Anti-Acanthamoeba metallopharmaceuticals: Amoebicidal activity and synergistic effect of copper(II) coordination compound.

Acanthamoeba spp. emerged as a clinically important pathogen related to amoebic keratitis. It is among the main causes of corneal transplantation and vision loss in ophthalmology. The treatment protocols have a low cure rate, high toxicity, and need for drug combination. Transition metal compounds have shown promising antiprotozoal effects. This study evaluates the amoebicidal activity of copper(II) coordination compounds in combination with chlorhexidine and the cytotoxicity to topical ocular application. These copper(II) coordination compounds were screened against Acanthamoeba castellanii trophozoites (ATCC 50492). The cytotoxicity on rabbit corneal cell line (ATCC-CCL 60) was performed. The compounds showed high amoebicidal potential, with inhibition of trophozoite viability above 80%. The Cp12 and Cp13 compounds showed Minimal Inhibitory Amoebicidal Concentration (MIAC) at 200 µM and mean inhibitory concentration (IC50) values lower than 10 µM. Against the cysts, Cp12 showed a reduction in viability (48%) in the longest incubation period. A synergistic effect for Cp12 with chlorhexidine was observed. The compounds have a dose-dependent effect against rabbit corneal cells. Compound Cp12 has potential for future application in developing ophthalmic formulations against Acanthamoeba keratitis and its use in multipurpose solutions is highlighted.

A chloroacetamide derivative as a potent candidate for fusariosis treatment.

Fusariosis has presented a significant increase in their incidence in the last years. This epidemiological panorama probably is due to the increasing profile of refractory susceptibility of Fusarium spp. to available drugs, especially in immunocompromised individuals. Thus, the development of new compounds with effectiveness on these organisms is a necessity. This study evaluated the antifungal potential of a chloroacetamide derivative (4-BFCA) against resistant Fusarium strains. As a result, the compound was effective against all strains (MIC range 12.5-50 µg/mL). The time kill assay demonstrated that 4-BFCA presents a concentration-dependent fungicidal action. Although its action mechanism has not yet been elucidated, it was possible to observe its efficacy through damages and alterations provoked along the hyphae of Fusarium spp. 4-BFCA maintained a high survival rate of Tenebrio molitor larvae, suggesting that it does not cause acute systemic toxicity on this host at the concentration evaluated. In addition, 4-BFCA was 83.33% effective in combating a fungal infection in vivo on the chorioallantoid membrane of embryonated eggs. Our results are very promising and arouse interest to investigate the action of 4-BFCA on Fusarium strains since it acts as a possible candidate for the development of new therapies for the treatment of fusariosis.

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.

Lipid core nanoparticles as a broad strategy to reverse fluconazole resistance in multiple Candida species.

Fungal resistance is the major problem related to fluconazole treatments. This study aims to develop innovative lipid core nanocapsules and nanostructured lipid carriers containing fluconazole, to study in vitro antifungal activity and to assess the possibility of resistance reversion in Candida albicans, C. glabrata, C. krusei, and C. tropicalis isolates. The action mechanism of nanoparticles was investigated through efflux pumps and scanning electron microscopy studies. The lipid core nanocapsules and nanostructured lipid carriers were prepared by interfacial deposition of preformed polymer and high-pressure homogenization methods, respectively. Both nanostructures presented sizes below 250 nm, SPAN < 1.6, negative zeta potential, pH slightly acid, high drug content and controlled drug release. The nanostructured lipid carriers were unable to reverse the fungal resistance. Lipid core nanoparticles displayed advantages such as a reduction in the effective dose of fluconazole and resistance reversion in all isolates tested - with multiple mechanisms of resistance. The main role of the supramolecular structure and the composition of the nanoparticles on antifungal mechanisms of action were discussed. The results achieved through this study have an impact on clinical therapy, with a potential application in the treatment of fungal infections caused by resistant isolates of Candida spp.