Teratogenic and anticonvulsant effects of zinc and copper valproate complexes in zebrafish

Cytotoxicity, genotoxicity and mutagenicity of mixed ternary mononuclear Mg complex based on valproic acid with 1,10-phenanthroline in Saccharomyces cerevisiae and V79 cells

Valproic acid (VA) is a widely used drug for the treatment of diseases affecting the central nervous system. Due to its epigenetic modulatory potential, it has been studied for possible therapeutic application in anticancer therapies. However, the VA exhibits different side effects in its application. Thus, synthetic coordination complexes with valproate can generate promising candidates for new active drugs with reduced toxicity. In this sense, we investigated the genotoxic and mutagenic potential of the sodium valproate and of the mixed ternary mononuclear Mg complex based on VA with 1,10-phenanthroline (Phen) ligand - [Mg (Valp)2Phen], in Saccharomyces cerevisiae and V79 cells. The MTT and clonal survival assays in V79 cells indicated that the Mg complex has higher cytotoxicity than sodium valproate. A similar cytotoxicity profile is observed in yeast. This fact is possibly due to the intercalation capacity of [Mg(Valp)2Phen], inducing DNA strand breaks, as observed in the comet assay and micronucleus test. In this sense, members of the NER, HR, NHEJ and TLS repair pathways are required for the repair of DNA lesions induced by [Mg(Valp)2Phen]. Interestingly, BER proteins apparently increase the cytotoxic potential of the drug. Furthermore, the [Mg(Valp)2Phen] showed higher cytotoxicity in V79 cells and yeast when compared to sodium valproate indicating applicability as a cytotoxic agent.

Chemically-induced epileptic seizures in zebrafish: A systematic review

The use of zebrafish as a model organism is gaining evidence in the field of epilepsy as it may help to understand the mechanisms underlying epileptic seizures. As zebrafish assays became popular, the heterogeneity between protocols increased, making it hard to choose a standard protocol to conduct research while also impairing the comparison of results between studies. We conducted a systematic review to comprehensively profile the chemically-induced seizure models in zebrafish. Literature searches were performed in PubMed, Scopus, and Web of Science, followed by a two-step screening process based on inclusion/exclusion criteria. Qualitative data were extracted, and a sample of 100 studies was randomly selected for risk of bias assessment. Out of the 1058 studies identified after removing duplicates, 201 met the inclusion criteria. We found that the most common chemoconvulsants used in the reviewed studies were pentylenetetrazole (n = 180), kainic acid (n = 11), and pilocarpine (n = 10), which increase seizure severity in a dose-dependent manner. The main outcomes assessed were seizure scores and locomotion. Significant variability between the protocols was observed for administration route, duration of exposure, and dose/concentration. Of the studies subjected to risk of bias assessment, most were rated as low risk of bias for selective reporting (94%), baseline characteristics of the animals (67%), and blinded outcome assessment (54%). Randomization procedures and incomplete data were rated unclear in 81% and 68% of the studies, respectively. None of the studies reported the sample size calculation. Overall, these findings underscore the need for improved methodological and reporting practices to enhance the reproducibility and reliability of zebrafish models for studying epilepsy. Our study offers a comprehensive overview of the current state of chemically-induced seizure models in zebrafish, highlighting the common chemoconvulsants used and the variability in protocol parameters. This may be particularly valuable to researchers interested in understanding the underlying mechanisms of epileptic seizures and screening potential drug candidates in zebrafish models.

Insight into Recent Drug Discoveries against Trypanosomatids and Plasmodium spp Parasites: New Metal-based Compounds

Scaffolds of metal-based compounds can act as pharmacophore groups in several ligands to treat various diseases, including tropical infectious diseases (TID). In this review article, we investigate the contribution of these moieties to medicinal inorganic chemistry in the last seven years against TID, including American trypanosomiasis (Chagas disease), human African trypanosomiasis (HAT, sleeping sickness), leishmania, and malaria. The most potent metal-based complexes are displayed and highlighted in figures, tables and graphics; according to their pharmacological activities (IC50 > 10µM) against Trypanosomatids and Plasmodium spp parasites. We highlight the current progresses and viewpoints of these metal-based complexes, with a specific focus on drug discovery.

Saccharomyces cerevisiae DNA repair pathways involved in repair of lesions induced by mixed ternary mononuclear Cu(II) complexes based on valproic acid with 1,10-phenanthroline or 2,2'- bipyridine ligands

The sodium valproate has been largely used as an anti-epilepsy drug and, recently, as a putative drug in cancer therapy. However, the treatment with sodium valproate has some adverse effects. In this sense, more effective and secure complexes than sodium valproate should be explored in searching for new active drugs. This study aims to evaluate the cytotoxicity of sodium valproate, mixed ternary mononuclear Cu(II) complexes based on valproic acid (VA) with 1,10-phenanthroline (Phen) or 2,2'- bipyridine (Bipy) ligands - [Cu₂(Valp)₄], [Cu(Valp)₂Phen] and [Cu(Valp)₂Bipy] - in yeast Saccharomyces cerevisiae, proficient or deficient in different repair pathways, such as base excision repair (BER), nucleotide excision repair (NER), translesion synthesis (TLS), DNA postreplication repair (PRR), homologous recombination (HR) and non-homologous end-joining (NHEJ). The results indicated that the Cu(II) complexes have higher cytotoxicity than sodium valproate in the following order: [Cu(Valp)₂Phen] > [Cu(Valp)₂Bipy] > [Cu₂(Valp)₄] > sodium valproate. The treatment with Cu(II) complexes and sodium valproate induced mutations in S. cerevisiae. The data indicated that yeast strains deficient in BER (Ogg1p), NER (complex Rad1p-Rad10p) or TLS (Rev1p, Rev3p and Rad30p) proteins are associated with increased sensitivity to sodium valproate. The BER mutants (ogg1Δ, apn1Δ, rad27Δ, ntg1Δ and ntg2Δ) showed increased sensitivity to Cu(II) complexes. DNA damage induced by the complexes requires proteins from NER (Rad1p and Rad10p), TLS (Rev1p, Rev3p and Rad30p), PRR (Rad6 and Rad18p) and HR (Rad52p and Rad50p) for efficient repair. Therefore, Cu(II) complexes display enhanced cytotoxicity when compared to the sodium valproate and induce distinct DNA lesions, indicating a potential application as cytotoxic agents.

Multiple endpoints of polylactic acid biomicroplastic toxicity in adult zebrafish (Danio rerio)

Although the toxicity of conventional microplastic types (i.e., petroleum derivatives) in different organisms is already known, knowledge about the effects of alternative biopolymers on aquatic vertebrates remains incipient. Thus, the aim of the present study is to test the hypothesis that the exposure of adult Danio rerio individuals to this pollutant for 30 days is enough to cause polylactic acid biomicroplastics (BioMPs of PLA) accumulation in their bodies, which leads to behavioral/neurotoxic, biochemical, and morphological changes. Based on our results, PLA BioMPs at concentrations of 2.5 and 5 mg/L accumulated in the liver, brain, gills and carcass of the assessed animals. However, such an accumulation was not able to cause locomotor damages or to trigger anxiety-like behavior in them. On the other hand, it was enough to cause behavioral changes (in shoal) predictive of co-specific social interaction and anti-predatory defensive response deficit likely related to cholinergic changes inferred by increased acetylcholinesterase activity and REDOX imbalance. This imbalance was featured by increased production of reactive species. We observed that the treatments have affected animals' pigmentation pattern. Therefore, our study highlights the toxicological potential of the herein assessed biopolymer, and this finding puts in check the innocuousness of this material, as well as expands our knowledge about how PLA BioMPs can affect the ichthyofauna in freshwater environments.

Recent advances in drug discovery against Mycobacterium tuberculosis: Metal-based complexes

Metal-based drugs are privileged motifs that act as primary pharmacophores in bioactive compounds for various diseases, including tuberculosis (TB). This potentially life-threatening and extremely contagious infectious disease is caused by Mycobacterium tuberculosis (Mtb). In 2018, TB infected about 10 million people and caused 1.2 million deaths worldwide. A large number of ligands are promising scaffolds in drug design, including heterocyclic, phosphines, schiff bases, thio and semicarbazones, aliphatic amines, cyclopalladated, cyanometallates and miscellaneous. Moreover, several metal-based complexes have been studied for the treatment of numerous illnesses, including infectious diseases. To contribute to drug design, we identified the metal-based organometallic complexes against Mtb. Thus, in this review article, we analysed the recent contributions of metal-based scaffolds for design of new anti-Mtb drugs in the last decade (2011-2020). Besides, metal-based approaches will be presented in order to find out new antitubercular agents.

Survival and malformation rate in oocytes and larvae of Cyprinus carpio by exposure to an industrial effluent

Pharmaceuticals are used for the prevention or treatment of diseases, and due to their manufacturing process they are continuously released to water bodies. One of the pharmacological groups detected in aquatic environments is non-steroidal anti-inflammatory drugs (NSAIDs) at trace concentrations. This study evaluated the survival and malformation rate in oocytes and larvae of Cyprinus carpio (C. carpio) after exposure to different proportions of an industrial effluent. Initially, the industrial effluent was sampled from an NSAID manufacturing plant located in the city of Toluca, State of Mexico, subsequently the physicochemical characterization and determination of the concentration of chemical compounds present were carried out. On the other hand, the lethal concentration 50 (LC50) and the effective concentration 50 (EC50) were calculated to determine the teratogenic index (TI), as well as the alterations to the embryonic development and the teratogenic effects on oocytes and larvae of C. carpio at the following proportions of the industrial effluent: 0.1, 0.3, 0.5, 0.7, 0.9 and 1.1%, following the Test Guideline 236, which describes a Fish Embryo Acute Toxicity test, the exposure times were 12, 24, 48, 72 and 96 h post-fertilization. The contaminants detected were NaClO (2.6 mg L^-1) and NSAIDs such as diclofenac, ibuprofen, naproxen and paracetamol in the range of 1.09-2.68 mg L^-1. In this study the LC50 was 0.275%, the EC50 0.133% and the TI 2.068. Several malformations were observed in all proportions of the industrial effluent evaluated, however the most severe such as spina bifida and paravertebral hemorrhage were observed at the highest effluent proportion. The industrial effluent evaluated in this study represents a risk for organisms that are in contact with it, since it contains chemical compounds that induce embryotoxic and teratogenic effects as observed in oocytes and larvae of C. carpio.