Biological and immunological activity of new imidazolidines against adult worms of Schistosoma mansoni

Therapeutic potential of hydantoin and thiohydantoin compounds against Schistosoma mansoni: An integrated in vitro, DNA, ultrastructural, and ADMET in silico approach

The study aimed to conduct in vitro biological assessments of hydantoin and thiohydantoin compounds against mature Schistosoma mansoni worms, evaluate their cytotoxic effects and predict their pharmacokinetic parameters using computational methods. The compounds showed low in vitro cytotoxicity and were not considered hemolytic. Antiparasitic activity against adult S. mansoni worms was tested with all compounds at concentrations ranging from 200 to 6.25 μM. Compounds SC01, SC02, and SC03 exhibited low activity. Compounds SC04, SC05, SC06 and SC07 caused 100 % mortality within 24 h of incubation at a concentration of 100 and 200 μM. Thiohydantoin SC04 exhibited the highest activity, resulting in 100 % mortality after 24 h of incubation at a concentration of 50 μM and IC50 of 28 µM. In the ultrastructural analysis (SEM), the compound SC04 (200 µM) induced integumentary changes, formation of integumentary blisters, and destruction of tubercles and spicules. Therefore, the SC04 compound shows promise as an antiparasitic against S. mansoni.

Chemotherapy for human schistosomiasis: how far have we come? What's new? Where do we go from here?

Globally, schistosomiasis threatens more than 700 million lives, mostly children, in poor localities of tropical and sub-tropical areas with morbidity due to acute and chronic pathological manifestations of the disease. After a century since the first antimonial-based drugs were introduced to treat the disease, anti-schistosomiasis drug development is again at a bottleneck with only one drug, praziquantel, available for treatment purposes. This review focuses on promising chemotypes as potential starting points in a drug discovery effort to meet the urgent need for new schistosomicides.

Synthesis and biological evaluation of novel imidazolidine derivatives as candidates to schistosomicidal agents

INTRODUCTION:

Schistosomiasis is an infectious parasitic disease caused by trematodes of the genus Schistosoma, which threatens at least 258 million people worldwide and its control is dependent on a single drug, praziquantel. The aim of this study was to evaluate the anti-Schistosoma mansoni activity in vitro of novel imidazolidine derivatives.

MATERIAL AND METHODS:

We synthesized two novel imidazolidine derivatives: (LPSF/PTS10) (Z)-1-(2-chloro-6-fluorobenzyl)-4-(4-dimethylaminobenzylidene)-5-thioxoimidazolidin-2-one and (LPSF/PTS23) (Z)-1-(2-chloro-6-fluoro-benzyl)-5-thioxo-4-(2,4,6-trimethoxy-benzylidene)-imidazolidin-2-one. The structures of two compounds were determined by spectroscopic methods. During the biological assays, parameters such as motility, oviposition, mortality and analysis by Scanning Electron Microscopy were performed.

RESULTS:

LPSF/PTS10 and LPSF/PTS23 were considered to be active in the separation of coupled pairs, mortality and to decrease the motor activity. In addition, LPSF/PTS23 induced ultrastructural alterations in worms, after 24 h of contact, causing extensive erosion over the entire body of the worms.

CONCLUSION:

The imidazolidine derivatives containing the trimetoxy and benzylidene halogens showed promising in vitro schistosomicidal activity.

In vivo study of schistosomicidal action of 1-benzyl-4-[(4-fluoro-phenyl)-hydrazono]-5-thioxo-imidazolidin-2-one

Praziquantel has been the drug most widely used therapy against different forms of schistosomiasis around the world. However, this treatment has shown ineffective in humans and in experimental models of Schistosoma mansoni. New therapeutic alternatives have been tested, including the imidazolidine derivative LPSF/PT-09, which has shown high therapeutic potential in vitro. In this work, we tested the schistosomal activity of this derivative in doses of 250mg/kg and 200mg/kg in mice experimentally infected with a high parasite load of S. mansoni. Parasitological evaluations related to the number of S. mansoni worms and their oviposition were performed during the acute phase of the disease and have demonstrated moderate effectiveness of 30-54,4%. However, LPSF/PT-09 did not influence oviposition of the parasites or the embryonic development of the eggs. The results obtained in this model showed that the imidazolidine derivative LPSF/PT-09 presented significant antischistosomal activity in vivo, posing as a potential candidate for this class of drugs. However, a better understanding of the pharmacokinetics and pharmacodynamics of the imidazolidine derivative LPSF/PT-09 is needed.

Synthesis, molecular properties, toxicity and biological evaluation of some new substituted imidazolidine derivatives in search of potent anti-inflammatory agents

The aim of this study was to design and synthesize pharmaceutical agents containing imidazolidine heterocyclic ring in the hope of developing potent, safe and orally active anti-inflammatory agents. A number of substituted-imidazolidine derivatives (3a-k) were synthesized starting from ethylene diamine and aromatic aldehydes. The imidazolidine derivatives (3a-k) were investigated for their anticipated anti-inflammatory, and analgesic activity in Wistar albino rats and Swiss albino mice, respectively. Bioactivity score, molecular and pharmacokinetic properties of the imidazolidine derivatives were calculated by online computer software programs viz. Molinspiration and Osiris property explorer. The results of biological testing indicated that among the synthesized compounds only three imidazolidine derivatives namely 4-[1,3-Bis(2,6-dichlorobenzyl)-2-imidazolidinyl]phenyl-diethylamine (3g), 4-[1,3-Bis(3-hydroxy-4-methoxybenzyl)-2-imidazolidinyl]phenyl-diethylamine (3i) and 4-(1,3-Bis(4-methoxybenzyl)-4-methylimidazolidin-2-yl)-phenyl-diethylamine (3j) possess promising anti-inflammatory and analgesic actions. Additionally these derivatives displayed superior GI safety profile (low severity index) with respect to the positive control, Indomethacin. All synthesized compounds showed promising bioactivity score for drug targets by Molinspiration software. Almost all the compounds were predicted to have very low toxicity risk by Osiris online software. Compound number (3i) emerged as a potential candidate for further research as it obeyed Lipinski's rule of five for drug likeness, exhibited promising biological activity in-vivo and showed no risk of toxicity in computer aided screening.

Evaluation of the anti-Schistosoma mansoni activity of thiosemicarbazones and thiazoles

Schistosomiasis is a chronic and debilitating disease caused by a trematode of the genus Schistosoma and affects over 207 million people. Chemotherapy is the only immediate recourse for minimizing the prevalence of this disease and involves predominately the administration of a single drug, praziquantel (PZQ). Although PZQ has proven efficacy, there is a recognized need to develop new drugs as schistosomicides since studies have shown that repeated use of this drug in areas of endemicity may cause a temporary reduction in susceptibility in isolates of Schistosoma mansoni. Hydrazones, thiosemicarbazones, phthalimides, and thiazoles are thus regarded as privileged structures used for a broad spectrum of activities and are potential candidates for sources of new drug prototypes. The present study determined the in vitro schistosomicidal activity of 10 molecules containing these structures. During the assays, parameters such motility and mortality, oviposition, morphological changes in the tegument, cytotoxicity, and immunomodulatory activity caused by these compounds were evaluated. The results showed that compounds formed of thiazole and phthalimide led to higher mortality of worms, with a significant decline in motility, inhibition of pairing and oviposition, and a mortality rate of 100% starting from 144 h of exposure. These compounds also stimulated the production of nitric oxide and tumor necrosis factor alpha (TNF-α), thereby demonstrating the presence of immunomodulatory activity. The phthalyl thiazole LpQM-45 caused significant ultrastructural alterations, with destruction of the tegument in both male and female worms. According to the present study, phthalyl thiazole compounds possess antischistosomal activities and should form the basis for future experimental and clinical trials.

Microbiological Evaluation of 4-substituted-imidazolidine Derivatives

In the present studies, two series of 4-substituted-imidazolidines (IIIa-i and IIIj,k) were synthesized by reacting different tetrahydro-di-Schiff bases (IIa-i and IIj,k) with p-diethylaminobenzaldehyde/ dimethylaminobenzaldehyde. The title compounds were evaluated for their antibacterial and antifungal actions against some selected microbes. The results of microbiological evaluation revealed that two compounds, 4-(1,3-bis(benzo[d][1,3]dioxol-5-ylmethyl)-4-methylimidazolidin-2-yl)-N,N-diethyl aniline (IIIj), 4-(1,3-bis(benzo[d][1,3]dioxol-5-ylmethyl)-4-methylimidazolidin-2-yl)-N,N-dimethyl aniline (IIIk) were good in their antibacterial as well as antifungal actions. Minimum inhibitory concentration values (MIC) of the compounds are reported.

In vitro evaluation of schistosomicidal potential of curcumin against Schistosoma japonicum

Curcumin is a polyphenol derived from the dietary spice turmeric. The aim of this study was to investigate the in vitro effect of curcumin against eggs, cercariae, pre-adults, and adults of Schistosoma japonicum compared to praziquantel. After incubated by different concentration of curcumin or praziquantel in different time, the percent hatching rates of eggs, the percent dead rates of cercariae, and the number of dead worms were observed. Curcumin showed time- and dose-dependent schistosomicidal effects on every life stages of S. japonicum. In addition, curcumin exhibited an optimal activity against the adult stage with no differential sensitivity between male and female worms and decreased motor activity of these worms without tegumental alterations. The promising in vitro effects on all stages of S. japonicum warrants further evaluation for the prophylactic and therapeutic values in the early and late schistosomiasis in field trials.

New imidazolidine derivatives as anti-Trypanosoma cruzi agents: structure-activity relationships

Imidazolidine derivatives are key components for the development of bioactive compounds for the treatment of many diseases, especially Chagas. In fact, others studies showed that the imidazolidine-2,4-dione has stood out by presenting a wide spectrum of pharmacological activities including anticonvulsants, antiarrhythmic, and antiparasitic. In the present study, we investigated the morphological alterations induced by imidazolidine derivates LPSF/NN-52 and LPSF/NN-100 on trypomastigotes forms of Trypanosoma cruzi through ultrastructural analysis by electron microscopy. Many concentrations were used to measure the antiparasitic propriety promoted by imidazolidine derivatives, and our study indicates that parasites treated with 13 μg mL(-1) of the imidazolidine derivates for 24 h revealed severe damage to the parasite's mitochondrial complex. Beyond that, also observed in treated parasites were the following: myelin bodies, enlargement of cytoplasm vacuole, fragmentation of endoplasmic reticulum, and some treated samples clearly showed signs of necrosis. To confirm the ultrastructural results, some assays were performed for knowledge cellular death induction promoted by imidazolidine derivates against immune spleen cells. The induction of the necrotic process through derivatives LPSF/NN-52 and LPSF/NN-100 showed similar results in relation to nifurtimox and benznidazole. In the last assays, it was demonstrated that NN-100 was efficient against epimastigotes and trypomastigotes forms and these results reinforce the mechanisms of action of both new imidazolidine derivatives against T. cruzi.

From innovation to application: social-ecological context, diagnostics, drugs and integrated control of schistosomiasis

Compared to malaria, tuberculosis and HIV/AIDS, schistosomiasis remains a truly neglected tropical disease. Schistosomiasis, perhaps more than any other disease, is entrenched in prevailing social-ecological systems, since transmission is governed by human behaviour (e.g. open defecation and patterns of unprotected surface water contacts) and ecological features (e.g. living in close proximity to suitable freshwater bodies in which intermediate host snails proliferate). Moreover, schistosomiasis is intimately linked with poverty and the disease has spread to previously non-endemic areas as a result of demographic, ecological and engineering transformations. Importantly though, thanks to increased advocacy there is growing awareness, financial and technical support to control and eventually eliminate schistosomiasis as a public health problem at local, regional and global scales. The purpose of this review is to highlight recent progress made in innovation, validation and application of new tools and strategies for research and integrated control of schistosomiasis. First, we explain that schistosomiasis is deeply embedded in social-ecological systems and explore linkages with poverty. We then summarize and challenge global statistics, risk maps and burden estimates of human schistosomiasis. Discovery and development research pertaining to novel diagnostics and drugs forms the centrepiece of our review. We discuss unresolved issues and emerging opportunities for integrated and sustainable control of schistosomiasis and conclude with a series of research needs.

Scanning electron microscopy of the human low-density lipoprotein interaction with the tegument of Schistosoma mansoni

The interaction between host molecules and Schistosoma mansoni has been regarded as a key feature for parasite survival. In this work, scanning electron microscopy was used to study the interaction of human low-density lipoprotein (LDL) with the tegument of the adult worm of S. mansoni. Worms were incubated in RPMI 1640 containing 10% of LPDS and 40 μg LDL/mL during 30, 60, and 120 min. Control worms were processed in the same way, without LDL. After the incubations, the samples were fixed and processed to scanning electron microscopy. The results demonstrated interaction of the LDL particles with the male parasite tegument. Male and female worms incubated without LDL from 0 (control) to 120 min did not show alterations in the tegument. It was observed a larger number of LDL particles on the dorsal region of male adult worm than others regions (anterior, posterior and gynecophoral canal). The female tegument did not show adherence of LDL. Aggregates on the tegument of the male worm were in greater number and size in the incubation times of 30 and 60 min than 120 min. The comparison between 30 and 120 min of incubation showed that the particles' size diminished from 2,650-860 nm to 634-363 nm, respectively. Such reduction can be due to the capture and the use of the lipids by the worm. Therefore, the internalization of lipids from LDL by the male worms seems to be a mechanism independent of endocytosis. Differences between males and females suggest lipid transference from male to female through gynecophoral canal.

Gold(I)-Catalyzed Intramolecular Hydroamination of N-Allylic,N'-Aryl Ureas to form Imidazolidin-2-ones

Treatment of N-allylic,N'-aryl ureas with a catalytic 1:1 mixture of di-tert-butyl-o-biphenylphoshphine gold(I) chloride and silver hexafluorophosphate (1 mol %) in chloroform at room temperature led to 5-exo hydroamination to form the corresponding imidazolidin-2-ones in excellent yield. In the case of N-allylic ureas that possessed an allylic alkyl, benzyloxymethyl, or acetoxymethyl substituent, gold(I)-catalyzed 5-exo hydroamination leads to formation of the corresponding trans-3,4-disubstituted imidazolidin-2-ones in excellent yield with ≥50:1 diastereoselectivity.