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PubMed2006

Synergistic bactericidal effect of carvacrol, cinnamaldehyde or thymol and refrigeration to inhibit Bacillus cereus in carrot broth.

Possible use of three different essential oil components as natural food preservatives was studied by examining their influence in the kinetics of growth from activated spores of four Bacillus cereus strains in tyndallized carrot broth over the temperature range 5-16 degrees C. Selected low concentrations of carvacrol, cinnamaldehyde, or thymol showed a clear antibacterial activity against B. cereus in the vegetable substrate. The addition of 2 microl cinnamaldehyde or 20 mg thymol to 100 ml of broth in combination with refrigeration temperatures (<or= 8 degrees C) was able to inhibit the outgrowth from activated spores of the psychrotrophic strain INRA TZ415 for at least 60 days, but only cinnamaldehyde did it even at the mild abuse temperature of 12 degrees C. Five microliters of carvacrol per 100 ml of inoculated carrot broth, however, were unable to inhibit bacterial growth at 8 degrees C.

Acrolein↗
PubMed2000

The effect of thymol and its derivatives on reactions generating reactive oxygen species.

The effects of thymol (TOH), thymoquinone (TQ) and dithymoquinone (TQ2) on the reactions generating reactive oxygen species (ROS) such as superoxide anion radical (O2*-), hydroxyl radical (HO*) and singlet oxygen (1O2) were tested using the chemiluminescence (CL) and spectrophotometry methods. All tested compounds acted as scavengers of various ROS. The rate constant of 1O2-dimols quenching by thymol was calculated.

Anti-Infective Agents↗
PubMed2005

Improvement of table grapes quality and safety by the combination of modified atmosphere packaging (MAP) and eugenol, menthol, or thymol.

Table grape is a nonclimacteric fruit that shows a rapid loss of quality during storage and is very susceptible to colonization by fungi, especially Botrytis cinerea, which is considered the most important disease of this commodity. To solve this problem, synthetic fungicides have been used, although legal restrictions and consumer's concern demand the search of other safe means. In the present paper, and as an alternative of synthetic fungicides, an active packaging to improve MAP effectiveness on preserving table grape (cv. Crimson Seedless) quality and safety was developed by the addition of 0.5 mL of eugenol, thymol, or menthol inside the packages. Packages were stored at 1 degree C for 35 days. The final gas composition inside the packages was 1.4-2.0 and 10.0-14.5 kPa of CO(2) and O(2), respectively, with no significant slight differences among treatments. Results showed that the addition of eugenol, thymol, or menthol improved the beneficial effect of MAP in terms of delaying weight loss and color changes, retarding degrees Brix/acidity ratio evolution, and maintaining of firmness. Thereafter, these treatments showed additional benefit in terms of delayed rates of rachis deterioration and berry decay. Finally, the total viable counts for both mesophilic aerobics and especially yeast and molds were significantly reduced in the grapes packaged with the natural antimicrobial compounds. All of the above effects led to maintenance of table grape quality and safety for longer storage periods (3 additional weeks as compared to controls under MAP only).

Carbon Dioxide↗
PubMed2002

Effectiveness of chlorhexidine-thymol varnish for caries reduction in permanent first molars of 6-7-year-old children: 24-month clinical trial.

OBJECTIVES: To determine the effect of chlorhexidine varnish on the prevention of caries in permanent first molars. METHODS: Two groups of 6-7-year-old school children were followed up in a clinical trial, a group of 86 children whose teeth were treated with a chlorhexidine-thymol varnish (Cervitec) and a control group of 95 children. The varnish was reapplied every 3 months and the caries increments were compared at 24 months. RESULTS: The DFS (decayed and filled surfaces in permanent first molars) increment in the control group (mean = 1.85; SD = 2.27) was higher than in the test group (mean = 0.95; SD = 1.38), resulting in a 48.6% caries reduction. This difference was statistically significant (P = 0.032). CONCLUSIONS: Chlorhexidine-thymol varnish is effective in preventing caries in permanent first molars.

Anti-Infective Agents, Local↗
PubMed2005

Suitability of bifidobacteria and thymol as biopreservatives in extending the shelf life of fresh packed plaice fillets.

AIMS: The present study was aimed to evaluate the microbiological and sensory characteristics of biopreserved packed fresh plaice (Pleuronectes platessa), during storage. METHODS AND RESULTS: Fish samples were treated with a Bifidobacterium bifidum strain and thymol as preservatives, stored at different temperatures (4 and 12 degrees C) and package atmospheres (in air, under vacuum, modified atmosphere). Data about the total viable count (TVC) were used to predict the shelf life of the fish fillets as affected by the preservatives used and the storage conditions. Data obtained revealed that B. bifidum could perform an efficient synergy with thymol, in controlling the hygiene biological markers. Besides, the tested bifidobacterial species, combined with low storage temperature and anoxia/hypoxia, showed a great efficacy against the main fresh packaged fish spoilage species (Pseudomonas spp., Photobacterium phosphoreum). CONCLUSIONS: The studied technique could be considered effective in fresh fish spoilage control. SIGNIFICANCE AND IMPACT OF THE STUDY: Great interest is developing on food biopreservation, because of the ever increasing needs to protect consumers' and environment's health, and to revalorize some important food characteristics, such as naturalness and authenticity, without leaving the safety aside.

Animals↗
PubMed2006

In vitro assessment of antimicrobial activity of carvacrol, thymol and cinnamaldehyde towards Salmonella serotype Typhimurium DT104: effects of pig diets and emulsification in hydrocolloids.

AIMS: To determine the effect of pig diets in vitro on the antimicrobial activity of carvacrol, thymol and cinnamaldehyde, and to identify an emulsifier/stabilizer that can stabilize the essential oil (EO) components in aqueous solution and retain their antimicrobial activity in the presence of the diets. METHODS AND RESULTS: Emulsification of essential oil components with hydrocolloid solution was achieved by blending with a Polytron. Antimicrobial activity was measured through in vitro assays to determine the inhibition of bacterial growth by measuring the optical density at 600 nm or plating on nutrition agar after incubation of the mixtures of an EO component with the culture of Salmonella serotype Typhimurium DT104 in the presence or absence of pig diets. The results generated through the in vitro assays indicated that pig diets were able to abolish the antimicrobial activity of EOs. Xanthan, fenugreek and yellow mustard gums were the best in forming stable emulsions of five different EO components among ten different plant polysaccharides and surfactants examined. Emulsification of all the EO components in the fenugreek gum solution did not alter their antimicrobial activity. However, the antimicrobial activity of geraniol was significantly reduced when emulsified with other polysaccharides and surfactants. Both fenugreek and xanthan gum solutions were unable to protect the antimicrobial activity of carvacrol and thymol when mixed with the diets. Although cinnamaldehyde required no emulsification, but a high concentration (equivalent to at least three times of minimum bactericidal concentration for cinnamon oil) to inhibit Salmonella growth significantly in the presence of the diets, emulsification in fenugreek gum appeared to be essential for cinnamaldehyde solution to retain its antimicrobial activity during storage. CONCLUSIONS: The diets for newly weaned pigs were a significant factor limiting the antimicrobial activity of EOs and their components. Cinnamaldehyde required a high concentration to retain its antimicrobial activity in the diets, in addition to its requirement for emulsification to stabilize its activity during the storage. SIGNIFICANCE AND IMPACT OF THE STUDY: The assay with the diets used in this study for measuring the antimicrobial activity can be used in vitro for rapid and effective screening of potential antimicrobials for swine production. This study has identified polysaccharides that are able to stabilize EO component solutions. It has also identified cinnamaldehyde for further in vivo studies that may have potential in future application in controlling Salmonella and possibly other enteric pathogens in swine production.

Acrolein↗
PubMed2004

Surface alteration of Saccharomyces cerevisiae induced by thymol and eugenol.

AIMS: This study aims to bring some information about the mechanism of the fungicidal action of thymol and eugenol; phenolic major components of thyme and clove essential oils respectively. Saccharomyces cerevisiae was used as yeast model. METHODS AND RESULTS: Treatment of yeast cells with these components led to their lysis as shown by the release of substances absorbing at 260 nm. In addition, scanning electron microscope observations revealed that the surface of the treated cells was significantly damaged. CONCLUSIONS: Antifungal activity of thymol and eugenol involve alteration of both membrane and cell wall of the yeast. SIGNIFICANCE AND IMPACT OF THE STUDY: This work is a preliminary contribution aiming to develop a new generation of efficient and natural antifungal agents.

Antifungal Agents↗
PubMed1987

Metabolism in rats of p-cymene derivatives: carvacrol and thymol.

The metabolism of carvacrol and thymol in rats was studied using gas chromatographic-mass spectrometric methods. The urinary excretion of metabolites was rapid. Only very small amounts were excreted after 24 hrs. Although large quantities of carvacrol and, especially, thymol were excreted unchanged (or as their glucuronide and sulphate conjugates), extensive oxidation of the methyl and isopropyl groups also occurred. This resulted in the formation of derivatives of benzyl alcohol and 2-phenylpropanol and their corresponding carboxylic acids. In contrast, ring hydroxylation of the two phenols was a minor reaction.

Animals↗
PubMed2006

Efficacy of chlorhexidine-thymol varnish (Cervitec) against plaque accumulation and gingival inflammation in a geriatric population.

OBJECTIVES: To determine whether the 3-monthly application of chlorhexidine (CHX)-thymol varnish is an effective method of controlling plaque and gingivitis in a group of institutionalised elderly as a complement to their usual oral hygiene practices. DESIGN: A 6-month double-blind clinical trial. SETTING: Two residential homes in Almería (Spain). PARTICIPANTS: Fifty-six dentate subjects aged above 64 years who completed the 6-month study. INTERVENTION: The study subjects were randomly assigned to one of two groups (Cervitec or placebo). Varnishes were applied twice in the first week of the study and were applied again a month later and every 3 months until the end of the study. The patients continued with their usual oral hygiene practices throughout the study. MEASUREMENT: Plaque index and gingival index scores were determined at baseline and after 1, 3 and 6 months. RESULTS: Treatment with Cervitec varnish had a statistically significant effect overtime on the gingival index score (p = 0.029), but not on the plaque index score (p = 0.651). The groups did not significantly differ in reductions in plaque or gingival index scores between baseline and 1, 3 or 6 months. CONCLUSION: According to these results, Cervitec, a CHX-thymol varnish, does not appear to reduce plaque and gingivitis by a 3-monthly application in the institutionalised elderly with poor oral hygiene. Wider studies are required to investigate different varnishing protocols in geriatric populations.

Aged↗
PubMed1975

Role of IgG fractions with high isoelectric points in the thymol turbidity test in syphilis. Evidence for an increase in basic IgG in early syphilis.

It is demonstrated that IgG fractions with isoelectric points above 7.6, isolated from pooled syphilitic sera, are able to elevate the thymol turbidity. The effect increases with increasing isoelectric points of the isolated fraction. IgG from individual syphilitic patients exerts a stronger effect on the thymol turbidity than normal IgG. It is concluded that elevated amounts of these basic immunoglobulins are present in the sera of syphilitic subjects.

Electrophoresis↗
PubMedDate not supplied

Effect of a varnish containing chlorhexidine and thymol (Cervitec) on approximal caries in 13- to 16-year-old schoolchildren in a low caries area.

BACKGROUND: Previous studies on the effect of the chlorhexidine and thymol-containing varnish (Cervitec((R))) have consistently shown a reduction in STREPTOCOCCUS MUTANS, while the data on the caries-inhibiting effect are conflicting. AIM: To measure the effect of a chlorhexidine- and thymol-containing varnish (Cervitec) on approximal caries in a low caries population. MATERIAL: Eighty-five schoolchildren, 13 years of age, entered the study after being selected on the basis of bitewing radiographs. Children with at least one approximal lesion were included after informed consent. METHODS: The study was carried out as a double-blind, randomized controlled trial according to a split-mouth design using Cervitec on one side and a placebo varnish on the other side. All approximal surfaces between molars and premolars were treated every 3rd month. After 2 years new bitewing radiographs were taken. A total of 73 children completed the 2-year study. RESULTS: Neither the difference in number of new lesions between the Cervitec-treated and the placebo-treated side (d: -0.21; 95% CI: -0.57; 0.16) nor the mean difference in number of already existing lesions that progressed (d: -0.01; 95% CI: -0.33; 0.30) were statistically significant (paired t test; p > 0.05). CONCLUSION: The results of our study do not indicate an effect of Cervitec on initiation or progression of approximal caries in a population with a low DMFS.

Adolescent↗
PubMed2001

Effect of carvacrol and thymol on odor emissions from livestock wastes.

A majority of the beef cattle and swine in the United States is produced in confined facilities. This generates significant environmental pollutants from the waste produced, including global warming gases, odor, and pathogens. The objectives of this study were to control the fermentation activity and pathogens in cattle and swine wastes with antimicrobial plant essential oils. Anaerobic one litre flasks with a working volume of 0.5 l were used to evaluate the effect of carvacrol and thymol on production of fermentation gas, short-chain volatile fatty acids, lactate, and bacterial populations. In cattle waste, 1 g l(-1) each of carvacrol and thymol completely inhibited the production of volatile fatty acids and lactate over 23 days. In swine waste, 2.5 g l(-1) carvacrol inhibited the production of all volatile fatty acids. We conclude that these essential oils are effective in controlling livestock waste odor emissions and field studies are warranted.

Air Pollution↗
PubMed2000

[Gas chromatographic determination of camphor, menthol, methyl salicylate, thymol in JEIL COOL PAP].

The contents of camphor, menthol, methyl salicylate and thymol in JEIL COOL PAP were determined with gas chromatography by using a stainless steel column (2 m x 3 mm i.d.) packed with 15% DEGS, Chromosorb W (AW-DMCS) 80-100 mesh. Temperature programming was from 70 degrees C to 180 degrees C. The quantitative determination was performed with diphenyl as the internal standard. The internal standard method showed good linearity (r = 0.9995-0.9999). The average recoveries were 99.63% (camphor), 99.83% (menthol), 100.0% (methyl salicylate) and 100.4% (thymol).

Camphor↗
PubMed2004

[Determination of carvacrol and thymol in Mosla chinensis by HPLC].

OBJECTIVE: To establish a quantitative method of determination of carvacrol and thymol in Mosla chinensis. METHOD: The sample was extracted with 95% ethanol, ODS column was used with methanol-water-acetic acid (60:40:2) as mobile phase. The detection wavelength was set at 274 nm. RESULT: The linearities of carvacrol and thymol were respectively in the range of 0.23-2.15 microg (r = 0.9999) and 0.39-2.36 microg (r = 0.9999); the average recoveries were 99.9% (RSD 1.4%) and 98.6% (RSD 1.3%); the RSD of repeatability were 1.1% and 1.6%. CONCLUSION: The method is reliable, and can be used for quality control of M. chinensis.

Chromatography, High Pressure Liquid↗
PubMed1994

Thymol derivatives from Phagnalon Sinaicum Bornm & Kneuck.

Phytochemical investigation of the aerial parts of Phagnalon sinaicum Bor. Kn. yielded thymol, three thymol derivatives, in addition to dammadienyl acetate, squalene and phytol. The structures of these compounds were elucidated by spectroscopic methods, m.p. and Co-TLC.

Magnetic Resonance Spectroscopy↗
PubMed2004

13C-CPMAS and 1H-NMR study of the inclusion complexes of beta-cyclodextrin with carvacrol, thymol, and eugenol prepared in supercritical carbon dioxide.

Beta-cyclodextrin (beta-CD) inclusion complexes with carvacrol (1), thymol (2), and eugenol (3) (components of essential oils of vegetable origin) were prepared by the supercritical CO2 technique, and their structural characterization was achieved by means of 1H-NMR in aqueous solution and 13C-CPMAS NMR in the solid state. Evidence of the formation of the inclusion complexes for all the examined systems was obtained by 1H-NMR in solution, while 2D-ROESY-NMR experiments were used to investigate the geometry of inclusion. In addition, the dynamics of these inclusion complexes in the kHz timescale was investigated by analysis of the 1H and 13C spin-lattice relaxation times in the rotating frame.

Carbon Dioxide↗
PubMedDate not supplied

Simultaneous quantification of eudesmanolides and thymol derivatives from tissues of Inula helenium and I. royleana by reversed-phase high-performance liquid chromatography.

A simple and rapid isocratic reversed-phase high-performance liquid chromatographic method for the quantification of alantolactone/isoalantolactone and three thymol derivatives in roots and root cultures of Inula helenium and I. royleana has been developed. The method could be applied to screen raw materials in search for highly productive plants and in vitro cultures.

Anti-Inflammatory Agents, Non-Steroidal↗