Effects of Essential Oil from Thymus vulgaris on Viability and Inflammation in Zebrafish Embryos

Innate immunity provides the initial response against pathogens and includes the inflammatory response. Regulation of the initiation and duration of neutrophil and mononuclear cell influx during inflammation determines both the successfulness of pathogen elimination and the level of resulting tissue damage. Zebrafish embryos provide excellent opportunities to visualize the inflammatory response. Neutrophil granules may be stained with Sudan black, and variation in neutrophil counts may be used to monitor the level of the response. Inflammation may be triggered by injuring the caudal fin, providing an opportunity for testing possible anti-inflammatory compounds in a whole-animal system. The use of homeopathic compounds as anti-inflammatory treatments is common in alternative medicine. Effects of unfractionated essential oil from Thymus vulgaris and its specific component, carvacrol, have been examined in cells in culture and in rodents. Our work extends this research to zebrafish, and includes toxicity and morphological studies as well as examination of anti-inflammatory effects following tail fin injury. Our results show that zebrafish are more sensitive to thyme oil compared to cells in culture, that cardiac defects arise due to thyme oil treatment, and that thyme oil reduces neutrophil infiltration during an inflammatory response.

Investigation of the Antifungal Activity and Mode of Action of Thymus vulgaris, Citrus limonum, Pelargonium graveolens, Cinnamomum cassia, Ocimum basilicum, and Eugenia caryophyllus Essential Oils

The antimicrobial activity of plant oils and extracts has been recognized for many years. In this study the activity of Thymus vulgaris, Citrus limonum, Pelargonium graveolens, Cinnamomum cassia, Ocimumbasilicum, and Eugenia caryophyllus essential oils (EOs) distributed by Pollena Aroma (Nowy Dwór Mazowiecki, Poland) was investigated against a group of 183 clinical isolates of C. albicans and 76 isolates of C. glabrata. All of the oils exhibited both fungistatic and fungicidal activity toward C. albicans and C. glabrata isolates. The highest activity was observed for cinnamon oil, with MIC (Minimum Inhibitory Concentration) values in the range 0.002⁻0.125% (v/v). The MIC values of the rest of the oils were in the range 0.005% (or less) to 2.5% (v/v). In most cases MFC (Minimum Fungicidal Concentration) values were equal to MIC or twice as high. Additionally, we examined the mode of action of selected EOs. The effect on cell wall components could not be clearly proved. Three of the tested EOs (thyme, lemon, and clove) affected cell membranes. At the same time, thyme, cinnamon, and clove oil influenced potassium ion efflux, which was not seen in the case of lemon oil. All of the tested oils demonstrated the ability to inhibit the transition of yeast to mycelium form, but the effect was the lowest in the case of cinnamon oil.

The determination of the botanical origin in honeys with over-represented pollen: combination of melissopalynological, sensory and physicochemical analysis

BACKGROUND

Pollen analysis of honey is the basic method for the determination of its botanical origin. However, the presence of over-represented pollen in honeys may lead the analysis to false results. This can be more severe if this pollen is present in unifloral under-represented honeys of commercial importance (e.g. thyme honey). In the present study, we investigated the abundance of over-represented pollen grains on several quality characteristics in honey samples. In particular, we mixed honeys characterised as over-represented, specifically chestnut and eucalyptus, with thyme honeys in different analogies, and we also analysed the melissopalynological, organoleptic, physicochemical (water content, electrical conductivity, colour) and volatile characteristics of the blends.

RESULTS

The most sensitive parameters were the microscopic characteristics, followed by the organoleptic ones. Blends of thyme honey with an originally low percentage of thyme pollen were the most influenced and could not be characterised as unifloral regarding their melissopalynological characteristics, even when they were mixed with small quantities of honeys with over-represented pollen (i.e. 5%).

CONCLUSION

The present study confirms that, in the case of presence of over-represented pollen in honeys, pollen analysis alone cannot give trustworthy results for the determination of the botanical origin, even though their exclusion during pollen analysis, when they are present in percentages of up to 30%, could provide more accurate results. Consequently, pollen analysis should also be combined with the other analyses, especially in honeys with under-represented and over-represented pollens, to give safer results for the botanical characterisation of honeys. © 2017 Society of Chemical Industry.

Multi-Response Extraction Optimization Based on Anti-Oxidative Activity and Quality Evaluation by Main Indicator Ingredients Coupled with Chemometric Analysis on Thymus quinquecostatus Celak

Thymus quinquecostatus Celak is a species of thyme in China and it used as condiment and herbal medicine for a long time. To set up the quality evaluation of T. quinquecostatus, the response surface methodology (RSM) based on its 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was introduced to optimize the extraction condition, and the main indicator components were found through an UPLC-LTQ-Orbitrap MSn method. The ethanol concentration, solid-liquid ratio, and extraction time on optimum conditions were 42.32%, 1:17.51, and 1.8 h, respectively. 35 components having 12 phenolic acids and 23 flavonoids were unambiguously or tentatively identified both positive and negative modes to employ for the comprehensive analysis in the optimum anti-oxidative part. A simple, reliable, and sensitive HPLC method was performed for the multi-component quantitative analysis of T. quinquecostatus using six characteristic and principal phenolic acids and flavonoids as reference compounds. Furthermore, the chemometrics methods (principal components analysis (PCA) and hierarchical clustering analysis (HCA)) appraised the growing areas and harvest time of this herb closely relative to the quality-controlled. This study provided full-scale qualitative and quantitative information for the quality evaluation of T. quinquecostatus, which would be a valuable reference for further study and development of this herb and related laid the foundation of further study on its pharmacological efficacy.

Ultrasound-assisted extraction of antimicrobial compounds from Thymus daenensis and Silybum marianum: Antimicrobial activity with and without the presence of natural silver nanoparticles

The present study is devoted to prepare a new antibacterial and antifungal agent based on in situ-synthesized silver nanoparticles at room temperature using Rosmarinus officinalis (R. officinalis) leaf extract. The Ag-NPs characterization by UV-visible, SEM, TEM and XRD revealed that the particles sizes were in the range of 10-33 nm. In this study, hydroalcoholic extracts were used with ultrasonic method. Ultrasonication has recently received attention as a novel bioprocessing tool for process intensification in many areas of downstream processing. The antimicrobial activities of T. daenensis and S. marianum extracts with and without the presence of Ag-NPs were investigated at concentrations from 12.5 to 50 mg/mL against Staphylococcus aureus (S. aureus, Gram-positive organism) and Escherichia coli (E. coli, Gram-negative organism), and fungal strains were Aspergillus oryzae (A. oryzae) and Candida albicans (C. albicans). Antimicrobial activity determined using agar disc diffusion method revealed that the activities of Ag-NPs/T. daenensis were superior to Ag-NPs/S. marianum and extracts (T. daenensis and S. marianum). The medicinal plant extract can be used to synthesize the Ag-NPs as an eco-friendly and inexpensive method in large scale. The results showed that the prepared Ag-NPs/extracts as good antibacterial and antifungal agents can be potentially applied against rapidly increasing of antibiotic resistance.

Near-infrared and Mid-infrared Spectroscopic Techniques for a Fast and Nondestructive Quality Control of Thymi herba

In this study, novel near-infrared and attenuated total reflectance mid-infrared spectroscopic methods coupled with multivariate data analysis were established enabling the determination of thymol, rosmarinic acid, and the antioxidant capacity of Thymi herba. A new high-performance liquid chromatography method and UV-Vis spectroscopy were applied as reference methods. Partial least squares regressions were carried out as cross and test set validations. To reduce systematic errors, different data pretreatments, such as multiplicative scatter correction, 1st derivative, or 2nd derivative, were applied on the spectra. The performances of the two infrared spectroscopic techniques were evaluated and compared. In general, attenuated total reflectance mid-infrared spectroscopy demonstrated a slightly better predictive power (thymol: coefficient of determination = 0.93, factors = 3, ratio of performance to deviation = 3.94; rosmarinic acid: coefficient of determination = 0.91, factors = 3, ratio of performance to deviation = 3.35, antioxidant capacity: coefficient of determination = 0.87, factors = 2, ratio of performance to deviation = 2.80; test set validation) than near-infrared spectroscopy (thymol: coefficient of determination = 0.90, factors = 6, ratio of performance to deviation = 3.10; rosmarinic acid: coefficient of determination = 0.92, factors = 6, ratio of performance to deviation = 3.61, antioxidant capacity: coefficient of determination = 0.91, factors = 6, ratio of performance to deviation = 3.42; test set validation). The capability of infrared vibrational spectroscopy as a quick and simple analytical tool to replace conventional time and chemical consuming analyses for the quality control of T. herba could be demonstrated.

Effect of thyme oil-alginate-based coating on quality and microbial safety of fresh-cut apples

BACKGROUND

Food preservation is critical for keeping fresh-cut products fresh, nutritious, safe, attractive and available for consumers. To improve the safety and quality of fresh-cut fruits, 15 essential oils (EOs) were screened to test the antimicrobial activity against Listeria monocytogenes (LM), Salmonella typhimurium (ST), Staphylococcus aureus (SA) and Escherichia coli O157:H7 (EC O157:H7). The effect of alginate-based edible coating (EC) incorporating different concentrations thyme oil on fresh-cut 'Red Fuji' apples was investigated.

RESULTS

Results showed that thyme oil, cinnamon oil and oregano oil were more effective in inhibiting the microbes than other EOs. The result showed that the combined usage of 0.5 µL mL^-1 thyme oil incorporated with alginate-based EC could significantly inhibit the microbial growth, respiration, weight loss, firmness and browning of fresh-cut 'Red Fuji' apples.

CONCLUSION

The edible coating and natural additives like thyme oil could be used to preserve the quality of fresh-cut fruits. It revealed that EC incorporated with 0.5 µL mL^-1 thyme oil can be a safe preservative for fresh-cut apples. © 2017 Society of Chemical Industry.

Quantification of DNA damage products by gas chromatography tandem mass spectrometry in lung cell lines and prevention effect of thyme antioxidants on oxidative induced DNA damage

Lung cancer has a high treatment cost and poor prognosis in comparison to other types of cancers. This work was involved in studying oxidative DNA base damage inhibition. Accordingly, standard carvacrol, thymol, thymoquinone with water and water-methanol extract of thyme (Origanum vulgare L. subsp. hirtum (link.) Ietswaart), thyme oil and thyme water were prepared and investigated for their efficacy to inhibit DNA oxidative damage formed by H₂O₂ in malignant lung cells (A549). The antioxidant capacity by ABTS assay was 271.73 ± 11.45 mg trolox equivalent/mL for thyme oil. HPLC analysis was carried out to determine the contents of different thyme extracts, results showing the presence of carvacrol, thymol, protocatechuic acid, caffeic acid, epicatechin and rosmarinic acid in water and water-methanol extracts while only carvacrol and thymol were found in thyme oil and thyme water. After DNA isolation from the cultured cells, the formed oxidative induced DNA damage products were analysed using GC-MS/MS. It was proven that the antioxidants in the cell culture media have succeeded to inhibit oxidative DNA base damage. Thymoquinone was shown to be the best protectant antioxidant among other antioxidants against the formation of oxidative DNA damage, whereas water-methanol extract of thyme was the best among the plant-sourced samples. Thymoquinone and thyme water-methanol extract were investigated for their efficacy on cultured healthy lung cells (BEAS-2B), and it was proven that they are efficient in protection against the oxidation of DNA of healthy lung cells too.

Qualitative and Quantitative Phytochemical Analysis of Different Extracts from Thymus algeriensis Aerial Parts

This study was performed to evaluate the metabolite recovery from different extraction methods applied to Thymus algeriensis aerial parts. A high-performance liquid chromatographic method using photodiode array detector with gradient elution has been developed and validated for the simultaneous estimation of different phenolic compounds in the extracts and in their corresponding purified fractions. The experimental results show that microwave-assisted aqueous extraction for 15 min at 100 °C gave the most phenolics-enriched extract, reducing extraction time without degradation effects on bioactives. Sixteen compounds were identified in this extract, 11 phenolic compounds and five flavonoids, all known for their biological activities. Color analysis and determination of chlorophylls and carotenoids implemented the knowledge of the chemical profile of this plant.

Synergistic Antifungal, Allelopatic and Anti-Proliferative Potential of Salvia officinalis L., and Thymus vulgaris L. Essential Oils

The current study aimed to investigate the chemical composition and the synergistic potential of two essential oils (EOs), as obtained from Salvia officinalis L. (SEO), and Thymus vulgaris L. (TEO). The antifungal potential was tested in vitro against Fusarium graminearum (Fg 06_17), the herbicidal effect was studied using weed seeds of Amaranthus retroflexus (ARET), Chenopodium album (CALB), Echinochloa crus-galli (EGAL), but also wheat seeds (WS) of the Lovrin variety and tomato seeds Saint-Pierre of the variety. The GC-MS profile highlights that the mains compounds identified in SEO were: caryophyllene (25.364%), camphene (14.139%), eucalyptol (13.902%), and β-pinene (11.230%), while in TEO, the predominant phytochemicals were: γ-terpinene (68.415%) and p-thymol (24.721%). The results indicated that the tested EOs alone as well as in combination have allelopathic effect against investigated seeds, while the synergistic effect of TEO and SEO in terms of fungal growth was demonstrated at a level of 0.06%. Thyme and sage EOs exhibited in vitro anti-proliferative activity on two melanoma cell lines, namely A375 human melanoma and B164A5 mouse melanoma alone, as well as in combination. SEO was most effective in terms of decreasing the cell viability of murine and human melanoma cell lines when compared to TEO.

Thymus mastichina L. essential oils from Murcia (Spain): Composition and antioxidant, antienzymatic and antimicrobial bioactivities

The compositions of essential oils (EOs) from Spanish marjoram (Thymus mastichina L.) grown in several bioclimatic zones of Murcia (SE Spain) were studied to determine their absolute and relative concentrations using gas chromatography-mass spectrometry. 1,8-Cineole and linalool were the main components, followed by α-pinene, β-pinene and α-terpineol. (-)-Linalool, (+)-α-terpineol and (+)-α-pinene were the most abundant enantiomers. When the antioxidant capacities of T. mastichina EOs and their compounds were measured by five methods, EOs and linalool, linalyl acetate, α-terpinene and γ-terpinene, among others, showed antioxidant activities. All four T. mastichina EOs inhibited both lipoxygenase and acetylcholinesterase activities, and they might be useful for further research into inflammatory and Alzheimer diseases. Bornyl acetate and limonene showed the highest lipoxygenase inhibition and 1,8-cineole was the best acetylcholinesterase inhibitor. Moreover, these EOs inhibited the growth of Escherichia coli, Staphylococcus aureus and Candida albicans due to the contribution of their individual compounds. The results underline the potential use of these EOs in manufactured products, such as foodstuff, cosmetics and pharmaceuticals.

Development of Burdock Root Inulin/Chitosan Blend Films Containing Oregano and Thyme Essential Oils

In this study, inulin (INU) extracted from burdock root was utilized as a new film base material and combined with chitosan (CHI) to prepare composite films. Oregano and thyme essential oils (OT) were incorporated into the INU-CHI film to confer the films with bioactivities. The physical and optical properties as well as antioxidant and antimicrobial activities of the films were evaluated. INU film alone showed poor physical properties. In contrast, the compatibility of INU and CHI demonstrated by the changes in attenuated total reflectance-Fourier transformation infrared spectrum of the INU-CHI film increased tensile strength and elongation at break of the INU film by 8.2- and 3.9-fold, respectively. In addition, water vapor permeability, water solubility, and moisture content of the films decreased proportionally with increasing OT concentration in the INU-CHI film. Incorporation of OT also increased the opacity of a and b values and decreased the L value of the INU-CHI films. All INU-CHI films containing OT exhibited antioxidant and antimicrobial properties. Particularly, the INU-CHI film with 2.0% OT exhibited the highest 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), 2,2-diphenyl-1-picrylhydrazyl radical scavenging, and antimicrobial activities against four pathogens. Thus, the INU-CHI film containing OT developed in this study might be utilized as an active packaging material in the food industry.

In-vitro antibacterial and antioxidant potential of winged prickly ash, green tea and thyme

Herbs and plants are mostly used as antimicrobials and antioxidants owing to the harmfulness and linked side-effects of synthetic chemical constituents. Plants and spices produce various metabolites with antibacterial and antioxidant potential. These metabolites are principally revealed as encouraging healing components or mediators which control ailments in human beings. The present study was aimed to characterize the extracts from selected medicinal plants through in-vitro activities. Winged prickly ash, green tea and thyme were selected and extracted through ethanol and methanol solutions. The extracts were assessed for antibacterial and antioxidant activities. The antibacterial potential of extracts showed the significant extent of the activity against Bacillus subtilis and E. coli. The maximum activity was noted in 80% methanolic fraction of Thymus vulgaris (15.20±0.64 mm) against Bacillus subtilis. Antioxidant potential exhibited the highest phenolic and flavonoid content in Camellia sinensis . The total phenolic content was significantly higher (1456.26±12.05 mg gallic acid) in 80% ethanolic fraction of Camellia sinensis. The flavonoid content in different plant extracts ranged from 8.17±2.02 to 376.29±7.11 mg/g. The radical scavenging DPPH assay also showed the significant antioxidant capacity of selected plants with the methanolic (50%) extract of Camellia sinensis found to be the most potent (78.95±7.12%). It was concluded that the alcoholic extracts of selected medicinal plants revealed the effective antibacterial and antioxidant activity, showing protective prospective against oxidative injury.

Allelopathic Potentials of <I> Artrmisia monosperma</I> and <I> Thymus vulgaris</I> on Growth and Physio-Biochemical Characteristics of Pea Seedlings

BACKGROUND AND OBJECTIVE

Several medicinal plants are reported as having allelochemicals potentials and favorable results have been obtained in this regard. The present investigation aimed to evaluate the effect of different concentrations of leaf aqueous extract of two medicinal plants, Artrmisia monosperma and Thymus vulgaris on growth criteria, physio-biochemical attributes and antioxidant enzyme activities of pea (Pisum sativum L.) seedlings.

MATERIALS AND METHODS

Germination of pea was performed in Petri dishes under different concentrations (0, 2, 4, 6, 8 and 10%) of leaf aqueous extracts of the two medicinal plants collected from natural habitats in Saudi Arabia. At the end of experiment (10 days), the growth and physio-biochemical characteristics of pea seedlings were measured. The data were statistically analyzed by one-way ANOVA analysis of variance using SPSS program.

RESULTS

Leaf aqueous extracts of A. monosperma and T. vulgaris reduced germination capability, shoot and root length, total free amino acids and proline content. Contrariwise, there was an increase in carbohydrates, proteins, K+, Ca2+ and the activity of antioxidant enzymes. Lipid peroxidation and H2O2 contents were significantly enhanced with increasing concentrations of both extracts. The highest inhibitory or stimulatory effects of leaf aqueous extract were observed at concentrations 8 and 10%. T. vulgaris was more effective than A. monosperma.

CONCLUSION

This investigation indicated that the two medicinal plants had allelopathic compounds with strong potential, which may play important role in weed control and used as an alternative of chemical compounds. The aqueous extract of T. vulgaris has allelopathic potential more than A. monosperma and could be evaluated as an allelopathic species.

Efficacy of Nanoencapsulated Thymus eriocalyx and Thymus kotschyanus Essential Oils by a Mesoporous Material MCM-41 Against Tetranychus urticae (Acari: Tetranychidae)

Inspite of well-established potentiality of plant essential oils as biopesticides, their environmentally low persistence is considered as a hindering obstacle for its commercialization. In the present study, chemical composition and toxicity of essential oils isolated from leaves of Thymus eriocalyx and Thymus kotschyanus were evaluated against two-spotted spider mite, Tetranychus urticae. The chemicals present in the crude oil were found to be thymol (28.83%), oleic acid (11.51%), palmitic acid (8.60%), borneol (5.72%), ρ-cymene (3.60%), and 1,8-cineole (3.57%) in the essential oil of T. eriocalyx, and camphene (35.59%), linalyl acetate (20.47%), linalool (14.75%), α-terpineol (13.87%), and geranyl acetate (3.07%) in the essential oil of T. kotschyanus. The essential oils had strong fumigant toxicity on the adult females of Te. urticae and their fumigation persistence was prolonged until 6 and 5 d, respectively, for T. eriocalyx and T. kotschyanus. Loading of essential oils in MCM-41 increased their stability and persistence was extended up to 20 and 18 d for T. eriocalyx and T. kotschyanus. Further, mite mortality increased from 80 to 203 mites by T. eriocalyx and from 58 to 186 mites by T. kotschyanus nanoencapsulated essential oils. Based on these results, nanoencapsulation of T. eriocalyx and T. kotschyanus essential oils in MCM-41 may be a useful method for their application in the management of Te. urticae.

Effect of thyme essential oil and Lactococcus lactis CBM21 on the microbiota composition and quality of minimally processed lamb's lettuce

The main aim of this work was to evaluate, at pilot scale in an industrial environment, the effects of the biocontrol agent Lactococcus lactis CBM21 and thyme essential oil compared to chlorine, used in the washing step of fresh-cut lamb's lettuce, on the microbiota and its changes in relation to the time of storage. The modification of the microbial population was studied through pyrosequencing in addition to the traditional plate counts. In addition, the volatile molecule and sensory profiles were evaluated during the storage. The results showed no significant differences in terms of total aerobic mesophilic cell loads in relation to the washing solution adopted. However, the pyrosequencing data permitted to identify the genera and species able to dominate the spoilage associations over storage in relation to the treatment applied. Also, the analyses of the volatile molecule profiles of the samples during storage allowed the identification of specific molecules as markers of the spoilage for each different treatment. The sensory analyses after 3 and 5 days of storage showed the preference of the panelists for samples washed with the combination thyme EO and the biocontrol agent. These samples were preferred for attributes such as flavor, acceptability and overall quality. These results highlighted the effect of the innovative washing solutions on the quality of lettuce through the shift of microbiota towards genera and species with lower potential in decreasing the sensory properties of the product.

Phytochemical investigations and antiproliferative secondary metabolites from Thymus alternans growing in Slovakia

CONTEXT

Thymus alternans Klokov (Lamiaceae) is a neglected species of the genus Thymus (Sect. Serpyllum) endemic to Carpathian area, where it is used as a flavouring agent and for medicinal purposes.

OBJECTIVE

The aim of the work was to identify antiproliferative constituents from the flowering aerial parts of this plant.

MATERIALS AND METHODS

Thymus alternans extracts were analyzed by HPLC-MSⁿ and subjected to extensive chromatographic separations. The isolated compounds (phenolics and triterpenes) were structurally elucidated by MS and 1D and 2D NMR experiments. Essential oil (EO) composition was determined by GC-FID and GC-MS. Six purified triterpenes and EO were assayed for in vitro antiproliferative activity against a panel of human cancer cells, namely, breast (MDA-MB 231), colon (HCT-15 and HCT116), lung (U1810), pancreatic (BxPC3), melanoma (A375) and cervical carcinoma (A431) cells.

RESULTS

The structures of the isolated compounds were achieved on the basis of H-NMR and MS experiments. Luteolin-4'-O-β-d-glucopyranoside (P1), chrysoeriol-7-O-β-d-glucopyranoside (P2), chrysoeriol-5-O-β-d-glucopyranoside (P3), apigenin-7-O-β-d-glucopyranoside (P4), rosmarinic acid (P5), rosmarinic acid-3'-O-β-d-glucopyranoside (P6), caffeic acid-3-O-β-d-glucopyranoside (P7), 3α-hydroxy-urs-12,15-diene (T1), α-amyrin (T2), β-amyrin (T3), isoursenol (T4), epitaraxerol (T5), and oleanolic acid (T6). GC-MS analysis revealed that the EO of T. alternans was devoid of phenols and belonged to the nerolidol-chemotype, that is typical of the Sect. Serpyllum. The six purified triterpenes (T1-T6) were active with IC₅₀ ranging from 0.5 to 5 μM being comparable or better than those of reference compounds betulinic acid and cisplatin. The EO exhibited significant effects on A375, MDA-MB 231 and HCT116 cell lines with IC₅₀ in the range of 5-8 μg/mL.

CONCLUSION

The reported results suggest that T. alternans can be considered as a good source of phytoconstituents with possible importance in the pharmaceutical field.

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.

Essential oils showing in vitro anti MRSA and synergistic activity with penicillin group of antibiotics

This study was planned in order to investigate effective essential oils to inhibit in-vitro growth of Methicillin resistant Staphylococcus aureus (MRSA). In this study using disc diffusion method anti MRSA activity of ten diverse essential oils extracted from traditional plants namely Thymus vulgaris L, Mentha pulegium, Ocimum sanctum, Mentha piperita, Cymbopogon citratus, Rosmarinus officinalis L., Cortex cinnamom, Citrus nobilis x Citrus deliciosa, Origanum vulgare and Mentha sp. was examined. All the essential oils inhibited growth of S. aureus to different extent, by exhibiting moderate to elevated zones of inhibitions. Essential oils of cinnamon (Cortex cinnamomi) and thyme (Thymus vulgaris L) were observed to be the most powerful against MRSA strains used in this study. At lowest concentration of 25μl/ml essential oils comprehensible zone of inhibition was found 9±0.085mm and 8±0.051mm respectively, and at elevated concentrations there was a total decline in growth of MRSA and a very clear zone of inhibition was observed. A synergistic effect of essential oils in amalgamation with amoxicillin a Penicillin group of antibiotic was also examined. Interestingly a strong synergism was observed with oregano (Origanum vulgare) and pennyroyal mint (Mentha pulegium) essential oils, which were not so effective alone driven out to be important synergistic candidate. Our results demonstrated that essential oils of cinnamon and thyme can be used as potential antimicrobial agent against the Methicillin-resistant Staphylococcus aureus infections and Amoxicillin antibacterial activity can be enhanced using active constituents present in oregano and pennyroyal mint essential oils.

Anesthetic Agents of Plant Origin: A Review of Phytochemicals with Anesthetic Activity

The majority of currently used anesthetic agents are derived from or associated with natural products, especially plants, as evidenced by cocaine that was isolated from coca (Erythroxylum coca, Erythroxylaceae) and became a prototype of modern local anesthetics and by thymol and eugenol contained in thyme (Thymus vulgaris, Lamiaceae) and clove (Syzygium aromaticum, Myrtaceae), respectively, both of which are structurally and mechanistically similar to intravenous phenolic anesthetics. This paper reviews different classes of phytochemicals with the anesthetic activity and their characteristic molecular structures that could be lead compounds for anesthetics and anesthesia-related drugs. Phytochemicals in research papers published between 1996 and 2016 were retrieved from the point of view of well-known modes of anesthetic action, that is, the mechanistic interactions with Na⁺ channels, γ-aminobutyric acid type A receptors, N-methyl-d-aspartate receptors and lipid membranes. The searched phytochemicals include terpenoids, alkaloids and flavonoids because they have been frequently reported to possess local anesthetic, general anesthetic, antinociceptive, analgesic or sedative property. Clinical applicability of phytochemicals to local and general anesthesia is discussed by referring to animal in vivo experiments and human pre-clinical trials. This review will give structural suggestions for novel anesthetic agents of plant origin.

Possible Molecular Mechanisms by Which an Essential Oil Blend from Star Anise, Rosemary, Thyme, and Oregano and Saponins Increase the Performance and Ileal Protein Digestibility of Growing Broilers

Phytogenic feed additives represent a potential alternative to antibiotics with attributed health and growth-promoting effects. Chickens supplemented with an essential oil blend, a Quillaja saponin blend, or a combination of both phytogenic preparations showed a comprehensively and significantly improved apparent ileal digestibility of crude protein and amino acids compared to control birds. Accordingly, holistic transcriptomic analyses of jejunum and liver samples indicated alterations of macromolecule transporters and processing pathways likely culminating in an increased uptake and metabolizing of carbohydrates and fatty acids. Complementary analyses in Caco-2 showed a significant increase in transporter recruitment to the membrane (SGLT1 and PEPT1) after addition of essential oils and saponins. Although the penetrance of effects differed for the used phytogenic feed additives, the results indicate for an overlapping mode of action including local effects at the intestinal border and systemic alterations of macronutrient metabolism resulting in an improved performance of broilers.

Effects of rosemary, thyme and lemongrass oils and their major constituents on detoxifying enzyme activity and insecticidal activity in Trichoplusia ni

Although there have been many reports on the synergistic interactions among the major constituents of plant essential oils regarding insecticidal activity, their underlying mechanism of synergy is poorly understood. In our previous studies, we found each of the two most abundant constituents of rosemary (Rosmarinus officinalis L.), thyme (Thymus vulgaris L.) and lemongrass (Cymbopogon citratus Stapf.) essential oils can be synergistic against the larvae of the cabbage looper, Trichoplusia ni at their natural proportion or equivalent blending ratios. In the present study, we investigated whether the enhanced toxicity between the major constituents could be the result of inhibited enzyme activity of cytochrome P450s, general esterases or glutathione S-transferases which are highly related to the development of insecticide resistance. Overall, although some combinations showed mild inhibitory activity, at least for these essential oils and their major constituents, inhibition of detoxication enzyme activity is unlikely to be a direct cause of increased toxicity in the cabbage looper. The results point to other factors, such as multiple modes-of-action or enhanced penetration through the cuticular layer, playing important roles in the elevated insecticidal activity. Moreover, application of enzyme inhibitors sometimes resulted in decreased activity when mixed with the target compounds, but these antagonistic interactions disappeared when they were applied separately, suggesting that the enzyme inhibitors can sometimes influence the penetrations of toxicants.

Inhibitory effect of Thymus vulgaris and Origanum vulgare essential oils on virulence factors of phytopathogenic Pseudomonas syringae strains

Pseudomonas syringae is a phytopathogenic bacterium that causes lesions in leaves during the colonisation process. The damage is associated with production of many virulence factors, such as biofilm and phytotoxins. The essential oils of Thymus vulgaris (thyme) and Origanum vulgare (oregano) have been demonstrated to inhibit P. syringae. The aim of this study was to investigate the effects of T. vulgaris and O. vulgare essential oils on production of virulence factors of phytopathogenic P. syringae strains, including anti-biofilm and anti-toxins activities. The broth microdilution method was used for determination of MIC and biofilm inhibition assays. Coronatine, syringomycin and tabtoxin were pheno- and genotypically evaluated. Both oils showed good inhibitory activity against P. syringae, with MIC values from 1.43 to 11.5 mg·ml^-1 for thyme and 5.8 to 11.6 mg·ml^-1 for oregano. Biofilm formation, production of coronatine, syringomycin and tabtoxin were inhibited by thyme and oregano essential oil in most strains. The results presented here are promising, demonstrating the bactericidal activity and reduction of virulence factor production after treatment with thyme and oregano oil, providing insight into how they exert their antibacterial activity. These natural products could be considered in the future for the control of diseases caused by P. syringae.

Chemical Composition and Anti-inflammatory Activity of Algerian Thymus vulgaris Essential Oil

This work aims to elucidate the chemical composition of two essential oil (EO) samples obtained from the leaves of Thymus vulgaris L. (Lamiaceae) collected in two regions of Northwestern Algeria (Tlemcen and Mostaganem) and to assess their in vivo acute toxicity and anti-inflammatory activity. Sixty-six compounds could be identified by means of simultaneous GC-FID and GC-MS, accounting for 99.3% of total thyme oil of Mostaganem (EO.TM) and 99.0% of Tlemcen (EO.TT). In both samples, thymol was the major component, amounting to 59.5% (EO.TM) and 67.3% (EO.TT) of the total oil. EO.TT proved to be acutely toxic to mice at a dose of 4500 mg/kg p.o., whereas EO.TM did not show signs of acute toxicity, even at the highest dose tested (5000 mg/kg p.o.). Both EO samples were proven to possess anti-inflammatory activities, significantly reducing carrageenan-induced paw edema in mice (after 6 hours at a dose -of 400 mg/kg p.o) at 58.4% for EO.TT and 50.4% for EO.TM, respectively. In conclusion, it could be demonstrated that EOs of T. vulgaris exhibit a considerable in vivo anti-inflammatory activity at non-toxic doses.

Insecticidal Properties of Essential Oils and Some of Their Constituents on the Turkestan Cockroach (Blattodea: Blattidae)

The Turkestan cockroach, Blatta lateralis (Walker), has become the most important peridomestic species in urban areas of the Southwestern United States. The aim of this study was to evaluate the use of botanical compounds to control this urban pest. We tested the acute toxicity and repellency of six botanical constituents and three essential oils on Turkestan cockroach nymphs. Chemical composition of the essential oils was also determined. Topical and fumigant assays with nymphs showed that thymol was the most toxic essential oil constituent, with a LD50 of 0.34 mg/nymph and a LC50 of 27.6 mg/liter air, respectively. Contact toxicity was also observed in assays with trans-Cinnamaldehyde, eugenol, geraniol, methyl eugenol, and p-Cymene. Methyl eugenol and geraniol had limited fumigant toxicity. The essential oils from red thyme, clove bud, and Java citronella exhibited toxicity against nymphs. Cockroaches avoided fresh dry residues of thymol and essential oils. Chemical analysis of the essential oils confirmed high contents of effective essential oil constituents. Our results demonstrated that essential oils and some of their constituents have potential as eco-friendly insecticides for the management of Turkestan cockroaches.