Anti-Trypanosoma cruzi Activity, Mutagenicity, Hepatocytotoxicity and Nitroreductase Enzyme Evaluation of 3-Nitrotriazole, 2-Nitroimidazole and Triazole Derivatives.

Chagas disease (CD), which is caused by Trypanosoma cruzi and was discovered more than 100 years ago, remains the leading cause of death from parasitic diseases in the Americas. As a curative treatment is only available for the acute phase of CD, the search for new therapeutic options is urgent. In this study, nitroazole and azole compounds were synthesized and underwent molecular modeling, anti-T. cruzi evaluations and nitroreductase enzymatic assays. The compounds were designed as possible inhibitors of ergosterol biosynthesis and/or as substrates of nitroreductase enzymes. The in vitro evaluation against T. cruzi clearly showed that nitrotriazole compounds are significantly more potent than nitroimidazoles and triazoles. When their carbonyls were reduced to hydroxyl groups, the compounds showed a significant increase in activity. In addition, these substances showed potential for action via nitroreductase activation, as the substances were metabolized at higher rates than benznidazole (BZN), a reference drug against CD. Among the compounds, 1-(2,4-difluorophenyl)-2-(3-nitro-1H-1,2,4-triazol-1-yl)ethanol (8) is the most potent and selective of the series, with an IC50 of 0.39 µM and selectivity index of 3077; compared to BZN, 8 is 4-fold more potent and 2-fold more selective. Moreover, this compound was not mutagenic at any of the concentrations evaluated, exhibited a favorable in silico ADMET profile and showed a low potential for hepatotoxicity, as evidenced by the high values of CC50 in HepG2 cells. Furthermore, compared to BZN, derivative 8 showed a higher rate of conversion by nitroreductase and was metabolized three times more quickly when both compounds were tested at a concentration of 50 µM. The results obtained by the enzymatic evaluation and molecular docking studies suggest that, as planned, nitroazole derivatives may utilize the nitroreductase metabolism pathway as their main mechanism of action against Trypanosoma cruzi. In summary, we have successfully identified and characterized new nitrotriazole analogs, demonstrating their potential as promising candidates for the development of Chagas disease drug candidates that function via nitroreductase activation, are considerably selective and show no mutagenic potential.

In silico and in vitro assessment of anti-Trypanosoma cruzi efficacy, genotoxicity and pharmacokinetics of pentasubstituted pyrrolic Atorvastatin-aminoquinoline hybrid compounds.

Atorvastatin (AVA) is a third-generation statin with several pleiotropic effects, considered the last synthetic pharmaceutical blockbuster. Recently, our group described the effects of AVA on DNA damage prevention and against Trypanosoma cruzi infection. In this study, our aim was to evaluate the efficacy, safety, and in silico pharmacokinetic profile of four hybrids of aminoquinolines with AVA 4a-d against T. cruzi using in vitro and in silico models. These synthetic compounds were designed by hybridization of the pentapyrrolic moiety of AVA with the aminoquinolinic unit of chloroquine or primaquine. Pharmacokinetics (ADME) and toxicity parameters were predicted by SwissADME, admetSAR and LAZAR in silico algorithms. The trypanocidal activity of AVA-quinoline hybrids were evaluated in vitro against amastigotes and trypomastigotes of T. cruzi, from Y (Tc II) and Tulahuen (Tc VI) strains. In vitro cardiocytotoxicity was assessed using primary cultures of mouse embryonic cardiac cells and in vitro hepatocytotoxicity on bidimensional and 3D-cultured HepG2 cells. Genotoxicity was evaluated by Ames test and micronucleus assay. Despite the overall good in silico ADMET profile, all tested compounds were predicted to be hepatotoxic. All hybrid derivatives presented high trypanocidal activity, against both trypomastigote and intracellular forms of T. cruzi, presenting EC50's lower than 1 µM besides superior selectivity than the reference drug, without evidences of cardiotoxicity in vitro. The compounds 4a and 4b presented a time-dependent toxicity in monolayer culture of HepG2 but no detectable toxic effects in their spheroids, opposing to the in silico prediction. We can conclude that the AVA-aminoquinoline hybrids presented a hit profile as antiparasitic agents in synthetic pharmaceutical innovation platforms.

A novel naphthoquinone derivative shows selective antifungal activity against Sporothrix yeasts and biofilms.

Sporotrichosis is a subcutaneous mycosis that affects humans and animals, with few therapeutic options available in the pharmaceutical market. We screened the in vitro antifungal activity of fourteen 1,4-naphthoquinones derivative compounds against Sporothrix brasiliensis and Sporothrix schenckii, the main etiological agents of sporotrichosis in Latin America. The most active compound was selected for further studies exploring its antibiofilm activity, effects on yeast morphophysiology, interaction with itraconazole, and selectivity to fungal cells. Among the fourteen 1,4-naphthoquinones tested, naphthoquinone 5, a silver salt of lawsone, was the most active compound. Naphthoquinone 5 was able to inhibit Sporothrix biofilms and induced ROS accumulation, mitochondrial disturbances, and severe plasmatic membrane damage in fungal cells. Furthermore, naphthoquinone 5 was ten times more selective towards fungal cells than fibroblast, and the combination of itraconazole with naphthoquinone 5 improved the inhibitory activity of the azole. Combined, the data presented here indicate that the silver salt naphthoquinone 5 exerts promising in vitro activity against the two main agents of sporotrichosis with important antibiofilm activity and a good toxicity profile, suggesting it is a promising molecule for the development of a new family of antifungals.

Plinia cauliflora (Mart.) Kausel (Jaboticaba) leaf extract: In vitro anti-Trypanosoma cruzi activity, toxicity assessment and phenolic-targeted UPLC-MSE metabolomic analysis.

ETHNOPHARMACOLOGICAL RELEVANCE: Plinia cauliflora (Mart.) Kausel, known as Brazilian grape or jaboticaba, is widely used in Brazilian traditional medicine to treat infectious and inflammatory disorders. However, several aspects of its biological potential remain unclear, such as toxicity and effects on pathogenic protozoa. AIM OF THE STUDY: Investigate the phenolic composition, the in vitro and in silico toxicity profile, and the anti-Trypanosoma cruzi activity of the phenolics-enriched hydromethanolic extract of P. cauliflora leaf. MATERIAL AND METHODS: Phytochemical analysis was performed ultra-performance liquid chromatography-mass spectrometry (UPLC-MSE). Mutagenicity, genotoxicity and eukaryotic cytotoxicity was evaluated by Ames test, cytokinesis-block micronucleus and colorimetric assays, respectively, alongside with a computational prediction of the major compound's pharmacokinetics and toxicity. Anti-T. cruzi activity was investigated on T. cruzi bloodstream trypomastigotes. RESULTS: A total of 14 phenolic compounds were identified, including 11 flavonoids and 2 phenolic acids. No positive response regarding mutagenic potential was detected in Salmonella strains TA97, TA98, TA100, TA102, TA104, both in absence or presence of metabolic activation. The extract induced significant dose-response reduction on nuclear division indexes of HepG2 cells, suggesting cytostatic effects, with no micronuclei induction on cytokinesis-block micronucleus assay. Likewise, it also presented cytotoxic effects, inducing HepG2 and F C3H dose and time dependently cell death through cell membrane damage and more evidently by mitochondrial dysfunction. A dose-response curve of in vitro trypanocidal activity was observed against T. cruzi bloodstream trypomastigotes after 2 and 24 h of exposure. In silico predictions of most abundant compounds' structural alerts, pharmacokinetics and toxicity profile indicates a moderately feasible druglikeness profile and low toxicity for them, which is compatible with in vitro results. CONCLUSIONS: The present study demonstrated that P. cauliflora leaf extract is a potential source of antiparasitic bioactive compounds, however it presents cytotoxic effects in liver cell lines.