[Botanical, phytochemical and pharmacologic studies of thyme].
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Botany↗
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[Chemical weed control in plantations of thyme (Thymus vulgaris L.)].
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Herbicides↗
[Systemic emulsions. 2. Use of different methods of formulation: the effect of essential oils of thyme on stability].
As part of an ongoing investigation on emulsifying techniques, we studied the influence of different essential oils from Thymus vulgaris on emulsion stability. All four chimiotypes tested (geraniol, linalol, carvacrol, and thymol) caused a marked decrease in stability. This instability cannot be explained by a change in the hydrophilic lipophilic balance since the HLBc of the new oil phase (essential oil + paraffine oil) was not significantly different from that of paraffine alone.
Drug Compounding↗
[Factors, controlling recirculation of stem cells. 3. Effect of thyme on migration and differentiation of hematopoietic stem cells settling out from bone marrow screened during irradiation].
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Animals↗
Do co-occurring plant species adapt to one another? The response of Bromus erectus to the presence of different Thymus vulgaris chemotypes.
Local modification of the soil environment by individual plants may affect the performance and composition of associated plant species. The aromatic plant Thymus vulgaris has the potential to modify the soil through leaching of water-soluble compounds from leaves and litter decomposition. In southern France, six different thyme chemotypes can be distinguished based on the dominant monoterpene in the essential oil, which is either phenolic or non-phenolic in structure. We examine how soils from within and away from thyme patches in sites dominated by either phenolic or non-phenolic chemotypes affect germination, growth and reproduction of the associated grass species Bromus erectus. To do so, we collected seeds of B. erectus from three phenolic and three non-phenolic sites. Seeds and seedlings were grown on soils from these sites in a reciprocal transplant type experiment in the glasshouse. Brome of non-phenolic origin performed significantly better on its home soil than on soil from a different non-phenolic or a phenolic site. This response to local chemotypes was only observed on soil collected directly underneath thyme plants and not on soil in the same site (<5 m away) but where no thyme plants were present. This is preliminary evidence that brome plants show an adaptive response to soil modifications mediated by the local thyme chemotypes. Reproductive effort was consistently higher in brome of phenolic origin than in brome of non-phenolic origin (on both thyme- and grass-soil), indicating that life-history variation may be related to environmental factors which also contribute to the spatial differentiation of thyme chemotypes. Moreover, we found that brome growing on thyme-soil in general was heavier than when growing on grass-soil, regardless of the origin of the brome plants. This is concordant with thyme-soil containing higher amounts of organic matter and nitrogen than grass-soil. Our results indicate that patterns of genetic differentiation and local adaptation may modify competitive interactions and possible facilitation effects in natural communities.
Adaptation, Physiological↗
Antimicrobial effect of spices and herbs on Shigella sonnei and Shigella flexneri.
Of 17 spices and herbs tested at 1% (wt/vol) in Mueller-Hinton (MH) agar, only cloves, thyme, oregano, allspice, basil, rosemary, and marjoram showed antimicrobial effects on Shigella. The MICs of thyme, oregano, basil, and rosemary (as determined by the agar dilution method) ranged from 0.5 to 1% (wt/vol) depending on the Shigella strain used. With the use of various combinations of temperatures (12, 22, and 37 degrees C), pHs (5.0, 5.5, and 6.0), and NaCl concentrations (1, 2, 3, and 4%, wt/vol) and the inclusion or exclusion of thyme or basil at 1% (wt/vol) in an MH agar model system, it was established that basil or thyme can contribute to combination processing as a growth-inhibitory factor for Shigella spp. In the presence of basil and thyme, Shigella flexneri did not develop CFU during the 7-day incubation period for, respectively, 14 and 16 of the 18 tested combinations, while growth was noted in the corresponding temperature-pH-NaCl concentration combinations without basil or thyme. A growth-inhibitory effect on Shigella sonnei was also noted. The results of an orientation study involving the addition of basil and thyme to spaghetti sauce prior to autoclaving and S. sonnei inoculation indicated that basil and thyme contributed to the reduction of S. sonnei after 16 days at 12 degrees C but not at 4 degrees C.
Colony Count, Microbial↗
Bioavailability of iron from four different local food plants in Jordan.
The bioavailability of iron from local plants (black cumin seeds, milk thistle seeds, sesame seeds and thyme leaves) was investigated. Apparent absorption of iron was calculated by subtracting fecal iron (using total collection of feces) from iron intake in Sprague-Dawley rats. Two trials of animal feeding were performed. Liver and serum concentrations of iron, and serum hemoglobin concentration were taken as response parameters for the bioavailability. Dry thyme was particularly rich in iron (117.2 mg/100 g dry matter) and milk thistle seeds in crude fiber (25 g/100 g dry matter). Rats fed the dry thyme diet or that supplemented with 5% egg white died but when the diet was supplemented with 10% egg white, the animals survived. Iron intake and apparent and total iron absorption were highest for the rats fed the dry thyme-egg white diet. Liver weights for the groups fed black cumin seeds and dry thyme were significantly higher (p<0.05) than those for the groups fed milk thistle and sesame seeds. Liver content of iron was highest for the animals fed black cumin seeds. Serum iron content increased significantly (p<0.05) for the animals fed black cumin seeds, and serum hemoglobin concentration increased significantly (p<0.05) in the groups fed milk thistle seed and black cumin seed diets, but decreased for the group fed the thyme-egg white diet. It is concluded from this study that iron was better utilized from black cumin seeds as indicated by liver storage of iron. On the other hand, thyme had the highest iron absorption but lowest utilization.
Animals↗
Determination of antioxidant potential of volatile extracts isolated from various herbs and spices.
Antioxidant activities of volatile extracts isolated from thyme, basil, rosemary, chamomile, lavender, and cinnamon were evaluated by two independent assays: the aldehyde/carboxylic acid assay and the conjugated diene assay. The volatile extracts were prepared from dried herbs and spices using liquid-liquid continuous extraction following steam distillation under reduced pressure (55 degrees C and 95 mmHg). The antioxidant activities of the extracts decreased in the following order in both of the lipophilic assay systems: thyme > basil > rosemary > chamomile > lavender and cinnamon. Thyme and basil extracts inhibited the oxidation of hexanal for 40 days at the levels of 10 microg/mL and 50 microg/mL, respectively. The extracts of thyme and basil were effective in retarding methyl linoleate deterioration at 40 degrees C, with activity increasing with concentration in the range 10-200 microg/mL. At a concentration of 50 microg/mL, thyme extract was similar in antioxidant activity to BHT and alpha-tocopherol in the conjugated diene assay. The antioxidant potentials of the volatile extracts used in this study were accurately measured by the lipophilic systems, such as the aldehyde/carboxylic acid assay and the conjugated diene assay.
Antioxidants↗
Repellency of essential oils to mosquitoes (Diptera: Culicidae).
The repellency of different concentrations (5, 10, 25, 50, 75, and 100%) and combinations of 5 essential oils (Bourbon geranium, cedarwood, clove, peppermint, and thyme) to Aedes aegypti (L.) and Anopheles albimanus Wiedemann when applied to human skin was determined in laboratory tests. Cedarwood oil failed to repel mosquitoes and only high concentrations of peppermint oil repelled Ae. aegypti. None of the oils tested prevented mosquito bite when used at the 5 or 10% concentration. Thyme and clove oils were the most effective mosquito repellents and provided 1 1/2 to 3 1/2 h of protection, depending on oil concentration. Clove oil (50%) combined with geranium oil (50%) or with thyme oil (50%) prevented biting by An. albimanus for 1 1/4 to 2 1/2 h. The potential for using essential oils as topical mosquito repellents may be limited by user acceptability; clove, thyme, and peppermint oils can be irritating to the skin, whereas both human subjects in this study judged the odor of clove and thyme oils unacceptable at concentrations > or = 25%.
Aedes↗
Antimicrobial activities of the essential oils of various plants against tomato late blight disease agent Phytophthora infestans.
The aim of this study was to find an alternative to synthetic fungicides currently used in the control of devastating oomycete pathogen Phytophthora infestans, causal agent of late blight disease of tomato. Antifungal activities of essential oils obtained from aerial parts of aromatic plants such as oregano (Origanum syriacum var. bevanii), thyme (Thymbra spicata subsp. spicata), lavender (Lavandula stoechas subsp. stoechas), rosemary (Rosmarinus officinalis), fennel (Foeniculum vulgare), and laurel (Laurus nobilis), were investigated against P. infestans. Both contact and volatile phase effects of different concentrations of the essential oils used were determined by using two in vitro methods. Chemical compositions of the essential oils were also determined by GC-MS analysis. Major compounds found in essential oils of thyme, oregano, rosemary, lavender, fennel and laurel were carvacrol (37.9%), carvacrol (79.8), borneol (20.4%), camphor (20.2%), anethole (82.8%) and 1,8-cineole (35.5%), respectively. All essential oils were found to inhibit the growth of P. infestans in a dose-dependent manner. Volatile phase effect of oregano and thyme oils at 0.3 microg/ml air was found to completely inhibit the growth of P. infestans. Complete growth inhibition of pathogen by essential oil of fennel, rosemary, lavender and laurel was, however, observed at 0.4-2.0 microg/ml air concentrations. For the determination of the contact phase effects of the tested essential oils, oregano, thyme and fennel oils at 6.4 microg/ml were found to inhibit the growth of P. infestans completely. Essential oils of rosemary, lavender and laurel were inhibitory at relatively higher concentrations (12.8, 25.6, 51.2 microg/ml respectively). Volatile phase effects of essential oils were consistently found to be more effective on fungal growth than contact phase effect. Sporangial production was also inhibited by the essential oil tested. Light and scanning electron microscopic (SEM) observation on pathogen hyphae, exposed to both volatile and contact phase of oil, revealed considerable morphological alterations in hyphae such as cytoplasmic coagulation, vacuolations, hyphal shrivelling and protoplast leakage.
Gas Chromatography-Mass Spectrometry↗
Modulation of pregnane X receptor- and electrophile responsive element-mediated gene expression by dietary polyphenolic compounds.
Based on animal models, dietary polyphenols are predicted to be promising chemopreventive agents in humans. Allspice, clove, and thyme extracts as well as defined dietary polyphenolic compounds were, therefore, tested for their ability to activate mechanisms related to phase 1 enzymes, i.e., the PXR-regulated CYP3A4 promoter, and phase 2 enzymes, i.e. the EpRE-regulated promoters of gastrointestinal glutathione peroxidase (GI-GPx) and heme oxygenase-1 (HO-1), examples of Nrf2-regulated genes. From the compounds tested, clove and thyme extracts as well as curcumin and resveratrol activated the PXR. PXR activation correlated with the activation of the CYP3A4 promoter in the case of thyme extract, curcumin, and resveratrol, but not in the case of clove extract. Allspice extract, EGCG, and quercetin did not activate PXR but enhanced CYP3A4 promoter activity. Thyme extract and quercetin activated the EpRE of HO-1. Both significantly activated the GI-GPx promoter, effects that depended on a functional EpRE. Resveratrol did not activate the isolated EpRE but enhanced the GI-GPx promoter activity, whereas clove extract even inhibited it. It is concluded that individual polyphenols as well as polyphenol-rich plant extracts may affect phase 1 and 2 enzyme expression by distinct mechanisms that must be elucidated, before potential health effects can reliably be predicted.
Catechin↗
Vasomodulating potential of mediterranean wild plant extracts.
The incidence of cardiovascular disease and endothelial dysfunction is low in the Mediterranean area, where the major proportion of daily calories comes from plant food, high in antioxidant polyphenols. It has been shown that a reduced production or enhanced inactivation of endothelium-derived nitric oxide (NO) is involved in the onset of endothelial dysfunction. We investigated the effects of Mediterranean wild plant, that is, wild artichoke and thyme, phenolic-rich extracts on NO release by porcine aortic endothelial cells (PAECs; by using indirect methods) and by cerebral cell membrane homogenates (by using direct NO detection). NO release by PAECs was significantly potentiated by 234% and 135% by wild artichoke and thyme extracts (10(-6) mol/L), respectively. Direct detection of NO release by brain membranes also showed significantly increased NO production after wild artichoke addition (+35.4%). Further, the release of another vasorelaxant factor by PAECs, that is, prostacyclin, was significantly increased by wild artichoke and thyme (10(-6) mol/L) (+269% and +190%, respectively). Investigation of the mechanism(s) of action of wild artichoke and thyme suggests maintenance of an intracellular reduced environment, as previously shown for ascorbate. Even though these data require in vivo confirmation, they suggest that regular intake of bioactive compounds from Mediterranean wild plants contributes to maintenance of proper vasomotion and to the low incidence of atherosclerosis and endothelial dysfunction recorded in the Mediterranean area.
Animals↗
Laboratory evaluation of some plant essences to control Varroa destructor (Acari: Varroidae).
This research was conducted to evaluate acaricidal effects of some plant essences on Varroa mites and the possibility of their usage for Varroa control. First, live Varroa mites were obtained from adult honeybees with CO2 in a newly designed apparatus. Thyme, savory, rosemary, marjoram, dillsun and lavender essences at concentrations of 2 and 1 g/100 g (w/w), caused a mite mortality rate of more than 97% and 95%, respectively. Also spearmint at 2 g/100 g was able to kill more than 97% of Varroa mites. When sprayed on worker honeybees infected with mites, thyme, savory, spearmint and dillsun essences at 2 g/100 g (w/w) caused 43-58% Varroa mortality. Toxicity of thyme, savory and spearmint essences for worker honeybees was not significantly different from that of controls (acetone and water), but dillsun essence caused 12% honeybee mortality. These results showed that essences of thyme, savory and spearmint have acaricidal properties that could be used for controlling Varroa in honeybee colonies.
Animals↗
Antimicrobial activity of Pelargonium essential oils added to a quiche filling as a model food system.
Eight essential oils obtained by steam distillation from the scented leaves of Pelargonium species and cultivars were added at 250, 500 and 1000 ppm to a quiche filling, inoculated with either Saccharomyces ludwigii or Zygosaccharomyces bailii (at 10(8) cfu g-1), Salmonella enteriditis or Listeria innocua (at 10(9) cfu g-1). The quiche fillings were then kept at 25 degrees C for 24 h and the residual number of micro-organisms determined using the pour plate technique. There was an effective antimicrobial activity by the Pelargonium essential oils at 250 ppm, comparable with that of commercial thyme oil, an excellent antimicrobial agent, against Saccharomyces ludwigii and Zygosaccharomyces bailii, and a lesser inhibition compared with commercial thyme against Salm, enteriditis. There was a greater diversity of activity against L. innocua, which was in some cases more effective than commercial thyme oil. At 500 ppm, there was a greatly increased inhibition of microbial growth using the Pelargonium essential oils, which was comparable with that of commercial thyme, clove, geranium and coriander oils. As there is no evidence for the toxicity of any of these novel Pelargonium oils, and their odour does not make the delicately flavoured quiche filling unpalatable, there is a strong potential for their use in food processing.
Colony Count, Microbial↗
Preservation of alpha-tocopherol in sunflower oil by herbs and spices.
The ability of some commercially available herb and spice extracts to preserve alpha-tocopherol in sunflower oil during heating at 85-105 degrees C was assessed using sunflower oil as a model system. The Rancimat was evaluated for the heating stage and was used throughout as it was shown to be viable: alpha-tocopherol did not evaporate under the test conditions. The delay in the onset of rancidity was found to be directly related to the initial alpha-tocopherol concentration (P < 0.01). Rosemary, thyme, turmeric, sage, oregano and cumin extracts (2000 mg.kg-1) delayed rancidity (P < 0.01) and preserved alpha-tocopherol (P < 0.01). Some preservation was observed with clove extract but coriander and cardamom extracts were pro-oxidants. With thyme extract, the log of the induction time (as an indicator of the delay in rancidity) was directly proportional to the temperature (85-100 degrees C). The ethyl acetate, hexane and methanol extracts of fresh sage were effective for preserving alpha-tocopherol (P < 0.01). With thyme, rosemary and sage extracts, the increase in the preservation of alpha-tocopherol was directly related to the concentration of the herb extract (P < 0.01) and was quite effective even at 100 mg.kg-1. The increased delay in the onset of rancidity was due directly to the improved preservation of alpha-tocopherol (P < 0.01). In further experiments, the preservative effect of turmeric was shown not to be due to its reported major antioxidant, curcumin, even though it delayed rancidity. When herb/spice extracts were examined mixed with thyme, bay and turmeric showed synergism (P < 0.01) whereas bay alone was slightly inhibitory. The mode of action appeared to be due to free radical activity rather than through singlet oxygen generation.
Drug Synergism↗
A pi-shaped ultrasonic tweezers concept for manipulation of small particles.
A pi-shaped ultrasonic actuator is proposed for the noncontact trapping, extraction, and transportation of small particles. In this actuator, two metal plates clamp a multilayer piezoelectric vibrator by a small bolt, and the metal plates are tapered in their lower parts so that a vibration gradient can be obtained. The flexural vibration of the metal plates is used to generate a sound field in the gap between the two tapered metal plates. At a driving frequency of about 152.8 kHz, shrimp eggs, grass seeds, thyme seeds, rice powder, fine salt, and fine sugar, which have an average diameter from several tens of micrometers to several hundreds of micrometers, can be trapped stably without contact with the actuator, and the particles insoluble in water can be extracted from water and transported in water by the actuator. In the noncontact trapping of small particles, the positions of trapped particles as well as the relationship among the number of trapped particles, vibration velocity, and input power are investigated. The number of trapped particles increases as the vibration velocity or input power increases. However, when the vibration velocity or input power is too large, the particles may be ejected out of the actuator and, therefore, cannot be stably trapped. The minimum vibration velocity to trap small particles increases as particle density increases for the particles that have the shape near to a sphere and a proper density. In the extraction of small particles from water, the relationship between the number of extracted thyme seeds and the input power is investigated. Increasing the input power can increase the extracted thyme seeds. However, there is a maximum particle number that can be extracted from water. In the transportation of thyme seeds in water, the dependence of the particle loss during the transportation on the speed and distance of transportation and the input power is experimentally estimated. As the distance and speed of transportation increase, the particle loss during the transportation increases. Increasing the input power increases the trapping effect and, therefore, decreases the particle loss.
Equipment Design↗
Content and composition of the essential oil of Thymus serpyllum L. growing wild in Estonia.
OBJECTIVE: The aim of this work was to analyze the essential oil content and its composition in the drug (Serpylli herba) of wild thyme (Thymus serpyllum L.) originating from 20 different natural places of growth in Estonia. MATERIAL AND METHODS: The quantitative content of essential oil was determined according to the method of European Pharmacopoeia. Gas chromatographic analysis of essential oils was carried out using a gas chromatography with flame ionization detector on two fused silica capillary columns with bonded stationary phases NB-30 and SW-10. The identification of the oil components was accomplished by comparing their retention indices on two columns with the retention indices values of standard compounds, with our retention indices data bank and with literature data. The results obtained were confirmed by gas chromatography / mass spectrometry. RESULTS: The content of essential oil is between 0.6 and 4 ml/kg and usually is not in conformity with European Pharmacopoeia standard (3 ml/kg). There were 55 components identified in the essential oil of wild thyme of Estonian origin. Differently from the data in the literature of foreign countries, thymol and carvacrol are not the main components of the essential oil of wild thyme growing in Estonia. The main components here are (E)-nerolidol, caryophyllene oxide, myrcene, (E)-beta-caryophyllene and germacrene D. CONCLUSION: In Estonia, the (E)-nerolidol-caryophyllene oxide, (E)-nerolidol-myrcene and myrcene chemotypes of wild thyme drug are distinguishable.
Anti-Inflammatory Agents, Non-Steroidal↗
[Inhibition of Paenibacillus larvae employing a mixture of essential oils and thymol].
In vitro antimicrobial activity of a mixture of two essential oils and thymol against Paenibacillus larvae, causal agent of American Foulbrood (AFB), was evaluated. The essential oils were extracted from cinnamon (Cinnamomum zeylanicum) and thyme (Thymus vulgaris). The third component used, thymol, is the major component of the essential oil of thyme which contains 39.9% of thymol. Minimal inhibitory concentration (MIC) in Mueller-Hinton broth by the tube dilution method and minimal bactericide concentration (MBC) on MYPGP agar were evaluated. Thyme registered MIC values of 150-250 microg/ml and MBC values of 200-300 microg/ml, while the MIC and MBC values obtained for cinnamon were of 50-100 microg/ml and 100-125 microg/ml. Thymol showed similar MIC and MBC values of 100-150 microg/ml. No significant differences between the bacterial strains were detected, but significant differences between essential oils and thymol activity were registered (P<0,01). An inhibitory synergetic effect on AFB was observed reducing MIC and MBC values due to the use of a mixture of 62.5% of thyme, 12.5% of cinnamon and 25% of thymol.
Anti-Bacterial Agents↗