Antifungal Activity Of Eugenol Research Articles

Eugenol Affects the Germ Tube Formation and Cell Adhesion of Candida albicans

Candida albicans is the most common fungal pathogen in humans. Antimicrobial resistance in C. albicans is increasingly reported. The antifungal activity of eugenol against clinically relevant fungi including C. albicans has been recently described. In this study, the antifungal effects of eugenol on major virulence factors of C. albicans were evaluated. C. albicans isolates were exposed to sub-MIC of eugenol. The crystal violet-based method was used to quantify the germ tube formation. Extracellular enzymatic activity (proteinase, phospholipase, and lipase) was determined using the agar plate test. The adhesion to buccal epithelial cells was monitored microscopically. Our result showed that eugenol possesses fungicidal activity against C. albicans. At sub-inhibitory doses, eugenol significantly suppressed germ tube formation and cell adhesion of C. albicans (p<0.05). However, the enzymatic activity of yeast cells exposed to eugenol was slightly reduced. Our data indicate the inhibitory effect of eugenol on the growth and the pathogenicity of C. albicans in terms of germ tube formation and adhesion.

Antifungal activity of eugenol and clove leaf essential oil (Syzygium aromaticum L.) against clinical isolates of candida species

Candida species are causative microorganisms of oropharyngeal, vulvovaginal, and skin infections. Clove (Syzygium aromaticum L.) and eugenol oil have considerable antifungal activity against human pathogenic fungi, including Candida species. The anticandidal action of the studied oils is significantly dependent on the concentration of eugenol and further main and minor constituents of the oils with well-known antifungal effects must have additional and synergistic activities. This study was conducted to compare the antifungal activity of clove leaf essential oil (Syzygium aromaticum L.) and eugenol to determine the role of the content other than eugenol in clove leaf essential oil as an antifungal against Candida species isolates from HIV-AIDS patients. Methods: This study is an in vitro test using the disk diffusion method to determine the zone of inhibition of clove leaf essential oil (Syzygium aromaticum L.) concentrations of 5%, 10%, and 15% as well as eugenol which was equivalent to the concentration of eugenol in clove leaf essential oil at concentrations of 5%, 10% and 15% in 40 isolates of Candida species.

EFFECT OF EUGENOL EMULSION IN POLYSORBATE-80 ON CLINICAL STRAINS OF CANDIDA ALBICANS

Candida albicans occupies a dominant position in the list of causative agents of candidal lesions of the ear. The development of new antifungal agents, an alternative source of which can be herbal essential oils and their components, remains a priority. One such agent with antiseptic, anti-inflammatory, and analgesic action is eugenol which is a phenol substance. Therefore, this article was aimed to study the effectiveness of the antifungal action of eugenol emulsified in Polysorbate-80 against clinical strains of C. albicans isolated from patients with external otomycosis. The study was performed using 6 clinical strains of C. albicans isolated from the ear canal of patients with otitis externa. The diagnosis of fungal disease was established based on the results of clinical and laboratory (microscopical and mycological) studies of pathological material. Analysis of mycological research showed that mainly representatives of the genus Aspergillus and Penicillium were revealed and only in 7% there were Candida genus fungi. C. albicans remained the dominant species of clinical significance. The results of our studies showed a high level of antifungal activity of eugenol on all clinical strains of C. albicans, including a remarkable inhibitory and fungicidal effect. At postmycostatic concentrations, the eugenol caused partial inhibition of reproduction of the clinical strains of fungi, which was replaced by a subsequent increased cell reproduction rate. So, the investigation has shown that C. albicans is the dominant species among fungi of the Candida genus in the structure of the microbial profile of otomycoses. The eugenol, emulsified in Polysorbate-80, has a high antifungal effect against clinical strains of C. albicans. At postmycostatic concentrations, the eugenol caused partial inhibition of reproduction of the clinical strains of fungi, which was replaced by a subsequent increase cell reproduction rate.

In vitro synergy of eugenol on the antifungal effects of voriconazole against Candida tropicalis and Candida krusei strains isolated from the genital tract of mares.

Due to the limited range of antifungals available to treat genital Candida infections and the emergence of resistant isolates, attention has focused on the antifungal potency of natural compounds with promising biological properties. To examine whether eugenol synergises the in vitro efficacy of voriconazole against Candida strains isolated from the genital tract of mares. In vitro experiment. The antifungal activity of eugenol and voriconazole was evaluated using the broth microdilution assay (CLSI- M27-A3). Synergism of eugenol and voriconazole against genital Candida isolates was evaluated by the microdilution checkerboard method. Minimum inhibitory concentration (MIC) values for eugenol and voriconazole ranged from 400 to 800µg/mL and 1 to 8µg/mL, respectively, for C.tropicalis isolates, and from 200 to 400µg/mL for eugenol and 2 to 16µg/mL for voriconazole against C.krusei isolates. Eugenol decreased the arithmetic mean MIC for voriconazole against C.tropicalis and C.krusei isolates from 2.66 to 0.46µg/mL and 7.77 to 0.41µg/mL respectively. The fractional inhibitory concentration index (FICI) values for the eugenol-voriconazole combination ranged from 0.25 to 0.88 and 0.19 to 0.63 for C.tropicalis and C.krusei isolates respectively. A synergistic effect of eugenol in combination with voriconazole was observed for 83.3% of C.tropicalis and 77.7% of C.krusei isolates. Antagonistic activity was not seen in any of the isolates tested. Since in vitro antifungal susceptibility tests are not systematic analyses, any selection bias could influence the results. In addition, in vitro susceptibility does not uniformly predict clinical success in vivo. Eugenol showed fungistatic and fungicidal effects against genital Candida isolates and, in combination, synergised the antifungal effects of voriconazole. The eugenol-voriconazole combination can lay the foundation for a therapeutic approach against isolates in which azole resistance has increased over time.

Antifungal activity of eugenol on Cryptococcus neoformans biological activity and Cxt1p gene expression.

Background and Purpose:The present study was targeted toward investigating the effects of eugenol on Cryptococcus neoformans biological activity and Cxt1p gene expression.Materials and Methods:For the purpose of the study, the growth, urease, synergism activity, and disk diffusion of C. neoformans were assessed in eugenol-treated culture. The minimum inhibitory concentration (MIC) was determined by the Clinical and Laboratory Standards Institute M27-A3 method at a concentration range of 0.062-2 mg/mL. Subsequently, the expression of Cxt1p genes was studied at the MIC50 concentration of eugenol using real-time polymerase chain reaction.Results:The obtained results showed that eugenol at the concentrations of 125 and 500 µg/mL resulted in 50% and 100% growth inhibition in C. neoformans, respectively. In terms of urease activity, the results showed that the addition of MIC50 of eugenol and fluconazole to urea medium reduced urease activity in C. neoformans. In the culture treated with eugenol, the inhibition zone of antifungal drugs, namely amphotericin B, itraconazole, and fluconazole, was increased to 36±0.002, 22±0.001, and 12±0.002 mm, respectively. The expression levels of Cxt1p in the eugenol-treated, fluconazole-treated, and non-treated samples were estimated at 46%, 58%, and 100%, respectively.Conclusion:The findings of the current study revealed that eugenol could cause C. neoformans growth inhibition and reduce Cxt1p expression in this species. As the results indicated, the susceptibility of C. neoformans to fluconazole was increased when combined with eugenol.

Eugenol Induces Phenotypic Alterations and Increases the Oxidative Burst in Cryptococcus.

Eugenol is a phenolic compound and the main constituent of the essential oil of clove India. Although there are reports of some pharmacological effects of eugenol, this study is the first that proposes to evaluate the antifungal effects of this phenol against both Cryptococcus gattii and C. neoformans cells. The effect of eugenol against yeast cells was analyzed for drug susceptibility, alterations in cell diameter, capsule properties, amounts of ergosterol, oxidative burst, and thermodynamics data. Data demonstrated that there is no interaction between eugenol and fluconazole and amphotericin B. Eugenol reduced the cell diameter and the capsule size, increased cell surface/volume, changed positively the cell surface charge of cryptococcal cells. We also verified increased levels of reactive oxygen species without activation of antioxidant enzymes, leading to increased lipid peroxidation, mitochondrial membrane depolarization and reduction of lysosomal integrity in cryptococcal cells. Additionally, the results showed that there is no significant molecular interaction between eugenol and C. neoformans. Morphological alterations, changes of cellular superficial charges and oxidative stress play an important role in antifungal activity of eugenol against C. gattii and C. neoformans that could be used as an auxiliary treatment to cutaneous cryptococcosis.

Antifungal Activity of Eugenol and its Association with Nystatin on Candida albicans

Objective: To evaluate the anti- Candida effect of eugenol and its antimicrobial interaction with nystatin. Material and Methods: The antimicrobial potential was assessed by microdilution technique (M27A3 reference method), by determining the minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) against C. albicans (ATCC 90028). The possible action of eugenol on the fungal cell wall was evaluated with the assistance of the osmotic protector sorbitol (0.8 M). The antimicrobial interaction with nystatin was assessed through the checkerboard method. All tests were performed in triplicate. Results: All groups showed reductions in PI and GBI values and improvements in oral health knowledge, but IG1 and IG2 showed statistically significant differences in these variables compared to CG. Conclusion: The eugenol has antifungal activity against C. albicans and its mechanism of action is probably not related to damage to the fungal cell wall. Association between eugenol and nystatin was not found to be an advantageous possibility for growth inhibition of C. albican .

Calcium dependence of eugenol tolerance and toxicity in Saccharomyces cerevisiae.

Eugenol is a plant-derived phenolic compound which has recognised therapeutical potential as an antifungal agent. However little is known of either its fungicidal activity or the mechanisms employed by fungi to tolerate eugenol toxicity. A better exploitation of eugenol as a therapeutic agent will therefore depend on addressing this knowledge gap. Eugenol initiates increases in cytosolic Ca2+ in Saccharomyces cerevisiae which is partly dependent on the plasma membrane calcium channel, Cch1p. However, it is unclear whether a toxic cytosolic Ca2+elevation mediates the fungicidal activity of eugenol. In the present study, no significant difference in yeast survival was observed following transient eugenol treatment in the presence or absence of extracellular Ca2+. Furthermore, using yeast expressing apoaequorin to report cytosolic Ca2+ and a range of eugenol derivatives, antifungal activity did not appear to be coupled to Ca2+ influx or cytosolic Ca2+ elevation. Taken together, these results suggest that eugenol toxicity is not dependent on a toxic influx of Ca2+. In contrast, careful control of extracellular Ca2+ (using EGTA or BAPTA) revealed that tolerance of yeast to eugenol depended on Ca2+ influx via Cch1p. These findings expose significant differences between the antifungal activity of eugenol and that of azoles, amiodarone and carvacrol. This study highlights the potential to use eugenol in combination with other antifungal agents that exhibit differing modes of action as antifungal agents to combat drug resistant infections.

Enhancement in antifungal activity of eugenol in immunosuppressed rats through lipid nanocarriers

In the present study eugenol loaded solid lipid nanoparticles (SLN) was prepared and characterized for particle size, polydispersity index, zeta potential, encapsulation efficiency, in vitro release and in vivo antifungal activity. Effect of addition of liquid lipid (caprylic triglyceride) to solid lipid (stearic acid) on crystallinity of lipid matrix of SLN was determined by using Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) techniques. Transmission electron microscopy (TEM) was carried out to determine the morphology of SLN. In vivo antifungal activity of eugenol loaded lipid nanoparticles was evaluated by using a model of oral candidiasis in immunosuppressed rats. Particle size results showed that d(90) of SLN(1) (single lipid matrix) and SLN(2) (binary lipid matrix) was 332±14.2 nm and 87.8±3.8 nm, respectively. Polydispersity index was found to be in the range of 0.27-0.4 which indicate moderate size distribution. Encapsulation efficiency of SLN(2) (98.52%) was found to be more than that of SLN(1) (91.80%) at same lipid concentration (2%, w/v). Increasing of the solid lipid concentration from 2% (w/v) to 4% (w/v) resulted in increase in encapsulation efficiency and the particle size. SLN(2) shows faster release of eugenol than that of SLN(1) due to smaller size and presence of liquid lipid which provide less barriers to the diffusion of drug from matrix. TEM study reveals the spherical shape of SLN. FT-IR, DSC and XRD results indicate less crystallinity of SLN(2) than that of SLN(1). In vivo studies show no significant difference in log cfu value of all the groups at 0 day. At 8th day, log cfu value of group treated with saline (control), standard antifungal agent, eugenol solution, SLN(1) and SLN(2) was found to be 3.89±.032, 2.69, 3.39±.088, 3.19±.028 and 3.08±0.124, respectively. The in vivo study results indicate improvement in the antifungal activity of eugenol when administrated in the form of SLN.

Antifungal activity of essential oils against wood degrading fungi and their applications as wood preservatives

Essential oils were screened for their antifungal activity against common wood inhabiting fungi. Subsequently, two pure essential oil extracts, eugenol and cinnamaldehyde, were evaluated for their efficacy on radiata pine wood durability. During the in vitro screening trial, variability in the tolerance of the tested fungi towards the selected essential oil was apparent. However, wood durability test on wood confirmed the antifungal activity of eugenol and cinnamaldehyde but highlighted the leaching (when exposed to wet conditions) of these compounds from treated wood. Blocks treated with 3% w/v eugenol without exposure to wet conditions had <1% weight loss when exposed to all three test fungi, Oligoporus placenta, Coniophora puteana and Antrodia Xantha. However, blocks which were exposed to water showed weight losses in the range of 13·4–23·1%. This study identified eugenol and cinnamaldehyde as potentially benign wood preservatives for treatment of timber not exposed to wet conditions.

Détermination in vitro de l'activité antifongique des vapeurs d'eugénol et d'huiles essentielles de Mentha pulegium L. et de Tanacetum annuum L. vis-à-vis de trois champignons responsables de la pourriture des pommes en post-récolte

The antifungal activity of eugenol and essential oils vapors of Mentha pulegium and Tanacetum annuum was examined against three apple rot fungi. Analysis by GC—MS of the essential oils obtained by hydrodistillation shows that M. pulegium oil contains mainly pulegone (90.2%), while that of T. annuum is dominated by sabinene (39.5%). The evaluation of the effect of plant extracts on fungal growth, by the technique of micro-atmosphere, reveals that 100 to 1200 μl/l essential oil of T. annuum does not affect the fungal growth; however, eugenol and oil of M. pulegium oil have completely stopped the growth of three fungi.

Antifungal Activity of Eugenol against Penicillium, Aspergillus, and Fusarium Species

The antifungal activity of eugenol in a model system against aspergilli (Aspergillus niger, Aspergillus terreus, and Emericella nidulans), penicilli (Penicillium expansum, Penicillium glabrum, and Penicillium italicum), and fusaria (Fusarium oxysporum and Fusarium avenaceum) was investigated. Minimum detection time (time to attain a colony diameter of 1 cm) and the kinetic parameters were evaluated. The effectiveness of the active compound seemed to be strain or genus dependent; 100 mg/liter represented a critical value for P. expansum, P. glabrum, P. italicum, A. niger, and E. nidulans because a further increase of eugenol resulted in fungistatic activity. The radial growth of A. terreus and F. avenaceum was inhibited at 140 mg/liter, and growth of F. oxysporum was completely inhibited at 150 mg/liter.

Antifungal activity of eugenol against Botrytis cinerea

The antifungal properties of eugenol were tested against ten plant pathogenic fungal species and detailed studies were conducted regarding in vitro activity of eugenol on Botrytis cinerea. The EC50 value of eugenol on mycelial radial growth of B. cinerea was 38.6 μg/mL; however, eugenol had no bioactivity against conidia germination. B. cinerea hyphae treated with eugenol showed strong propidium iodide fluorescence in the cytosol. Eugenol increased the concentration of potassium ion and cellular materials in the medium. Furthermore, light and scanning electron microscopy observations on hyphae exposed to eugenol revealed considerable morphological alterations in hyphae, such as cytoplasmic coagulation, vacuolation, and hyphal shriveling. Eugenol induced the generation of H2O2 and increased free Ca2+ in the cytoplasm. These results strongly support the idea that the antifungal activity of eugenol is due to membrane binding and permeability alteration, leading to destabilization and disruption of the plasma membrane.

Antifungal Activity of Eugenol and Various Eugenol-Containing Essential Oils against 38 Clinical Isolates of Candida albicans

The antifungal activity of eugenol containing essential oils - pimento oil (Pimenta dioica (L.) Merr), bay oil (Pimenta racemosa (Mill.) J. W. Moore), clove oil (Szygium aromaticum (L.) Merr. & M. Perry), and cinnamon oil (Cinnamomum zeylanicum Blume) was investigated against 38 clinical isolates of Candida albicans (12 oropharyngeal, 16 vaginal and 10 skin damaging strains). The strains isolated from skin infections were more susceptible to all of the investigated essential oils whereas the oropharyngeal strains were more resistible. The strongest antifungal activity against clinical isolates of oropharyngeal, vagina and skin strains of Candida albicans possesses clove oil, followed by cinnamon oil, pimento oil and bay oil. Anticandidial action of the investigated oils is significantly due to its major component eugenol, but also minor constituents of the essential oils, such as methyleugenol, chavicol and linalool, must have additional and/or synergistic effects to explain the obtained anticandidal data of each essential oil sample.

Antifungal activity of essential oil isolated from Ocimum gratissimum L. (eugenol chemotype) against phytopathogenic fungi

An investigation of antifungal activity of the essential oil obtained by steam-distillation (1.1% w/w) of the aerial parts of Ocimum gratissimum and of an ethanolic extract from the steam-distillation residue was carried out using the agar diffusion method. The results revealed that the essential oil inhibited the growth of all fungi tested, including the phytopathogens, Botryosphaeria rhodina, Rhizoctonia sp. and two strains of Alternaria sp., while the extract from the residue was inactive. The essential oil was subjected to TLC bioautography used to detect fungitoxic constituents. The compound that showed antifungal activity was isolated and identified as eugenol. GC/MS analysis showed that eugenol was the main constituent of the essential oil studied. The antifungal activity of eugenol was evaluated against a species of Alternaria isolated from tomato (A1) and Penicillium chrysogenum. The minimal inhibitory concentrations of eugenol were 0.16 and 0.31 mg/disc for Alternaria sp. (A1) and P. chrysogenum, respectively.