BackgroundPatients submitted to hemodialysis therapy are more susceptible to infection, especially to infection by Gram-positive bacteria. Various research works have attempted to discover new antimicrobial agents from plant extracts and other natural products.MethodsThe present study aimed to assess the antibacterial activities of Copaifera duckei, C. reticulata, and C. oblongifolia oleoresins; sodium hypochlorite; and peracetic acid against clinical and environmental isolates recovered from a Hemodialysis Unit. The Minimum Inhibitory Concentration and the Fractionated Inhibitory Concentration Index were determined; the ability of the tested compounds/extracts to inhibit biofilm formation was evaluated by calculating the MICB50 and IC50.ResultsC. duckei was the most efficient among the assayed Copaifera species, and its oleoresin was more effective than peracetic acid and sodium hypochlorite. Copaifera oleoresins and disinfectants did not act synergistically at any of the tested combinations. Certain of C. duckei oleoresin, peracetic acid, and sodium hypochlorite concentrations inhibited biofilm formation and eradicated 50% of the biofilm population.ConclusionC. duckei oleoresin is a potential candidate for disinfectant formulations. Based on these results and given the high incidence of multi-resistant bacteria in hemodialysis patients, it is imperative that new potential antibacterial agents like C. duckei oleoresin, which is active against Staphylococcus, be included in disinfectant formulations.

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The essential oil (EO) of the flowers from Banisteriopsis campestris was analysed by GC and GC-MS. Fatty acids were the most abundant class of compounds in the EO, followed by long-chain alkanes and oxygenated sesquiterpenes and monoterpenes. The main constituents were hexadecanoic acid (39.43 %), (E)-nerolidol (10.51 %), triacontane (9.08 %), heptacosane (5.49 %) and linalool (3.23 %). The antimicrobial activity of the EO was evaluated against aerobic and anaerobic oral bacteria and some yeasts by broth microdilution method. The EO inhibited the growth of all tested oral bacteria, showing strong activity against S. sanguinis with minimum inhibitory concentration (MIC) of 25 μg mL -1 . Considerable antibacterial activity was also observed for the anaerobes Porphyromonas gingivalis and Actinomyces naeslundii with MIC of 50 μg mL -1 . The EO of B. campestris flower showed moderate activity for S. mutans, S. mitis, A. actinomycetemcomitans and Fusobacterium nucleatum with MICs ranging between 200 and 400 μg mL -1 . The antifungal activity was evaluated against C. albicans, C. tropicalis and C. glabrata. The MIC results were above 3000 μg mL -1 , indicating inactivity against these yeasts. This study revealed that the OE of B. campestris flowers has promising antibacterial activity and this is the first report on its chemical composition and antimicrobial activity Resumo O óleo essencial (EO) das flores de Banisteriopsis campestris foi analisado por CG e GC-EM. Os ácidos graxos foram a classe de compostos mais abundantes no OE, seguidos por alcanos de cadeia longa, sesquiterpenos oxigenados e monoterpenos oxigenados. Os principais constituintes foram ácido palmítico (39,43 %), (E)-nerolidol (10,51 %), triacontano (9,08 %), heptacosano (5,49 %) e linalol (3,23 %). A atividade antimicrobiana do EO foi avaliada contra bactérias bucais aeróbias e anaeróbias e algumas espécies de Candida pelo método de microdiluição em caldo. O EO inibiu o crescimento de todas as bactérias bucais testadas, apresentando forte atividade contra a bactéria aeróbia S. sanguinis com concentração inibitória mínima (CIM) de 25 µg.mL -1 . Considerável atividade antibacteriana foi também observada para as bactérias anaeróbias Porphyromonas gingivalis e Actinomyces naeslundii com CIM de 50 µg.mL -1 . O EO da flor de B. campestris mostrou moderada atividade para S. mutans, S. mitis, A. actinomycetemcomitans e Fusobacterium nucleatum com concentrações inibitórias minimas entre 200 e 400 µg.mL -1 . A atividade antifúngica foi avaliada contra C. albicans, C. tropicalis e C. glabrata. Os resultados de MIC estiveram acima de 3.000 µg.mL -1 , indicando inatividade contra estas leveduras. Este estudo revelou que o OE das flores