Antiparasitic activity of chalcones analogue against Trichomonas vaginalis: biochemical, molecular and in silico aspects.

Trichomonas vaginalis is the etiologic agent of trichomoniasis, a worldwide distributed sexually transmitted infection (STI) that affects the genitourinary tract. Even though this disease already has a treatment in the prescription of drugs of the 5-nitroimidazole class, described low treatments adhesion, adverse side effects and cases of resistant isolates demonstrate the need for new formulations. With this in mind, chalcones emerge as a potential alternative to be tested, being compounds widely distributed in nature, easy to chemically synthesize and presenting several biological activities already reported. In this experiment, we evaluated the antiparasitic activity of 10 chalcone at a concentration of 100 µM against ATCC 30236 T. vaginalis isolates, considering negative (live trophozoites), positive (Metronidazole 100 µM) and vehicle (DMSO 0.6%) controls. Compounds 3a, 3c, 3 g and 3i showed promising results, with MICs set at 70 µM, 80 µM, 90 µM and 90 µM, respectively (p < 0,05). Cytotoxicity assays were performed on VERO and HMVII cell lines and revealed low inhibition rates at concentrations bellow 20 µM. To elucidate a possible mechanism of action for these molecules, the DPPH, ABTS and FRAP assays were performed, in which none of the four compounds presented antioxidant activity. Assays to verify ROS and lipid peroxidation in the parasite membrane were performed. None of the tested compounds identified ROS accumulation after incubation with trophozoites. 3 g molecule promoted an increase in MDA production after incubation. Results presented in this paper demonstrate the promising trichomonicidal profile, although further tests are still needed to optimize their performance and better elucidate the mechanisms of action involved.

2'-Hydroxychalcones as an alternative treatment for trichomoniasis in association with metronidazole.

The treatment for trichomoniasis, based on 5'-nitroimidazol agents, has been presenting failures related to allergic reactions, side effects, and the emergence of resistant isolates. There are no alternative drugs approved for the treatment of these cases; thus, the search for new active molecules is necessary. In this scenario, chalcones have been extensively studied for their promising biological activities. Here, we presented the synthesis of three hydroxychalcones (3a, b, and c), in vitro and in silico analyses against Trichomonas vaginalis. The in vitro biological evaluation showed that hydroxychalcone 3c presented anti-T. vaginalis activity, with complete death in 12 h of incubation at minimum inhibitory concentration (MIC) of 100 µM. 3c showed a dose-dependent cytotoxicity against mammalian VERO cell line, but the association of 3c at 12.5 µM and metronidazole (MTZ) at 40 µM showed 95.31% activity against T. vaginalis trophozoites after 24 h of exposure and did not affect the VERO cell growth, appearing to be a good alternative. In silico analysis by molecular docking showed that 3c could inhibit the activity of TvMGL (methionine gamma-lyase), TvLDH (lactate dehydrogenase), and TvPNP (purine nucleoside phosphorylase) affecting the T. vaginalis survival and also suggesting a different mechanism of action from MTZ. Therefore, these results propose that hydroxychalcones are promising anti-T. vaginalis agents and must be considered for further investigations regarding trichomoniasis treatment.

Application of differential scanning calorimetry in the analysis of apprehended formulations of anabolic androgenic steroids.

Over the past ten years, there has been a significant increase in the amount of formulations containing anabolic androgenic steroids apprehended worldwide. A considerable amount of these illicit preparations is falsified imposing a series of challenges for the analytical identification of alleged active ingredients due to the presence of interferers. In this sense, the aim of this work was to identify and quantify the active ingredient using cholesterol as internal standard in eight apprehended formulations of anabolic androgenic steroids in either tablet, capsule or injectable forms employing visual inspection and instrumental analysis of Fourier Transform Infrared Spectroscopy, Gas Chromatography - Mass Spectrometry and Differential Scanning Calorimetry. The assessed samples were kindly provided by the Brazilian Federal Police as representative samples from an apprehension made in July of 2017. Qualitatively, 25% of the analyzed materials were determined to be falsified as they were composed of excipients only while the others had the alleged active ingredient confirmed. However, after quantitative analysis, the majority of samples were placed as counterfeit materials as the active substance was found in concentrations lower than stated in the label. Preliminary visual inspection provided important information to distinguish genuine from falsified samples. It should be noted that this work was one of the few available reports to employ Differential Scanning Calorimetry in the analysis of anabolic agents, which proved to be an important complementary tool for the detection of the active ingredient, when present, along with the calorimetric profile of the formulations studied. Fourier Transform Infrared Spectroscopy and Gas-Chromatography - Mass Spectrometry were also efficient analytical tools in order to identify and to characterize substances present in fraudulent preparations.