thujone demands a cautious interpretation of these results. The therapeutic margin of Thujone appears to be small, as a dose-related incidence of seizures was noted in 2-year National Toxicology Program studies in rats and mice. The dose level in the diabetic rat study is also considerably higher than a daily intake that is acceptable for humans (0.1 mg/kg bw/day).
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risk assessment of Thujone in foods and medicines containing sage and wormwood evidence for a need of regulatory changes
Regulatory Toxicology and Pharmacology, 2010Co-Authors: Dirk W Lachenmeier, Michael UebelackerAbstract:Abstract Thujone is a natural substance found in plants commonly used in foods and beverages, such as wormwood and sage, as well as in herbal medicines. The current limits for Thujone in food products are based on short-term animal studies from the 1960s, which provided evidence for a threshold-based mechanism, yet only allowed for the derivation of preliminary values for acceptable daily intakes (ADI) based on the no-observed effect level (NOEL). While the 2008 European Union Regulation on flavourings deregulated the food use of Thujone, the European Medicines Agency introduced limits for the substance in 2009. The present study re-evaluates the available evidence using the benchmark dose (BMD) approach instead of NOEL, and for the first time includes data from a long-term chronic toxicity study of the National Toxicology Program (NTP). The NTP data provide similar results to the previous short-term studies. Using dose–response modelling, a BMD lower confidence limit for a benchmark response of 10% (BMDL10) was calculated as being 11 mg/kg bw/day for clonic seizures in male rats. Based on this, we propose an ADI of 0.11 mg/kg bw/day, which would not be reachable even for consumers of high-levels of Thujone-containing foods (including absinthe). While fewer data are available concerning Thujone exposure from medicines, we estimate that between 2 and 20 cups of wormwood or sage tea would be required to reach this ADI, and view that the short-term medicinal use of these herbs can also be regarded as safe. In conclusion, the evidence does not point to any need for changes in regulations but confirms the current limits as sufficiently protective for consumers.
Thomas Kuballa - One of the best experts on this subject based on the ideXlab platform.
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rapid determination of total Thujone in absinthe using 1h nmr spectroscopy
International Journal of Spectroscopy, 2011Co-Authors: Yulia B Monakhova, Thomas Kuballa, Dirk W LachenmeierAbstract:1H NMR spectroscopy is utilized to quantify total Thujone (sum of - and -isomers) in absinthe. For sample preparation, a simple dilution with buffer is required. Thujone produces a distinct peak of the CH2 group in the cyclopentanone moiety in the 2.13–2.11 ppm range. No overlap with other typical constituents such as anethole or fenchone occurs. The detection limit of 0.3 mg/L is adequate to control the EU maximum limit. The relative standard deviation was 6%, and linearity was observed from 1 to 100 mg/L. Applicability was proven by analysis of 69 authentic absinthes. The correlation between NMR and our previous method consisting of liquid-liquid extraction followed by GC/MS was significant (). The simple and cheap NMR method can be used for rapid screening of absinthes for total Thujone content while chromatographic techniques are recommended for more specific (- and -Thujone isomers) analysis if required.
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determination of the biologically active flavour substances Thujone and camphor in foods and medicines containing sage salvia officinalis l
Chemistry Central Journal, 2011Co-Authors: Stephan G Walch, Thomas Kuballa, Wolf Stuhlinger, Dirk W LachenmeierAbstract:The sage plant Salvia officinalis L. is used as ingredient in foods and beverages as well as in herbal medicinal products. A major use is in the form of aqueous infusions as sage tea, which is legal to be sold as either food or medicine. Sage may contain two health relevant substances, Thujone and camphor. The aim of this study was to develop and validate an analytical methodology to determine these active principles of sage and give a first overview of their concentrations in a wide variety of sage foods and medicines. A GC/MS procedure was applied for the analysis of α- and β-Thujone and camphor with cyclodecanone as internal standard. The precision was between 0.8 and 12.6%, linearity was obtained from 0.1 - 80 mg/L. The recoveries of spiked samples were between 93.7 and 104.0% (average 99.1%). The time of infusion had a considerable influence on the content of analytes found in the teas. During the brewing time, Thujone and camphor show an increase up to about 5 min, after which saturation is reached. No effect was found for preparation with or without a lid on the pot used for brewing the infusion. Compared to extracts with ethanol (60% vol), which provide a maximum yield, an average of 30% Thujone are recovered in the aqueous tea preparations. The average Thujone and camphor contents were 4.4 mg/L and 16.7 mg/L in food tea infusions and 11.3 mg/L and 25.4 mg/L in medicinal tea infusions. The developed methodology allows the efficient determination of Thujone and camphor in a wide variety of sage food and medicine matrices and can be applied to conduct surveys for exposure assessment. The current results suggest that on average between 3 and 6 cups of sage tea could be daily consumed without reaching toxicological thresholds.
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long term stability of Thujone fenchone and pinocamphone in vintage preban absinthe
Journal of Agricultural and Food Chemistry, 2009Co-Authors: Dirk W Lachenmeier, Theodore A. Breaux, David Nathanmaister, Thomas KuballaAbstract:Research was conducted to ascertain whether analyses of vintage absinthe samples represent their original composition in the early 1900s. Absinthe stored in traditional green glass bottles and irradiated with ultraviolet light for up to 200 h exhibited unchanged composition. Samples stored in clear glass exhibited an 18% reduction in β-Thujone content and a concurrent decoloration. These experiments indicate the stability of Thujone in vintage absinthes, as these were stored in green glass bottles. The preserved color of the preban absinthes subjected to analysis indicates that no significant light exposure occurred throughout the duration of storage, and therefore provides indirect proof that no loss of terpenes occurred. The stability of absinthe was further demonstrated through the reanalysis of samples from 2001−2005, which exhibited no changes in Thujone content as of 2008. A previous evaluation of preban absinthe was therefore valid and not confounded by significant Thujone deterioration over time.
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chemical composition of vintage preban absinthe with special reference to Thujone fenchone pinocamphone methanol copper and antimony concentrations
Journal of Agricultural and Food Chemistry, 2008Co-Authors: Dirk W Lachenmeier, Theodore A. Breaux, David Nathanmaister, Evamaria Sohnius, Kerstin Schoeberl, Thomas KuballaAbstract:Thirteen samples of authentic absinthe dating from the preban era (i.e., prior to 1915) were analyzed for parameters that were hypothesized as contributing to the toxicity of the spirit, including naturally occurring herbal essences (Thujone, pinocamphone, fenchone), methanol, higher alcohols, copper, and antimony. The total Thujone content of preban absinthe was found to range between 0.5 and 48.3 mg/L, with an average concentration of 25.4 ± 20.3 mg/L and a median concentration of 33.3 mg/L. The authors conclude that the Thujone concentration of preban absinthe was generally overestimated in the past. The analysis of postban (1915–1988) and modern commercial absinthes (2003–2006) showed that the encompassed Thujone ranges of all absinthes are quite similar, disproving the supposition that a fundamental difference exists between preban and modern absinthes manufactured according to historical recipes. Analyses of pinocamphone, fenchone, base spirits, copper, and antimony were inconspicuous. All things co...
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behaviour of Thujone during distillation and possible concentration ranges in pre ban absinthe
Journal of the Science of Food and Agriculture, 2007Co-Authors: Dirk W Lachenmeier, Thomas KuballaAbstract:A discrepancy in the magnitude of Thujone concentrations in distilled pre-ban absinthe has existed until now. Concentrations of 260 mg L−1 were derived at by theoretical calculations. Tests of authentic pre-ban absinthes and studies concerning absinthes produced according to historic recipes found concentrations below 10 mg L−1. In this study, the behaviour of Thujone during distillation was studied and a significant discrimination was determined (80% yield in water-cum-steam distillation). The Thujone concentrations in distilled pre-ban absinthe were then calculated with regard to the composition of wormwood derived from a literature review. Due to the large deviations of oil content and Thujone concentration of wormwood, a typical Absinthe Suisse de Pontarlier from Duplais' 1855 recipe might have contained between zero and a maximum of 76 mg L−1 of Thujone, the average was calculated as 23 mg L−1 with a standard deviation of 21 mg L−1. It was proven that the previous calculations overestimated the Thujone content of distilled absinthe and the discrepancy was resolved as our new calculations are in good accord with the experimental findings. Copyright © 2007 Society of Chemical Industry
Girija Kuttan - One of the best experts on this subject based on the ideXlab platform.
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augmentation of humoral and cell mediated immune responses by Thujone
International Immunopharmacology, 2011Co-Authors: Kodappully Sivaraman Siveen, Girija KuttanAbstract:Abstract Thujone, a naturally occurring monoterpene, was found to enhance the total WBC count, bone marrow cellularity, number of α-esterase positive cells, number of plaque forming cells in spleen and circulating antibody titer in Balb/c mice (1 mg/kg body weight, intraperitoneally for 5 days). Thujone treatment enhanced proliferation of splenocytes and thymocytes, both in the presence and absence of specific mitogens. Administration of Thujone was found to stimulate the cell-mediated immunological response in normal and tumor bearing Balb/c mice. A significant enhancement in natural killer (NK) cell mediated cytotoxicity, antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent complement mediated cytotoxicity (ACC) in both normal as well as tumor-bearing animals was observed after the administration of Thujone. Production of cytokines such as IL-2 and IFN-γ was significantly enhanced by the administration of Thujone. The stimulatory effect of Thujone on cytotoxic T lymphocyte (CTL) generation was determined by Winn's neutralization assay using CTL sensitive EL4 thymoma cells. Thujone treatment showed a significant increase in CTL production in both the in vivo and in vitro models, as indicated by a significant increase in the life span of tumor bearing animals. All these results indicate that administration of Thujone could enhance the immune response of mice. There was a significant reduction in solid tumor development, mediated by the presence of alert immune responses during Thujone administration.
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Thujone inhibits lung metastasis induced by b16f 10 melanoma cells in c57bl 6 mice
Canadian Journal of Physiology and Pharmacology, 2011Co-Authors: Kodappully Sivaraman Siveen, Girija KuttanAbstract:The antimetastatic potential of Thujone, a naturally occurring monoterpene, was evaluated. Metastasis was induced in C57BL/6 mice by injecting highly metastatic B16F-10 melanoma cells through the lateral tail vein. Administration of thu- jone (1 mg·(kg body weight) -1 ), prophylactically and simultaneously with tumor induction, inhibited tumor nodule formation in the lungs by 59.45% and 57.54%, respectively, with an increase in the survival rate (33.67% and 32.16%) of the meta- static tumor bearing animals. These results correlated with biochemical parameters such as lung collagen hydroxyproline, hexosamine and uronic acid contents, serum sialic acid and g-glutamyl transpeptidase levels, and histopathological analysis. Treatment with Thujone downregulated the production of proinflammatory cytokines such as tumor necrosis factor-a, inter- leukin (IL)-1b, IL-6, and granulocyte-monocyte colony-stimulating factor. Thujone administration downregulated the expres- sion of matrix metalloproteinase (MMP)-2, MMP-9, extracellular signal-regulated kinase (ERK)-1, ERK-2, and vascular endothelial growth factor (VEGF) and also upregulated the expression of nm-23, tissue inhibitor of metalloproteinase (TIMP)-1, and TIMP-2 in the lung tissue of metastasis-induced animals. Treatment with Thujone inhibited the activity of MMP-2 and MMP-9 in gelatin zymographic analysis. Thujone treatment significantly inhibited the invasion of B16F-10 melanoma cells across the collagen matrix in a Boyden chamber. Thujone also inhibited the adhesion of tumor cells to col- lagen-coated microtire plate wells and the migration of B16F-10 melanoma cells across a polycarbonate filter in vitro. These results indicate that Thujone can inhibit the lung metastasis of B16F-10 cells through inhibition of tumor cell proliferation, adhesion, and invasion, as well as by regulating expression of MMPs, VEGF, ERK-1, ERK-2, TIMPs, nm23, and levels of proinflammatory cytokines and IL-2 in metastatic animals.
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Thujone inhibits lung metastasis induced by B16F-10 melanoma cells in C57BL/6 mice
Canadian Journal of Physiology and Pharmacology, 2011Co-Authors: Kodappully Sivaraman Siveen, Girija KuttanAbstract:The antimetastatic potential of Thujone, a naturally occurring monoterpene, was evaluated. Metastasis was induced in C57BL/6 mice by injecting highly metastatic B16F-10 melanoma cells through the lateral tail vein. Administration of thu- jone (1 mg·(kg body weight) -1 ), prophylactically and simultaneously with tumor induction, inhibited tumor nodule formation in the lungs by 59.45% and 57.54%, respectively, with an increase in the survival rate (33.67% and 32.16%) of the meta- static tumor bearing animals. These results correlated with biochemical parameters such as lung collagen hydroxyproline, hexosamine and uronic acid contents, serum sialic acid and g-glutamyl transpeptidase levels, and histopathological analysis. Treatment with Thujone downregulated the production of proinflammatory cytokines such as tumor necrosis factor-a, inter- leukin (IL)-1b, IL-6, and granulocyte-monocyte colony-stimulating factor. Thujone administration downregulated the expres- sion of matrix metalloproteinase (MMP)-2, MMP-9, extracellular signal-regulated kinase (ERK)-1, ERK-2, and vascular endothelial growth factor (VEGF) and also upregulated the expression of nm-23, tissue inhibitor of metalloproteinase (TIMP)-1, and TIMP-2 in the lung tissue of metastasis-induced animals. Treatment with Thujone inhibited the activity of MMP-2 and MMP-9 in gelatin zymographic analysis. Thujone treatment significantly inhibited the invasion of B16F-10 melanoma cells across the collagen matrix in a Boyden chamber. Thujone also inhibited the adhesion of tumor cells to col- lagen-coated microtire plate wells and the migration of B16F-10 melanoma cells across a polycarbonate filter in vitro. These results indicate that Thujone can inhibit the lung metastasis of B16F-10 cells through inhibition of tumor cell proliferation, adhesion, and invasion, as well as by regulating expression of MMPs, VEGF, ERK-1, ERK-2, TIMPs, nm23, and levels of proinflammatory cytokines and IL-2 in metastatic animals.
Jorg Bohlmann - One of the best experts on this subject based on the ideXlab platform.
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the gymnosperm cytochrome p450 cyp750b1 catalyzes stereospecific monoterpene hydroxylation of sabinene in Thujone biosynthesis in western redcedar
Plant Physiology, 2015Co-Authors: Andreas Gesell, Markus Blaukopf, Lina Madilao, Macaire M S Yuen, Stephen G Withers, Jim Mattsson, John H Russell, Jorg BohlmannAbstract:Western redcedar (WRC; Thuja plicata) produces high amounts of oxygenated Thujone monoterpenoids associated with resistance against herbivore feeding, particularly ungulate browsing. Thujones and other monoterpenoids accumulate in glandular structures in the foliage of WRC. Thujones are produced from (+)-sabinene by sabinol and sabinone. Using metabolite analysis, enzyme assays with WRC tissue extracts, cloning, and functional characterization of cytochrome P450 monooxygenases, we established that trans-sabin-3-ol but not cis-sabin-3-ol is the intermediate in Thujone biosynthesis in WRC. Based on transcriptome analysis, full-length complementary DNA cloning, and characterization of expressed P450 proteins, we identified CYP750B1 and CYP76AA25 as the enzymes that catalyze the hydroxylation of (+)-sabinene to trans-sabin-3-ol. Gene-specific transcript analysis in contrasting WRC genotypes producing high and low amounts of monoterpenoids, including a glandless low-terpenoid clone, as well as assays for substrate specificity supported a biological role of CYP750B1 in α- and β-Thujone biosynthesis. This P450 belongs to the apparently gymnosperm-specific CYP750 family and is, to our knowledge, the first member of this family to be functionally characterized. In contrast, CYP76AA25 has a broader substrate spectrum, also converting the sesquiterpene farnesene and the herbicide isoproturon, and its transcript profiles are not well correlated with Thujone accumulation.
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The Gymnosperm Cytochrome P450 CYP750B1 Catalyzes Stereospecific Monoterpene Hydroxylation of (+)-Sabinene in Thujone Biosynthesis in Western Redcedar
Plant Physiology, 2015Co-Authors: Andreas Gesell, Markus Blaukopf, Lina Madilao, Macaire M S Yuen, Stephen G Withers, Jim Mattsson, John H Russell, Jorg BohlmannAbstract:Western redcedar (WRC; Thuja plicata) produces high amounts of oxygenated Thujone monoterpenoids associated with resistance against herbivore feeding, particularly ungulate browsing. Thujones and other monoterpenoids accumulate in glandular structures in the foliage of WRC. Thujones are produced from (+)-sabinene by sabinol and sabinone. Using metabolite analysis, enzyme assays with WRC tissue extracts, cloning, and functional characterization of cytochrome P450 monooxygenases, we established that trans-sabin-3-ol but not cis-sabin-3-ol is the intermediate in Thujone biosynthesis in WRC. Based on transcriptome analysis, full-length complementary DNA cloning, and characterization of expressed P450 proteins, we identified CYP750B1 and CYP76AA25 as the enzymes that catalyze the hydroxylation of (+)-sabinene to trans-sabin-3-ol. Gene-specific transcript analysis in contrasting WRC genotypes producing high and low amounts of monoterpenoids, including a glandless low-terpenoid clone, as well as assays for substrate specificity supported a biological role of CYP750B1 in α- and β-Thujone biosynthesis. This P450 belongs to the apparently gymnosperm-specific CYP750 family and is, to our knowledge, the first member of this family to be functionally characterized. In contrast, CYP76AA25 has a broader substrate spectrum, also converting the sesquiterpene farnesene and the herbicide isoproturon, and its transcript profiles are not well correlated with Thujone accumulation.
Michal P Dybowski - One of the best experts on this subject based on the ideXlab platform.
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the determination of α and β Thujone in human serum simple analysis of absinthe congener substance
Forensic Science International, 2016Co-Authors: Michal P Dybowski, Andrzej L DawidowiczAbstract:Abstract Absinthe is a strong spirit beverage, mostly green in color, containing besides ethyl alcohol (main component), alcoholic macerate of wormwood and other plants such as star anise and fennel seed. Due to the potential risks associated with the presence of α- and β-Thujone many countries have implemented strict rules limiting the content of these congeners in alcohol products. The presented paper describes a simple and sensitive method for the determination of α- and β-Thujone in human serum using Solid Phase Extraction as a sample preparation method combined with GC/MS analysis. The procedure involves the protein precipitation process, which generally degrades the protein–analyte complex, and SPE isolation of Thujone from the examined materials. The described method is characterized by a low LOD and a very high recovery of the analytes. The present method for the estimation of α- and β-Thujone concentration in human fluids after the consumption of alcoholic beverages and other foods containing the substance is applicable in forensic and clinical toxicology because of its simplicity and rapidness with high sensitivity.
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The determination of α- and β-Thujone in human serum – Simple analysis of absinthe congener substance
Forensic Science International, 2015Co-Authors: Michal P Dybowski, Andrzej L DawidowiczAbstract:Abstract Absinthe is a strong spirit beverage, mostly green in color, containing besides ethyl alcohol (main component), alcoholic macerate of wormwood and other plants such as star anise and fennel seed. Due to the potential risks associated with the presence of α- and β-Thujone many countries have implemented strict rules limiting the content of these congeners in alcohol products. The presented paper describes a simple and sensitive method for the determination of α- and β-Thujone in human serum using Solid Phase Extraction as a sample preparation method combined with GC/MS analysis. The procedure involves the protein precipitation process, which generally degrades the protein–analyte complex, and SPE isolation of Thujone from the examined materials. The described method is characterized by a low LOD and a very high recovery of the analytes. The present method for the estimation of α- and β-Thujone concentration in human fluids after the consumption of alcoholic beverages and other foods containing the substance is applicable in forensic and clinical toxicology because of its simplicity and rapidness with high sensitivity.
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fast determination of α and β Thujone in alcoholic beverages using solid phase extraction and gas chromatography
Food Control, 2012Co-Authors: Andrzej L Dawidowicz, Michal P DybowskiAbstract:Abstract Determination of α- and β-Thujone concentration in various foodstuffs is of great importance due to their antagonistic action against GABA receptors. The present study describes a fast, simple and sensitive method of α- and β-Thujone analysis in alcoholic beverages using gas chromatography combined with solid phase extraction (SPE). The developed method is characterized by: high yield (above 98%); and low sufficient detection limit 0.033 mg/L; high precision (RSD below 1.8%); excellent linearity for α- and β-Thujone performed in the concentration range 5.0–300.0 mg/L for α-Thujone and 0.5–30.0 mg/L for β-Thujone with R2 = 0.9995 and R2 = 0.9992, respectively. The presented analytical approach constitutes substantial improvement on the previously reported methods, which involve solvent consuming liquid–liquid extraction or less selective and difficult to calibrate solid phase micro-extraction (SPME).
