Activity Of Thymol Research Articles

Effects of thymol:carvacrol association on health and zootechnical performance of tambaqui Colossoma macropomum

Research in aquaculture shows that isomers thymol and carvacrol are extremely promising additives in fish diet, being classified as potent immunostimulant, antioxidant, and growth promoters. In this study, the effects of the thymol:carvacrol combination (1:1 ratio) on health parameters and zootechnical performance of tambaqui (Colossoma macropomum) were evaluated. The compounds were incorporated in concentrations of 0, 500, 1000, 1500, and 2000 mg/kg of feed. At intervals of 30 and 60 days, fish were sampled to evaluate haematological, biochemical, and immunological parameters, and after 60 days, zootechnical performance, parasitic load, and resistance to bacteriosis were evaluated. After 30 days, the fish that received the highest concentrations of thymol:carvacrol showed a reduction in the number of thrombocytes, a decrease in the number of lymphocytes, and an increase in eosinophils (p â"°¤ 0.05). After 60 days of feeding, haematological parameters were similar between all groups. Regarding the antiparasitic effect of the compounds, all groups that received supplemented diets had a high parasitic load (monogenean infestation) that did not differ from the control group. Regarding the prevention of bacteriosis, high mortality was detected in all groups after experimental challenge with Aeromonas jandaei, with no greater protection for fish fed with thymol:carvacrol. In conclusion, it was observed that the haematological results are different from those described in the literature of aquatic animals and corroborate with research of mammals. Therefore, the anti-inflammatory/immunosuppressive action of thymol and carvacrol are highlighted, which is relevant from a pharmaceutical and medicinal point of view. However, the use of these additives for aquaculture deserves to be discussed carefully, as the cost-benefit of this supplementation for the fish farmer is not a consensus.

Bioconjugated Thymol-Zinc Oxide Nanocomposite as a Selective and Biocompatible Antibacterial Agent against Staphylococcus Species.

Owing to the rapid spread of antibiotic resistance among Staphylococcus species, effective and low-risk alternatives to antibiotics are being actively searched. Thymol (THO), the most abundant component of the oil extracted from thyme, can be considered as a natural antibacterial alternative. However, the low antibacterial activity and non-selectivity of THO limit its usage as a universal anti-Staphylococcus agent. Herein, we report the bioconjugation of THO with ZnO nanoparticle (ZO), which resulted in the TZ nanocomposite (NC), as a potent and selective antibacterial agent against Staphylococcus species, particularly S. epidermidis. The cell-free supernatant (CFS) of ATCC 25923 cultures was employed for the production of TZ NC. Successful production of TZ NC was confirmed via X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, and ultraviolet–visible (UV–Vis) studies. TZ NC had selective efficacy against Staphylococcus species, with MIC values 2–32-fold lower than THO. The antibacterial mechanisms of TZ NC are proposed to involve membrane rupture, suppression of biofilm formation, and modulation of new cell wall and protein-synthesis-associated cellular pathways. Its biocompatibility against HCT116 cells was also checked. Our findings suggest that the TZ nanocomposite could improve the selectivity and bactericidal activity of THO against target species.

Action of thymol, carvacrol and eugenol on Penicillium and Geotrichum isolates resistant to commercial fungicides and causing postharvest citrus decay

This study aimed to evaluate the antifungal activity of oregano and clove essential oils and their main components (thymol, carvacrol and eugenol) against Penicillium digitatum, as well as against isolates of Penicillium italicum and Geotrichum candidum resistant to imazalil or guazatine, respectively. In vitro tests were conducted by a direct contact method on potato dextrose agar medium. The results indicated that the essential oils and their main components were effective in inhibiting fungal growth, with thymol displaying the highest efficacy. The antifungal activity of thymol was evaluated further on orange fruit infected experimentally with a suspension of spores of P. digitatum, G. candidum or a mixture of both fungi, using isolates resistant to chemical fungicides. Treatment of the oranges with the thymol solutions reduced or totally inhibited the development of fruit decay, depending on the thymol concentration used. These essential oils and their main components demonstrated a strong antifungal effect against Penicillium spp. and G. candidum resistant to chemical fungicides. They may have potential as active compounds for the formulation of natural preparations to use as alternatives to synthetic fungicides for the management of green, blue and sour rot in citrus fruit.

Effect of temperature on antimicrobial activity and mode of action of thymol against Staphylococcus aureus

Effect of temperature on antimicrobial activity and mode of action of thymol against Staphylococcus aureus

IN VITRO ANTIFUNGAL ACTIVITY OF TIMOL AND CARVACROL ON CANDIDA SPECIES

Aim: to evaluate the in vitro action of thymol and carvacrol against the yeasts of Candida albicans ATCC10231 and Candida krusei ATCC34135. Method: A laboratory study was performed to evaluate antifungal activity. The characterization of the Minimal Inhibitory Concentration (MIC) of the thymol essential oil was carried out using the technique where the microdilution is performed, in which a plate containing 96 wells is used. The determination of the Minimum Fungicidal Concentration (MFC) was performed by dripping 10 μL of each of the concentrations evaluated on Sabouraud agar plates. Results: The MIC of thymol and carvacrol for C. albicans was 40 μg/mL and for Candida krusei it did not present antifungal activity. While the MIC of nystatin was 0.03mg for both species with thymol and carvacrol. Conclusion: Thymol presented satisfactory antifungal activity against the pathogens studied, but carvacrol did not present antifungal activity.

Antifungal activity study of the monoterpene thymol against Cryptococcus neoformans

Cryptococcus neoformans is a yeast fungus, which causes cryptococcosis, triggered by basidiospore inhalation and consequent dissemination to the central nervous system. In this study, we analyzed the antifungal action of thymol against 10 clinical strains of C. neoformans and analyzed the interaction of this monoterpene with sterols. The MICs of thymol ranged from 20 to 51 μg/ml, while the MFC values varied between 40 and 101 μg/ml. For the strains ICB-2601 and LM-39, in the presence of ergosterol, the MIC of thymol was 64 μg/ml, and in the presence of cholesterol, its MIC was 32 μg/ml. Based on the results, thymol presents antifungal action and seems to interact with ergosterol, but not with cholesterol. Complementary studies are needed to analyze its full effects.

Cytotoxicity and genotoxicity of thymol verified in murine macrophages (RAW 264.7) after antimicrobial analysis in Candida albicans, Staphylococcus aureus, and Streptococcus mutans

Thymol is a phytocompound present in many plants and several biological effects have been reported, such as antimicrobial effect. However, the biocompatibility of this plant product should be checked. Thereby, the action of thymol was evaluated in C. albicans, S. aureus, and S. mutans, as well as in murine macrophages (RAW 264.7). Firstly, the effect of thymol was analyzed in planktonic cultures of microorganisms and the most effective concentration was evaluated in biofilms. Cytotoxicity, quantification of TNF-α and genotoxicity were checked. The results were analyzed by T-Test or ANOVA and Tukey's Test (P ≤ .05). Thymol provided inhibitory and microbicidal effects for planktonic cultures and reduction of biofilms. High concentrations affected the viability of RAW 264.7. Production of TNF-α and frequency of micronuclei were similar to the control group. Thus, thymol showed antimicrobial effect, biocompatibility in some concentrations and absence of genotoxicity.

Action of thymol on spontaneous excitatory transmission in adult rat spinal substantia gelatinosa neurons

Thymol, which is contained in thyme essential oil, has various actions including antinociception and nerve conduction inhibition. Although thymol activates transient receptor potential (TRP) channels expressed in heterologous cells, it remains to be examined whether this is so in native neurons. It has not yet been examined how thymol affects synaptic transmission. In order to know how thymol modulates excitatory transmission with a focus on TRP activation, we investigated its effect on glutamatergic spontaneous excitatory transmission in lamina II (substantia gelatinosa; SG) neurons with which nerve terminals expressing TRP channels make synaptic contacts. The experiment was performed by using the blind whole-cell patch-clamp technique in adult rat spinal cord slices. Superfusing thymol (1mM) for 3min reversibly increased the frequency of spontaneous excitatory postsynaptic current (sEPSC) with a minimal increase in its amplitude in all neurons examined. Seventy-seven% of the neurons produced an outward current at a holding potential of −70mV. The sEPSC frequency increase and outward current produced by thymol were concentration-dependent with almost the same half-maximal effective concentration (EC50) values of 0.18 and 0.14mM, respectively. These activities were repeated at a time interval of 30min, although the sEPSC frequency increase but not outward current recovered with a slow time course. Voltage-gated Na+-channel blocker tetrodotoxin did not affect the thymol activities. The sEPSC frequency increase was inhibited by TRPA1 antagonist HC-030031 but not TRPV1 and TRPM8 antagonist (capsazepine and BCTC, respectively), while these antagonists had no effect on the outward current. This was so, albeit the two thymol activities had similar EC50 values. It is concluded that thymol increases the spontaneous release of L-glutamate onto SG neurons by activating TRPA1 channels while producing an outward current without TRP activation. Considering that the SG plays a pivotal role in modulating nociceptive transmission from the periphery, these actions of thymol could contribute to at least a part of its antinociceptive effect.

Thymian und Primelwurzel - ein starkes Doppel gegen akute Bronchitiden

Herbal combinations of thyme and primrose root are very suitable for the therapy of acute bronchitis. Two clinical studies with adults (n = 340) document that on the one hand these combinations lead to a significantly quicker recovery of the bronchitis symptoms compared to a placebo treatment. On the other hand they cause a comparably quick symptom improvement or symptom relief respectively, regardless of their pharmaceutical form. Children also benefit from this therapy. Thus the results from two post-marketing studies with a total of 949 children prove that the phytocombination is characterized by good efficacy and an excellent tolerability in this population. These effects are based on the combination of the two herbal drugs that perfectly complement each other due to their synergistic secretolytic effect. In particular the different mechanisms of action of thymol (direct secretolytic effect on the cells of the respiratory tract) and of the saponines (indirect reflex secretolysis) should be pointed out. Moreover these mechanisms of action intensify the synergistic effect. These results are supported by first in vitro investigations on the inhibition of the IL-8 synthesis in human monocytes.

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.