Commercial Thyme Research Articles

Commercial thyme essential oil as natural beverage preservative and molecular docking study on its mode of action against Saccharomyces cerevisiae

Commercial thyme essential oil as natural beverage preservative and molecular docking study on its mode of action against Saccharomyces cerevisiae

Chemical, antioxidant, and antifungal analysis of oregano and thyme essential oils from Ecuador: Effect of thyme against Lasiodiplodia theobromae and its application in banana rot

The objective of this study was to evaluate the antioxidant capacity by spectrophotometric methods, the in vitro and in vivo antifungal effect against Lasiodiplodia theobromae and the constitution of the essential oils (EO) of oregano and thyme in comparison with their commercial counterparts. The results showed by the EOs of extracted thyme (T-EO), commercial thyme (CT-EO), extracted oregano (O-EO) and commercial oregano (CO-EO), demonstrated antioxidant profiles with a radical neutralizing potential (DPPH•) of IC50: 1.11±0.019; 1.08±0.05; 40.56±0.227 and 0.69±0.004mg/mL, respectively. They also revealed a ferric ion reducing capacity (FRAP) of 93.05±0.52; 97.72±0.42; 21.85±0.57 and 117.24±0.64mg Eq Trolox/g. A reduction in β-carotene degradation of 65.71±0.04; 51.97±0.66; 43.58±1.56 and 57.46±1.56 %. A total phenol content (Folin-Ciocalteu) of 132.97±0.77; 141.89±2.56; 152.04±0.10 and 25.66±0.40mg EGA/g. Chemical characterization performed by gas chromatography mass spectrometry (GC-MS) showed that the respective major components of the samples were thymol (T-EO: 45.78%), thymol (CT-EO: 43.57%), alloaromadendrene (O-EO: 25.17%) and carvacrol (CO-EO: 62.06%). Regarding antifungal activity, it was evident that at the in vitro level, both commercial EOs had a MIC of 250ppm while the extracted thyme EO had a MIC of 500ppm; In vivo studies demonstrated that the application of thyme EO had a behavior similar to the synthetic fungicide, slowing down rot in bananas under storage conditions. Finally, partial least squares discriminant analysis (PLS-DA) and heat maps suggest p-cymene, carvacrol, linalool, eucalyptol, 4-terpineol, (z)-β-terpineol, alkanhol, caryophyllene, β-myrcene, d-limonene, α-terpinene, α-terpineol, d-α-pinene, camphene, caryophyllene oxide, δ-cadinene, terpinolene and thymol as relevant biomarkers associated with the assessed bioactive properties demonstrating the potential of extracted essential oils for the development of a botanical biofungicide.

Domateste Meloidogyne incognita ve Fusarium oxysporum f.sp. radicis lycopersici hastalık kompleksinin bazı esansiyel yağlar kullanılarak yönetimi

The effects of commercial thyme (Origanum vulgare L.), sage (Salvia officinalis L.), garlic (Allium sativum L.), sesame (Sesame indicum L.) , rosemary (Rosmarinus officinalis L., syn. Salvia rosmarinus Spenn.), lemon (Citrus limon (L.) Osbeck) and mustard (Brassica nigra L.) essential oils (Botalife Natural and Aromatic Products Inc., Türkiye) on disease severity were investigated in simultaneous inoculation of Meloidogyne incognita (Kofoid and White, 1919) Chitwood, 1949 and Fusarium oxysporum f.sp. radicis lycopersici (Jarvis & Shoemaker) (FORL) on tomato. Nematicide (Velum®, Fluopyram, Bayer Crop Production Inc., Türkiye) and fungicide (Cebir®, Fludioxonil + Metalaxyl, Hektaş Crop Production Inc., Türkiye) were used as positive controls. The negative control was only plants with nematode and fungus inoculation. The study was set up in a randomized plot design with 5 replications for each essential oil. In simultaneous inoculations, 1000 M. incognita second juvenile larvae/1ml and 3x106 spore/ml FORL were used for each seedling. The essential oil applications were applied to the soil at a dose of 1000 ppm for each pot, one day after the nematode and fungus inoculation. The study was terminated after 60 days, and the evaluation was based on gall, egg mass, and disease severity. Fungal growth and nematode development on roots were found lower in all tested oils applications than in negative control but fungicidal and nematicidal activity varied. Thyme and garlic essential oils had the highest control effect on nematode and fungus with 55.20% in simultaneous inoculation and this effect was higher than only nematicide (38.84%) and only fungicide (33.20%) applications. Sage (38.84%), rosemary (33.28%), and mustard (38.92%) essential oils were found to suppress disease severity higher than sesame (22.16%) and lemon (22.16%). It has been determined that thyme and garlic essential oils are good alternatives to manage root-knot nematode and FORL disease complexes.

Agar Plate Methods for Assessing the Antibacterial Activity of Thyme and Oregano Essential Oils against S. epidermidis and E. coli.

The resistance to antimicrobials (AMR), especially antibiotics, represents a serious problem and, at the same time, a challenge. In the last decade, a growing interest in the use of essential oils (EOs) as antimicrobial substances was observed. Commercial thyme and oregano EOs are reported to be the main responsible of the oil antimicrobial efficacy against both Gram-positive and Gram-negative pathogenic bacteria. The aim of the present work was to study the efficacy of EOs against Staphylococcus epidermidis and Escherichia coli in long-time treatments. In a preliminary microdilution test, a MIC value was obtained for thyme EO against S. epidermidis and E. coli. After that, disk diffusion and disk volatilization tests were set up to study the influence of main cultural parameters on EO activity in liquid or vapor phase. Both bacteria were inhibited by thyme and oregano EOs when applied pure (100% v/v) or diluted (75% and 50% v/v): a higher inhibition was observed in a disk diffusion test in which the antimicrobial effect was due to both liquid and vapor phase components. Finally, a comparison with literature data was carried out even if it was not so easy because standard methods are usually modified and adapted to specific case study. For this reason, the results have to be interpreted in relation to the analytical method applied.

Does adding thyme and rosemary essential oils to sunflower oil during shallow-frying increase the lipid quality of Atlantic bonito?

The impact of the addition of commercial thyme (TEO) and rosemary essential oil (REO) and butylated hydroxytoluene (BHT, 0.01%) combined with sunflower oil on the lipid quality of Atlantic bonito was investigated during shallow frying. Atlantic bonito treated with TEO and REO had significantly lower lipid content than control and BHT-treated samples (p < 0.05). As compared to controls, the addition of both synthetic and natural antioxidants to sunflower oil resulted in a significant decrease in the peroxide values (PV), free fatty acids (FFA), and thiobarbituric acid reactive substances (TBARs) values of samples. These decreases had a similar effect in both essential oils (EOs) groups, inversely proportional to the increased used concentration. The addition of all EOs into the sunflower oil, except for 0.9% REO group, significantly increased the amount of total saturated fatty acid (∑SFA). Although the addition of EOs at different concentrations has a significant effect on the total monounsaturated fatty acids (∑MUFA) of fried Atlantic bonito, the highest MUFAs content was observed in the 0.6% thyme EO group. Our results indicated that the use of commercial TEO and REO seems to be effective in the protection of the amount of fatty acid compositions of Atlantic bonito, especially eicosapentaenoic (EPA) and docosahexaenoic acids (DHA). As a result, the lipid quality of Atlantic bonito during shallow frying was improved by all EOs used for the current study. • Antioxidant properties of essential oils on the lipid quality were evaluated. • Essential oil addition to shallow frying increased the lipid quality of Atlantic bonito. • Frying using thyme and rosemary essential oils appears to reduce the amount of lipid. • Thyme and rosemary essential oil seem to be effective in the protection of fatty acid composition.

Enhancing sunflower oil by the addition of commercial thyme and rosemary essential oils: The effect on lipid quality of Mediterranean horse mackerel and anchovy during traditional pan-frying

The effect of sunflower oil treated with varying proportions of rosemary and thyme essential oils (0.3%, 0.6%, 0.9%, and 1.2%) on the lipid quality of Mediterranean horse mackerel and anchovy during traditional pan-frying was assessed in this research. Concentrations of rosemary and thyme essential oils greater than 0.9% applied to sunflower oil tend to reduce the lipid content of horse mackerel, while anchovies fried in sunflower oil with only a few concentrations of rosemary essential oil seemed to avoid a rise in lipid content that leads to frying. The addition of thyme and rosemary essential oils with the different percentages in frying oil significantly caused a reduction in the peroxide and thiobarbituric acid values of all fish samples after pan-frying (p < 0.05). However, the free fatty acid contents of all fried fish samples did not change significantly by the addition of EOs to sunflower oil (p > 0.05). According to our results, the amount of EPA and DHA in Mediterranean horse mackerel during traditional pan-frying was affected by the type of essential oils and their concentration in sunflower oil. Using EOs at different concentrations, on the other hand, has no noticeable impact on the retention of highly unsaturated fatty acids in anchovies. It shows that all of the essential oils used significantly reduce lipid oxidation and protect against EPA and DHA reduction as a result of frying in Mediterranean horse mackerel.

Morphological, Chemical, and Genetic Characteristics of Korean Native Thyme Bak-Ri-Hyang (Thymus quinquecostatus Celak.).

Bak-ri-hyang (Thymus quinquecostatus Celak.) is an important medicinal and aromatic plant in Korea. T. quinquecostatus population and is always mixed with other thyme cultivars during cultivation and marketing. Hence, this study aimed to determine the genetic variability and the essential oil composition of three Korean native thyme, T. quinquecostatus cultivars collected from the Wolchul, Jiri, and Odae mountains, in comparison with six commercial thyme cultivars (T. vulgaris), to distinguish Bak-ri-hyang from other thyme cultivars. The composition of essential oils obtained from nine individuals was analyzed by gas chromatography–mass spectrometry (GC–MS). The random amplified polymorphic DNA (RAPD) analysis was accomplished using 16 different primers. The GC–MS analysis revealed that Wolchul, creeping, golden, and orange cultivars belong to the geraniol chemotype. Whereas the Odae, lemon, and silver cultivars belong to the thymol chemotype. Further, linalool was the most abundant component in carpet and Jiri cultivars. The RAPD analysis demonstrated that all thyme cultivars showed characteristic RAPD patterns that allowed their identification. In total, 133 bands were obtained using 16 primers, and 124 bands were polymorphic, corresponding to 93.2% polymorphism. Cluster analysis of RAPD markers established the presence of clear separation from nine thyme cultivars. The highest dissimilarity and similarity coefficient of the RAPD markers were 0.58 and 0.98, respectively. According to the RAPD patterns, the nine thyme cultivars could be divided into two major clusters. Among three Korean cultivars, the Wolchul and Odae cultivars were placed into the same cluster, but they did not show identical clustering with their essential oil compositions. The findings of the present study suggest that RAPD analysis can be a useful tool for marker-assisted identification of T. quinquecostatus from other Thymus species.

Investigation of Anti-archaeal Activities of Some Commercial Essential Oils on Extremely Halophilic Archaea

In this study, the anti-archaeal activity of thyme (Thymus spp.), mint (Mentha piperita), black garlic (Allium sativum) commercial essential oils were investigated on the extremely halophilic archaea. Halococcus morrhuae strain 123, Haloarchaeon 129, Halorubrum sp. 140, Natrinema pallidum strain 153, Natrialba aegyptia strain 213, Haloterrigena thermotolerans strain 415, Halococcus thailandensis strain 514 and Halobacterium noricense strain 714 were used as extremely halophilic archaea strains. SW25 broth - agar media were used for the growth of cultures. Commercial essential oils were tested at 1/10, 1/50 and 1/100 concentrations. Agar disc diffusion method was applied for antimicrobial activity. Bacitracin (B10), Novobiocin (NV5), Penicillin G (P10), Fusidic acid (FA10) antibiotic discs and Haloferax sp. HSC4 extremely halophilic archaea type culture were used as control. Commercial thyme, mint and black garlic essential oils tested in the study were found to have anti-archeal activity against all halophilic archaeal strains, 5 strains and 3 strains, respectively. According to our results, the highest inhibition zone diameters were obtained from thyme essential oil. Keywords: Thyme, Mint, Black Garlic, Essential Oil, Archaea DOI: 10.7176/JSTR/5-8-07

Micronization of thymol by RESS and its larvicidal activity against Aedes aegypti (Diptera, Culicidae)

Abstract Micronization techniques by supercritical fluid has been drawing attention from chemical and pharmaceutical industries due to its potential and innovation. Thymol is a phenolic compound with high antimicrobial and efficient antioxidant activities, due to its non-toxic and antimutagenic features is classified as Generally Recognized as Safe by the Food & Drug Administration. However, the highly volatile nature and low water-solubility allows the application of optimization technologies. Mosquitoes are vectors from devastating pathogens and parasites causing millions of deaths every year. Many studies have been carried out to identify new insecticides obtained from secondary metabolites of plants, looking for effective alternatives to vector control. Therefore, the present study sought to evaluate the method of micronization through Rapid Expansion of Supercritical Solutions in thymol, characterizing the particles by physicochemical properties and demonstrating the biological activity over fourth instar Aedes aegypti L. (Diptera, Culicidae) larvae in comparation to commercial thyme oil. The micronization process led to a reduction of 77.5 times in particle size and an increase of 37.28% in solubility, with improvement in larvicidal activity. Micronized thymol has shown higher effectiveness in cumulative mortality for Aedes aegypti (80% in 2 h) when compared with thyme essential oil (66.7% in 2 h) and in nature thymol (31.7% in 2 h). Micronization may increase bioavailability in order to optimize biological effects of chemicals compounds, opening new areas of study and new applications for this biochemical compound.

Thyme extract increases mucociliary-beating frequency in primary cell lines from chronic obstructive pulmonary disease patients

Chronic obstructive pulmonary disease (COPD) is a respiratory disorder characterized by a progressive and irreversible airflow limitation. COPD is associated to a chronic inflammatory response with infiltration of inflammatory cells in the surface epithelium of large airways and abnormalities in structure and functions of cilia. Thyme (Thymus vulgaris L.) is a traditional medicinal plant of the Mediterranean area used to treat respiratory disorders. We previously evidenced that thyme extract reduce IL-1beta and IL-8, by downregulating the activated NF-κB levels, suggesting its potential therapeutically use in COPD. Cilia beating frequency (CBF) is dramatically impaired in COPD and different pharmacological agents can modulate cilia function. Herein we evaluated the effect of a commercial thyme extract in modulating CBF by measuring its activity in stimulating cAMP, Ca2+ levels and CBF in a MucilAir 3D human COPD airway epithelia reconstituted in vitro system using salmeterol, YM976, isoproterenol and GSK1016790 A as positive controls. Results showed that thyme extract increased cAMP levels starting from 12 h post-treatment, decreased extracellular Ca2+ levels and increased the CBF in airway epithelia from COPD donors. Overall, this work demonstrated that thyme extract is effective in stimulating CBF by inducing an increase of cAMP and Ca2+ levels, thus supporting its therapeutical use in the treatment of COPD.

Acaricidal Activity and Synergistic Effect of Thyme Oil Constituents against Carmine Spider Mite (Tetranychus Cinnabarinus (Boisduval)).

Studies examining the use of essential oils as replacements for synthetic insecticides require an understanding of the contribution of each constituent present, interactions among these components, and how they relate to overall toxicity. In the present study, the chemical composition of commercial thyme oil was identified by gas chromatography-mass spectrometry. Thyme oil and blends of its major constituents were tested for their acaricidal activitities against carmine spider mites (Tetranychus cinnabarinus (Boisduval)) using a slide-dip bioassay. Natural thyme oil showed greater toxicity than any single constituent or blend of constituents. Thymol was the most abundant component (34.4%), and also possessed the strongest acaricidal activity compared with other single constituents. When tested individually, four constituents (linalool, terpinene, p-cymene and carvacrol) also had activity, while α-pinene, benzoic acid and ethyl gallate had almost no activity. The toxicity of blends of selected constituents indicated a synergistic effect among the putatively active and inactive constituents, with the presence of all constituents necessary to reach the highest toxicity. The results indicated that thyme oil and some of its major constituents have the potential to be developed into botanical acaricides.

Microencapsulation of essential thyme oil by spray drying and its antimicrobial evaluation against Vibrio alginolyticus and Vibrio parahaemolyticus

The aims of this research were first, to evaluate the antibacterial potential of commercial thyme essential oil against V. alginolyticus and V. parahaemolyticys and second, using the spray drying technique to produce microcapsules. chemical compounds of thyme oil and microcapsules were identified and quantified being thymol the chemical component present at the highest concentration. Oil-in-water (O/W) emulsions were prepared and the microcapsules were obtained with a spray dryer using maltodextrin as wall material (ratio 1:4). Thyme oil and the microcapsules exhibited antimicrobial activity against V. parahaemolyticus and V. alginolyticus. The spray drying process did not affect the antimicrobial activity of thyme essentialoil.

Volatile fraction of commercial thyme honeys produced in Mediterranean regions and key volatile compounds for geographical discrimination: A chemometric approach

ABSTRACTThe aim of the present study was to investigate the volatile fraction and discriminate 34 commercial thyme honeys from Morocco, Egypt, Spain, and Greece according to geographical origin, using key volatile compounds in combination with chemometrics. Sixty-two volatile compounds belonging to different classes were identified and semi-quantified using headspace solid phase micro-extraction coupled to gas chromatography/mass spectrometry (HS-SPME-GC/MS). Applying chemometric analyses to 17 volatiles (p < 0.05), honeys were successfully discriminated according to geographical origin. Correct classification rate was 88.2% using the cross-validation method. Volatile compounds proved to be a powerful tool for discriminating commercial thyme honeys from different countries.

Bioactivity of essential oils in phytopathogenic and post-harvest fungi control

Commercial thyme and lavender essential oils were analysed by GC/MS. Sixty-six compounds accounting for 98.6–99.6% of total essential oil were identified. Thymol (52.14 ± 0.21%), followed by p-cymene (32.24 ± 0.16%), carvacrol (3.71 ± 0.01%) and γ-terpinene (3.34 ± 0.02%), were the main compounds in thyme essential oil, while large amounts of oxygenated monoterpenes linalool acetate (37.07 ± 0.24%) and linalool (30.16 ± 0.06%) were found in lavender one. In vitro antifungal activity of the essential oils was evaluated at 200 and 300 μg/mL against 10 phytopathogenic and post-harvest fungi, which significantly affect agriculture. Micelial growth inhibition was calculated for each tested fungus and dose. Thyme essential oil showed satisfactory results with 90–100% growth inhibition in almost all the assayed fungi at 300 μg/mL, while lavender essential oil showed no noteworthy inhibition data at either dose, and its growth was even enhanced. Thyme essential oil represents a natural alternative to control harvest and post-harvest fungi, and to extend the shelf-life of agriculture products.

Characterization and classification of commercial thyme honeys produced in specific Mediterranean countries according to geographical origin, using physicochemical parameter values and mineral content in combination with chemometrics

The aim of the present study was to provide information on physicochemical (pH, free, lactonic, and total acidity, electrical conductivity, moisture, ash, lactonic/free acidity), colour parameters (L*, a*, b*), and mineral content (Ag, Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Mo, Ni, Pb, Sb, Se, Si, Ti, Tl, V, Zn) of 34 commercial thyme honeys produced in Egypt, Morocco, Greece, and Spain, in terms of characterization and geographical discrimination using MANOVA/LDA, chemometric analyses. Conventional physicochemical and colour parameters were determined using official methods of analysis. Minerals were quantified using inductively coupled plasma optical emission spectroscopy (ICP-OES). Results showed that all honey samples analysed met the standard quality criteria set by the EU. In order to classify honeys according to geographical origin, MANOVA and LDA were applied in sequence. Respective classification rates based on cross-validation method were: 91.2, 76.5, and 88.2%, using 10 physicochemical and colour parameters, 12 minerals, and their combination, respectively. Testing whether the determined physicochemical parameters of commercial Mediterranean thyme honeys could be applied to routine quality control serving as honey origin predictors showed positive results. Finally, such a combination of data enhances honey quality control and authentication efforts, at an international level.

Development of novel antimicrobial films based on poly(lactic acid) and essential oils

Abstract Novel biocomposite films based on poly (lactic acid) (PLA) were prepared by incorporating essential oils as active additive with different concentrations (0.5, 1.5, 2 and 5%). Different types of essential oils from Rosemary, Myrtle and Thyme were used. The optical, thermal, mechanical, water vapour permeability and antifungal properties of all films was carried out. The analysis of essential oils by GC-MS showed the presence of terpene and phenolic compounds that are the most important compounds in essential oils. The addition of different essential oils does not affect the colour change of the films significantly. Thermal degradation of studied films showed a small decrease in the initial degradation temperature when the concentration of essential oil increased, however maximum degradation temperature was similar. Thermal analysis by differential scanning calorimetric (DSC) showed that PLA films containing 5% of commercial essential oils of myrtle and thyme could reduce the polymer chain to crystallize. The mechanical properties are improved by the incorporation of essential oils in the PLA matrix. The effect of commercial essential oil of myrtle in the transfer of humidity from the atmosphere to food is low compared with those containing the commercial essential oils of rosemary and thyme. Finally, the addition of 1.5% commercial thyme and 5% natural myrtle increase significantly the antifungal activity against Aspergillus.niger sp.

Characterization and Differentiation of Greek Commercial Thyme Honeys According to Geographical Origin Based on Quality and Some Bioactivity Parameters Using Chemometrics

Thirty-three commercial thyme honeys (Thymus spp.) were characterized and classified according to geographical origin based on quality parameters, total phenolic content and radical scavenging activity. Quality parameter analysis included the determination of: pH, free, lactonic and total acidity, electrical conductivity, moisture, ash, hydroxymethylfurfural (HMF) content and diastase activity, using official methods of analysis. Finally, total phenolic content and % radical scavenging activity (%RSA) were estimated using the Folin–Ciocalteu and the 1,1-diphenyl-2-picryl-hydrazil [DPPH·] assay, respectively. Results showed that thyme honeys analyzed: (1) met all the quality criteria set by the EU; (2) showed variations in total phenolic content and radical scavenging activity; (3) possessed a special food character since total phenolic content was positively correlated with radical scavenging activity and (4) were successfully classified (correct prediction rate 93.9%) according to geographical origin applying chemometric analyses to the data collected. Practical Applications The present study highlights quality criteria and bioactive properties of Greek commercial thyme honeys, produced in different regional departments in Greece. Such parameters determined, give an enhanced functional food character to this product which can lead to consumers' awareness on nutritional foods of specific regional origin. In addition, the use of chemometric analyses on quality parameters, total phenolic content and radical scavenging activity proved to be a strong key for correct geographical classification of Greek commercial thyme honey.

UV spectroscopy and chemometrics: A simple approach to herbal quality control

Recently, the application of multivariate analyses to spectroscopic and chromatographic data has been widely used in the quality control of herbal medicine [1]. In this sense, the work presented describes a simple technique developed using UV spectroscopy together with chemometric techniques of hierarchical cluster analysis (HCA), principal component analysis (PCA), and soft independent modeling of class analogy (SIMCA) in herbal authentication. This model was successfully used to authenticate Thymus vulgaris and discriminate it from Thymus, Satureja, Origanum, Plectranthus and Eriocephalus species, all traded in the Egyptian market as different types of thyme [2]. The model was also applied to authenticate 25 samples of monofloral Yemeni Sidr honey; one of the most expensive honey types worldwide and extensively adulterated [3]. In the former case, the model was constructed using UV spectroscopic data from methanolic extracts of 30 samples of T. vulgaris. PCA and HCA discriminated 20 samples of different botanical origins while 12 samples of commercial thyme were segregated into thyme or non-thyme using SIMCA. In case of the Sidr honey study, HCA and PCA achieved segregation of the genuine Sidr samples from the lower priced local polyfloral and non-Sidr samples. The SIMCA model was used to identify genuine Sidr honey samples as well as detect admixture with lower priced polyfloral honey by detection limits > 10%.

A Modern Approach to the Authentication and Quality Assessment of Thyme Using UV Spectroscopy and Chemometric Analysis

Recently, the fields of chemometrics and multivariate analysis have been widely implemented in the quality control of herbal drugs to produce precise results, which is crucial in the field of medicine. Thyme represents an essential medicinal herb that is constantly adulterated due to its resemblance to many other plants with similar organoleptic properties. To establish a simple model for the quality assessment of Thymus species using UV spectroscopy together with known chemometric techniques. The success of this model may also serve as a technique for the quality control of other herbal drugs. The model was constructed using 30 samples of authenticated Thymus vulgaris and challenged with 20 samples of different botanical origins. The methanolic extracts of all samples were assessed using UV spectroscopy together with chemometric techniques: principal component analysis (PCA), soft independent modeling of class analogy (SIMCA) and hierarchical cluster analysis (HCA). The model was able to discriminate T. vulgaris from other Thymus, Satureja, Origanum, Plectranthus and Eriocephalus species, all traded in the Egyptian market as different types of thyme. The model was also able to classify closely related species in clusters using PCA and HCA. The model was finally used to classify 12 commercial thyme varieties into clusters of species incorporated in the model as thyme or non-thyme. The model constructed is highly recommended as a simple and efficient method for distinguishing T. vulgaris from other related species as well as the classification of marketed herbs as thyme or non-thyme.

Chemical fingerprinting and bioactivity of Amazonian Ecuador Croton lechleri Müll. Arg. (Euphorbiaceae) stem bark essential oil: A new functional food ingredient?

Abstract Croton lechleri essential oil has been obtained by steam distillation of fresh stem bark from Amazonian Ecuador adult plants (yield: 0.61 ml/kg [0.061%]; density: 1.01 g/ml), and then chemically characterised by GC (Gas Chromatography) and GC–MS (gas chromatography–mass spectrometry). Seventy-four chemicals were detected and identified; the most abundant in descending order, were the sesquiterpenes sesquicineole (17.29%), α-calacorene (11.29%), 1,10-di-epi-cubenol (4.75%), β-calacorene (4.34%) and epi-cedrol (4.09%). Monoterpenes checked with a relative peak area higher than 2.0% were α-pinene (2.01%), p-cymene (2.61%), limonene (4.20%) and borneol (2.67%). The structure of the main chemicals were confirmed by GC–MS and 1H NMR analyses. Spectrophotometric 1,1-diphenyl-2-picrylhydrazyl (DPPH) and DPPH-(high performance) thin layer chromatography (DPPH-(HP)TLC) bioautographic assays showed a lower radical scavenging capacity (IC50) with respect to commercial thyme essential oil and BHA (butylated hydroxyl anisole), pointing out, however, that the C. lechleri essential oil fraction, characterised by α-calacorene, β-calacorene and δ-cadalene, was the most involved in the bioactivity. Similar results were obtained with β-carotene bleaching assay, where the IC50 values were 0.291 ± 0.024 mg/ml for C. lechleri essential oil, 0.164 ± 0.013 and 1.34 × 10−4 ± 10−5 mg/ml for thyme essential oil and BHA, respectively. (HP)TLC-bioautographic assay performed with Gram positive and Gram negative bacteria revealed a minimum inhibitory concentration (MIC) values comprised between 0.10 mg/ml (Escherichia coli) and 10.10 mg/ml (for e.g. Pseudomonas aeruginosa), and the fraction mainly characterised by sesquicineole (97.38%) as the most involved in antibacterial capacity. Ames test employing Salmonella typhimurium TA98 and TA100 with and without a metabolic activation mixture (S9 mix) demonstrated the absence of mutagenicity of the C. lechleri essential oil between a concentration range of 10−2 and 100 mg/plate. The same results were achieved by Saccharomyces cerevisiae D7 strain assay. An interesting mutagen-protective efficacy was evidenced by a 30% and 33% revertants reduction of TA98 strain treated with 2-aminoanthracene and nitrofluorene (2 μg/plate), suggesting, above all, the possibility to employ C. lechleri essential oil as a new flavouring protective ingredient for foods or dietary supplements against potential mutagens formed during cooking and/or processing in general.