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.

The enantiomers (R)-(+)-β-citronellol and (S)-(−)-β-citronellol are present in many medicinal plants, but little is understood about their bioactivity against Candida yeasts. This study aimed to evaluate the behavior of positive and negative enantiomers of β-citronellol on strains of Candida albicans and C. tropicalis involved in candidemia. The minimum inhibitory concentration (MIC) and minimum fungicide concentration (MFC) were determined. The evaluation of growth kinetics, mechanism of action, and association studies with Amphotericin B (AB) using the checkerboard method was also performed. R-(+)-β-citronellol and S-(−)-β-citronellol presented a MIC_50% of 64 µg/mL and a MFC_50% of 256 µg/mL for C. albicans strains. For C. tropicalis, the isomers exhibited a MIC_50% of 256 µg/mL and a MFC_50% of 1024 µg/mL. In the mechanism of action assay, both substances displayed an effect on the fungal membrane but not on the fungal cell wall. Synergism and indifference were observed in the association of R-(+)-β-citronellol and AB, while the association between S-(−)-β-citronellol and AB displayed synergism, additivity, and indifference. In conclusion, both isomers of β-citronellol presented a similar profile of antifungal activity. Hence, they can be contemplated in the development of new antifungal drugs providing that further research is conducted about their pharmacology and toxicity.

In the current context of emerging drug-resistant fungal pathogens such as Candida albicans and Candida parapsilosis, discovery of new antifungal agents is an urgent matter. This research aimed to evaluate the antifungal potential of 2-chloro-N-phenylacetamide against fluconazole-resistant clinical strains of C. albicans and C. parapsilosis. The antifungal activity of 2-chloro-N-phenylacetamide was evaluated in vitro by the determination of the minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), inhibition of biofilm formation and its rupture, sorbitol and ergosterol assays, and association between this molecule and common antifungal drugs, amphotericin B and fluconazole. The test product inhibited all strains of C. albicans and C. parapsilosis, with a MIC ranging from 128 to 256 µg.mL^-1, and a MFC of 512-1,024 µg.mL^-1. It also inhibited up to 92% of biofilm formation and rupture of up to 87% of preformed biofilm. 2-chloro-N-phenylacetamide did not promote antifungal activity through binding to cellular membrane ergosterol nor it damages the fungal cell wall. Antagonism was observed when combining this substance with amphotericin B and fluconazole. The substance exhibited significant antifungal activity by inhibiting both planktonic cells and biofilm of fluconazole-resistant strains. Its combination with other antifungals should be avoided and its mechanism of action remains to be established.

Aspergillus genus causes many diseases, and the species Aspergillus flavus is highly virulent. Treatment of aspergillosis involves azole derivatives such as voriconazole and polyenes such as amphotericin B. Due to an increase in fungal resistance, treatments are now less effective; the search for new compounds with promising antifungal activity has gained importance. The aims of this study were to evaluate the effects of the synthetic amide 2-chloro-N-phenylacetamide (A1Cl) against strains of Aspergillus flavus and to elucidate its mechanism of action. Thus, the minimum inhibitory concentration, minimum fungicidal concentration, conidial germination, associations with antifungal agents, cell wall activities, membrane activities and molecular docking were evaluated. A1Cl presented antifungal activity against Aspergillus flavus strains with a minimum inhibitory concentration of between 16 and 256 μg/mL and a minimum fungicidal concentration between 32 and 512 μg/mL. The minimum inhibitory concentration of A1Cl also inhibited conidial germination, but when associated with amphotericin B and voriconazole, it promoted antagonistic effects. Binding to ergosterol on the fungal plasma membrane is the likely mechanism of action, along with possible inhibition of DNA synthesis through the inhibition of thymidylate synthase. It is concluded that the amide 2-chloro-N-phenylacetamide has promising antifungal potential.

As dermatofitoses são infecções superficiais que caracterizam-se pelo acometimento de pele, pelo e unhas, apresentando fungos do gênero Microsporum como importantes causadores dessas afecções. Assim, o presente estudo teve como objetivo realizar uma revisão de literatura sobre o gênero Microsporum, destacando-se as possíveis dermatofitoses que espécies desse gênero podem causar, assim como, características epidemiológicas, patogênicas, imunológicas, o diagnóstico e o tratamento farmacológico atualmente empregado. M.canis e M.gypseum tem se apresentado como as principais espécies do gênero Microsporum do ponto de vista clínico-epidemiológico, com predomínio de dermatofitoses associadas a M. canis. Observa-se que fungos desse gênero causam principalmente tinea capitis e tinea corporis, de forma que o diagnóstico pode ser do tipo clínico, através da análise das lesões e, sobretudo, laboratorial por meio de microscopia utilizando-se hidróxido de potássio (KOH) para a elucidação das estruturas fúngicas. Para que haja a infecção, torna-se importante a acidez da pele, além disso, a resposta imunológica tem sido associada aos Toll Like Receptors. O tratamento farmacológico pode ser feito com alilaminas, azólicos ou griseofulvina, em que fenômenos de resistência já tem sido associados a esses fármacos. Assim, os dados presentes nesta pesquisa podem nortear outras pesquisas que tenham fungos do gênero Microsporum como foco.

O presente trabalho trata-se da análise qualitativa de classes de metabólitos secundários presentes em amostras de cinco espécies de plantas medicinais oriundas do horto das Faculdades Nova Esperança, sendo elas: Justicia pectoralis Jacq var. stenophylla Leonard, Symphytum officinale L., Dysphania ambrosioides L., Ocimum basilicum L. e Artemisia vulgaris L. buscando-se conhecer o perfil de metabólitos secundários produzidos pelas espécies por triagem fitoquímica e RMN1H. Para análise qualitativa uma alíquota de cada extrato foi submetida isoladamente a ensaios específicos, estabelecidos na literatura, para identificar a presença das seguintes classes de constituintes: Flavonoides, Saponinas, Alcaloides, Taninos e Terpenoides, bem como por espectros de RMN de 1H. Dessa forma foram realizadas comparações com a literatura no intuito de verificar a presença das classes de metabolitos relacionadas com as atividades biológicas. Os dados permitiram constatar o predomínio de classes como: flavonoides, alcaloides e terpenos nas espécies, aliado as identificações dessas classes de compostos por meio de regiões características nos espectros de RMN de 1H nosermitindo o direcionamento de um perfil fitoquímico para cada planta separadamente.