In silico prediction of ADMET parameters and in vitro evaluation of antioxidant and cytotoxic activities promoted by indole-thiosemicarbazone compounds.

Cancer is a complex and multifactorial disease characterized by uncontrolled cell growth and is one of the main causes of death in the world. This work aimed to evaluate a small series of 10 different indole-thiosemicarbazone compounds as potential antitumor agents. This is a pioneering study. For this, the antioxidant and cytotoxic capacity against normal and tumor cells was evaluated. The results showed that the compounds were able to promote moderate to low antioxidant activity for the ABTS radical scavenging assay. ADMET in silico assays showed that the compounds exhibited good oral bioavailability. As for toxicity, they were able to promote low cytotoxicity against normal cells, in addition to not being hemolytic. The compounds showed promising in vitro antitumor activity against the T47D, MCF-7, Jurkat and DU-145 strains, not being able to inhibit the growth of the Hepg2 strain. Through this in vitro study, it can be concluded that the compounds are potential candidates for antitumor agents.

Preliminary evaluation of the toxicological, antioxidant and antitumor activities promoted by the compounds 2,4-dihydroxy-benzylidene-thiosemicarbazones an in silico, in vitro and in vivo study.

Thiosemicarbazones are promising classes of compounds with antitumor activity. For this study, six 2,4-dihydroxy-benzylidene-thiosemicarbazones compounds were synthesized. These compounds were submitted to different assays in silico, in vitro and in vivo to evaluate the toxicological, antioxidant and antitumor effects. The in silico results were evaluated by the SwissADME and pkCSM platforms and showed that all compounds had good oral bioavailability profiles. The in vitro and in vivo toxicity assays showed that the compounds showed low cytotoxicity against different normal cells and did not promote hemolytic effects. The single dose acute toxicity test (2000 mg/kg) showed that none of the compounds were toxic to mice. In in vitro antioxidant activity assays, the compounds showed moderate to low activity, with PB17 standing out for the ABTS radical capture assay. The in vivo antioxidant activity highlighted the compounds 1, 6 and 8 that promoted a significant increase in the concentration of liver antioxidant enzymes. Finally, all compounds showed promising antitumor activity against different cell lines, especially MCF-7 and DU145 lines, in addition, they inhibited the growth of sarcoma 180 at concentrations lower than 50 mg/kg. These results showed that the evaluated compounds can be considered as potential antitumor agents.

Thiazolidine derivatives: In vitro toxicity assessment against promastigote and amastigote forms of Leishmania infantum and ultrastructural study.

Neglected diseases, such as Leishmaniasis, constitute a group of communicable diseases that occur mainly in tropical countries. Considered a public health problem with limited treatment. Therefore, there is a need for new therapies. In this sense, our proposal was to evaluate in vitro two series of thiazolidine compounds (7a-7e and 8a-8e) against Leishmania infantum. We performed in vitro evaluations through macrophage cytotoxicity assays (J774) and nitric oxide production, activity against promastigotes and amastigotes, as well as ultrastructural analyzes in promastigotes. In the evaluation of cytotoxicity, the thiazolidine compounds presented CC50 values between 8.52 and 126.83 µM. Regarding the evaluation against the promastigote forms, the IC50 values ranged between 0.42 and 142.43 µM. Compound 7a was the most promising, as it had the lowest IC50. The parasites treated with compound 7a showed several changes, such as cell body shrinkage, shortening and loss of the flagellum, intense mitochondrial edema and cytoplasmic vacuolization, leading the parasite to cell inviability. In assays against the amastigote forms, the compound showed a low IC50 (0.65 µM). These results indicate that compound 7a was efficient for both evolutionary forms of the parasite. In silico studies suggest that the compound has good oral bioavailability. These results show that compound 7a is a potential drug candidate for the treatment of Leishmaniasis.

Dimethyl 2-[(acridin-9-yl)methyl-idene]malonate.

In the title compound, C(19)H(15)NO(4), the acridine system is essentially planar (r.m.s. deviation = 0.015 Å). The crystal packing exhibits π-π inter-actions between pairs of centrosymmetric mol-ecules, one of them between the central heterocyclic rings and others between the outer benzene rings of the acridine systems, with centroid-centroid distances of 3.692 (1) and 3.754 (1) Å, respectively. These pairs are further linked by additional π-π inter-actions along the a-axis direction through one of the two outer benzene ring of neighboring mol-ecules, with a centroid-centroid distance of 3.642 (2) Å.

Enhanced antiproliferative activity of the new anticancer candidate LPSF/AC04 in cyclodextrin inclusion complexes encapsulated into liposomes.

LPSF/AC04 (5Z)-[5-acridin-9-ylmethylene-3-(4-methyl-benzyl)-thiazolidine-2,4-dione] is an acridine-based derivative, part of a series of new anticancer agents synthesized for the purpose of developing more effective and less toxic anticancer drugs. However, the use of LPSF/AC04 is limited due to its low solubility in aqueous solutions. To overcome this problem, we investigated the interaction of LPSF/AC04 with hydroxypropyl-ß-cyclodextrin (HP-ß-CyD) and hydroxypropyl-γ-cyclodextrin (HP-γ-CyD) in inclusion complexes and determine which of the complexes formed presents the most significant interactions. In this paper, we report the physical characterization of the LPSF/AC04-HP-CyD inclusion complexes by thermogravimetric analysis, differential scanning calorimetry, infrared spectroscopy absorption, Raman spectroscopy, (1)HNMR, scanning electron microscopy, and by molecular modeling approaches. In addition, we verified that HP-ß-CyD complexation enhances the aqueous solubility of LPSF/AC04, and a significant increase in the antiproliferative activity of LPSF/AC04 against cell lines can be achieved by the encapsulation into liposomes. These findings showed that the nanoencapsulation of LPSF/AC04 and LPSF/AC04-HP-CyD inclusion complexes in liposomes leads to improved drug penetration into the cells and, as a result, an enhancement of cytotoxic activity. Further in vivo studies comparing free and encapsulated LPSF/AC04 will be undertaken to support this investigation.

Ethyl 2-(3-phenyl-thio-ureido)-5,6-di-hydro-4H-cyclo-penta-[b]thio-phene-3-carboxyl-ate.

In the title compound, C(17)H(18)N(2)O(2)S(2), the angle between the mean plane defined by the atoms of the 5,6-dihydro-4H-cyclo-penta-[b]thio-phene moiety (r.m.s. deviation = 0.19 Å) and the phenyl ring is 72.8°(2). The mol-ecular conformation is stabilized by an intra-molecular N-H⋯O inter-action, which generates an S(6) ring motif. In the crystal, pairs of N-H⋯S hydrogen bonds link the mol-ecules to form inversion dimers with an R(2) (2)(8) ring motif.

Solid dispersions of imidazolidinedione by PEG and PVP polymers with potential antischistosomal activities.

Solid dispersions have been used as a strategy to improve the solubility, dissolution rate, and bioavailability of poor water-soluble drugs. The increase of the dissolution rate presented by (5Z)-3-(4-chloro-benzyl)-5-(4-nitro-benzylidene)-imidazolidine-2,4-dione (LPSF/FZ4) from the solid dispersions is related to the existence of intermolecular interactions of hydrogen bond type (>N-H···O<) between the amide group (>N-H) of the LPSF/FZ4 and the ether group (-O-) of the polyethyleneglycol polymer, or the carbonyl (C=O) of the polyvinylpyrrolidone polymer (PVP). The intensity of these interactions is directly reflected in the morphology acquired by LPSF/FZ4 in these systems, where a new solid phase, in the form of amorphous aggregates of irregular size, was identified through scanning electron microscopy and confirmed in the characterizations achieved using X-ray diffraction and thermal analysis of DSC. The solid dispersions with the polymer PVP, in higher concentrations, were revealed to be the best option to be used in the formulations of LPSF/FZ4 in both theoretical and experimental studies.

2-Amino-4,5,6,7-tetra-hydro-benzo[b]thio-phene-3-carbonitrile.

The title compound, C(9)H(10)N(2)S, was synthesized according to Gewald procedures by the reaction of cyclo-hexa-none with malonitrile and sulfur in the presence morpholine. The cyclo-hexane ring adopts a half-chair conformation and the thio-phene ring is essentially planar (r.m.s. deviation = 0.05 Å). The crystal packing is stabilized by two inter-molecular N-H⋯N hydrogen bonds, which link the mol-ecules into centrosymmetric rings with graph-set motif R(2) (2)(12).

2-(2-Nitro-anilino)-5,6,7,8-tetra-hydro-4H-cyclo-hepta-[b]thio-phene-3-carbonitrile.

The title compound, C(16)H(15)N(3)O(2)S, was synthesized by the reaction of 2-amino-5,6,7,8-tetra-hydro-4H-cyclo-hepta-[b]thio-phene-3-carbonitrile and o-fluoro-nitro-benzene. The thio-phene and nitro-phenyl rings and amino and carbonitrile groups are coplanar with a maximum deviation of 0.046 (2) Šand a dihedral angle of 0.92 (6)° between the rings. The cyclo-hepta ring adopts a chair conformation. Intra-molecular N-H⋯O and C-H⋯S inter-actions occur. In the crystal, the mol-ecules form layers that are linked by π-π stacking inter-actions between the thio-phene and benzene rings [centroid-centroid distances = 3.7089 (12) and 3.6170 (12) Å].

2-(2-Nitro-anilino)-4,5,6,7-tetra-hydro-benzo[b]thio-phene-3-carbonitrile.

The title compound, C(15)H(13)N(3)O(2)S, was synthesized by the reaction of 2-amino-5,6,7,8-tetra-hydro-4H-cyclo-hepta-[b]thio-phene-3-carbonitrile and o-fluoro-nitro-benzene. The dihedral angle between the thio-phene and nitro-phenyl rings is 75.15 (2)°. In the crystal, inter-molecular N-H⋯N and C-H⋯O inter-actions lead to the formation of a supra-molecular chain extending along the c-axis direction.

Solid dispersions to enhance the delivery of a potential drug candidate LPSF/FZ4 for the treatment of schistosomiasis.

Drug candidate LPSF/FZ4 with promising schistosomicidal properties in vitro was previously synthesized. However, LPSF/FZ4 has limited aqueous solubility (<1 µg/mL), leading to ineffective dissolution and, therefore, no meaningful in vivo comparative studies could be pursued. This study was aimed to develop a proper amorphous solid dispersion (SD) to enhance the solubility and dissolution rate of LPSF/FZ4 such that its biological activity could be investigated. To better understand its physiological behavior, the pKa of LPSF/FZ4, a monoprotic weak acid with NH group at the imidazolidine ring, was first determined to be 8.13 using an automated SiriusT3. The development of SD systems for LPSF/FZ4 involved the evaluation of various water-soluble polymer carriers such as PVP K-29/32, PVP K-90, HPMC K4M, PVPVA 64 and SOLUPLUS®. The most promising SD systems were selected through in vitro dissolution studies under nonsink conditions, together with physicochemical characterization as well as accelerated stability study. It was shown that SD of 10% LPSF/FZ4 in SOLUPLUS® and PVP K-90 could significantly increase the area-under-the-curve value of the nonsink dissolution profile (AUC values of the SD in SOLUPLUS® and PVP K-90 were 1381.03 and 1342.34 µL/mL·min, respectively, and that of the pure crystalline drug was 0.02 µL/mL·min), a useful surrogate for the in vivo bioavailability. Cmax values for the SD in SOLUPLUS® (12.50 µL/mL) and PVP K-90 (25.86 µL/mL) were also higher than the one of the crystalline drug (0.02 µL/mL). The SD system of LPSF/FZ4 in SOLUPLUS® showed a significant increase in schistosomicidal activity in an animal model as compared with the conventional treatment using crystalline drug, consistent with the AUC trend from the nonsink dissolution. Thus this SD system of LPSF/FZ4 could be useful as a potential formulation for treating schistosomiasis.

Effect of thiazolidine LPSF SF29 on the growth and morphology of Trypanosoma cruzi.

Chagas disease, caused by the protozoan Trypanosoma cruzi, is an endemic illness in Latin America. Efforts have been made by several groups to develop new effective and safe anti-T. cruzi drugs. In the present work, we show that thiazolidine LPSF SF29 inhibited growth of the epimastigote and amastigote forms and caused lysis in the trypomastigote form of T. cruzi, leading to death of the protozoan. Mitochondrial dysfunction was also observed. The thiazolidine induced ultrastructural alterations such as detachment of the flagellar membrane, intense mitochondrial swelling, formation of myelin-like figures and the appearance of autophagosomes. Taken together, these results suggest that this new thiazolidine is active against T. cruzi and constitutes a promising drug for the therapy of Chagas disease.

Chemical synthesis, docking studies and biological effects of a pan peroxisome proliferator-activated receptor agonist and cyclooxygenase inhibitor.

The compound (5Z)-5-[(5-bromo-1H-indol-3-yl)methylene]-3-(4-chlorobenzyl)-thiazolidine-2,4-dione (LYSO-7) was synthesised in order to obtain a new type of anti-inflammatory drug, designed with hybrid features to inhibit cyclooxygenase (COX) and also to activate peroxisome proliferator-activated receptor (PPAR). Results obtained from docking (in silico) studies corroborated with experimental data, showing the potential affinity between the studied ligand and targets. The specificity of LYSO-7 for COX-enzymes was detected by the inhibition of COX-1 and COX-2 activities by 30% and 20%, respectively. In transactivation reporter gene assays LYSO-07 showed a pan partial agonist effect on the three PPAR subtypes (PPARγ, PPARα and PPARß/δ). The agonist action on PPARγ was also observed by a pharmacological approach, as the reduction in the Escherichia coli lipopolysaccharide (LPS)-induced interleukin 1 beta (IL-1ß) secretion and nitric oxide (NO) production by mouse neutrophils was blocked by GW9962, a specific PPARγ antagonist. Additionally, the in vivo effect was measured by reduced carrageenan-induced neutrophil influx into the subcutaneous tissue of mice. Taken together, these data show that LYSO-7 displays a potent in vivo anti-inflammatory effect during the innate acute response, which is dependent on its associated COX inhibitory activities and PPAR activation.