The essential oil (EO) composition of leaves of Campomanesia aurea was analyzed by GC-MS. The plant was collected in April (EOA) and October (EOO) in São Francisco de Assis/RS. The essential oils were obtained by hydrodistillation in a modified Clevenger apparatus. The yields were 4.44% in April, and 6.15%, in October. Thirty-one compounds were identified in EOA, accounting for 96.87% of the total, and twenty-eight compounds were identified in EOO, accounting for 99.46% of the total. For EOA, the major identified monoterpene was p-cymene (8.33%) and the major identified sesquiterpene was α-cadinol (10.72%), while regarding EOO the major identified monoterpene was repeatedly Terpinolene (3.43%), whereas the major identified sesquiterpene was α-cadinol (12.79%). The antibacterial activity of the essential oil was evaluated against the three Listeria monocytogenes from the American Type Culture Collection (strains ATCC 7644, 19114 and 13932). The essential oil showed a MIC of 10 mg/mL against the strains ATCC 7644 and 19114, with bacteriostatic effect of 20 mg/mL and a MIC of 20 mg/mL for ATCC 13932. Regarding the antibiofilm activity, o EOO showed the best results with an inhibition of 90% in the sessile growth with an applied concentration of 4.0 mg/mL.

Cephalexin (CEX) is an antibiotic commonly used to treat bacterial infections in humans and animals. However, it can be considered a micropollutant. Thus, this study evaluated the degradation of CEX using ultraviolet irradiation (UV-C) and analyzed the by-products as well as their residual antimicrobial activity. A reactor with a mercury vapor lamp was used for the degradation. Irradiated CEX solution were collected over a period of 4 h and analyzed by High Performance Liquid Chromatography coupled with Mass Spectrometry. For the residual antimicrobial activity the susceptibility test was performed by broth microdilution against Staphylococcus aureus and Escherichia coli microorganisms. It was found that CEX, after treatment, generated a metabolite with a mass of 150 m/z in 15 min, and a 4- and 8-fold increase in the minimum inhibitory concentration of the drug against S. aureus and E. coli, could be observed, respectively, after 20 min. Therefore, this treatment proved to be effective in the degradation of CEX, being able to degrade 81% of the initial molecule of the drug in 20 min. Furthermore, the antimicrobial activity of the CEX solution decreased as the irradiation time increased, indicating loss of antimicrobial function of the initial CEX molecule and the resulting by-products.

No abstract

As abelhas nativas são importantes animais para diversas áreas de estudo, não só pelas peculiaridades do mel produzido, mas por seus exemplos de organização ecológica e por todos os demais produtos e subprodutos dessas atividades, com destaque para a produção de própolis e geoprópolis, amplamente trabalhados na meliponicultura, uma área da zootecnia que se dedica a estudar as abelhas sem ferrão (chamadas de meliponinas), como as nativas do Brasil. O objetivo desse trabalho foi avaliar o potencial antibacteriano do extrato etanólico da própolis (EEP) da abelha nativa Scaptotrigona affinis postica frente as bactérias Listeria monocytogenes, Staphylococcus aureus, Streptococcus mutans e Escherichia coli, considerando esta como uma possibilidade de uso de um recurso natural eficaz no controle das bactérias listadas, bem como dos malefícios associados a ocorrência delas. As amostras de própolis foram coletadas em meliponário localizado na cidade de Barra do Corda/MA, sendo dissolvido 100 g de amostra coletada em 1000 mL de álcool 70% para a obtenção do seu extrato etanólico, com posterior evaporação do solvente. A possível ação inibitória do EEP foi avaliada por meio da técnica de Disco Difusão em ágar, sendo utilizado como padrão antibacteriano o antibiótico Ciprofloxacino (a 60 µg/mL), com testagem do extrato etanólico da própolis nas concentrações de 0,25 mg/mL, 0,5 mg/mL, 1 mg/mL e 2 mg/mL. Dentre as seis ATCC’s bacterianas testadas o Ciprofloxacino se mostrou mais eficiente frente a Escherichia coli (ATCC 25922). As amostras de extrato etanólico da própolis da abelha Scaptotrigona affinis postica, em todas as concentrações testadas, não apresentaram atividade antimicrobiana contra os microrganismos testados, requerendo mais estudos e caracterizações.