Staphylococcus aureus is able to rapidly develop mechanisms of resistance to various drugs and to form strong biofilms, which makes it necessary to develop new antibacterial drugs. The essential oil of Melaleuca alternifolia is used as an antibacterial, a property believed to be mainly due to the presence of terpinen-4-ol. Based on this, the objective of this study was to evaluate the antibacterial and antibiofilm potential of terpinen-4-ol against S. aureus. The Minimal Inhibitory and Minimal Bactericidal Concentrations (MIC and MBC) of terpinen-4-ol were determined, and the effect of its combination with antibacterial drugs as well as its activity against S. aureus biofilms were evaluated. In addition, an in silico analysis of its pharmacokinetic parameters and a molecular docking analysis were performed. Terpinen-4-ol presented a MIC of 0.25% (v/v) and an MBC of 0.5% (v/v) (bactericidal action); its association with antibacterials was also effective. Terpinen-4-ol has good antibiofilm activity, and the in silico results indicated adequate absorption and distribution of the molecule in vivo. Molecular docking indicated that penicillin-binding protein 2a is a possible target of terpinen-4-ol in S. aureus. This work highlights the good potential of terpinen-4-ol as an antibacterial product and provides support for future pharmacological studies of this molecule, aiming at its therapeutic application.

Staphylococcus genus is widely spread in nature being part of the indigenous microbiota of skin and mucosa of animal and birds. Some Staphylococcus species are frequently recognized as etiological agents of many animal and human opportunistic infections This is the first report testing the antibiotic resistance-modifying activity of Turnera ulmifolia against methicillin-resistant Staphylococcus aureus – MRSA strain.

A candidíase apresenta-se como uma infecção fúngica superficial ou profunda causada por leveduras pertencentes ao gênero Candida, sendo considerada a principal infecção micótica em ambiente nosocomial. O objetivo do presente estudo foi determinar a concentração inibitória mínima - CIM do óleo essencial de Cinnamomum zeylanicum Blume, Citrus limon Risso, Eucalyptus citriodora HK, Eugenia uniflora L., Peumus boldus Benth e de Rosmarinus officinialis L. sobre cepas de Candida albicans, C. guilliermondii, C. krusei, C. parapsilosis, C. stellatoidea e C. tropicalis. Os ensaios de atividade antifúngica foram realizados através da técnica de difusão em meio sólido. Os óleos essenciais de C. zeylanicum e P. boldus mostraram os mais destacáveis resultados, visto que inibiram o crescimento de 58% das cepas ensaiadas e apresentaram CIM de 4%. Candidiasis occurs as a superficial or profound fungal infection caused by yeasts belonging to the Candida genus. This infectious has been considered the main mycotic infection in the nosocomial environment. The aim of this study was to determine the minimum inhibitory concentration - MIC of Cinnamomum zeylanicum Blume, Citrus limon Risso, Eucalyptus citriodora HK, Eugenia uniflora L., Peumus boldus Benth and Rosmarinus officinialis L. essential oils against Candida albicans, C. guilliermondii, C. krusei, C. parapsilosis, C. stellatoidea e C. tropicalis strains. The antifungal activity assays were carried out by solid medium diffusion technique. C. zeylanicum and P. boldus essential oils showed the most prominent results which inhibited the growth of 58% of the assayed yeasts strains and presented MIC of 4%

O objetivo deste estudo foi investigar a interferência dos óleos essenciais de Lippia sidoides Cham, Plectranthus amboinicus Lour Spr., Conyza bonariensis L. e Eucalyptus citriodora Hook sobre o efeito de antibióticos utilizados na clínica. Os ensaios foram realizados com ampicilina (10 µg/mL), cefalotina (30 µg/mL), cloranfenicol (30 µg/mL), gentamicina (10 µg/mL) e tetraciclina (30 µg/mL) isolados e em associação com os óleos essenciais (4% v/v) através do método de difusão em meio sólido utilizando discos de papel de filtro. Os resultados mostraram interferência de alguns óleos essenciais sobre a atividade dos antibióticos ensaiados. Observou-se o desenvolvimento de halos de inibição do crescimento bacteriano com diferentes diâmetros quando da aplicação de antibióticos isolados e em combinação com os óleos essenciais. A ocorrência de comportamento sinérgico ou antagônico foi observada mais proeminentemente nas interações com cepas de S. aureus e S. epidermidis. De outra forma, observou-se uma menor interferência dos óleos essenciais no efeito dos antibióticos sobre as cepas Gram negativas, principalmente P. aeruginosa. Estes resultados mostram que o uso de produtos derivados de plantas pode em algumas situações interferir sobre a efetividade de antibióticos de uso no tratamento clínico.

The genus Candida is one of the main causes of otomycosis. The growing index of fungal strains resistant to antifungals makes necessary the search for new agents and α-pinene is a phytoconstituent present in plants with remarkable antimicrobial activity, which becomes an interesting object of study. Thus, the objective of this research was to evaluate the antifungal activity of α-pinene against Candida species isolated from otomycosis, determining the Minimum Inhibitory and Fungicide Concentrations, micromorphological analysis and verifying the effects of the association with boric acid. α-pinene showed significant antifungal activity, with greater inhibitory activity against C. parapsilosis, fungicidal action and proved to be effective in inhibiting fungal structures, such as pseudo-hyphae and promoting a marked decrease in blastoconidia. The combination of α-pinene with boric acid produced additive effects that may be interesting for use in clinical practice. Graphical Abstract

The increased incidence of opportunistic fungal infections, associated with greater resistance to the antifungal drugs currently in use has highlighted the need for new solutions. In this study twenty four coumarin derivatives were screened in vitro for antifungal activity against strains of Aspergillus. Some of the compounds exhibited significant antifungal activity with MICs values ranging between 16 and 32 µg/mL. The structure-activity relationships (SAR) study demonstrated that O-substitutions are essential for antifungal activity. It also showed that the presence of a short aliphatic chain and/or electron withdrawing groups (NO₂ and/or acetate) favor activity. These findings were confirmed using density functional theory (DFT), when calculating the LUMO density. In Principal Component Analysis (PCA), two significant principal components (PCs) explained more than 60% of the total variance. The best Partial Least Squares Regression (PLS) model showed an r² of 0.86 and q²_cv of 0.64 corroborating the SAR observations as well as demonstrating a greater probe N1 interaction for active compounds. Descriptors generated by TIP correlogram demonstrated the importance of the molecular shape for antifungal activity.