Pump-Free Microfluidic Rapid Mixer Combined with a Paper-Based Channel.

Capillary forces are commonly employed to transport fluids in pump-free microfluidic platforms such as paper-based microfluidics. However, since paper is a porous material consisting of nonuniform cellulose fibers, it has some limitations in performing stable flow functions like mixing. Here, we developed a pump-free microfluidic device that enables rapid mixing by combining paper and plastic. The device was fabricated by laminating transparency film and double-sided adhesive and is composed of an overlapping inlet ending in a paper-based reaction area. The mixing performance of the developed device was confirmed experimentally using aqueous dyes and pH indicators. In addition, the absolute mixing index was evaluated by numerically calculating the concentration field across the microfluidic channels. To demonstrate the utility of the new approach, the detection of an organophosphate pesticide was carried out using a colorimetric enzymatic inhibition assay. The developed device and a smartphone application were used to detect organophosphate pesticide on food samples, demonstrating the potential for onsite analysis.

Myclobutanil enantioselective risk assessment in humans through in vitro CYP450 reactions: Metabolism and inhibition studies.

Myclobutanil is a chiral triazole fungicide that is employed worldwide. Although enantiomers have the same physical-chemical properties, they may differ in terms of activity, metabolism, and toxicity. This investigation consisted of in vitro enantioselective metabolism studies that employed a human model to assess the risks of myclobutanil in humans. A LC-MS/MS enantioselective method was developed and validated. The enzymatic kinetic parameters (VMAX, KMapp, and CLINT) determined for in vitro rac-myclobutanil and S-(+)-myclobutanil metabolism revealed enantioselective differences. Furthermore, human CYP450 enzymes did not metabolize R-(-)-myclobutanil. The predicted in vivo toxicokinetic parameters indicated that S-(+)-myclobutanil may be preferentially eliminated by the liver and suffer the first-pass metabolism effect. However, because CYP450 did not metabolize R-(-)-myclobutanil, this enantiomer could reach the systemic circulation and stay longer in the human body, potentially causing toxic effects. The CYP450 isoforms CYP2C19 and CYP3A4 were involved in rac-myclobutanil and S-(+)-myclobutanil metabolism. Although there were differences in the metabolism of the myclobutanil enantiomers, in vitro inhibition studies did not show significant enantioselective differences. Overall, the present investigation suggested that myclobutanil moderately inhibits CYP2D6 and CYP2C9 in vitro and strongly inhibits CYP3A and CYP2C19 in vitro. These results provide useful scientific information for myclobutanil risk assessment in humans.

Pre-clinical evaluation of quinoxaline-derived chalcones in tuberculosis.

New effective compounds for tuberculosis treatment are needed. This study evaluated the effects of a series of quinoxaline-derived chalcones against laboratorial strains and clinical isolates of M. tuberculosis. Six molecules, namely N5, N9, N10, N15, N16, and N23 inhibited the growth of the M. tuberculosis H37Rv laboratorial strain. The three compounds (N9, N15 and N23) with the lowest MIC values were further tested against clinical isolates and laboratory strains with mutations in katG or inhA genes. From these data, N9 was selected as the lead compound for further investigation. Importantly, this chalcone displayed a synergistic effect when combined with moxifloxacin. Noteworthy, the anti-tubercular effects of N9 did not rely on inhibition of mycolic acids synthesis, circumventing important mechanisms of resistance. Interactions with cytochrome P450 isoforms and toxic effects were assessed in silico and in vitro. The chalcone N9 was not predicted to elicit any mutagenic, genotoxic, irritant, or reproductive effects, according to in silico analysis. Additionally, N9 did not cause mutagenicity or genotoxicity, as revealed by Salmonella/microsome and alkaline comet assays, respectively. Moreover, N9 did not inhibit the cytochrome P450 isoforms CYP3A4/5, CYP2C9, and CYP2C19. N9 can be considered a potential lead molecule for development of a new anti-tubercular therapeutic agent.

The Inhibition of Inflammasome by Brazilian Propolis (EPP-AF).

Propolis extracts have gained the attention of consumers and researchers due to their unique chemical compositions and functional properties such as its anti-inflammatory activity. Recently, it was described a complex that is also important in inflammatory processes, named inflammasome. The inflammasomes are a large molecular platform formed in the cell cytosol in response to stress signals, toxins, and microbial infections. Once activated, the inflammasome induces caspase-1, which in turn induces the processing of inflammatory cytokines such as IL-1 ß and IL-18. So, to understand inflammasomes regulation becomes crucial to treat several disorders including autoinflammatory diseases. Since green propolis extracts are able to regulate inflammatory pathways, this work purpose was to investigate if this extract could also act on inflammasomes regulation. First, the extract was characterized and it demonstrated the presence of important compounds, especially Artepillin C. This extract was effective in reducing the IL-1 ß secretion in mouse macrophages and this reduction was correlated with a decrease in activation of the protease caspase-1. Furthermore, we found that the extract at a concentration of 30 µ g/mL was not toxic to the cells even after a 18-hour treatment. Altogether, these data indicate that Brazilian green propolis (EPP-AF) extract has a role in regulating the inflammasomes.

Capillary electrophoresis and hollow fiber liquid-phase microextraction for the enantioselective determination of albendazole sulfoxide after biotransformation of albendazole by an endophytic fungus.

Hollow fiber liquid-phase microextraction and CE were applied for the determination of albendazole sulfoxide (ASOX) enantiomers in liquid culture medium after a fungal biotransformation study. The analytes were extracted from 1 mL of liquid culture medium spiked with the internal standard (rac-hydroxychloroquine) and buffered with 0.50 mol/L phosphate buffer, pH 10. The analytes were extracted into 1-octanol impregnated in the pores of the hollow fiber, and into an acid acceptor solution inside the polypropylene hollow fiber. The electrophoretic separations were carried out in 0.05 mol/L tris(hydroxymethyl)aminomethane buffer, pH 9.3, containing 3.0% w/v sulfated-ß-CD (S-ß-CD) with a constant voltage of +15 kV and detection at 220 nm. The method was linear over the concentration range of 250-5000 ng/mL for each ASOX enantiomer. Within-day and between-day assay precision and accuracy for the analytes were studied at three concentration levels and the values of RSD% and relative error % were lower than 15%. The developed method was applied for the determination of ASOX after a biotransformation study employing the endophytic fungus Penicillium crustosum (VR4). This study showed that the endophytic fungus was able to metabolize the albendazole to ASOX enantioselectively. In addition, it was demonstrated that hollow fiber liquid-phase microextraction coupled to CE can be an excellent and environmentally friendly technique for the analysis of samples obtained in biotransformation studies.