The high mortality rate of candidemia and the limited option for the treatment of Candida spp. infection have been driving the search for new molecules with antifungal property. In this context, coordination complexes of metal ions and ligands appear to be important. Therefore, this study aimed to synthesize two new copper(II) complexes with 2-thiouracil and 6-methyl-2-thiouracil ligands and to evaluate their mutagenic potential and antifungal activity against Candida. The complexes were synthesized and characterized by infrared vibrational spectroscopy, CHN elemental analysis, UV-Vis experiments and ESI-HRMS spectrometry studies. The antifungal activity was evaluated by broth microdilution against 21 clinical isolates of Candida species. The mutagenic potential was evaluated by the Ames test. The complexes were Cu(Bipy)Cl₂(thiouracil) (Complex 1) and Cu(Bipy)Cl₂(6-methylthiouracil) (Complex 2). Complex 1 showed fungicidal and fungistatic activities against all isolates. Furthermore, the Minimum Inhibitory Concentration (MIC) from 31 to 125 µg/mL and inhibition percentage of 9.9% against the biofilms of C. krusei and C. glabrata were demonstrated. At the concentrations tested, complex 1 exhibited no mutagenic potential. Complex 2 and the free ligands exhibited no antifungal activity at the concentrations evaluated. Since complex 1 presented antifungal activity against all the tested isolates and no mutagenic potential, it could be proposed as a potential new drug for anti-Candida therapy.

Ocotea minarum is a native plant from Brazil, popularly known as “canelinha” or “canela vassoura.” The objective of this study was to investigate the chemical composition of the extracts of the bark and the leaves of O. minarum and to evaluate its antimicrobial and antioxidant activities. The phenolic compounds, flavonoids and tanins, were quantified with the reagents Folin-Ciocalteu, aluminium chloride, and vanillin. The chemical profile was performed by HPLC-DAD. The minimum inhibitory concentration was evaluated by the microdilution in a broth method. The antioxidant activity was measured by the capture of free radicals 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid). In addition, protection against oxidative hemolysis and generation of malondialdehyde were evaluated in human erythrocytes. The composition of the extracts included the caffeic acid, p-coumaric acid, and rosmarinic acid, besides the flavonoids quercetin and luteolin. The EEL showed bacteriostatic action of 1000 μg/mL for all evaluated Salmonella Typhimurium, Salmonella Enteritidis, Pseudomonas aeruginosa, and Proteus mirabilis, and the EHEB had a moderate antifungal action against Candida krusei and Cryptococcus gattii (250 μg/mL). IC₅₀ values of 8.19 (EEL) and 4.51 μg/mL (EEB) in the assay with DPPH and 6.25 (EEL) and 2.87 μg/mL (EEB) in the assay with ABTS were obtained. Up to the 3rd hour of oxidative hemolysis testing induced by AAPH, the EEB and EEL had a protective action, reducing the malondialdehyde. In conclusion, the data indicate that the O. minarum extracts can be evaluated as bioactive supplies for the development of new drugs for the prevention and treatment of diseases related to oxidative stress and microbial infections.

Salmonella spp. are important foodborne pathogens often associated with infectious outbreaks caused by consuming contaminated food. Although these microorganisms are widely distributed in several animal production chains, there are few records of their occurrence in aquaculture. This study aimed to evaluate the presence and antimicrobial resistance of Salmonella spp. isolated from fish farms. Samples were collected from three fish farms, covering water, fish, and epilithic biofilm. Salmonella isolates were identified by PCR, and serotyping was performed using the slide agglutination method, according to the Kaufman-White system. Susceptibility to antimicrobial agents was assessed using the Kirby and Bauer disk diffusion method. The presence of class 1 and 2 integrons was determined by PCR. Ninety samples were examined, of which 13 (14.44%) were positive for S. enterica, of which 5 strains were isolated from lagoon water, 3 from fish, and 5 from epilithic biofilm. Among the samples, the serotypes S. Minnesota, S. Panamá, and S. Anatum were identified. Antimicrobial resistance rates were highest for sulfonamides (92.30%), trimethoprim (84.61%), tetracycline (46.15%), and streptomycin (46.15%). Multiple antibiotic resistance was confirmed in 84.61% of the isolates, with 100% presenting integron class 1 and 7.69% integron class 2. This study demonstrated a high prevalence of multiresistant bacteria in fish farms, which reinforces public health concerns due to the use of antibiotics and the risk associated with food from farmed freshwater fish. Given these results, the need for new external research into control and prevention strategies for Salmonella spp. is evident. in aquaculture, as well as greater regulation in fish production chains.