Trypanosoma cruzi killing and immune response boosting by novel phenoxyhydrazine-thiazole against Chagas disease.

Trypanosoma cruzi (T. cruzi) causes Chagas, which is a neglected tropical disease (NTD). WHO estimates that 6 to 7 million people are infected worldwide. Current treatment is done with benznidazole (BZN), which is very toxic and effective only in the acute phase of the disease. In this work, we designed, synthesized, and characterized thirteen new phenoxyhydrazine-thiazole compounds and applied molecular docking and in vitro methods to investigate cell cytotoxicity, trypanocide activity, nitric oxide (NO) production, cell death, and immunomodulation. We observed a higher predicted affinity of the compounds for the squalene synthase and 14-alpha demethylase enzymes of T. cruzi. Moreover, the compounds displayed a higher predicted affinity for human TLR2 and TLR4, were mildly toxic in vitro for most mammalian cell types tested, and LIZ531 (IC50 2.8 µM) was highly toxic for epimastigotes, LIZ311 (IC50 8.6 µM) for trypomastigotes, and LIZ331 (IC50 1.9 µM) for amastigotes. We observed that LIZ311 (IC50 2.5 µM), LIZ431 (IC50 4.1 µM) and LIZ531 (IC50 5 µM) induced 200 µg/mL of NO and JM14 induced NO production in three different concentrations tested. The compound LIZ331 induced the production of TNF and IL-6. LIZ311 induced the secretion of TNF, IFNγ, IL-2, IL-4, IL-10, and IL-17, cell death by apoptosis, decreased acidic compartment formation, and induced changes in the mitochondrial membrane potential. Taken together, LIZ311 is a promising anti-T. cruzi compound is not toxic to mammalian cells and has increased antiparasitic activity and immunomodulatory properties.

Thiazolyl-isatin derivatives: Synthesis, in silico studies, in vitro biological profile against breast cancer cells, mRNA expression, P-gp modulation, and interactions of Akt2 and VIM proteins.

The literature reports that thiazole and isatin nuclei present a range of biological activities, with an emphasis on anticancer activity. Therefore, our proposal was to make a series of compounds using the molecular hybridization strategy, which has been used by our research group, producing hybrid molecules containing the thiazole and isatin nuclei. After structural planning and synthesis, the compounds were characterized and evaluated in vitro against breast cancer cell lines (T-47D, MCF-7 and MDA-MB-231) and against normal cells (PBMC). The activity profile on membrane proteins involved in chemoresistance and tumorigenic signaling proteins was also evaluated. Among the compounds tested, the compounds 4c and 4a stood out with IC50 values of 1.23 and 1.39 µM, respectively, against the MDA-MB-231 cell line. Both compounds exhibited IC50 values of 0.45 µM for the MCF-7 cell line. Compounds 4a and 4c significantly decreased P-gp mRNA expression levels in MCF-7, 4 and 2 folds respectively. Regarding the impact on tumorigenic signaling proteins, compound 4a inhibited Akt2 in MDA-MB-231 and compound 4c inhibited the mRNA expression of VIM in MCF-7.

Structural design, synthesis, and anti-Trypanosomatidae profile of new Pyridyl-thiazolidinones.

The present work reports the synthesis of a novel series of pyridine-thiazolidinones with anti-Trypanosoma cruzi and leishmanicidal activities (compounds 10-27), derived from 2 or 4-pyridine thiosemicarbazones (1-9). The in vitro assays were performed with Trypanosoma cruzi trypomastigotes and amastigotes, as well as with Leishmania amazonensis promastigotes and amastigotes. The cytotoxicity profile was evaluated using the cell line RAW 264.7. From the 18 pyridine-thiazolidinones, 5 were able to inhibit trypomastigotes. Overall, all compounds inhibited amastigotes, highlighting compounds 15 (0.60 µM), 18 (0.64 µM), 17 (0.81 µM), and 27 (0.89 µM). Compounds 15 and 18 were able to induce parasite cell death through necrosis induction. Analysis by scanning electron microscopy showed that T. cruzi trypomastigotes treated with compounds 15 and 18 induced morphological changes such as shortening, retraction and curvature of the parasite body and leakage of internal content. Regarding the antiparasitic evaluation against Leishmania amazonensis, only compound 27 had a higher selectivity compared to Miltefosine against the amastigote form (IC50 = 5.70 µM). Our results showed that compound 27 presented an antiparasitic activity for both Trypanosoma cruzi and Leishmania amazonensis. After in silico evaluation, it was suggested that the new pyridine-thiazolidinones had an appropriate drug-likeness profile. Our results pointed out a new chemical frame with an anti-Trypanosomatidae profile. The pyridine-thiazolidinones presented here for the first time could be used as a starting point for the development of new antiparasitic agents.

Synthesis, ADMET Prediction, and Antitumor Profile of Phenoxyhydrazine- 1,3-thiazoles Derivatives.

BACKGROUND: Cancer is one of the most important barriers to increasing life expectancy in all countries in the 21st century. Investigations of new anti-cancer drugs with low side effects are an urgent demand for medicinal chemists. Considering the known antitumor and immunomodulatory activity of thiazoles, this work presents the synthesis and antineoplastic activity of new thiazoles. METHODS: The 22 new compounds (2a-v) were synthesized from different thiosemicarbazones and 2-bromoacetophenone. The compounds were evaluated on: MOLT-4, HL-60, HL-60/MX1, MM1S, SKMEL-28, DU145, MCF-7, and T47d. RESULTS: Compound 2b induced cellular viability on MOLT-4 (37.1%), DU145 (41.5%), and HL- 60/MX1 (58.8%) cells. On MOLT-4 cells, compound 2b exhibited an IC50 of 8.03 µM, and against DU145 cells, an IC50 of 6.04µM. Besides, at IC50 and fold of IC50, 20% to 30% of dead cells were found, most due to necrosis/late apoptosis. Most compounds no showed cytotoxicity against fibroblast cells L929 at the concentrations tested. The compound did not alter the cell cycle of DU145 cells when compared to the negative control. Therefore, compound 2b stands out against DU145 and MOLT-4 cells. CONCLUSION: Our study reinforced the importance of 1,3-thiazoles nuclei in antitumor activity. In addition, derivative 2b stands out against DU145 and MOLT-4 cells and could be a starting point for developing new antineoplastic agents.

A Novel High-Content Screening-Based Method for Anti-Trypanosoma cruzi Drug Discovery Using Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes.

Chagas disease is caused by Trypanosoma cruzi infection and remains a relevant cause of chronic heart failure in Latin America. The pharmacological arsenal for Chagas disease is limited, and the available anti-T. cruzi drugs are not effective when administered during the chronic phase. Cardiomyocytes derived from human-induced pluripotent stem cells (hiPSC-CMs) have the potential to accelerate the process of drug discovery for Chagas disease, through predictive preclinical assays in target human cells. Here, we aimed to establish a novel high-content screening- (HCS-) based method using hiPSC-CMs to simultaneously evaluate anti-T. cruzi activity and cardiotoxicity of chemical compounds. To provide proof-of-concept data, the reference drug benznidazole and three compounds with known anti-T. cruzi activity (a betulinic acid derivative named BA5 and two thiazolidinone compounds named GT5A and GT5B) were evaluated in the assay. hiPSC-CMs were infected with T. cruzi and incubated for 48 h with serial dilutions of the compounds for determination of EC50 and CC50 values. Automated multiparametric analyses were performed using an automated high-content imaging system. Sublethal toxicity measurements were evaluated through morphological measurements related to the integrity of the cytoskeleton by phalloidin staining, nuclear score by Hoechst 33342 staining, mitochondria score following MitoTracker staining, and quantification of NT-pro-BNP, a peptide released upon mechanical myocardial stress. The compounds showed EC50 values for anti-T. cruzi activity similar to those previously described for other cell types, and GT5B showed a pronounced trypanocidal activity in hiPSC-CMs. Sublethal changes in cytoskeletal and nucleus scores correlated with NT-pro-BNP levels in the culture supernatant. Mitochondrial score changes were associated with increased cytotoxicity. The assay was feasible and allowed rapid assessment of anti-T. cruzi action of the compounds, in addition to cardiotoxicity parameters. The utilization of hiPSC-CMs in the drug development workflow for Chagas disease may help in the identification of novel compounds.

Synthesis, anticancer activity and mechanism of action of new phthalimido-1,3-thiazole derivatives.

In this work, 22 new compounds were obtained and evaluated for their cytotoxic activity on peripheral blood mononuclear cells (PBMC) and eight different tumor cell lines. All compounds displayed IC50 values above 100 µM when assayed against PBMCs. The cytotoxic assays in tumor cell lines revealed that sub-series of phthalimido-bis-1,3-thiazoles (5a-f) exhibited the best anti-tumor activity profile, presenting viability values below 59 %. As a result, the IC50 value was calculated for compounds 5a-f and 4c, and compounds 5b and 5e were selected for further assays due to their best IC50s. Considering the results presented by the sub-series 5a-f, the importance of the 1,3-thiazole ring in improving the anti-tumor activity was pointed out. Together, the results highlighted the anti-tumor activity of phthalimido-bis-1,3-thiazole derivatives.

Evaluation of the influence of temperature on the protein-tannic acid complex.

Precipitation of blood products from plasma fractionation has played a fundamental role in the industrial purification of important therapeutic products. Only a few studies have been reported by using tannins as proteins precipitant agent from whole plasma while, several conditions have been analyzed. Here, we decided to verify the effect of the temperature on the precipitation process of plasma proteins using tannic acid (TA). Plasma proteins were precipitated with tannic acid by using different temperature incubations. Subsequently, the protein-TA complex was analyzed by SDS-PAGE and quantified. In addition, the protein activity of the complex was measured after heating, as well as the structural changes of the complexes were accompanied by thermogravimetric analysis, differential scanning calorimetry and circular dichroism. In all conditions tested, tannic acid was able to precipitate without selectively separating the proteins in the mixture by using different temperatures during the precipitation process. Furthermore, the protein concentration from the plasma precipitate was not affected by different temperatures and the plasma precipitate was able to dissolve fibrin clots in vitro.

The design, synthesis, and in vitro trypanocidal and leishmanicidal activities of 1,3-thiazole and 4-thiazolidinone ester derivatives.

Chagas and leishmaniasis are both neglected tropical diseases, whose inefficient therapies have made them remain the cause for millions of deaths worldwide. Given this, we synthesized 27 novel 1,3-thiazoles and 4-thiazolidinones using bioisosteric and esterification strategies to develop improved and safer drug candidates. After an easy, rapid and low-cost synthesis with satisfactory yields, compounds were structurally characterized. Then, in vitro assays were performed, against Leishmania infantum and Leishmania amazonensis promastigotes, Trypanosoma cruzi trypomastigotes and amastigotes, for selected compounds to determine IC50 and SI, with cytotoxicity on LLC-MK2 cell lines. Overall, 1,3-thiazoles exhibited better trypanocidal activity than 4-thiazolidinones. The compound 1f, an ortho-bromobenzylidene-substituted 1,3-thiazole (IC50 = 0.83 µM), is the most potent of them all. In addition, compounds had negligible cytotoxicity in mammalian cells (CC50 values > 50 µM). Also noteworthy is the examination of the cell death mechanism of T. cruzi, which showed that compound 1f induced necrosis and apoptosis in the parasite. Scanning electron microscopy analysis demonstrated that the treatment of Trypanosoma cruzi trypomastigote cells with the compound 1f at different IC50 concentrations promoted alterations in the shape, flagella and body surface, inducing parasite death. Together, our data revealed a novel series of 1,3-thiazole structure-based compounds with promising activity against Trypanosoma cruzi and Leishmania spp., broadening ways for scaffold optimization.

Study of in vitro biological activity of thiazoles on Leishmania (Leishmania) infantum.

OBJECTIVES: In the prospection of possible agents against neglected diseases, thiazole compounds are presented as promising candidates and are known to have activity against trypanosomatid parasites. Thus, this work aimed to evaluate the effects of thiazole compounds on Leishmania infantum, the aetiological agent of visceral leishmaniasis. METHODS: Thiazole compounds (five thiazoacetylpyridines [TAPs-01, -04, -05, -06, -09) and five thiazopyridines [TPs-01, -04, -05, -06, -09]) were tested regarding their leishmanicidal activity on both promastigote and amastigote forms of L. infantum. Cytotoxicity was tested using peritoneal macrophages of BALB/c mice. Ultrastructural analyses were performed to identify possible intracellular targets of the most effective compound on promastigote forms. To observe routes that can clarify the possible mechanism of action of the compounds on the intracellular amastigote forms, the nitrite dosage was performed. RESULTS: All compounds inhibited the growth of promastigote and presented low cytotoxicity, being more selective to the parasite than to mammalian cells. All compounds tested were able to decrease macrophage infection. There was a significant decrease in the survival rate of the amastigote when compared with the untreated cells, with TAP-04 presenting the best index. TAP-04 induced ultrastructural changes that are related to cell death by apoptosis. None of the macrophage groups infected with L. infantum and subsequently treated showed increased nitrite release. CONCLUSIONS: The low toxicity to mammalian cells and the leishmanicidal activity observed demonstrate that the synthesis of drugs based in thiosemicarbazone nucleus, thiazole and pyridine derivatives are promising for the treatment of visceral leishmaniasis.

In vitro and in vivo activities of multi-target phtalimido-thiazoles on Schistosomiasis mansoni.

Schistosomicidal activity of six phthalimido-thiazoles derivatives with substitutions at the position three of the thiazole ring were analyzed in an experimental model. The substituents biphenyl (2i) and 2- naphthyl (2j) at a concentration of 80 µg/mL caused 100% mortality of the parasite in culture after 24 h and 48 h respectively. An evaluation of ultrastructural parasites showed damage in the tegument, formation of bubbles and partial destruction of the tubercles. The in vivo anti-parasitic activity with the derivate 2i was performed by administering it orally and intraperitoneally in a 400 mg/kg/5days regimen. Decreases in the number of eggs in the gut (45.1%) and a reduction of the percentage of mature (23.7%) and increased unviable (53.8%) eggs were observed. Our results also showed a reduction in the number of recovered worms after treatment with 2i (oral administration: 81, 25%). The results demonstrated that the prototypes which were tested had a significant anti-schistosomal effect against S. mansoni, suggesting that these derivatives are promising candidates for further research into the chemotherapy of schistosomiasis.

Tannic acid as a precipitating agent of human plasma proteins.

The search for plasma proteins precipitation methods has been increasing due to the plasma protein therapeutic needs in world-wide. Thus, this work evaluates the tannic acid (TA) ability to precipitate proteins from human plasma. In this study, TA-plasma protein complexes were studied at different pH conditions, tannin/plasma ratio and reaction mixing time. The complexes formed from combinations of TA and plasma proteins were analyzed by gel electrophoresis, protein quantification, particle size, charge, mass spectrometry, microscopic image, and circular dichroism. It was possible to verify the precipitate formation in all tested pH values, with high precipitation at pH 5. The native PAGE analysis showed three mainly bands corresponding independent of the pHs used. It was possible to observe a gradual growing of precipitate protein in the first precipitation process (P1) when increased the TA/plasma ratio. 15 min of incubation was enough to precipitate 72.3% of proteins. Spectroscopic analyzes showed albumin signals and the electron microscopy analysis of IgG-TA confirmed the compact form of a precipitate. According to CD, formation of the IgG-TA complexes does not cause a major structural change of the protein. From the results obtained, it was possible to establish some parameters for plasma proteins precipitation using TA.

2-(phenylthio)ethylidene derivatives as anti-Trypanosoma cruzi compounds: Structural design, synthesis and antiparasitic activity.

Chagas disease is an illness caused by the protozoan parasite Trypanosoma cruzi. The current chemotherapy is based on benznidazole, and, in some countries, Nifurtimox, which is effective in the acute phase of the disease, but its efficacy in the chronic phase remains controversial. It can also cause serious side effects that lead sufferers to abandon treatment. In the present work, is reported the synthesis and trypanocidal activity of new 2-(phenylthio)ethylidene thiosemicarbazones (4-15) and 1,3-thiazoles (16-26). The cyclization of thiosemicarbazones into 1,3-thiazoles presents an improvement in the cytotoxic profile for T. cruzi parasite, denoting selective compounds. Compound 18 was identified as the most promising of all compounds tested, showing an IC50 of 2.6 µM for the trypomastigote form and a non-cytotoxic effect on mouse spleen cells, reaching a selective index of 95.1. Among the 22 compounds tested, six compounds present a better trypanocidal activity, and five compounds have an equipotent activity compared to benznidazole. Flow cytometry and ultrastructural analysis were performed and indicate that compound 18 causes parasite cell death through apoptosis and acts via an autophagic pathway.

Schistosomicidal and prophylactic activities of phthalimido-thiazoles derivatives on schistosomula and adult worms.

Schistosomiasis is a major public health problem worldwide, especially in poor communities. Praziquantel is currently the only drug available to treat schistosomiasis and it shows low efficacy against schistosomula and juveniles stages of Schistosoma mansoni, allowing lower cure rate in areas with high endemicity. There is an urgent need to identify new antischistosomal drugs. Previous works identified phthalimido-thiazoles as privileged structures acting as schistossomicidal agent. In this way, a phthalimido-thiosemicarbazide intermediate and eight phthalimido-thiazoles derivatives were evaluated concerning the in vitro antischistosomal activity compounds in adult phase of Schistosoma mansoni and examined alterations on the tegumental surface. The results revealed that compounds 2f, 2 l and 2 m caused significant mortality in adult worms at concentrations range of 20 µg/mL to 100 µg/mL. These compounds were also selected in view to verify the activity against the schistosomula. Compound 2 m promoted 100% of mortality of larval forms until doses of 2.5 µg/mL within 48 h. In addition, when compound 2 m was administered orally at dose of 200 mg/kg for 5 consecutive days to the infected mouse with adult schistosomes, a reduction in the parasite burden was observed. Furthermore, scanning electron microscopy revealed that compound 2 m kill the parasite by tegumental damage and bubbles generation.

Multi-target compounds acting in cancer progression: Focus on thiosemicarbazone, thiazole and thiazolidinone analogues.

Currently, cancer and its progression to metastasis result in a large number of deaths. The lack of new drugs, appropriate clinical trials for metastasis preventive drugs and incomplete understanding of the molecular machinery are the major obstacles in metastasis prevention and treatment. On the other hand, thiosemicarbazones and their bioisosteres, thiazole and thiazolidinone are recurring in a wide range of biologically active compounds that reach different targets within tumor context and represent a promising start point to access potential candidates in metastatic cancer. Therefore, the search for new lead compounds showing highest anticancer potency and less adverse effects is the major challenger in drug discovery. The search was based from 1994 to 2018, focusing on thiosemicarbazone, thiazole and thiazolidinone cores that allowed us to discuss how the three multi-target motifs have been used for the target-based design and development of anticancer agents. In the lasts years, thiosemicarbazone, thiazole, and thiazolidinone cores are recurrent in many approaches for cancer therapy. In our search, it was verified that due to its biodiversity and versatility the anticancer potential of such structures has been assigned to distinct mechanisms reinforcing the value of these cores in the anticancer drug development. The present article aims point out the current application of thiosemicarbazone, thiazole and thiazolidinone cores in the design of anticancer agents within tumor progression, acting via varied targets such as cathepsins, NDRG1 gene and kinases, showing in vitro tests, in vivo tests and clinical trials. In our search it was possible to verify that thiazole is the most studied and the most important of the three structures. Therefore, we hope to provide new insights and valuable inspiration in the research of new drugs and development and contribute to the management of cancer.

Privileged Structures in the Design of Potential Drug Candidates for Neglected Diseases.

BACKGROUND: Privileged motifs are recurring in a wide range of biologically active compounds that reach different pharmaceutical targets and pathways and could represent a suitable start point to access potential candidates in the neglected diseases field. The current therapies to treat these diseases are based in drugs that lack of the desired effectiveness, affordable methods of synthesis and allow a way to emergence of resistant strains. Due the lack of financial return, only few pharmaceutical companies have been investing in research for new therapeutics for neglected diseases (ND). METHODS: Based on the literature search from 2002 to 2016, we discuss how six privileged motifs, focusing phthalimide, isatin, indole, thiosemicarbazone, thiazole, and thiazolidinone are particularly recurrent in compounds active against some of neglected diseases. RESULTS: It was observed that attention was paid particularly for Chagas disease, malaria, tuberculosis, schistosomiasis, leishmaniasis, dengue, African sleeping sickness (Human African Trypanosomiasis - HAT) and toxoplasmosis. It was possible to verify that, among the ND, antitrypanosomal and antiplasmodial activities were between the most searched. Besides, thiosemicarbazone moiety seems to be the most versatile and frequently explored scaffold. As well, phthalimide, isatin, thiazole, and thiazolidone nucleus have been also explored in the ND field. CONCLUSION: Some described compounds, appear to be promising drug candidates, while others could represent a valuable inspiration in the research for new lead compounds.

Phthalimido-thiazole as privileged scaffold: activity against immature and adult worms of Schistosoma mansoni.

Phthalimide, 1,3-thiazole, and thiazolidinone cores are considered privileged scaffolds and represent an attractive starting point to design new bioactive compounds for neglected tropical disease (NTD). Schistosomiasis is a NTD, caused by Schistosoma worms which praziquantel (PZQ) is the only drug used to treat humans, but the decrease in the effect after treatment has been reported. Recently, some phthalimide-thiazole derivatives exhibited in vitro antischistosomal activity against adult worms with significant ultrastructural changes and a lower cytotoxic effect on splenocytes. This new biological phthalimido-thiazole profile has motivated us to evaluate a new generation of such molecules in immature and adult worms. Thus, a phthalimido-thiazolidinone derivative, (3c), and three phthalimido-thiazoles (6c, 7a, and 7h) were evaluated concerning their in vitro activity on schistosomulae and adult worms. The results showed that these compounds brought a significant reduction on the mortality, inhibited oviposition, and then induced mortality in immature and adult worms alike. According to scanning electron microscopy, the tegument was the principal target for 7a and 7h and revealed gradual damage to the tegument surface, inducing destruction and decomposition of the tegument in the same areas and exposition of subtegumental tissue and of muscle tissue. Furthermore, they caused less toxicity in splenocytes than PZQ. Compounds 7a and 7h revealed to possess promising activity against larval forms. According to the present study, the privileged structure phthalimido-thiazoles act as a molecular framework that has antischistosomal activity and most form the basis to the next pre-clinical tests. Graphical abstract.

Synthesis, anticancer activity and mechanism of action of new thiazole derivatives.

Thiazole derivatives are recognized to possess various biological activities as antiparasitic, antifungal, antimicrobial and antiproliferative. The present work reports the synthesis of 22 new substances belonging to two classes of compounds: thiosemicarbazones and thiazoles, with the purpose of developing new drugs that present high specificity for tumor cells and low toxicity to the organism. A cytotoxic screening was performed to evaluate the performance of the new derivatives in five tumor cell lines. Eight compounds were shown to be promising in at least three tumor cell lines. These compounds had their IC50 determined within 72 h and the activity structure ratio was assessed. The effect of the best compounds on PBMC and hemolytic activity assay was then evaluated. The compound 1d was considered the most promising among the samples tested and its influence on cell cycle, DNA fragmentation and mitochondrial depolarization was evaluated.

Structural design, synthesis and pharmacological evaluation of thiazoles against Trypanosoma cruzi.

Chagas disease is one of the most significant health problems in the American continent. benznidazole (BDZ) and nifurtimox (NFX) are the only drugs approved for treatment and exhibit strong side effects and ineffectiveness in the chronic stage, besides different susceptibility among T. cruzi DTUs (Discrete Typing Units). Therefore, new drugs to treat this disease are necessary. Thiazole compounds have been described as potent trypanocidal agents. Here we report the structural planning, synthesis and anti-T. cruzi evaluation of a new series of 1,3-thiazoles (7-28), which were designed by placing this heterocycle instead of thiazolidin-4-one ring. The synthesis was conducted in an ultrasonic bath with 2-propanol as solvent at room temperature. By varying substituents attached to the phenyl and thiazole rings, substituents were observed to retain, enhance or greatly increase their anti-T. cruzi activity. In some cases, methyl at position 5 of the thiazole (compounds 9, 12 and 23) increased trypanocidal property. The exchange of phenyl for pyridinyl heterocycle resulted in increased activity, giving rise to the most potent compound against the trypomasigote form (14, IC50trypo = 0.37 µM). Importantly, these new thiazoles were toxic for trypomastigotes without affecting macrophages and cardiomyoblast viability. The compounds were also evaluated against cruzain, and five of the most active compounds against trypomastigotes (7, 9, 12, 16 and 23) inhibited more than 70% of enzymatic activity at 10 µM, among which compound 7 had an IC50 in the submicromolar range, suggesting a possible mechanism of action. In addition, examination of T. cruzi cell death showed that compound 14 induces apoptosis. We also examined the activity against intracellular parasites, revealing that compound 14 inhibited T. cruzi infection with potency similar to benznidazole. The antiparasitic effect of 14 and benznidazole in combination was also investigated against trypomastigotes and revealed that they have synergistic effects, showing a promising profile for drug combination. Finally, in mice acutely-infected with T. cruzi,14 treatment significanty reduced the blood parasitaemia and had a protective effect on mortality. In conclusion, we report the identification of compounds (7), (12), (15), (23) and (26) with similar trypanocidal activity of benznidazole; compounds (9) and (21) as trypanocidal agents equipotent with BDZ, and compound 14 with potency 28 times better than the reference drug without affecting macrophages and cardiomyoblast viability. Mechanistically, the compounds inhibit cruzain, and 14 induces T. cruzi cell death by an apoptotic process, being considered a good starting point for the development of new anti-Chagas drug candidates.

Anti-liver cancer activity in vitro and in vivo induced by 2-pyridyl 2,3-thiazole derivatives.

A total of 24 hybrid compounds containing pyridyl and 1,3-thiazole moieties were screened against HL-60 (leukemia), MCF-7 (breast adenocarcinoma), HepG2 (hepatocellular carcinoma), NCI-H292 (lung carcinoma) human tumor cell lines and non-tumor cells (PBMC, human peripheral blood mononuclear cells). Most of them were highly potent in at least one cell line tested (IC50≤3µM), being HL-60 the most sensitive and HepG2 the most resistant cell line. Among them, TAP-07 and TP-07 presented cytotoxic activity in all tumor cell lines, including HepG2 (IC50 2.2 and 5.6µM, respectively) without antiproliferative effects to normal cells (PBMC) (IC50>30µM), making TAP-07 and TP-07, the compounds with the most favorable selectivity index. TAP-07 and TP-07 induced apoptosis in HepG2 cells and presented in vivo antitumor activity in hepatocellular xenograft cancer model in C.B-17 severe combined immunodeficient mice. Systemic toxicological verified by biochemical and histopathological techniques reveled no major signs of toxicity after treatment with TAP-07 and TP-07. Together the results indicated the anti-liver cancer activity of 2-pyridyl 2,3-thiazole derivatives.