Background/Objectives: Antifungal resistance to azoles, coupled with the increasing prevalence of Candida albicans infections, represents a significant public health challenge and has driven the search for new natural compounds that can act as alternatives or adjuvants to the current antifungals. Ellagic acid (EA) has demonstrated antifungal activity; however, its effects are not fully understood. In this study, we investigated the in vitro anti-Candida activity of EA and its ability to potentiate the effects of fluconazole (FLZ) on C. albicans. Methods: The Minimum Inhibitory Concentration (MIC) of EA was determined by broth microdilution and its interaction with FLZ was assessed using a checkerboard assay. Additionally, we examined the effects of EA on yeast-to-hypha transition, inhibition of biofilm formation, time–kill kinetics, hemolytic activity, and cytotoxicity in HeLa ATCC^® CCL-2™ cells. Results: EA exhibited MIC values ranging from 250 to 2000 µg/mL and showed synergistic and additive interactions with FLZ, resulting in a marked reduction in the MIC values of FLZ (up to 32-fold) and EA (up to 16-fold). In the time–kill assay, the most effective combinations were 4× EA MIC, 2× EA MIC, and FIC EA + FLZ, which showed fungicidal activity. Furthermore, EA did not show hemolytic activity and demonstrated low and dose-dependent cytotoxicity in HeLa cells, with no cytotoxic effects observed in combination with FLZ. EA and the synergistic combination of EA and FLZ interfered with both the yeast-to-hypha transition process in C. albicans cells and biofilm formation. In addition to its antifungal efficacy, EA demonstrated a favorable safety profile at the concentrations used. Conclusions: This study presents promising results regarding the potential use of EA in combination with FLZ for the treatment of C. albicans infections.

Silybin, a flavonolignan extracted from the seeds of the plant species Silybum marianum (L.) Gaertn., has a variety of pharmacological activities, including antimicrobial activity against several microorganisms of clinical interest. This review analyzes the existing studies on silybin’s antimicrobial activity and possible mechanisms of action. Silybin has been shown to inhibit the growth of Gram-positive and Gram-negative bacteria, as well as some fungi, viruses, and protozoa. In general, possible mechanisms of antimicrobial action include the inhibition of efflux pumps, prevention of biofilm formation, reduction of the expression of virulence factors, induction of apoptosis-like effects, and plasma membrane damage, as well as the inhibition of nucleic acid and protein synthesis. Silybin has been shown to have synergistic effects when combined with conventional antibiotics against both drug-sensitive and drug-resistant microorganisms. However, the low bioavailability observed for this flavonolignan has been a challenge to its clinical use. In this context, nanotechnology has been used to increase silybin’s bioavailability while enhancing its antimicrobial activity. Furthermore, certain structural modifications have been able to enhance its antimicrobial activity in comparison to that of the natural molecule. Overall, this review provides insights into the scientific understanding of the mechanism of action of silybin and its desired properties for the effective treatment of infections.

Ellagic acid (EA), a naturally occurring phenolic compound, has garnered significant interest as a potential antifungal agent owing to increasing fungal resistance and a scarce therapeutic pipeline. This review consolidates the evidence of the broad-spectrum activity of EA against critical priority pathogens, including Candida auris and Cryptococcus neoformans. We highlight its multi-target mechanisms of action, such as the impairment of cell wall integrity and plasma membrane disruption resulting from the inhibition of ergosterol biosynthesis, and inhibition of key enzymes, such as laccase. In addition to its direct growth-inhibitory effects, EA exhibits antivirulence properties, reducing biofilm formation and hyphal morphogenesis. Notably, it demonstrates synergistic potential with conventional antifungals, such as fluconazole, enhancing efficacy and potentially hindering the emergence of resistance. Although its poor solubility and bioavailability pose therapeutic challenges, advanced formulations such as liposomal systems show promise for improving its delivery. We conclude that EA is a promising candidate for developing new antifungal strategies, particularly as a synergistic agent or in nanoformulations, warranting further investigation to translate its potential into clinical practice.

Background/Objectives: The emergence of methicillin-resistant Staphylococcus aureus (MRSA) necessitates innovative strategies to overcome conventional resistance mechanisms. This study investigated the potential of the natural flavonolignan silibinin (SIL) as an antivirulence agent against S. aureus, with a particular emphasis on its putative multi-target antibacterial activity and its capacity to potentiate the effects of ciprofloxacin (CIP). Methods: The antibacterial and antivirulence properties of SIL were assessed using both in vitro and in silico approaches. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined, and its synergistic interaction with CIP was evaluated using checkerboard assays. Inhibition of biofilm formation, as well as disruption of established biofilms, was assessed using an MTT-based viability assay. Staphyloxanthin (STX) inhibition was examined through pigment extraction and spectrophotometric quantification of pathway intermediates. Molecular docking studies were conducted to predict the binding affinities of the compounds to key bacterial targets, while safety was evaluated through haemolytic and cytotoxicity assays. Results: SIL exhibited weak to moderate direct antibacterial activity (MICs of 256–512 µg/mL), which is characteristic of many natural product scaffolds. Notably, SIL potentiated the activity of CIP, reducing its MIC by up to fourfold against selected resistant strains of S. aureus. SIL significantly inhibited biofilm formation and disrupted established mature biofilms in a strain-dependent manner. In vitro metabolic profiling and in silico analyses provided mechanistic insights into the effects of SIL on STX biosynthesis. Precursor accumulation data suggest inhibition at the diapophytoene desaturase (CrtN) catalytic step, representing a potential mechanism not previously reported for flavonolignans. Molecular docking studies further predicted favourable binding affinities for CrtM and other key targets. Importantly, SIL exhibited no haemolytic activity and low cytotoxicity in macrophages at synergistic concentrations. Conclusions: This study provides evidence that SIL functions as a dual-action agent, potentiating ciprofloxacin efficacy while reducing STX production and inhibiting biofilm formation, thereby impairing key virulence mechanisms of S. aureus. These findings, together with its favourable safety profile, provide a strong rationale for the development of silibinin-based topical adjuvants to combat drug-resistant Staphylococcus infections in humans.

As micoses sistêmicas representam um problema de saúde pública no Brasil e são doenças endêmicas em alguns estados, como no Maranhão. São causadas por fungos que estão presentes no ambiente associados ao solo, vegetais, materiais em decomposição e excretas de aves. As condições climáticas podem influenciar a proliferação e a disseminação destes agentes, contribuindo com o aumento do número de casos de internações. Neste contexto, o objetivo deste estudo foi avaliar a correlação entre as condições climáticas e as internações por micoses em São Luís (MA), no período de 1998 a 2016. Após a aprovação do Comitê de Ética em Pesquisa da Universidade CEUMA, a coleta de dados secundários referentes aos aspectos climáticos e de internações por micoses foi realizada em bases nacionais. A análise de Correlação de Spearman foi aplicada para os dados mensais de internações por micoses e precipitação ou temperatura máxima/ mínima. Foram registrados 786 casos de internações por micoses em São Luís, no período avaliado. Uma correlação positiva entre a precipitação (p< 0,05) e o número de internações por micoses foi observada, enquanto para as temperaturas mínima (p< 0,05) e máxima (p> 0,05), as correlações foram negativas. Os resultados deste estudo destacam que quanto maior a temperatura, menor o número de internações por micoses em São Luís. Este estudo destaca a importância da vigilância epidemiológica das micoses no Estado do Maranhão e da avaliação da modulação das condições ambientais na proliferação de fungos patogênicos. PALAVRAS-CHAVE: São Luís, fungos, precipitação, temperatura.