ABSTRACT Propolis is a rich source of bioactive molecules made by bees by collecting an infinite variety of secondary metabolites from plants. This study determined the chromatographic and mass spectrometry profile along with the biological activity of propolis produced by the native Brazilian bee Melipona quadrifasciata. A hydroalcoholic crude extract was prepared and partitioned in solvents of different polarities, generating aqueous, dichloromethane, ethyl acetate, butanol and insoluble fractions. The phenolic and flavonoid content was also determined in crude aqueous and methanolic extracts as well. The antioxidant activity was determined by three different methods and correlated with the phenolic and flavonoid content. Extracts and fractions were tested against the herpes simplex virus type 1, and the cytotoxicity was evaluated in fibroblast L929 cells. The chromatographic and mass spectrometry analysis revealed the presence of catechin, epicatechin, aromadendrin, naringenin, pinocembrin and p-coumaric acid. The methanolic extract, ethyl acetate fraction and insoluble fraction possess higher phenolic and flavonoid content along with better antioxidant activities. The ethyl acetate and butanol fractions, along with the FM14 and FM45 subfractions demonstrated better viral inhibition, with 50% inhibitory concentrations of 90.5, 294, 188 and 58.5 µg ml−1, respectively. Among these, the ones presenting the best selectivity index were the ethyl acetate and FM45 fractions, with a pronounced virucidal effect. The methanolic extract stood out in the antioxidant activities and showed no cytotoxicity bellow 125 µg ml−1, exhibiting the most promising biological activity. Although this propolis seems to act in the early stages of herpetic infections, it is still difficult to correlate this activity with a single constituent of this complex mixture, suggesting a synergism in the extract components. To our knowledge, this is the first study of its kind with this propolis type.

Abstract The production of KPC (Klebsiella pneumoniae carbapenemase) is the major mechanism of resistance to carbapenem agents in enterobacterias. In this context, forty KPC-producing Enterobacter spp. clinical isolates were studied. It was evaluated the activity of antimicrobial agents: polymyxin B, tigecycline, ertapenem, imipenem and meropenem, and was performed a comparison of the methodologies used to determine the susceptibility: broth microdilution, Etest® (bioMérieux), Vitek 2® automated system (bioMérieux) and disc diffusion. It was calculated the minimum inhibitory concentration (MIC) for each antimicrobial and polymyxin B showed the lowest concentrations for broth microdilution. Errors also were calculated among the techniques, tigecycline and ertapenem were the antibiotics with the largest and the lower number of discrepancies, respectively. Moreover, Vitek 2® automated system was the method most similar compared to the broth microdilution. Therefore, is important to evaluate the performance of new methods in comparison to the reference method, broth microdilution.