In vitro determination of the combination of ciclopirox and terbinafine in the treatment of dermatophytosis.

INTRODUCTION: The cases of dermatophytosis are increasing and they are associated with a higher number of therapeutic failures leading the doctor to prescribe combinations of antifungals as therapy. The objective was to evaluate the interaction of terbinafine and ciclopirox, the most commonly antifungals used in the clinic, in dermatophyte isolates. METHODOLOGY: The minimum inhibitory concentrations (MIC) of ciclopirox and terbinafine were determined by the broth microdilution method according CLSI and the checkerboard assay was used to evaluate the interaction between the antifungal agents. RESULTS: For terbinafine the mic50 was 0.125 ug/mL and mic90 was 0.250 ug/mL. For ciclopirox the values were 2.0 ug/mL for mic50 and 4.0 ug/mL for mic90. No synergistic interaction was observed for the dermatophyte isolates tested. CONCLUSION: These results suggest that the use of terbinafine in combination with ciclopirox, which is widely used in the clinic, may not be a good choice for the treatment of onychomycosis.

Quinolines derivatives as promising new antifungal candidates for the treatment of candidiasis and dermatophytosis.

Fungal infections have emerged as a current serious global public health problem. The main problem involving these infections is the expansion of multidrug resistance. Therefore, the prospection of new compounds with efficacy antifungal becomes necessary. Thus, this study evaluated the antifungal profile and toxicological parameters of quinolines derivatives against Candida spp. and dermatophyte strains. As a result, a selective anti-dermatophytic action was demonstrated by compound 5 (geometric means (GM = 19.14 µg ml-1)). However, compounds 2 (GM = 50 µg ml-1) and 3 (GM = 47.19 µg ml-1) have presented only anti-Candida action. Compounds 3 and 5 did not present cytotoxic action. Compound 5 did not produce dermal and mucosal toxicity. In addition, this compound showed the absence of genotoxic potential, suggesting safety for topical and systemic use. Quinolines demonstrated a potent anti-dermatophytic and anti-yeast action. Moreover, compound 5 presented an excellent toxicological profile, acting as a strong candidate for the development of a new effective and safe compound against dermatophytosis of difficult treatment.

Chloroacetamide derivatives as a promising topical treatment for fungal skin infections.

The aim of this study was to evaluate the antifungal potential of 11 chloroacetamide derivatives and derivative incorporated into a film-forming system (FFS) as a potential alternative for the topical treatment of superficial and skin mycoses. The minimum inhibitory concentration (MIC) evaluation followed Clinical and Laboratory Standards Institute protocols M27-A3 (Candida) and M28-A2 (dermatophytes). Compounds 2, 3, and 4 were the most effective against Candida species (MIC range: 25-50 µg/mL) and dermatophytes (MIC range: 3.12-50 µg/mL). Compound 2 maintained its antifungal activity when incorporated in a FFS, with MIC values equivalent to the free compound. In addition, the compound does not act through complexation with ergosterol, suggesting that it may act on other targets of the fungal cell membrane. Chloroacetamide derivatives presented anti-Candida and anti-dermatophytic effectiveness. The FFS containing compound 2 has shown to be superior to traditional topical treatment of superficial and cutaneous fungal infections. It was found that these new chemical entities, with their applicability, are an excellent alternative to the topical treatment of fungal skin infections.

Clioquinol is a promising preventive morphological switching compound in the treatment of Candida infections linked to the use of intrauterine devices.

PURPOSE: Candida biofilm infections are frequently linked to the use of biomaterials and are of clinical significance because they are commonly resistant to antifungals. Clioquinol is an antiseptic drug and is effective against multidrug-resistant Candida. We investigated the effect of clioquinol and two other 8-hydroxyquinoline derivatives on Candida biofilm. METHODOLOGY: The ability to inhibit biofilm formation, inhibit preformed biofilm and remove established biofilms was evaluated using in vitro assays on microtitre plates. The action of clioquinol on biofilm in intrauterine devices (IUDs) was also investigated, describing the first protocol to quantify the inhibitory action of compounds on biofilms formed on IUDs. RESULTS: Clioquinol was found to be the most effective 8-hydroxyquinoline derivative among those tested. It prevented more than 90 % of biofilm formation, which can be attributed to blockade of hyphal development. Clioquinol also reduced the metabolic activity of sessile Candida but the susceptibility was lower compared to planktonic cells (0.031-0.5 µg ml-1 required to inhibit 50 % planktonic cells and 4-16 µg ml-1 to inhibit 50 % preformed biofilms). On the other hand, almost complete removal of biofilms was not achieved for the majority of the isolates. Candida spp. also showed the ability to form biofilm on copper IUD; clioquinol eradicated 80-100 % of these biofilms. CONCLUSION: Our results indicate a potential application in terms of biomaterials for 8-hydroxyquinoline derivatives. Clioquinol could be used as a coating to prevent morphological switching and thus prevent biofilm formation. Furthermore, clioquinol may have future applications in the treatment of Candida infections linked to the use of IUDs.

In vitro synergism of a water insoluble fraction of Uncaria tomentosa combined with fluconazole and terbinafine against resistant non-Candida albicans isolates.

CONTEXT: Uncaria tomentosa D.C. (Rubiaceae) has several biological activities, including activity against resistant Candida strains. The synergistic interaction with terbinafine or fluconazole can be an important alternative to overcome this resistance. OBJECTIVES: The potential synergy between a water insoluble fraction (WIF) from Uncaria tomentosa bark and the antifungals terbinafine (TRB) and fluconazole (FLZ) against non-Candida albicans resistant strains was investigated. MATERIALS AND METHODS: TRB and FLZ, alone and combined with WIF, were tested by the checkerboard procedure using the micro-dilution technique against seven isolates of Candida glabrata and C. krusei. The molecular interactions occurring outside the cell wall were evaluated by scanning electron microscopy, Fourier transform infrared (FT-IR) and differential scanning calorimetry (DSC) analysis. RESULTS: The checkerboard inhibitory assay demonstrated synergy for WIF:TRB and WIF:FLZ combinations, respectively. The best synergistic cell damage was demonstrated unequivocally for the associations of WIF and TRB (1.95:4.0 µg/mL) and WIF and FLZ (1.95:8.0 µg/mL). The comparison of the FT-IR spectra of the antifungal alone, and in combination with WIF, allows recognizing clear differences in 3000, 1600, 1400, and 700-800 cm-1 bands. Additionally, modifications on TRB and FLZ thermograms were clearly noticed after their combination with WIF. CONCLUSIONS: DSC and infrared analysis demonstrated intermolecular interactions between WIF and either TRB or FLZ. Hence, quite likely the synergistic effect is related to interaction events occurring outside the cell wall between antifungal and cat's claw proanthocyanidins. A direct action on the cell wall is suggested, without connection with the ABC efflux pump mechanism.

Antifungal activity against Cryptococcus neoformans strains and genotoxicity assessment in human leukocyte cells of Euphorbia tirucalli L.

In the last times, focus on plant research has increased all over the world. Euphorbia tirucalli L., a plant known popularly as Aveloz, and originally used in Africa, has been drawing attention for its use in the United States and Latin America, both for use as an ornamental plant and as a medicinal plant. E. tirucalli L. is a member of the family Euphorbiaceae and contains many diterpenoids and triterpenoids, in particular phorbol esters, apparently the main constituent of this plant, which are assumed to be responsible for their activities in vivo and in vitro. The in vitro antifungal activities of Euphorbia tirucalli (L.) against opportunistic yeasts were studied using microbroth dilution assay. The results showed that aqueous extract and latex preparation were effective against ten clinical strains of Cryptococcus neoformans in vitro (Latex and extract MIC range of 3.2 - > 411 µg/mL). Aiming the safe use in humans, the genotoxic effects of E. tirucalli were evaluated in human leukocytes cells. Our data show that both aqueous extract and latex preparation have no genotoxic effect in human leukocytes cells in vitro. Although the results cannot be extrapolated by itself for use in vivo, they suggest a good perspective for a therapeutic application in future. In conclusion, our results show that the aqueous extract and latex preparation from E. tirucalli L. are antifungal agents effectives against several strains of C. neoformans and do not provoke DNA damage in human leukocyte cells, considering the concentrations tested.

Antifungal activity against Cryptococcus neoformans strains and genotoxicity assessment in human leukocyte cells of Euphorbia tirucalli L.

In the last times, focus on plant research has increased all over the world. Euphorbia tirucalli L., a plant known popularly as Aveloz, and originally used in Africa, has been drawing attention for its use in the United States and Latin America, both for use as an ornamental plant and as a medicinal plant. E. tirucalli L. is a member of the family Euphorbiaceae and contains many diterpenoids and triterpenoids, in particular phorbol esters, apparently the main constituent of this plant, which are assumed to be responsible for their activities in vivo and in vitro. The in vitro antifungal activities of Euphorbia tirucalli (L.) against opportunistic yeasts were studied using microbroth dilution assay. The results showed that aqueous extract and latex preparation were effective against ten clinical strains of Cryptococcus neoformans in vitro (Latex and extract MIC range of 3.2 - > 411 µg/mL). Aiming the safe use in humans, the genotoxic effects of E. tirucalli were evaluated in human leukocytes cells. Our data show that both aqueous extract and latex preparation have no genotoxic effect in human leukocytes cells in vitro. Although the results cannot be extrapolated by itself for use in vivo, they suggest a good perspective for a therapeutic application in future. In conclusion, our results show that the aqueous extract and latex preparation from E. tirucalli L. are antifungal agents effectives against several strains of C. neoformans and do not provoke DNA damage in human leukocyte cells, considering the concentrations tested.