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Malassezia furfur is a yeast known as the etiological agent of seborrheic dermatitis. We evaluated the action of five different antimicrobials (amphotericin B, chloramphenicol, ketoconazole, fluconazole, and nystatin) on inhibiting biofilm formation and removing biofilm already formed by M. furfur. The assays were carried out using the microdilution method, and scanning electron microscopy images were used to analyze the biofilm structure. According to the results obtained, the percentage of inhibition was higher for chloramphenicol, followed by ketoconazole, nystatin, and amphotericin B. Regarding the eradication of the biofilm formed, the highest percentage was chloramphenicol, followed by ketoconazole and nystatin. Amphotericin B did not affect biofilm eradication, whereas fluconazole did not cause significant changes inhibiting or removing M. furfur biofilm. Therefore, except for fluconazole, all evaluated antimicrobials had inhibiting effects on the biofilm of M. furfur, either in its formation and/or eradication. Although the results achieved with chloramphenicol have been highlighted, further in vitro and in vivo studies are still needed in order to include this antimicrobial in the therapy of seborrheic dermatitis due to its toxicity, especially to the bone marrow. [ABSTRACT FROM AUTHOR]

Introduction: Simvastatin is an antilipidemic drug that has already demonstrated antibacterial activities on oral and non-oral microorganisms. Silver nanoparticles also exhibit antimicrobial properties, particularly for coating implant surfaces. In this study, we evaluated the effects of combining simvastatin with silver nanoparticles on the formation and viability of biofilms consolidated on titanium discs. Methods: Silver nanoparticles were first biosynthesized using the fungus Fusarium oxysporum and then characterized using Dynamic Light Scattering, X-ray Diffraction, Transmission Electron Microscopy, and energy dispersive spectroscopy. Species of Streptococcus oralis, Streptococcus mutans, Porphyromonas gingivalis, Methicillin-sensitive Staphylococcus aureus, and Methicillin-resistant Staphylococcus aureus were used and tested using Minimum Inhibitory Concentration assays with concentrations of silver nanoparticles and simvastatin alone and in combination. Biofilm inhibition and viability tests were performed on titanium surfaces. Toxicity tests were also performed on Galleria mellonella moth larvae. Results: The silver nanoparticles had a spherical shape without the formation of aggregates as confirmed by Transmission Electron Microscopy. Dynamic Light Scattering revealed nanoparticles with an average diameter of 53.8 nm (±1.23 nm), a polydispersity index of 0.23 and a zeta potential of −25 mV (±2.19 mV). The silver nanoparticles inhibited the growth of the strains tested in the range of 0.001592 and 63.75, while simvastatin alone inhibited the growth of the same strains in the range of 3.125–62.5 µg/mL. The antibacterial activity test of the combination of the two substances showed a reduction in the Minimum Inhibitory Concentration of about two to eight times, showing synergistic effects on Staphylococcus aureus and additive effects on Streptococcus oralis and Porphyromonas gingivalis. As for biofilm, sub-inhibitory concentrations of the combination of substances showed better antibacterial activity in inhibiting the formation of Streptococcus oralis biofilm, and this combination also proved effective in eradicating already established biofilms compared to the substances alone. The combination of silver nanoparticles and simvastatin showed low toxicity to Galleria mellonella moth larvae. Conclusions: The results presented indicate that the combination of the two substances could be an alternative for the prevention and reduction of biofilms on implants. These findings open up new possibilities in the search for alternatives for the treatment of peri-implant infections, as well as the possibility of using lower doses compared to single drugs, achieving the same results and reducing potential toxic effects. [ABSTRACT FROM AUTHOR]

Ocimum gratissimum (OG) is a species rich in essential oils (EO), which is known for its antimicrobial and antioxidant properties. This study aimed to encapsulate the essential oil of Ocimum gratissimum (OGE), determine its chemical composition, and evaluate its antioxidant and antimicrobial activities against six pathogenic bacteria, comparing it with the free essential oil (OGF). The EO was extracted by hydrodistillation using a Clevenger-type apparatus, and an oil-in-water emulsion was prepared using a combination of biopolymers: maltodextrin (MA), cashew gum (CG), and inulin (IN). The chemical profile was identified using gas chromatography–mass spectrometry (GC–MS). Antioxidant activity was assessed using the Oxygen Radical Absorbance Capacity with fluorescein (ORAC-FL) method, while the Minimum Inhibitory Concentrations (MIC) and Minimum Bactericidal Concentrations (MBC) were determined by the microdilution method. Microparticles were formed using the spray-drying method, achieving an encapsulation efficiency of 45.2%. The analysis identified eugenol as the main compound both before and after microencapsulation. The OGE microparticles demonstrated high inhibitory and bactericidal effects against S. aureus, S. choleraesuis, and E. coli, with MIC values of 500 µg·mL−1 and MBC values of 1000 µg·mL−1, as well as antioxidant activity of 1914.0 µmol-TE·g−1. Therefore, it can be inferred that the EO of OG maintained its antimicrobial and antioxidant effects even after microencapsulation by spray-drying, making it a promising natural ingredient. [ABSTRACT FROM AUTHOR]

Bacterial pathogens cause significant economic losses in fish farms worldwide. The frequent use of antibiotics is a growing concern due to the adverse effects on human health and the environment. We evaluate the antibacterial activity of the Artemisia annua and its bioactive components against the Aeromonas hydrophila, Streptococcus agalactiae and Flavobacterium columnare, the main bacteria that affect fish culture. Bioactive components of the A. annua were obtained using an alcoholic extraction process, yielding 10.6% of dry material. The alcoholic extract of A. annua (ae‐Aa) bioactive compounds was fractionated, obtaining the fractions F1 + 2, F3, F4, F5 and F6. Artemisinin up to 10.0 mg.ml‐1 was ineffective in controlling studied bacteria. Microorganisms tested were all sensitive to ae‐Aa (MIC and MBC 0.40 to 2.50 mg.ml‐1). The ae‐Aa components F3, F4, F5 and F6 were also effective (MIC and MBC 0.015 to 2.00 mg.ml‐1). F3 showed the most effective antibacterial activity (MIC 0.015 to 0.5 mg.ml‐1 and MBC 0.015 to 2.0 mg.ml‐1). The ae‐Aa and its bioactive components presented efficacy to inhibit growth and eliminate bacterial pathogens and can be an alternative to synthetic antibiotics for farmed fish. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate in vitro the antifungal, antibiofilm and antiproliferative activities of the extract from the leaves of Guapira graciliflora Mart. The phytochemical characterization of the extract was performed using electrospray ionization mass spectrometry (ESI-MS). The antimicrobial activity of the extract and its fractions was evaluated using the broth microdilution method against species of Candida. The inhibition of C. albicans biofilm was evaluated based on the number of colony-forming units (CFU) and metabolic activity (MTT). The antiproliferative activity of the extract and its fraction was evaluated in the presence of human tumor and non-tumor cells, and the cytotoxicity of the extract was determined on the RAW 264.7 macrophage line - both using the sulforhodamine B method. The phytochemical characterization indicated the presence of the flavonoids rutin and kaempferol. The extract and the methanol fraction exhibited moderate antifungal activity against C. albicans, C. krusei, and C. glabrata, and strong activity against C. dubliniensis. In the biofilms at 24 and 48 hours, the concentration of 12500 μg/mL of the extract was the most effective at reducing the number of CFU s/mL (44.4% and 42.9%, respectively) and the metabolic activity of C. albicans cells (34.6% and 52%, respectively). The extract and its fractions had no antiproliferative effect on the tumor lines tested, with mean activity (log GI50) equal to or greater than 1.71 μg/mL. Macrophage cell viability remained higher than 80% for concentrations of the extract of up to 62.5 μg/mL. G. graciliflora has flavonoids in its chemical composition and demonstrates potential antifungal and antibiofilm activity, with no evidence of a significant change in the viability of human tumor and non-tumor cell lines. [ABSTRACT FROM AUTHOR]

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The effects of chitosan based edible coating enriched with pequi peel extract (PPE) on quality and safety of tomatoes stored at 22 °C for 16 days were investigated. The addition of PPE into chitosan matrix reduced in 22% the weight loss and in 50% the total color variation. Concerning firmness and yeast and mold counts, similar improvements were observed for chitosan and chitosan-extract coatings, recording a delaying of the softening process in around 2 days and lowering in microbial counts to an estimated value of 1.5 × 103 CFU/g. The application of PPE alone showed effective in controlling fungal growth on tomatoes, by reducing in approximately 70% when compared to uncoated fruits. These results suggest that the combination of PPE with chitosan is suitable as an effective edible coating, improving fresh weight retention and reducing color change in tomatoes together with retaining the benefits of chitosan in delaying fungal growth. Practical applications Fungal diseases are one of the most common causes of tomatoes losses, making necessary the use of fungicides. Pequi peel extract has antifungal activity against some fungal pathogens of tomatoes and can be incorporated into chitosan-based edible coatings in order to avoid the development of fungal diseases and maintain the parameters related to quality during postharvest storage. [ABSTRACT FROM AUTHOR]