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At least 19 recordsLinked to original sources
PubMed2003

Health effects of exposure to thyme dust in a group of thyme growing farmers.

Medical examinations were performed in a group of 47 thyme farmers from eastern Poland while threshing thyme (Thymus vulgaris). As a reference group 63 urban dwellers were examined not exposed to organic dusts. The examinations included an interview concerning the occurrence of respiratory disorders and work-related symptoms, physical examination, lung function tests, skin prick tests with four microbial allergens and agar-gel precipitation tests with 12 antigens. 63.8% of thyme handling farmers reported occurrence of work-related symptoms while threshing thyme. The most common complaints were: blocking of the nose (reported by 18 farmers--38.3%), dry cough (14 persons--29.8%) and general weakness (13 persons--27.7%). The mean spirometric values in the farmers group were within a normal range and did not show a significant post-work decline. The farmers showed positive skin reactions to microbial antigens in the range of 4.3-14.9%, and a frequency of positive precipitin reactions 0-56.5%. The reference group responded to most allergens with a significantly lower frequency of positive results compared to the examined group. In conclusion, thyme farmers engaged in threshing this herb represent a group of elevated professional risk because of high incidence of work-related symptoms and common occurrence of positive skin and precipitin reactions to bacterial and fungal allergens associated with organic dust.

Adult↗
PubMedDate not supplied

Comparison of planar chromatographic methods (TLC, OPLC, AMD) applied to essential oils of wild thyme and seven chemotypes of thyme.

Essential oils analysis is more often realized by gas chromatography. However, thin-layer chromatography (TLC) remains the reference for Pharmacopoeia. Nevertheless classical TLC has its own limitations but it is always a good technique because it is simple, rapid and less expensive. Actually the reproducibility, the separation quality and the possibility to obtain good and reproducible quantitative determinations have been improved significantly with automated sample applicator, scanner densitometers and two new chromatographic planar methods: the optimum performance laminar chromatography (OPLC) and automated multiple development (AMD). In this work, we show and compare the performance of these methods and TLC through a study of seven thyme chemotypes and wild thyme essential oil.

Autoanalysis↗
PubMed1999

Beneficial effects of thyme oil on age-related changes in the phospholipid C20 and C22 polyunsaturated fatty acid composition of various rat tissues.

The aim of this study was to determine any age-related changes in phospholipid polyunsaturated fatty acid composition, in particular C20 and C22 fatty acids in rat liver, brain, kidney and heart, and to assess and compare the effects of dietary supplementation (42.5 mg/kg body weight/day) of the natural antioxidant thyme oil and its major component thymol throughout the rat life span. The fatty acid composition in the various tissues from young (7 months) and aged (28 months) rats was determined and compared. Livers from aged control, thyme oil and thymol treated rats exhibited an increase in 22:6(n-3). In contrast, 22:6(n-3) content of brain, kidney and heart declined in aged rats in all three dietary groups. However, aged rats treated with thyme oil and thymol displayed significantly higher levels of 22:6(n-3) than the respective age-matched controls. Tissue compositions of 20:4(n-6) were found to be significantly lower in the liver and kidney from aged control rats but not those fed either thyme oil or thymol. In aged rats, the composition of 20:4(n-6) in all tissues was highest in rats fed either thyme oil or thymol. These results show that dietary supplementation with thyme oil tended to maintain higher PUFA levels in all tissues studied. The majority of protection provided by thyme oil was by virtue of its thymol component, which comprises 49% of the whole oil. Thymol administered alone did not provide significantly higher protection than the whole oil, suggesting that other components within thyme oil are also contributing antioxidant activity.

Aging↗
PubMed2001

Occupational airborne contact dermatitis caused by thyme dust.

The aim of the study was to assess occupational hazards to the farmer's skin associated with processing thyme (Thymus vulgaris L.). 46 farmers were studied during the threshing of dried thyme. They were questioned about work-related skin problems and examined before and after work. In all persons, serum thyme-specific IgE was measured. Skin prick tests, the Ouchterlony test and the migration inhibition test were carried out with allergens of airborne bacteria and fungi present in the working environment. Of the 46 farmers studied, 4 showed skin symptoms after 5-30 min of exposure to thyme dust. Thyme-specific IgE was found in 1 person with work-related symptoms, but also in 2 asymptomatic farmers. Therefore, the importance of IgE seems to be questionable in eczema related to thyme dust. Skin and blood tests with microbial allergens also showed no significant differences between the symptomatic and asymptomatic farmers. To our knowledge, this is the 1st description of occupational airborne contact dermatitis caused by thyme dust. The etiology of thyme-related skin symptoms remains obscure, although an irritant mechanism seems probable.

Adult↗
PubMed2003

Influence of nitrogen fertilizers on the yield and composition of thyme (Thymus vulgaris).

The influence of nitrogen fertilizers on the yield of crop, as well as on the production and composition of the essential oil and some other chemical characteristics of thyme, was investigated. Different levels of fertilizers (N = 0, 45, 90, and 135 kg x ha(-)(1)) were applied. It was found that fertilizers increase thyme crop, but differences in the yield of essential oil were not remarkable. However, the use of certain amounts of nitrogen fertilizers resulted in higher yields of essential oil obtainable from the cultivation area unit (dm(3) ha(-)(1)). Totally, 61 constituents were identified in thyme essential oil by capillary GC and GC-MS. Thymol was the dominating compound in the all analyzed oils (44.4-58.1%), followed by p-cymene (9.1-18.5%), gamma-terpinene (6.9-18.9%), and carvacrol (2.4-4.2%). Differences in the percentage of these and other compounds in thyme herb cultivated under different fertilization doses were not significant; very slight changes in the percentage composition were detected after drying. Some variations in the amount of individual constituents expressed in arbitrary units per kilogram of herb (which is almost equivalent to mg x kg(-)(1)) were observed. The highest amounts of sugars and sucrose, in particular, were determined in the second year of thyme cultivation. Differences in the content of dry soluble substances were not meaningful, and there was no effect of nitrogen fertilizers on this chemical characteristic. Some effect of fertilization on the content of vitamin C and carotenes was observed in the first year of thyme cultivation. It was determined that nitrogen fertilizers influence the amount of nitrates, which was highest in the second-year-first-harvest.

Ascorbic Acid↗
PubMed2002

GC/MS evaluation of thyme (Thymus vulgaris L.) oil composition and variations during the vegetative cycle.

Capillary GC/MS analysis based on polar and non-polar columns has been applied to evaluation of the volatile oils hydrodistilled from thyme (Thymus vulgaris L.) plants. The adopted methodology has been used to monitor seasonal variations in the composition of the oil obtained from thyme herbs harvested at different periods during the plant vegetative and life cycles. Oils from thyme plants of young (2 years) and old (5 years) cultivations have been evaluated from four and two collections, respectively, effected throughout May/December growth period. Generally, the oil was found to be rich in the active monoterpene phenols (thymol and carvacrol) and their corresponding monoterpene hydrocarbon (HC) precursors (p-cymene and gamma-terpinene), which collectively showed synchronized patterns of variation during the different collection periods and in different seasons. The oil from old plant collected in May/June period (0.15% v/w) was characterized by significantly lower levels of monoterpene HCs (mainly gamma-terpinene) and the highest levels of the oxygenated monoterpenes (linalool and borneol), monoterpene phenols (mainly thymol) and their derivatives (mainly carvacrol methyl ether), sesquiterpenes (mainly beta-caryophyllene) and their oxygenated derivatives (e.g. caryophyllene oxide) in comparison with all other samples. A characteristic presence of camphor and thymodihydroquinone was also observed in the old plant oils. On the other hand, the young plant, collected in June/July just before the end of the vegetative cycle, provided the best oil yield (1.2%) with also the highest % content of the monoterpene phenols (thymol: 51.2% and carvacrol: 4%). This latter growth period can represent the best harvest time of young thyme plants in order to obtain an essential oil with better quality and quantity.

Gas Chromatography-Mass Spectrometry↗
PubMed1994

Factors that interact with the antibacterial action of thyme essential oil and its active constituents.

The viable counts of Salmonella typhimurium on nutrient agar (NA) decreased upon the addition of either the essential oil of thyme or its constituent thymol, especially under anaerobic conditions. Antagonistic effects of thymol against Staphylococcus aureus were also greater under anaerobic conditions. In contrast to the phenolic constituents of the oil, thymol and carvacrol, the chemically related terpenes p-cymene and gamma-terpinene had no antagonistic effects against Salm. typhimurium. The addition of Desferal to NA counteracted the antibacterial effects of both thyme oil and thymol. No support was obtained, however, for a possible role of iron in the oxygen-related antibacterial action of the thyme oil and thymol or for the observed effect of Desferal. In the presence of thymol, the viable counts of Salm. typhimurium obtained on a minimal medium (MM) were lower than those obtained on NA. Addition of bovine serum albumin (BSA) neutralized the antibacterial action of thymol. It is suggested that the effects of BSA or Desferal are due to their ability to bind phenolic compounds through their amino and hydroxylamine groups, respectively, thus preventing complexation reactions between the oil phenolic constituents and bacterial membrane proteins. This hypothesis is supported by the marked decrease in the viable counts of Salm. typhimurium caused by either thyme oil or thymol when the pH of the medium was changed from 6.5 to 5.5 or the concentration of Tween 80 in the medium was reduced.

Aerobiosis↗
PubMed1996

In vitro inhibition of Helicobacter pylori by extracts of thyme.

Extracts of several plants were tested for inhibitory activity against Helicobacter pylori. Among these plants thyme (aqueous extract) and cinnamon (alcoholic extract) were the most effective. Since aqueous extract of thyme is easier to produce and consume, it was further investigated. Compared with several antibacterials, the thyme extract had a significant inhibitory effect on H. pylori, reducing both its growth and potent urease activity. From the results of this study, the aqueous extract of thyme possesses a therapeutic potential which merits validation by clinical studies.

Anti-Bacterial Agents↗
PubMed2000

Effect of thyme oil and thymol dietary supplementation on the antioxidant status and fatty acid composition of the ageing rat brain.

The present study measured changes in antioxidant enzyme activity in, and the phospholipid fatty acid composition of the ageing rat brain and tested whether dietary supplementation with thyme oil or thymol could provide beneficial effects. There were significant declines in superoxide dismutase (EC 1.15.1.1) and glutathione peroxidase (EC 1.11.1.9) activities and the total antioxidant status in the untreated rats with age, while thyme-oil- and thymol-fed rats maintained significantly higher antioxidant enzyme activities and total antioxidant status. The proportions of 18:2n-6, 20:1n-9, 22:4n-6 and 22:5n-3 in the brain phospholipids resulting from all three dietary treatments were significantly higher in 28-month-old rats than in 7-month-old rats. Only 20:1n-9 levels in 28-month-old thyme-oil- and thymol-treated rats were significantly higher than in the age-matched control. The proportion of 22:6n-3 in brain phospholipids, which declined with age in control rats, was also significantly higher in rats given either supplement. This latter finding is particularly important as optimum levels of 22:6n-3 are required for normal brain function. These results highlight the potential benefit of thyme oil as a dietary antioxidant.

Aging↗
PubMed2000

Azo dye-mediated regulation of total phenolics and peroxidase activity in thyme (Thymus vulgaris L.) and rosemary (Rosmarinus officinalis L.) clonal lines.

Thyme (Thymus vulgaris L.) and rosemary (Rosmarinus officinalis L.) clonal lines, which were previously isolated from a heterogeneous seed population by plant tissue culture techniques, have been targeted as potential plants for phytoremediation of organic pollutants such as azo dyes and related aromatic compounds. Three thyme clonal lines and three rosemary clonal lines were tested for the ability to grow on hormone-free medium containing 0.01% of azo dye Poly S-119. The results showed that dye tolerance was associated with reduced phenolics and enhanced peroxidase activity in these clonal lines. There was a clear inverse correlation between total phenolics and peroxidase activity in these plants in response to Poly S-119. The tolerance of these clonal lines showed variations at different growing stages. These observations suggested that the peroxidase activity was inducible. Because peroxidases are involved in lignification, wound healing, aromatic compound degradation, pathogen defense, and stiffening, the results suggest that azo dye stimulated the defense response of thyme and rosemary clonal plants by increasing the peroxidase activity. Stereomicroscopic observations revealed that the azo dye was sequestered within the growing axis of the plant roots, which may also enhance the polymerization of azo dye onto the cell wall with the help of enhanced peroxidase activity.

Azo Compounds↗
PubMed1999

Dietary supplementation of thyme (Thymus vulgaris L.) essential oil during the lifetime of the rat: its effects on the antioxidant status in liver, kidney and heart tissues.

This study aimed not only to identify age-related changes in certain antioxidant systems, but to assess whether dietary supplementation of thyme oil could address the unfavourable antioxidant-pro-oxidant balance that occurs with age. The present study has shown that there were significant declines in the superoxide dismutase activities in the liver and heart of old rats, although kidney showed no decline. Liver glutathione peroxidase (GSHPx) activity was found to have increased significantly in old rats, while a significant decrease was observed in kidney. Heart GSHPX activity was not found to differ significantly between young and old rats. There were also significant declines in the total antioxidant status in each tissue examined. A general feature of these various antioxidant parameters measured was that their activities remained higher in rats whose diets were supplemented with thyme oil, suggesting that they retained a more favourable antioxidant capacity during their life span.

Aging↗
PubMed1996

Labiatae allergy: systemic reactions due to ingestion of oregano and thyme.

BACKGROUND: There are no cases described in the medical literature of systemic allergic reactions due to oregano (Origanum vulgare) or thyme (Thymus vulgaris). These herbs belong to the Lamiaceae (Labiatae) family which comprises other plants such as hyssop (Hyssopus officinalis), basil (Ocimum basilicum), marjoram (Origanum majorana), mint (Mentha piperita), sage (Salvia officinalis) and lavender (Lavandula officinalis). OBJECTIVE: We describe three systemic allergic reactions caused by oregano and thyme in the same patient. METHODS: Skin tests with inhalant allergens and plants of the Labiatae family were done. We used the prick by prick technique with dried commercial plants and prick tests with extracts prepared with the Frugoni method in our patient and in ten control patients. Total serum IgE was determined by Phadezym IgE PRIST (Pharmacia). Specific IgE was measured by two methods: CAP system (Pharmacia) and Phadezym RAST (Pharmacia Diagnostics, Uppsala, Sweden) with activated discs of the allergenic extracts that were prepared in our laboratory. RESULTS: Skin tests with inhalants were positive to grasses. Skin tests with plants of the Labiatae family were positive in all cases when the skin prick technique was used; tests were negative with basil and lavender, and positive with all the others when we used the prick by prick technique. We did not detect any positive skin tests nor specific IgE to plants of the Labiatae family in control patients. Total serum IgE was 406 U/mL. Specific IgE was detected to all herbs tested; higher levels were obtained with the CAP system. CONCLUSIONS: Plants belonging to the Labiatae family seem to show cross-sensitivity on the basis of clinical history and in vitro and in vivo test results.

Food Hypersensitivity↗
PubMed2004

Inductively coupled plasma optical emission spectrometric determination of minerals in thyme honeys and their contribution to geographical discrimination.

Twenty-four Spanish thyme honey samples were analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES). Twenty-four minerals were quantified for each honey. The elements Al, As, Ba, Ca, Cr, Cu, Fe, K, Li, Mg, Mn, Na, P, Pb, S, Se, Si, Sr, and Zn were detected in all samples; seven elements are very abundant (Ca, K, Mg, Na, P, S, and Si), and six are not abundant (Al, Cu, Fe, Li, Mn, and Zn). Eleven of them are trace elements (As, Ba, Cd, Co, Cr, Ni, Mo, Pb, Se, Sr, and V) at <1 mg kg(-)(1). Classification of thyme honeys according to their origin (coast, mountains) was achieved by pattern recognition techniques on the mineral data. By means of principal component analysis, a good separation by geographical origin is obtained when scores for the two first principal components are plotted. Classification functions of 11 metals (Al, As, Cr, Cu, K, Li, Mg, Na, P, S, and V) were obtained using stepwise discriminant analysis and applied to classify correctly approximately 100% of the honey samples.

Honey↗
PubMed1996

Effect of honey versus thyme on Rubella virus survival in vitro.

In this paper, we assess the antiviral properties of honey solutions and thyme extracts at varying concentrations. This was done by testing these solutions in vitro using monkey kidney cell cultures that were infected with the Rubella virus. Our results indicated that honey had good anti-Rubella activity, while thyme did not. These results may justify the continuing use of honey in traditional medicines from different ethnic communities worldwide and in some modern medications such as cough syrups.

Antiviral Agents↗
PubMed2001

[Studies on antimicrobial activity of extracts from thyme].

The extracts from thyme by water and ethanol, thyme essential oil, thymol and carvacrol were used as antimicrobial agents in this paper. The results show that all antimicrobial agents used have strong inhibition activity against Staphalococcus aureus, Bacillus subtilis, Escherichia coli.

Anti-Bacterial Agents↗
PubMed2002

Human platelet aggregation inhibitors from thyme (Thymus vulgaris L.).

Two antiaggregant compounds, thymol (compound 1) and 3,4,3',4'-tetrahydroxy-5,5'-diisopropyl-2,2'-dimethylbiphenyl (compound 2) were isolated from the leaves of thyme (Thymus vulgaris L.). The structures were determined by (1)H-, (13)C-NMR and mass spectra (MS) studies. These compounds inhibited platelet aggregation induced by collagen, ADP, arachidonic acid (AA) and thrombin except that compound 2 did not inhibit platelet aggregation induced by thrombin.

Humans↗
PubMed2004

Control of Aeromonas on minimally processed vegetables by decontamination with lactic acid, chlorinated water, or thyme essential oil solution.

Aeromonas is an opportunistic pathogen, which, although in low numbers, may be present on minimally processed vegetables. Although the intrinsic and extrinsic factors of minimally processed prepacked vegetable mixes are not inhibitory to the growth of Aeromonas species, multiplication to high numbers during processing and storage of naturally contaminated grated carrots, mixed lettuce, and chopped bell peppers was not observed. Aeromonas was shown to be resistant towards chlorination of water, but was susceptible to 1% and 2% lactic acid and 0.5% and 1.0% thyme essential oil treatment, although the latter provoked adverse sensory properties when applied for decontamination of chopped bell peppers. Integration of a decontamination step with 2% lactic acid in the processing line of grated carrots was shown to have the potential to control the overall microbial quality of the grated carrots and was particularly effective towards Aeromonas.

Aeromonas↗