Investigation of the antileishmanial activity and mechanisms of action of acetyl-thiohydantoins.

The currently available treatment options for leishmaniasis are associated with high costs, severe side effects, and high toxicity. In previous studies, thiohydantoins demonstrated some pharmacological activities and were shown to be potential hit compounds with antileishmanial properties. The present study further explored the antileishmanial effect of acetyl-thiohydantoins against Leishmania amazonensis and determined the main processes involved in parasite death. We observed that compared to thiohydantoin nuclei, acetyl-thiohydantoin treatment inhibited the proliferation of promastigotes. This treatment caused alterations in cell cycle progression and parasite size and caused morphological and ultrastructural changes. We then investigated the mechanisms involved in the death of the protozoan; there was an increase in ROS production, phosphatidylserine exposure, and plasma membrane permeabilization and a loss of mitochondrial membrane potential, resulting in an accumulation of lipid bodies and the formation of autophagic vacuoles on these parasites and confirming an apoptosis-like process. In intracellular amastigotes, selected acetyl-thiohydantoins reduced the percentage of infected macrophages and the number of amastigotes/macrophages by increasing ROS production and reducing TNF-α levels. Moreover, thiohydantoins did not induce cytotoxicity in murine macrophages (J774A.1), human monocytes (THP-1), or sheep erythrocytes. In silico and in vitro analyses showed that acetyl-thiohydantoins exerted in vitro antileishmanial effects on L. amazonensis promastigotes in apoptosis-like and amastigote forms by inducing ROS production and reducing TNF-α levels, indicating that they are good candidates for drug discovery studies in leishmaniasis treatment. Additionally, we carried out molecular docking analyses of acetyl-thiohydantoins on two important targets of Leishmania amazonensis: arginase and TNF-alpha converting enzyme. The results suggested that the acetyl groups in the N1-position of the thiohydantoin ring and the ring itself could be pharmacophoric groups due to their affinity for binding amino acid residues at the active site of both enzymes via hydrogen bond interactions. These results demonstrate that thiohydantoins are promising hit compounds that could be used as antileishmanial agents.

Structural requirements for hydantoins and 2-thiohydantoins to induce lymphoproliferative popliteal lymph node reactions in the mouse.

The ability of a large number of hydantoins and 2-thiohydantoins to induce primary local lymphoproliferative popliteal lymph node (PLN) reactions has been investigated, as judged by PLN weight enlargement, in an attempt to evaluate the discriminating potential of the PLN reaction to low mol. wt chemicals and to establish structure-activity relationships. Among a series of nineteen hydantoins and related compounds only 5,5-diphenylhydantoin (phenytoin), its major metabolite 5-(p-hydroxyphenyl)-5-phenylhydantoin, 5,5-diphenyl-2-thiohydantoin and N-(5-nitro-2-furfurylidene)-1-aminohydantoin (nitro-furantoin) elicited marked PLN reactions in C57BL/6J mice. In DBA/2 mice, PLN responses to the aforementioned compounds were considerably less or virtually absent. A number of hydantoin derivatives and related compounds with one phenyl group and/or other substituents at the 1,3 or 5 position induced only slightly elevated or suppressed PLN responses in C57BL/6J mice. The influence of polar, and lipophilic aliphatic and aromatic substituents at the 5 position were compared among a series of 22 3-methyl-2-thiohydantoin as well as 21 3-phenyl-2-thiohydantoin amino acid derivatives for their ability to elicit primary PLN reactions in C57BL/6J mice. Substitution with only one aromatic group at the 5 position seemed to be necessary to induce PLN enlargements to 2-thiohydantoins already substituted at the 3 position with a methyl group or even more pronounced when substituted with a phenyl group. p-Hydroxylation of 5-benzyl-3-phenyl-2-thiohydantoin significantly diminished the PLN response. In contrast, p-hydroxylation of one of two phenyl groups as in 5-(p-hydroxyphenyl)-5-phenylhydantoin had little effect on lymphoproliferative PLN reactions. The presence of a hydroxyl group in a non-aromatic cyclic substituent as in hexahydro-6-hydroxy-2-methyl-3-thioxo-1H-pyrrolo[1,2-c]imidazol-1- one had no effect on the PLN reaction. A series of aliphatic substituents in the 5 position of 2-thiohydantoins showed that the number of carbon atoms of the substituents as well as the position of side chains in the isomer, rather than the methyl or phenyl group in the 3 position of the 2-thiohydantoin molecule, determined the strength of the PLN enlargement. It is concluded that the PLN weight increase assay appears to be able to discriminate between subtle chemical differences as studied with a large series of hydantoin and 2-thiohydantoin derivatives. The PLN assay may therefore be useful as a preliminary short-term screening method for identification of (classes of) compounds able to induce lymphoproliferative reactions.(ABSTRACT TRUNCATED AT 400 WORDS)

Synthesis of 3-dialkylaminopropyl-2-thiohydant derivatives as potential antiarrhythmic agents.

A series of 3-dialkylaminopropyl-5-monosubstituted-2-thiohydantoins were synthesized as potential antiarrhythmic agents; their pharmacological activity is comparable to that of quinidine, but weaker than that of phenytoin.

A search for new anticonvulsant compounds among 3-aryl-5-benzylidene derivatives of 2-thiohydantoin.

13 New 3-aryl-5-benzylidene-2-thiohydantoins were obtained by condensation of 3-o-tolyl- and 3-m-tolyl-2--thiohydantoin with aromatic aldehydes. The structure of the obtained compounds was confirmed by IR spectra. Derivatives of 2-thiohydantoin 1-13 show weak anticonvulsant activity in pentetrazole test and show no protecting activity against the maximal electric shock.

Synthesis of 3-aryl-2-thiohydantoin- and 3-arylhydantoin-5-acetic acids and screening of some of their pharmacological properties.

Seven 3-aryl-2-thiohydantoin-5-acetic acids were obtained from asparagine and arylisothiocyanates. After desulphuration of these compounds by monochloroacetic acid seven 3-arylhydantoin-5-acetic acids were obtained. The structure of these compounds was confirmed by their IR spectra. None of the compounds neither showed the anticonvulsive activity in the electroconvulsions and pentylenetetrazole tests nor inhibited the prostaglandin synthetase.