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PubMed2002

Systemic availability and pharmacokinetics of thymol in humans.

Essential oil compounds such as found in thyme extract are established for the therapy of chronic and acute bronchitis. Various pharmacodynamic activities for thyme extract and the essential thyme oil, respectively, have been demonstrated in vitro, but availability of these compounds in the respective target organs has not been proven. Thus, investigation of absorption, distribution, metabolism, and excretion are necessary to provide the link between in vitro effects and in vivo studies. To determine the systemic availability and the pharmacokinetics of thymol after oral application to humans, a clinical trial was carried out in 12 healthy volunteers. Each subject received a single dose of a Bronchipret TP tablet, which is equivalent to 1.08 mg thymol. No thymol could be detected in plasma or urine. However, the metabolites thymol sulfate and thymol glucuronide were found in urine and identified by LC-MS/MS. Plasma and urine samples were analyzed after enzymatic hydrolysis of the metabolites by headspace solid-phase microextraction prior to GC analysis and flame ionization detection. Thymol sulfate, but not thymol glucuronide, was detectable in plasma. Peak plasma concentrations were 93.1+/-24.5 ng ml(-1) and were reached after 2.0+/-0.8 hours. The mean terminal elimination half-life was 10.2 hours. Thymol sulfate was detectable up to 41 hours after administration. Urinary excretion could be followed over 24 hours. The amount of both thymol sulfate and glucuronide excreted in 24-hour urine was 16.2%+/-4.5% of the dose.

Administration, Oral↗

PubMed2003

Effect of thymol on kinetic properties of Ca and K currents in rat skeletal muscle.

BACKGROUND: Thymol is widely used as a general antiseptic and antioxidant compound in the medical practice and industry, and also as a stabilizer to several therapeutic agents, including halothane. Thus intoxication with thymol may occur in case of ingestion or improper anesthesia. In the present study, therefore, concentration-dependent effects of thymol (30-600 micro-grams) were studied on calcium and potassium currents in enzymatically isolated rat skeletal muscle fibers using the double vaseline gap voltage clamp technique. RESULTS: Thymol suppressed both Ca and K currents in a concentration-dependent manner, the EC50 values were 193 +/- 26 and 93 +/- 11 microM, with Hill coefficients of 2.52 +/- 0.29 and 1.51 +/- 0.18, respectively. Thymol had a biphasic effect on Ca current kinetics: time to peak current and the time constant for inactivation increased at lower (100-200 microM) but decreased below their control values at higher (600 microM) concentrations. Inactivation of K current was also significantly accelerated by thymol (200-300 microM). These effects of thymol developed rapidly and were partially reversible. In spite of the marked effects on the time-dependent properties, thymol caused no change in the current-voltage relationship of Ca and K peak currents. CONCLUSIONS: Present results revealed marked suppression of Ca and K currents in skeletal muscle, similar to results obtained previously in cardiac cells. Furthermore, it is possible that part of the suppressive effects of halothane on Ca and K currents, observed experimentally, may be attributed to the concomitant presence of thymol in the superfusate.

Animals↗

PubMed1988

Stimulation of guinea pig neutrophil superoxide anion-producing system with thymol.

Thymol stimulated O2- production in guinea pig neutrophils. O2- production occurred about 30 sec after the addition of thymol, and its rate was independent of extracellular Ca2+. Thymol-induced activity was inhibited by trifluoperazine (TFP), an inhibitor of protein kinase c, and its IC50 was less than that for 12-O-tetradecanoyl phorbol 13-acetate (TPA) induced activity. After complete activation, O2- production was reversed by addition of TFP or by washing out and resuspending in a stimuli-free medium. The responsiveness of the thymol-pulsed cells to another stimulus, TPA, was somewhat more than resting cells, but the responsiveness of the former cells to thymol was about half that of the latter cells. The ATP level of cells was reduced to one half its initial value during activation by thymol. These data suggest that the magnitude of thymol-induced O2- production in neutrophils is dependent on the initial density of the binding sites of the cells with thymol and the initial intracellular ATP concentration.

Animals↗

PubMed2004

Surface activity of thymol: implications for an eventual pharmacological activity.

In the present work, we studied the ability of thymol to affect the organization of model membranes and the activity of an intrinsic membrane protein, the GABA(A) receptor (GABA(A)-R). In this last aspect, we tried to elucidate if the action mechanism of this terpene at the molecular level, involves its binding to the receptor protein, changes in the organization of the receptor molecular environment, or both. The self-aggregation of thymol in water with a critical micellar concentration approximately = 4 microM and its ability to penetrate in monomolecular layers of soybean phosphatidylcholine (sPC) at the air-water interface, even at surface pressures above the equilibrium, lateral pressure of natural bilayers were demonstrated. Thymol affected the self-aggregation of Triton X-100 and the topology of sPC vesicles. It also increased the polarity of the membrane environment sensed by the electrochromic dye merocyanine. A dipolar moment of 1.341 Debye was calculated from its energy-minimized structure. Its effect on the binding of [3H]-flunitrazepam ([3H]-FNZ) to chick brain synaptosomal membranes changed qualitatively from a tendency to the inhibition to a clear activatory regime, up on changing the phase state of the terpene (from a monomeric to a self-aggregated state). Above its CMC, thymol increased the affinity of the binding of [3H]-FNZ (K(d-control)= 2.9, K(d-thymol)= 1.7 nM) without changing the receptor density (B(max-control)= 910, B(max-thymol)= 895 fmol/mg protein). The activatory effect of thymol on the binding of [ [3H]-FNZ was observed even in the presence of the allosteric activator gamma-aminobutyric acid (GABA) at a concentration of maximal activity, and was blocked by the GABA antagonist bicuculline. Changes in the dipolar arrangement and in the molecular packing of GABA(A)-R environment are discussed as possible mediators of the action mechanism of thymol.

Air↗

PubMed2005

Allosteric positive interaction of thymol with the GABAA receptor in primary cultures of mouse cortical neurons.

Thymol is a naturally occurring phenolic monoterpene known for its anti-microbial and anti-oxidant properties. It is used in dental practice and in anaesthetic halothane preparations. Recent studies have reported enhanced GABA(A) receptor-operated chloride channel activity and increased binding affinity of [(3)H]flunitrazepam in the presence of thymol. In the present work, we more closely examined the pharmacological action of thymol on the native GABA(A) receptor by using primary cultures of cortical neurons. Thymol enhanced GABA-induced (5 microM) chloride influx at concentrations lower than those exhibiting direct activity in the absence of GABA (EC(50) = 12 microM and 135 microM, respectively). This direct effect was inhibited by competitive and non-competitive GABA(A) receptor antagonists. Thymol increased [(3)H]flunitrazepam binding (EC(50) = 131 microM) and showed a tendency to increase [(3)H]muscimol binding. These results confirm that thymol is a positive allosteric modulator of the GABA(A) receptor. The thymol structural analogues menthol and cymene, which lack an aromatic ring or a hydroxyl group, did not affect [(3)H]flunitrazepam binding. Using a pharmacophoric model that includes a hydrogen bond donor group as well as an aromatic ring with two aliphatic substituents, we propose to demonstrate the molecular essential features of these compounds to interact with GABA(A) receptors. Thymol (0-1 mM) did not affect cellular viability.

Anesthetics, Intravenous↗

PubMed2002

Voltage-dependent block of neuronal and skeletal muscle sodium channels by thymol and menthol.

BACKGROUND AND OBJECTIVE: Thymol is a naturally occurring phenol derivative used in anaesthetic practice as a stabilizer and preservative of halothane, usually at a concentration of 0.01%. Although analgesic effects have long been described for thymol and its structural homologue menthol, a molecular basis for these effects is still lacking. We studied the blocking effects of thymol and menthol on voltage-activated sodium currents in vitro as possible molecular target sites. METHODS: Whole cell sodium inward currents via heterologously (HEK293 cells) expressed rat neuronal (rat type IIA) and human skeletal muscle (hSkM1) sodium channels were recorded in the absence and presence of definite concentrations of either thymol or menthol. RESULTS: When depolarizing pulses to 0 mV were started from a holding potential of -70 mV, half-maximum blocking concentrations (IC50) for the skeletal muscle and the neuronal sodium channel were 104 and 149 mumol for thymol and 376 and 571 mumol for menthol. The blocking potency of both compounds increased at depolarized holding potentials with the fraction of inactivated channels. The estimated dissociation constant Kd for thymol and menthol from the inactivated state was 22 and 106 mumol for the neuronal and 23 and 97 mumol for the skeletal muscle sodium channel, respectively. CONCLUSIONS: The results suggest that antinociceptive and local anaesthetic effects of thymol and menthol might be mediated via blockade of voltage-operated sodium channels with the phenol derivative thymol being as potent as the local anaesthetic lidocaine.

Analgesics↗

PubMed2002

Effects of thymol on calcium and potassium currents in canine and human ventricular cardiomyocytes.

1. Concentration-dependent effects of thymol (1 - 1000 microM) was studied on action potential configuration and ionic currents in isolated canine ventricular cardiomyocytes using conventional microelectrode and patch clamp techniques. 2. Low concentration of thymol (10 microM) removed the notch of the action potential, whereas high concentrations (100 microM or higher) caused an additional shortening of action potential duration accompanied by progressive depression of plateau and reduction of V(max). 3. In the canine cells L-type Ca current (I(Ca)) was decreased by thymol in a concentration-dependent manner (EC(50): 158+/-7 microM, Hill coeff.: 2.96+/-0.43). In addition, thymol (50 - 250 microM) accelerated the inactivation of I(Ca), increased the time constant of recovery from inactivation, shifted the steady-state inactivation curve of I(Ca) leftwards, but voltage dependence of activation remained unaltered. Qualitatively similar results were obtained with thymol in ventricular myocytes isolated from healthy human hearts. 4. Thymol displayed concentration-dependent suppressive effects on potassium currents: the transient outward current, I(to) (EC(50): 60.6+/-11.4 microM, Hill coeff.: 1.03+/-0.11), the rapid component of the delayed rectifier, I(Kr) (EC(50): 63.4+/-6.1 microM, Hill coeff.: 1.29+/-0.15), and the slow component of the delayed rectifier, I(Ks) (EC(50): 202+/-11 microM, Hill coeff.: 0.72+/-0.14), however, K channel kinetics were not much altered by thymol. These effects on Ca and K currents developed rapidly (within 0.5 min) and were readily reversible. 5. In conclusion, thymol suppressed cardiac ionic channels in a concentration-dependent manner, however, both drug-sensitivities as well as the mechanism of action seems to be different when blocking calcium and potassium channels.

Action Potentials↗

PubMed2006

Incorporation of thymol into corncob granules for reduction of odor and pathogens in feedlot cattle waste.

Confined animal feeding operations can be a source of odor emissions, global warming gases, water pollution, and food contamination. Laboratory studies have indicated that plant oils with antimicrobial activity can be used to control pathogens and odor emissions from cattle and swine wastes. However, these oils are aromatic and may volatilize when applied topically. Our objectives were to evaluate the volatility of thymol from a feedlot surface and the effectiveness of topically applying thyme oil (2.5% thymol), incorporated into corncob granules and added once per week, to control odor emissions and total coliforms in feedlot manure. In the first study, thymol either volatilized or was degraded within 28 d after topical application. In a second study, thyme oil (2.5% thymol) was incorporated into corncobs and applied to pen surfaces weekly. Manure samples from 6 locations in each pen were collected from 3 untreated and 3 thymol-corncob-treated pens (15 x 150 m; fifty 400-kg cattle/pen), 3 times per week for 8 wk. Samples were analyzed for thymol concentration, total VFA, branched-chain VFA, aromatic compounds, and the number of Escherichia coli and total coliform bacteria. Over the 8 wk, with the exception of wk 7, the desired thymol concentration of 15 to 20 micromol/g DM was maintained in the manure. Concentrations of VFA and branched chain-VFA increased over time in untreated and treated pens. However, the rate of VFA accumulation in treated pens (7.5 +/- 1.3 micromol.g DM(-1).wk(-1)) was less (P < 0.01) than the rate of accumulation in untreated pens (18.0 +/- 2.1 micromol.g DM(-1).wk(-1)). Likewise, the rate of branched-chain VFA accumulation in treated pens (0.31 +/- 0.04 micromol.g DM(-1).wk(-1)) was less (P < 0.01) than in untreated pens (0.55 +/- 0.06 micromol.g DM(-1).wk(1)). The concentrations of E. coli in treated pens (2.9 +/- 1.2 x 10(5) cfu.g DM(-1)) were 91% less (P < 0.04) than in untreated pens (31.1 +/- 4.0 x 10(5) cfu.g DM(-1)). Similarly, concentrations of coliforms in treated pens (3.7 +/- 1.3 x 10(5) cfu.g DM(-1)) were 89% less (P < 0.04) than those of untreated pens (35.3 +/- 4.2 x 10(5) cfu.g DM(-1)). These results indicate that odor emissions and total coliforms can be reduced in feedlot manure with a once per week application of thymol incorporated in a granular form. However, corncobs are bulky, and other granular carriers with a greater carrying capacity for thyme oil should be explored.

Animal Husbandry↗

PubMed1991

Chlorhexidine and thymol release from a varnish system.

The release of chlorhexidine and/or thymol from an antimicrobial containing varnish in an in vitro model was investigated. Four varnishes with the same polymer base were studied; one with chlorhexidine only, one with thymol only, one with both agents and a placebo varnish without the active agents. Microscope glass slides were covered with the varnishes and stored in water. During the following three months liquid samples were regularly withdrawn and analysed for chlorhexidine and thymol content. The released amounts of chlorhexidine and/or thymol were determined by means of U.V. spectrophotometry. The results showed that chlorhexidine was released slowly from the chlorhexidine-only varnish compared with the thymol release from the thymol-only varnish. In the case of the clinically tested varnish (containing both active ingredients chlorhexidine and thymol) the amounts of thymol and chlorhexidine released were comparable. Most important, however, was the observation that in the last mentioned case both agents continued to be released after 3 months.

Chlorhexidine↗

PubMed2004

Thymol and carvacrol binding to DNA: model for drug-DNA interaction.

Thymol and carvacrol can bind to major and minor grooves of B-DNA. The aim of this study was to examine the interaction of calf thymus DNA with thymol and carvacrol in aqueous solution and physiological pH with thymol/DNA and carvacrol/DNA (phosphate) molar ratios of 1/20, 1/10, 1/5, and 1/1. Fourier transform infrared and UV-visible difference spectroscopy were used to determine the thymol and carvacrol binding mode, binding constant, sequence selectivity, DNA secondary structure, and structural variations of thymol/DNA and carvacrol/DNA complexes in aqueous solution. Spectroscopic evidence showed that the thymol and carvacrol interaction occurred mainly through H-bonding of the thymol and carvacrol OH group to the guanine N7, cytosine N3, and backbone phosphate group with overall binding constant of K(thymol-DNA) = 2.43 x 10(3) M(-1), K(carvacrol-DNA) = 1.55 x 10(3) M(-1). In thymol and carvacrol-DNA complexes, DNA remains in the B-family structure.

Animals↗

PubMed1999

The protective action of thymol against carbon tetrachloride hepatotoxicity in mice.

The protective action of thymol (paramethyl-isopropyl-phenol) was investigated against carbon tetrachloride (CCl(4))-induced hepatotoxicity in male Swiss albino mice. The CCl(4)at a dose of 20 microl kg(-1)produced damage to liver cells and was followed by the significant increase (P<0.001) in serum alanine aminotransferase (ALT) activity and hepatic lipid peroxidation after 24 h. The hepatocellular necrosis was further confirmed by histopathological examination of liver section. Oral administration of thymol in a single dose (300 mg kg(-1)) resulted in significant (P<0.05) amelioration of CCl(4)-induced hepatotoxicity. Thymol also inhibited lipid peroxidation induced by CCl(4)in vivo. The protection offered by thymol was also evident from histopathology photomicrograph. In a separate in vitro assay, thymol inhibited the non-enzymatic lipid peroxidation of normal mice liver homogenate induced by Fe(3+)-ascorbate. The present study suggests that thymol protects the liver against CCl(4)-induced toxicity and the protection may be mediated through its ability to inhibit lipid peroxidation. However, other interactions between thymol and CCl(4)remains to be elucidated. 1999 Academic Press.

Alanine Transaminase↗

PubMed2005

Stimulatory actions of thymol, a natural product, on Ca(2+)-activated K(+) current in pituitary GH(3) cells.

Drugs that influence the opening of potassium (K(+)) channels and as a consequence cause hyperpolarization of cell membrane possess clinical potential. The large conductance Ca(2+)-activated K(+) (BK) channel is highly selective for K(+). Activation of this channel is Ca(2+)- and voltage-dependent. We have investigated the effects of thymol, a natural product, on ion currents in pituitary GH(3) cells. The patch-clamp technique was used to investigate the effect of thymol (100 microM) in these cells. Thymol reversibly stimulated the Ca(2+)-activated K(+) current with an EC (50) value of 75 microM. In a cell-attached configuration, application of thymol to the bath increased the activity of BK channels. BAPTA (1 mM) attenuated thymol-stimulated channel activity. In an experiment using the inside-out configuration, thymol exposed to the intracellular face of excised patches did not modify the single-channel conductance of these channels whereas it enhanced the channel activity. Neither menthol (100 microM) nor zingerone (100 microM) had an effect on BK-channel activity while AAPH (100 microM) suppressed it significantly. The stimulatory actions of thymol on Ca(2+)-activated K(+) currents may be associated with the underlying cellular mechanisms through which it affects neuronal or neuroendocrine functions.

Animals↗

PubMed1995

The action of thymol on oral bacteria.

Several effects of thymol, a plant-derived antimicrobial agent, on Porphyromonas gingivalis, Selenomonas artemidis and Streptococcus sobrinus were examined. The extremely rapid efflux of intracellular constituents evoked by thymol is consistent with its postulated membranotropic effects. Correlations between leakage-inducing concentrations of thymol and minimal inhibitory concentrations and minimal bactericidal concentrations suggest that membrane perforation is a principal mode of action of this substance. The thymol-induced decline in intracellular ATP in S. sobrinus appears to be entirely attributable to leakage, whereas in P. gingivalis thymol may also inhibit ATP-generating pathways. Relative changes in the transmembrane potential of resting cells of S. sobrinus pulsed with glucose are as sensitive to thymol as is leakage from this organism. The effects of thymol on transmembrane potential are probably secondary to those arising from leakage of intracellular substances.

Adenosine Triphosphate↗

PubMed2005

Antioxidant potential of thymol determined by chemiluminescence inhibition in human neutrophils and cell-free systems.

Thyme essential oil and thymol have antimicrobial, antifungal and antioxidant activities. Their antioxidant activity has been studied almost exclusively by means of chemical testing in order to be able to use it for food preservation purposes. The aim of this luminol amplified chemiluminescence (LACL) study was to investigate whether thymol can interfere with the production of reactive oxygen species, nitric oxide and the nitric oxide-derived peroxynitrite released by human neutrophils after activation by fMLP and PMA with and without the addition of the L-arginine (L-Arg) nitric oxide donor to the medium. The lowest thymol concentration that was still active in reducing LACL was 2.73 microg/ml, and there was a progressive linear inhibition of LACL from this concentration to 21.87 microg/ml, the highest thymol concentration investigated. This was also observed in the case of both fMLP and PMA stimulation with or without L-Arg. In cell-free systems using H(2)O(2)/HOCl(-) and SIN-1 as radical producers, a significant scavenging activity of thymol was present already at 0.08 and 0.68 microg/ml respectively, and these are very low concentrations. These findings can be related to the phenolic structure of thymol, because phenolic compounds have redox properties and play an important role in adsorbing and neutralizing free radicals and peroxynitrite, and in decomposing peroxides. Our findings in human neutrophils are pharmacologically relevant as they imply that thymol is a potential antioxidant and anti-inflammatory agent in human cells.

Antioxidants↗

PubMed2006

Anti-inflammatory activity of thymol: inhibitory effect on the release of human neutrophil elastase.

Elastase, a serine proteinase released by activated human neutrophils, can degrade a wide variety of biomacromolecules including elastin, and is considered a marker of inflammatory diseases. As the logical strategy to protect tissue is to inhibit excessive elastase activity, experimental and clinical researches have concentrated on trying to find efficient elastase inhibitors. As thymol, one of the major components of thyme oil with a phenolic structure, has been credited with a series of pharmacological properties, that include antimicrobial and antioxidant effects, the aim of this study was to explore whether it can also interfere with the release of elastase by human neutrophils stimulated with the synthetic chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (fMLP). After the neutrophils were incubated with increasing amounts of thymol (2.5, 5, 10, 20 microg/ml), elastase release was initiated by fMLP and measured using MeO-Suc-Ala-Ala-Pro-Val-MCA. The results showed that thymol inhibited fMLP-induced elastase release in a concentration-dependent manner, with the effects of 10 and 20 microg/ml being statistically significant. The behavior of cytosolic calcium mobilization revealed by fura-2 closely resembled that of elastase, thus suggesting that they may be related. The hydrophobic nature of thymol means that it can approach ion channel proteins through the lipid phase of the membrane, alter the local environment of calcium channels and thus inhibit capacitative calcium entry. In brief, thymol inactivates calcium channels machinery, thus triggering a corresponding reduction in elastase. The antibacterial and antimycotic activity of thymol is already well known, but our findings that it inhibits elastase extend our knowledge of the anti-inflammatory activity of this interesting molecule that is already credited with antioxidant activity. These two latter characteristics make thymol a molecule that can have helpful effects in controlling the inflammatory processes present in many infections.

Adult↗

PubMed1986

Some properties and mechanisms of thymol-induced release of calcium from the calcium-store in guinea-pig taenia caecum.

The properties and mechanisms of Ca release induced by thymol from the intracellular Ca-store in the guinea-pig taenia caecum were investigated and compared with those by carbachol, using an intact muscle and a microsomal fraction. In Ca, Na-free, EGTA-containing K-solution, a transient contraction was evoked by each drug, and carbachol produced the contraction following treatment with thymol; however, a reversed sequence did not. The efflux of preloaded 45Ca in the presence and absence of ATP from taenia microsomes was accelerated by increasing concentrations of Ca ions outside. The minimal concentration to stimulate 45Ca-efflux was below 0.2 microM in both cases, and the Km values for Ca ions in the presence and absence of ATP were estimated to be 0.65 microM and 2.0 microM Ca ions, respectively. Thymol, which has been reported to be one of the most potent stimulators of the Ca-induced Ca release in the sarcoplasmic reticulum of skeletal muscle, enhanced the 45Ca-efflux from the taenia microsomes in the presence of ATP dose-dependently, and its mode of action seemed bimodal. That is, at 0.5 mM, thymol lowered the concentration of Ca ions which are needed to induce stimulation of 45Ca-efflux, whereas, at 1 mM, the stimulative effect of thymol on 45Ca-efflux was to augment the maximum rate of 45Ca-efflux, independent of concentrations of Ca ions. Carbachol (1 mM) did not have an effect on 45Ca-efflux with or without 0.1 mM GTP. In conclusion, the possibility has been suggested that in the guinea-pig taenia caecum, carbachol might release stored Ca ions via unknown pathway(s), whereas thymol directly releases Ca ions in a ATP-regulated fashion. Further, carbachol would be more efficacious for releasing stored Ca ions. Notwithstanding, the Ca-stores and/or the Ca-releasing mechanisms, which are utilized by both thymol and carbachol, seemed to share a common part(s) to some degree.

Adenosine Triphosphate↗

PubMed2007

Antifungal activity of thyme (Thymus vulgaris L.) essential oil and thymol against moulds from damp dwellings.

AIMS: To characterize antifungal activities of essential oil of thyme (Thymus vulgaris L.) and pure thymol, as comparative substance, on different mould species isolated from damp dwellings. METHODS AND RESULTS: Fifty samples of wall scrapes were collected from damp dwellings in Zagreb, the capital of Croatia. The members of the following mould genera were recovered from the samples: Aspergillus (44%), Penicillium (18%) Alternaria, Ulocladium, Absidia and Mucor (8%) Cladosporium, Trichoderma and Rhizopus (6%), and Chaetomium (2%). Two strains of Stachybotrys chartarum were isolated from damp dwellings in Slovakia. Antifungal activities of the thyme essential oil, which contains p-cymene (36.5%), thymol (33.0%) and 1,8-cineole (11.3%) as main components, and pure thymol were determined by the dilution method and exposure to vaporous phase of the oil. Minimum inhibitory concentrations (MIC) of both thymol and essential oil were bellow 20 microg ml(-1), except for Mucor spp. (50.20 microg ml(-1)). Thymol exhibited approximately three-times stronger inhibition than essential oil of thyme. The vaporous phase of the thyme essential oil (82 microg l(-1)) in glass chambers strongly suppressed the sporulation of moulds during 60 days of exposure. CONCLUSION: The thyme essential oil possesses a wide range spectrum of fungicidal activity. The vaporous phase of the oil exhibited long-lasting suppressive activity on moulds from damp dwellings. SIGNIFICANCE AND IMPACT OF THE STUDY: Essential oil of thyme and thymol could be used for disinfection of mouldy walls in the dwellings in low concentration.

Antifungal Agents↗

PubMedDate not supplied

[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↗