Maternal exposure to glyphosate-based herbicide causes vascular dysfunction in offspring female rats

This study analyzed how glyphosate exposure in the gestational period affects vascular function in their female offspring and whether oxidative stress is involved in this effect. To this, pregnant Wistar rats were exposed through drinking water to 0.2% of a glyphosate commercial formulation, and we analyzed the response to acetylcholine and phenylephrine in the aorta from offspring of Glyphosate-based herbicide (O-GBH) and controls (O-CON) rats at six months of age. Relaxation to acetylcholine was reduced in O-GBH than in O-CON. Acute Indomethacin and Apocynin increased relaxation to acetylcholine in O-GBH. The aorta from O-GBH was hyperactive to phenylephrine; the preincubation with N-nitro-L-arginine methyl ester (L-NAME) increased contraction to phenylephrine more in O-CON than O-GBH. TEMPOL similarly reduced phenylephrine response, and L-NAME prevented this effect. The TBARS and GSH levels were increased in O-GBH than in O-CON. Results reinforce the concept that oxidative stress during the perinatal period contributes to the development of vascular changes in adulthood. Results also reveal that oxidative stress parameters altered, and the current levels considered safe for exposure to Glyphosate deserve further investigation, especially in the female gender.

1,3-Thiazole derivatives as privileged structures for anti-Trypanosoma cruzi activity: Rational design, synthesis, in silico and in vitro studies

Chagas disease is a deadly and centenary neglected disease that is recently surging as a potential global threat. Approximately 30% of infected individuals develop chronic Chagas cardiomyopathy and current treatment with the reference benznidazole (BZN) is ineffective for this stage. We presently report the structural planning, synthesis, characterization, molecular docking prediction, cytotoxicity, in vitro bioactivity and mechanistic studies on the anti-T. cruzi activity of a series of 16 novel 1,3-thiazoles (2-17) derived from thiosemicarbazones (1a, 1b) in a two-step and reproducible Hantzsch-based synthesis approach. The anti-T. cruzi activity was evaluated in vitro against the epimastigote, amastigote and trypomastigote forms of the parasite. In the bioactivity assays, all thiazoles were more potent than BZN against epimastigotes. We found that the compounds presented an overall increased anti-tripomastigote selectivity (Cpd 8 was 24-fold more selective) than BZN, and they mostly presented anti-amastigote activity at very low doses (from 3.65 μM, cpd 15). Mechanistic studies on cell death suggested that the series of 1,3-thiazole compounds herein reported cause parasite cell death through apoptosis, but without compromising the mitochondrial membrane potential. In silico prediction of physicochemical properties and pharmacokinetic parameters showed promising drug-like results, being all the reported compounds in compliance with Lipinski and Veber rules. In summary, our work contributes towards a more rational design of potent and selective antitripanosomal drugs, using affordable methodology to yield industrially viable drug candidates.

Maternal exposure to glyphosate-based herbicide causes changes in the vascular function of offspring adult rats

This study analyzed how glyphosate exposure in the gestational period affects vascular function in their offspring, focusing on the influence of age and whether oxidative stress is involved in this effect. To this, pregnant Wistar rats were exposed through drinking water to 0.2% of a glyphosate commercial formulation, and we analyzed the response to acetylcholine and phenylephrine in the aorta from offspring of glyphosate herbicide-based (O-GHB) and controls (O-CON) rats at 3, 6, and 12 months of age. O-GHB groups showed no changes in arterial blood pressure or aorta histological analysis. Relaxation to acetylcholine was reduced in O-GHB than O-CON. Acute TEMPOL increased relaxation to acetylcholine in O-GHB at 6 and 12 months of age. The aorta from O-GHB was hyperactive to phenylephrine only at 6 months of age. Preincubation with N-nitro-L-arginine methyl ester (L-NAME) increased contraction to phenylephrine more in O-CON than O-GHB. TEMPOL similarly reduced phenylephrine response. This effect was prevented by L-NAME. Results reinforce the concept that oxidative stress during the perinatal period contributes to the development of vascular changes in adulthood. Results also reveal that although no changes in cardiac or histological parameters have been demonstrated, the current levels considered safe for exposure to glyphosate deserve further investigation, especially during pregnancy.

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.

Identification of novel Zika virus inhibitors: a screening using thiosemicarbazones and thiazoles templates

BACKGROUND

Zika virus (ZIKV) remains an important cause of congenital infection, fetal microcephaly, and Guillain-Barré syndrome in the population. In 2016, WHO declared a cluster of microcephaly cases and other neurological disorders reported as a global public health emergency in Brazil. There is still no specific treatment for Zika virus fever, only palliative care. Therefore, there is a need for new therapies against this disease. According to the literature, thiosemicarbazone, phthalimide and thiazole are privileged structures with several biological activities, including antiviral activity against various viruses.

OBJECTIVE

Based on this, this work presents an antiviral screening using previously synthesized compounds derived from thiosemicarbazone, phthalimide, and thiazole as new hits active against ZIKV.

METHODS

After synthesis and characterization, all compounds were submitted to Cytotoxicity by MTT and Antiviral activity against ZIKV assays.

RESULTS

Compounds 63, 64, 65, and 73 exhibited major reductions in the ZIKV title from this evaluation. Compounds 63 (99.74%), 64 (99.77%), 65 (99.92%), and 73 (99.21%) showed a higher inhibition than the standard 6MMPr (98.74%) at the CC20 dose. These results revealed new chemical entities with anti-ZIKV activity.

CONCLUSION

These derivatives are promising candidates for further assays. In addition, the current approach brings a new privileged scaffolding, which may drive future drug discovery for ZIKV.

Structural design, synthesis and anti-Trypanosoma cruzi profile of the second generation of 4-thiazolidinones chlorine derivatives

Chagas disease causes more deaths in the Americas than any other parasitic disease. Initially confined to the American continent, it is increasingly becoming a global health problem. In fact, it is considered to be an "exotic" disease in Europe, being virtually undiagnosed. Benznidazole, the only drug approved for treatment, effectively treats acute-stage Chagas disease, but its effectiveness for treating indeterminate and chronic stages remains uncertain. Previously, our research group demonstrated that 4-thiazolidinones presented anti-T. cruzi activity including in the in vivo assays in mice, making this fragment appealing for drug development. The present work reports the synthesis and anti-T. cruzi activities of a novel series of 4-thiazolidinones derivatives that resulted in an increased anti-T. cruzi activity in comparison to thiosemicarbazones intermediates. Compounds 2c, 2e, and 3a showed potent inhibition of the trypomastigote form of the parasite at low cytotoxicity concentrations in mouse splenocytes. Besides, all the 2c, 2e, and 3a tested concentrations showed no cytotoxic activity on macrophages cell viability. When macrophages were submitted to T. cruzi infection and treated with 2c and 3a, compounds reduced the release of trypomastigote forms. Results also showed that the increased trypanocidal activity induced by 2c and 3a is independent of nitric oxide release. Flow cytometry assay showed that compound 2e was able to induce necrosis and apoptosis in trypomastigotes. Parasites treated with the compounds 2e, 3a, and 3c presented flagellum shortening, retraction and curvature of the parasite body, and extravasation of the internal content. Together, these data revealed a novel series of 4-thiazolidinones fragment-based compounds with potential effects against T. cruzi and lead-like characteristics.

Study of acute oral toxicity of the thiazole derivative N-(1-methyl-2-methyl-pyridine)-N-(p-bromophenylthiazol-2-yl)-hydrazine in a Syrian hamster

The thiazole derivative N-1-methyl-2-methyl-pyridine)-N-(p-bromophenylthiazol-2-yl)-hydrazine was used to evaluate the acute oral toxicity in Syrian hamsters. The concentration of the doses (300 mg/kg and 2000 mg/kg) were based on the "Class Acute Toxicity Method" displayed in the OECD-423 guide. In addition, renal and liver biochemical tests were performed, as well as histopathological analysis. Our results showed that the compound's lethal dose (LD50) was 1000 mg/kg and classified as category 4 according to the criteria adopted in the experiment's protocol. Biochemical analysis of the liver function's parameters showed that the LD50 values in all animals were higher than the reference values. However, the analyze of the kidney injury parameters showed an increase in the urea's dosage but a decrease in the albumin's dosage in all animals when compared to the reference values. Kidney biochemical analysis also showed that creatinine's level was only higher than the reference values in one animal. Massive damages in the liver were observed, such as hypertrophy and hyperplasia of the hepatocyte, coagulation necrosis, the presence of mononuclear cells in the sinusoidal capillaries, steatosis, cholestasis, and congestion of sinusoidal capillaries and central-lobular veins. The animals presented renal injuries related to congestion of glomerular and interstitial capillaries, nephrosis of contorted proximal and distal tubules and congestion in the medullary region. In conclusion, the thiazole derivative was well tolerated although it caused acute liver and kidney damages. Therefore, these results showed the need of further investigation of this compound in vivo to evaluate the potential therapeutic effects with chronic models.

Dual Parasiticidal Activities of Phthalimides: Synthesis and Biological Profile against Trypanosoma cruzi and Plasmodium falciparum

Chagas disease and malaria are two neglected tropical diseases (NTDs) that prevail in tropical and subtropical regions in 149 countries. Chagas is also present in Europe, the US and Australia due to immigration of asymptomatic infected individuals. In the absence of an effective vaccine, the control of both diseases relies on chemotherapy. However, the emergence of parasite drug resistance is rendering currently available drugs obsolete. Hence, it is crucial to develop new molecules. Phthalimides, thiosemicarbazones, and 1,3-thiazoles have been used as scaffolds to obtain antiplasmodial and anti-Trypanosoma cruzi agents. Herein we present the synthesis of 24 phthalimido-thiosemicarbazones (3 a-x) and 14 phthalimido-thiazoles (4 a-n) and the corresponding biological activity against T. cruzi, Plasmodium falciparum, and cytotoxicity against mammalian cell lines. Some of these compounds showed potent inhibition of T. cruzi at low cytotoxic concentrations in RAW 264.7 cells. The most active compounds, 3 t (IC₅₀ =3.60 μM), 3 h (IC₅₀ =3.75 μM), and 4 j (IC₅₀ =4.48 μM), were more active than the control drug benznidazole (IC₅₀ =14.6 μM). Overall, the phthalimido-thiosemicarbazone derivatives were more potent than phthalimido-thiazole derivatives against T. cruzi. Flow cytometry assay data showed that compound 4 j was able to induce necrosis and apoptosis in trypomastigotes. Analysis by scanning electron microscopy showed that T. cruzi trypomastigote cells treated with compounds 3 h, 3 t, and 4 j at IC₅₀ concentrations promoted changes in the shape, flagella, and surface of the parasite body similar to those observed in benznidazole-treated cells. The compounds with the highest antimalarial activity were the phthalimido-thiazoles 4 l (IC₅₀ =1.2 μM), 4 m (IC₅₀ =1.7 μM), and 4 n (IC₅₀ =2.4 μM). Together, these data revealed that phthalimido derivatives possess a dual antiparasitic profile with potential effects against T. cruzi and lead-like characteristics.

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.

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.

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, IC_50trypo = 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.

Desing and synthesis of potent anti-Trypanosoma cruzi agents new thiazoles derivatives which induce apoptotic parasite death

Chagas disease, caused by the kinetoplastid protozoan parasite Trypanosoma cruzi, remains a relevant cause of illness and premature death and it is estimated that 6 million to 7 million people are infected worldwide. Although chemotherapy options are limited presenting serious problems, such as low efficacy and high toxicity. T. cruzi is susceptible to thiazoles, making this class of compounds appealing for drug development. Previously, thiazoles resulted in an increase in anti-T. cruzi activity in comparison to thiosemicarbazones. Here, we report the structural planning, synthesis and anti-T. cruzi evaluation of new thiazoles derivatives (3a-m and 4a-m), designed from molecular hybridization associated with non-classical bioisosterism. 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 comparison to the corresponding thiosemicarbazones. In most cases, electron-withdrawing substituents, such as bromine, 3,4-dichloro and nitro groups, greatly increased antiparasitic activity. Specifically, new thiazoles were identified that inhibit the epimastigote proliferation and were toxic for trypomastigotes without affecting macrophages viability. These compounds were also evaluated against cruzain. However, inhibition of this enzyme was not observed, suggesting that the compounds work through another mechanism. In addition, examination of T. cruzi cell death showed that these molecules induce apoptosis. In conclusion, except for compounds 3h and 3k, all thiazoles derivatives evaluated exhibited higher cytotoxic activity against the trypomastigote forms than the reference medicament benznidazole, without affecting macrophages viability. Compounds 4d and 4k were highlights, CC50 = 1.2 e 1.6 μM, respectively. Mechanistically, these compounds do not inhibit the cruzain, but induce T. cruzi cell death by an apoptotic process, being considered a good starting point for the development of new anti-Chagas drug candidates.

New 1,3-thiazole derivatives and their biological and ultrastructural effects on Trypanosoma cruzi

In previous studies, the compound 3-(bromopropiophenone) thiosemicarbazone was described as a potent anti-Trypanosoma cruzi and cruzain inhibitor. In view to optimize this activity, 1,3-thiazole core was used as building-block strategy to access new lead generation of anti T. cruzi agents. In this way a series of thiazole derivatives were synthesized and most of these derivatives exhibited antiparasitic activity similar to benznidazole (Bzd). Among them, compounds (1c) and (1g) presented better selective index (SI) than Bzd. In addition, compounds showed inhibitory activity against the cruzain protease. As observed by electron microscopy, compound (1c) treatment caused irreversible and specific morphological changes on ultrastructure organization of T. cruzi, demonstrating that this class of compounds is killing parasites.

2-Pyridyl thiazoles as novel anti-Trypanosoma cruzi agents: structural design, synthesis and pharmacological evaluation

The present work reports on the synthesis, anti-Trypanosoma cruzi activities and docking studies of a novel series of 2-(pyridin-2-yl)-1,3-thiazoles derived from 2-pyridine thiosemicarbazone. The majority of these compounds are potent cruzain inhibitors and showed excellent inhibition on the trypomastigote form of the parasite, and the resulting structure-activity relationships are discussed. Together, these data present a novel series of thiazolyl hydrazones with potential effects against Chagas disease and they could be important leads in continuing development against Chagas disease.

Novel phthalimide derivatives with TNF-α and IL-1β expression inhibitory and apoptotic inducing properties

24 compounds were synthesized and their immunomodulation of TNF-α and IL-1β was evaluated.