Semisynthetic eugenol derivatives as antifungal agents against dermatophytes of the genus Trichophyton.

PURPOSE: Eugenol, the main component of clove bud essential oil (Eugenia caryophyllus), has been linked to antimicrobial, anti-inflammatory, insecticidal and immunomodulatory properties. The purpose of this study was to evaluate the antifungal and cytotoxic activity of eugenol, the essential oil of Eugenia caryophyllus, and some semisynthetic derivatives of eugenol against dermatophytes of the genus Trichophyton. METHODOLOGY: We evaluated the antifungal effect of the compounds, determining the minimum inhibitory concentrations (MICs) by the microdilution method and the minimum fungicidal concentrations by cultures from the inhibitions. Additionally, the inhibition of the radial growth of the mycelium of the dermatophyte fungi was tested by poisoned substrate. Cytotoxicity was measured by the colorimetric method on Vero cells. RESULTS: All of the eugenol compounds tested exhibited antifungal properties, showing MICs of 62.5-500 µg ml-1 , determined within three dermatophyte species: Trichophyton rubrum, Trichophyton mentagrophytes and Trichophyton tonsurans. Among these derivatives, methyl isoeugenol, at concentrations of 300 and 100 µg ml-1, was found to completely inhibit (100 %) radial growth of the mycelium of all three species after 20 days of treatment. Additionally, phenotypic variations related to the decrease in pigment production of T. rubrum were observed after treatment with O-ethyl and O-butyl isoeugenol derivatives. Meanwhile, all of the tested (iso)eugenol molecules exhibited moderate toxicity in Vero cells [50 % cytotoxic concentration (the concentration required for a 50 % reduction in cell viability; CC50): 54.06-265.18 µg ml-1 ). CONCLUSION: The results suggest that the semisynthetic eugenol derivatives (SEDs) show promising antifungal activity and selectivity against dermatophyte fungi.

In vitro susceptibility of Microsporum spp. and mammalian cells to Eugenia caryophyllus essential oil, eugenol and semisynthetic derivatives.

BACKGROUND: Microsporum spp. are keratinophilic dermatophytes that mainly invade the stratum corneum of the skin and hair causing clinical symptoms associated with tinea. Its treatment has several limitations, and the search for new active molecules is necessary. OBJECTIVE: To evaluate the antifungal and cytotoxic potential of Eugenia caryophyllus essential oil (EO), eugenol, isoeugenol and methylisoeugenol against Microsporum canis, M. gypseum and Vero cells. METHODS: The EO was extracted by conventional heating-assisted hydrodistillation, the eugenol obtained commercially and the derivatives through Williamson synthesis. Minimal inhibitory concentration (MICs), minimum fungicidal concentration, inhibition of radial mycelial growth and germination inhibition were used to evaluate the antifungal activity. In addition, a colorimetric test was conducted to evaluate cytotoxic activity. RESULTS: MIC and MFC values for all compounds were 62.5-500 µg/mL for both of the species of Microsporum evaluated. Also, concentrations of 300 µg/mL of the compounds inhibited 100% of M. canis mycelium. The inhibition of germination was observed after 6 hours of treatment (11.86 ± 3.46-85.31 ± 0%). No cytotoxicity was observed in Vero cells (CC50  > 105 µg/mL), whereas terbinafine showed CC50 31.00 ± 0.61 µg/mL. CONCLUSIONS: Our study indicates an interesting bioactivity of isoeugenol and methylisoeugenol against M. canis, M. gypseum and mammalian cells.

Actividad antimicrobiana del ácido acético 5% y el cepillo Colgate 360° antibacterial®: un estudio in vitro / Antimicrobial activity of acetic acid and Colgate 360° antibacterial toothbrush®: an in vitro study

Introducción: el cepillo dental se convierte en una fuente potencial de patógenos orales cuando no se hace un proceso de desinfección después de su uso, sobre todo en pacientes con infecciones en el sistema estomatognático o poblaciones que no hacen recambio frecuente de este instrumento. El objetivo de este estudio fue comparar la actividad antimicrobiana del ácido acético 5% con la del cepillo Colgate 360° antibacterial® como posibles estrategias en la desinfección del cepillo dental. Métodos: se utilizaron 48 cabezas de cepillos dentales que fueron inoculadas con Staphylococcus aureus, Streptococcus mutans y Cándida albicans separadamente. Las cabezas fueron divididas en tres grupos: cabezas tratadas con ácido acético 5% (vinagre blanco casero, La Constancia®) por 10 minutos, cabezas 360° con actividad antibacterial y controles tratados con solución salina. Posteriormente se hizo recuento de UFC/ml de los microorganismos remanentes en las cabezas de cepillos después del tratamiento o tiempo de acción. Resultados: frente a S. aureus, el cepillo Colgate 360° antibacterial® mostró mejor efecto antimicrobiano que el ácido acético 5% (PI: 72,11 5). Los dos tratamientos evaluados mostraron capacidad similar para eliminar S. mutans de las cabezas de cepillos (p > 0,05); mientras que para C. albicans, el mejor efecto antimicrobiano lo obtuvo el ácido acético 5% (PI: 99,9%). Conclusión: in vitro el vinagre blanco de uso casero y el cepillo Colgate 360° antibacterial® eliminan microorganismos que colonizan cabezas de cepillos dentales como S. aureus, S. mutans y C. albicans, convirtiéndose en alternativas en diversas poblaciones para mantener el cepillo dental libre de microorganismos.

Introduction: toothbrushes may become a potential source of oral pathogens when not properly disinfected once they have been used, especially in patients with infections of the stomatognathic system or among populations that do not often replace this instrument. The goal of this study was to compare the antimicrobial activity of 5% acetic acid with that of Colgate 360º antibacterial toothbrush® as possible strategies for toothbrush disinfection. Methods: this study included 48 toothbrush heads that were separately inoculated with Staphylococcus aureus, Streptococcus mutans and Cándida albicans. The heads were sorted out into three groups: heads treated with 5% acetic acid (white domestic vinegar, La Constancia®) for 10 minutes; 360º toothbrush heads with antibacterial properties, and control heads treated with saline solution. This was followed by calculations of CFU/ml of the microorganism remaining in the heads after treatment or time of action. Results: in presence of S. aureus, Colgate 360º antibacterial toothbrush® proved to have better antimicrobial activity than 5% acetic acid (PI:72.11 5). The two assessed treatments showed a similar capacity to eradicate S. mutans from the brush heads (p> 0,05); concerning C. albicans, the best antimicrobial activity was observed in the 5% acetic acid (PI: 99,9%). Conclusion: in vitro, both white domestic vinegar and Colgate 360º antibacterial toothbrush® remove microorganisms colonizing toothbrush heads, such as S.aureus, S. mutans y C. albicans, and are therefore considered good alternatives for keeping toothbrushes free of microoorganisms among several populations.