Terpinen-4-ol inhibits the growth of Sporothrix schenckii complex and exhibits synergism with antifungal agents.

Aim: This study investigated the effect of terpinen-4-ol against Sporothrix schenckii complex and its interactions with antifungals. Materials & methods: The antifungal activity of terpinen-4-ol was evaluated by broth microdilution. The potential effect on cellular ergosterol concentration was evaluated by spectrophotometry. The antibiofilm activity was evaluated by violet crystal staining and XTT reduction assay. The potential pharmacological interactions with antifungals were evaluated by the checkerboard assay. Results: terpinen-4-ol (T-OH) showed minimal inhibitory concentrations ranging from 4 to 32 mg/l decreasing cellular ergosterol content and presented a SMIC ranging from 64 to 1024 mg/l for Sporothrix spp. The combinations of T-OH with itraconazole or terbinafine were synergistic. Conclusion: T-OH has antifungal activity against Sporothrix spp. and acts synergistically with standard antifungals.

Proton pump inhibitors versus Cryptococcus species: effects on in vitro susceptibility and melanin production.

Aim: This study aimed to evaluate the effects of proton pump inhibitors (PPIs) on growth and melanin production by Cryptococcus spp. Materials & methods: Minimum inhibitory concentrations (MICs) of omeprazole, esomeprazole, rabeprazole, pantoprazole and lansoprazole against Cryptococcus spp. were determined and the effect of PPIs on melanin production was evaluated, in the presence or absence of copper sulfate or glutathione. Results: PPIs showed MICs ranging from 125-1000 µg/ml and decreased melanization by Cryptococcus cells. Addition of copper sulfate or gluthatione restored melanogenesis of cells grown in the presence of PPIs. The presence of PPIs and glyphosate decreased copper sulfate toxicity (1 mM). Conclusion: PPIs inhibited melanogenesis of Cryptococcus spp., possibly by chelating copper or inhibiting copper ATPase transport.

Pentamidine inhibits the growth of Sporothrix schenckii complex and exhibits synergism with antifungal agents.

AIM: The purpose of this study was to evaluate the effects of the antileishmanials meglumine antimoniate and pentamidine against Sporothrix schenckii complex. MATERIALS & METHODS: The antifungal activity of the two antileishmanials was assessed by broth microdilution. The interaction between the antileishmanials and antifungal drugs (amphotericin B, itraconazole and terbinafine) was evaluated by the checkerboard assay. The effect of prior exposure of Sporothrix spp. yeast cells to antileishmanials was evaluated by broth microdilution. RESULTS: Only pentamidine showed antifungal activity against Sporothrix spp. Synergistic interactions were observed between pentamidine and the antifungals. Also, the pre-exposure to meglumine antimoniate reduced the susceptibility of Sardinella brasiliensis and S. schenckii sensu stricto to amphotericin B and itraconazole. CONCLUSION: Pentamidine showed antifungal activity against Sporothrix spp., indicating it is a possible therapeutic alternative for the treatment of sporotrichosis.

An alternative method for the analysis of melanin production in Cryptococcus neoformans sensu lato and Cryptococcus gattii sensu lato.

Melanin is an important virulence factor for several microorganisms, including Cryptococcus neoformans sensu lato and Cryptococcus gattii sensu lato, thus, the assessment of melanin production and its quantification may contribute to the understanding of microbial pathogenesis. The objective of this study was to standardise an alternative method for the production and indirect quantification of melanin in C. neoformans sensu lato and C. gattii sensu lato. Eight C. neoformans sensu lato and three C. gattii sensu lato, identified through URA5 methodology, Candida parapsilosis ATCC 22019 (negative control) and one Hortaea werneckii (positive control) were inoculated on minimal medium agar with or without L-DOPA, in duplicate, and incubated at 35°C, for 7 days. Pictures were taken from the third to the seventh day, under standardised conditions in a photographic chamber. Then, photographs were analysed using grayscale images. All Cryptococcus spp. strains produced melanin after growth on minimal medium agar containing L-DOPA. C. parapsilosis ATCC 22019 did not produce melanin on medium containing L-DOPA, while H. werneckii presented the strongest pigmentation. This new method allows the indirect analysis of melanin production through pixel quantification in grayscale images, enabling the study of substances that can modulate melanin production.

Chemical Characterization and Cytoprotective Effect of the Hydroethanol Extract from Annona coriacea Mart. (Araticum).

INTRODUCTION: Annona coriacea Mart. (araticum) is a widely distributed tree in the cerrado. Its value is attributed principally to the consumption of its fruit which possesses a large nutritive potential. The objective was to identify the chemical profile and evaluate the antimicrobial and cytoprotective activity of the hydroethanol extract of A. coriacea Mart. (HEAC) leaves against the toxicity of mercury chloride. MATERIALS AND METHODS: The characterization of components was carried out using high-performance liquid chromatography (HPLC). The minimum inhibitory concentration (MIC) was determined by microdilution method in broth with strains of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. For evaluation of the modulatory and cytoprotective activity of aminoglycoside antibiotics (gentamicin and amikacin) and mercury chloride (HgCl2), the substances were associated with the HEAC at subinhibitory concentrations (MIC/8). RESULTS AND DISCUSSION: The HPLC analysis revealed the presence of flavonoids such as Luteolin (1.84%) and Quercetin (1.19%) in elevated concentrations. The HEAC presented an MIC ≥512 µg/mL and significant antagonistic action in aminoglycosides modulation, and it also showed cytoprotective activity to S. aureus (significance P < 0.0001) and E. coli (significance P < 0.05) bacteria against the mercury chloride heavy metal with significance, this action being attributed to the chelating properties of the flavonoids found in the chemical identification. CONCLUSIONS: The results acquired in this study show that the HEAC presents cytoprotective activity over the tested strains in vitro and can also present antagonistic effect when associated with aminoglycosides, reinforcing the necessity of taking caution when combining natural and pharmaceutical products. SUMMARY: The hydroalcoholic extract of A. coriacea Mart. presents in vitro cytoprotective activity against the toxic effect of Hg. Abbreviations Used: HPLC-DAD: High-performance liquid chromatography with a diode array detector; MIC: Minimum inhibitory concentration; DMSO: Dimethyl sulfoxide.