Antibacterial, antibiofilm, and antivirulence potential of the main diterpenes from Copaifera spp. oleoresins against multidrug-resistant bacteria.

To evaluate the antibacterial, antibiofilm and antivirulence potential of the main diterpenes from Copaifera spp. oleoresins against multidrug-resistant (MDR) bacteria. Antimicrobial assays included determination of the Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), Minimum Inhibitory Concentration of Biofilm (MICB50), as well as synergistic and antivirulence assays for eight diterpenes against MDR. The tests revealed that two diterpenes (named 1 and 5) showed the best results, with MIC and MBC between 12.5 and 50 µg/mL against most MDR bacteria. These diterpenes exhibited promising MICB50 in concentration between 3.12-25 µg/mL but showed no synergistic antimicrobial activity. In the assessment of antivirulence activity, diterpenes 1 and 5 inhibited only one of the virulence factors evaluated (Dnase) produced by some strains of S. aureus at subinhibitory concentration (6.25 µg/mL). Results obtained indicated that diterpenes isolated from Copaifera oleoresin plays an important part in the search of new antibacterial and antibiofilm agents that can act against MDR bacteria.

Biosynthesis and characterization of gold nanoparticles using Brazilian red propolis and evaluation of its antimicrobial and anticancer activities.

Gold nanoparticles (AuNPs) are highlighted due to their low toxicity, compatibility with the human body, high surface area to volume ratio, and surfaces that can be easily modified with ligands. Biosynthesis of AuNPs using plant extract is considered a simple, low-cost, and eco-friendly approach. Brazilian Red Propolis (BRP), a product of bees, exhibits anti-inflammatory, anti-tumor, antioxidant, and antimicrobial activities. Here, we described the biosynthesis of AuNPs using BRP extract (AuNPextract) and its fractions (AuNPhexane, AuNPdichloromethane, AuNPethyl acetate) and evaluated their structural properties and their potential against microorganisms and cancer cells. AuNPs showed a surface plasmon resonance (SPR) band at 535 nm. The sizes and morphologies were influenced by the BRP sample used in the reaction. FTIR and TGA revealed the involvement of bioactive compounds from BRP extract or its fractions in the synthesis and stabilization of AuNPs. AuNPdichloromethane and AuNPhexane exhibited antimicrobial activities against all strains tested, showing their efficacy as antimicrobial agents to treat infectious diseases. AuNPs showed dose-dependent cytotoxic activity both in T24 and PC-3 cells. AuNPdichloromethane and AuNPextract exhibited the highest in vitro cytotoxic effect. Also, the cytotoxicity of biogenic nanoparticles was induced by mechanisms associated with apoptosis. The results highlight a potential low-cost green method using Brazilian red propolis to synthesize AuNPs, which demonstrated significant biological properties.

Antibacterial activity of 15-deoxygoyazensolide isolated from the stems of Minasia alpestris (Asteraceae) against oral pathogens.

This work reports the isolation of the sesquiterpene lactone 15-deoxygoyazensolide from the stems of Minasia alpestris and the evaluation of its antimicrobial activity against the following oral pathogens: Enterococcus faecalis, Streptococcus salivarius, Streptococcus sobrinus, Streptococcus mutans, Streptococcus mitis, Streptococcus sanguinis, and Lactobacillus casei. Despite the cytotoxicity and genotoxicity of other sesquiterpene lactones of the furanoheliangolide-type, our results revealed that this compound exhibits low antibacterial activity against the evaluated oral pathogens; however, an interesting selectivity against E. faecalis (minimum inhibitory concentration [MIC]=40 µg mL(-1)) and S. sobrinus (MIC=60 µg mL(-1)) was observed.

Estudo fitoquímico preliminar e bioensaio toxicológico frente a larvas de Artemia salina Leach. de extrato obtido de frutos de Solanum lycocarpum A. St.-Hill (Solanaceae) / Phytochemical screening and toxicological bioassay with brine shrimp larvae (Artemia salina Leach) of an extract obtained from fruits of Solanum lycocarpum A. St-Hill

Neste trabalho, avaliou-se o perfil fitoquímico e a toxicidade preliminar frente a larvas de Artemia salina do extrato etanólico de frutos de Solanum lycocarpum. O extrato foi submetido à análise fitoquímica preliminar para identificação das principais classes de metabolitos secundários presentes e testado frente a larvas de A. salina para obtenção das concentrações letais médias (CL50%). Os testes fitoquímicos demonstraram a presença de fenóis, taninos, saponinas, alcalóides e esteroides livres. O extrato foi fracionado em diferentes solventes para a avaliação da toxicidade frente à A. salina, apresentando considerável citotoxicidade na fração hidroalcoólica (CL50% = 285,546 µg/mL).

The phytochemical profile of ethanolic extract of Solanum lycocarpum fruits was analyzed and preliminary toxicity tests were performed against brine shrimp larvae. The extract was subjected to preliminary phytochemical analysis to identify the main classes of secondary metabolites and tested against the larvae of A. salina to obtain the median lethal concentrations (LC50%). The phytochemical tests showed the presence of phenols, tannins, saponins, alkaloids and free steroids. The extract was fractionated with various solvents for toxicity testing against the larvae and the hydroalcoholic fraction showed considerable cytotoxicity (CL50% = 285.546 µg/mL).