In vitro tripanocidal effect of 1,8-dioxooctahydroxanthenes (xanthenodiones) and tetraketones and improvement of cardiac parameters in vivo

Recent Advances in the Discovery of SIRT1/2 Inhibitors via Computational Methods: A Perspective

Sirtuins (SIRTs) are classified as class III histone deacetylases (HDACs), a family of enzymes that catalyze the removal of acetyl groups from the ε-N-acetyl lysine residues of histone proteins, thus counteracting the activity performed by histone acetyltransferares (HATs). Based on their involvement in different biological pathways, ranging from transcription to metabolism and genome stability, SIRT dysregulation was investigated in many diseases, such as cancer, neurodegenerative disorders, diabetes, and cardiovascular and autoimmune diseases. The elucidation of a consistent number of SIRT-ligand complexes helped to steer the identification of novel and more selective modulators. Due to the high diversity and quantity of the structural data thus far available, we reviewed some of the different ligands and structure-based methods that have recently been used to identify new promising SIRT1/2 modulators. The present review is structured into two sections: the first includes a comprehensive perspective of the successful computational approaches related to the discovery of SIRT1/2 inhibitors (SIRTIs); the second section deals with the most interesting SIRTIs that have recently appeared in the literature (from 2017). The data reported here are collected from different databases (SciFinder, Web of Science, Scopus, Google Scholar, and PubMed) using "SIRT", "sirtuin", and "sirtuin inhibitors" as keywords.

Theracurmin Modulates Cardiac Inflammation in Experimental Model of Trypanosoma cruzi Infection

Theracurmin is a nanoparticle formulation derived from curcumin, a bioactive compound known for its antioxidant and anti-inflammatory properties. Trypanosoma cruzi, the etiological agent of Chagas disease, triggers an intense inflammatory response in mammals and also causes severe tissue damage. To evaluate the immunomodulatory and antiparasitic effects of Theracurmin, Swiss mice were experimentally infected with 10³ trypomastigote forms of the Colombian strain of T. cruzi and submitted to daily therapy with 30 mg/kg of Theracurmin. In addition, daily benznidazole therapy (100 mg/kg) was performed as a positive control. We evaluated the systemic and tissue parasitism, the survival and the body mass rate, the release of inflammatory mediators (TNF, IL-6, IL-15, CCL2 and creatine kinase) and the tissue inflammation at day 30 post-infection. Theracurmin therapy reduced the parasitemia curve without altering the animals' survival rate, and it protected mice from losing body mass. Theracurmin also reduced CCL2 in cardiac tissue, IL-15 in cardiac and skeletal tissue, and plasma CK. Even without effects on TNF and IL-6 production and tissue amastigote nests, Theracurmin reduced the leukocyte infiltrate in both evaluated tissues, even in the case of more effective results observed to the benznidazole treatment. Our data suggest Theracurmin has an immunomodulatory (CCL2, IL-15, CK and tissue leukocyte infiltration) and a trypanocidal effect (on circulating parasites) during experimental infection triggered by the Colombian strain of T. cruzi. Further investigations are necessary to comprehend the Theracurmin role performed in combination with benznidazole or other potential anti-T. cruzi chemical compounds.

Protective effects of Theracurmin treatment during experimental infection of the Colombian strain of Trypanosoma cruzi at the testicular site

Introduction

Chagas' disease is a tropical neglected illness caused by Trypanosoma cruzi and remains one of the most significant causes of morbidity and mortality in South and Central Americas. The disease is caused by a moderate to intense and persistent inflammatory response characterized by local upregulated expression and production of inflammatory mediators that favors the activation and recruitment of distinct cells of the immune system into different tissues to eliminate the parasites. Theracurmin is a curcumin's derived formulation of nanoparticles. Its anti-inflammatory properties make this bioactive compound a mitigating factor in pathological cases after an overwhelming inflammatory response.

Methods

Our research focused on the testicular investigation in 28 mice infected by 103 trypomastigote forms of Colombian strain of T. cruzi and preventively treated with Theracurmin. The mice were treated with 30 mg/Kg of Theracurmin during the period of 30 days. At the 30th day post infection animals were euthanized, and its testicles were collected to morphological and immunological assays.

Results

The animals infected and treated with Theracurmin presented a reduction in the testicular levels of IL-15 and IL-6. The volume density (%) of the tunica propria was also higher in all infected animals, but Theracurmin decreased this parameter in the treated animals. In the intertubular area, the percentage of some intertubular components was decreased in the infected animals such as the percentage and volume of Leydig cells, connective tissue, and macrophages.

Discussion

Furthermore, our data pointed to the daily use of Theracurmin in the diet as a protective element of the testicular function.

Exploring the In Situ Formation Mechanism of Polymeric Aluminum Chloride-Silica Gel Composites under Mechanical Grinding Conditions: As a High-Performance Nanocatalyst for the Synthesis of Xanthene and Pyrimidinone Compounds

The use of mechanical ball milling to facilitate the synthesis of organic compounds has attracted intense interest from organic chemists. Herein, we report a new process for the preparation of xanthene and pyrimidinone compounds by a one-pot method using polymeric aluminum chloride (PAC), silica gel, and reaction raw materials under mechanical grinding conditions. During the grinding process, polymeric aluminum chloride and silica gel were reconstituted in situ to obtain a new composite catalyst (PAC-silica gel). This catalyst has good stability (six cycles) and wide applicability (22 substrates). The Al-O-Si active center formed by in situ grinding recombination was revealed to be the key to the effective catalytic performance of the PAC-silica gel composites by the comprehensive analysis of the catalytic materials before and after use. In addition, the mechanism of action of the catalyst was verified using density functional theory, and the synthetic pathway of the xanthene compound was reasonably speculated with the experimental data. Mechanical ball milling serves two purposes in this process: not only to induce the self-assembly of silica and PAC into new composites but also to act as a driving force for the catalytic reaction to take place. From a practical point of view, this "one-pot" catalytic method eliminates the need for a complex preparation process for catalytic materials. This is a successful example of the application of mechanochemistry in materials and organic synthesis, offering unlimited possibilities for the application of inorganic polymer materials in green synthesis and catalysis promoted by mechanochemistry.

New Insights Into Blue Light Phototherapy in Experimental Trypanosoma cruzi Infection

The search for an effective etiologic treatment to eliminate Trypanosoma cruzi, the causative agent of Chagas disease, has continued for decades and yielded controversial results. In the 1970s, nifurtimox and benznidazole were introduced for clinical assessment, but factors such as parasite resistance, high cellular toxicity, and efficacy in acute and chronic phases of the infection have been debated even today. This study proposes an innovative strategy to support the controlling of the T. cruzi using blue light phototherapy or blue light-emitting diode (LED) intervention. In in vitro assays, axenic cultures of Y and CL strains of T. cruzi were exposed to 460 nm and 40 µW/cm² of blue light for 5 days (6 h/day), and parasite replication was evaluated daily. For in vivo experiments, C57BL6 mice were infected with the Y strain of T. cruzi and exposed to 460 nm and 7 µW/cm² of blue light for 9 days (12 h/day). Parasite count in the blood and cardiac tissue was determined, and plasma interleukin (IL-6), tumoral necrosis factor (TNF), chemokine ligand 2 (CCL2), and IL-10 levels and the morphometry of the cardiac tissue were evaluated. Blue light induced a 50% reduction in T. cruzi (epimastigote forms) replication in vitro after 5 days of exposure. This blue light-mediated parasite control was also observed by the T. cruzi reduction in the blood (trypomastigote forms) and in the cardiac tissue (parasite DNA and amastigote nests) of infected mice. Phototherapy reduced plasma IL-6, TNF and IL-10, but not CCL2, levels in infected animals. This non-chemical therapy reduced the volume density of the heart stroma in the cardiac connective tissue but did not ameliorate the mouse myocarditis, maintaining a predominance of pericellular and perivascular mononuclear inflammatory infiltration with an increase in polymorphonuclear cells. Together, these data highlight, for the first time, the use of blue light therapy to control circulating and tissue forms of T. cruzi. Further investigation would demonstrate the application of this promising and potential complementary strategy for the treatment of Chagas disease.

Evaluation of Antiviral Activity of Cyclic Ketones against Mayaro Virus

Mayaro virus (MAYV) is a neglected arthropod-borne virus found in the Americas. MAYV infection results in Mayaro fever, a non-lethal debilitating disease characterized by a strong inflammatory response affecting the joints and muscles. MAYV was once considered endemic to forested areas in Brazil but has managed to adapt and spread to urban regions using new vectors, such as Aedes aegypti, and has the potential to cause serious epidemics in the future. Currently, there are no vaccines or specific treatments against MAYV. In this study, the antiviral activity of a series of synthetic cyclic ketones were evaluated for the first time against MAYV. Twenty-four compounds were screened in a cell viability assay, and eight were selected for further evaluation. Effective concentration (EC₅₀) and selectivity index (SI) were calculated and compound 9-(5-(4-chlorophenyl]furan-2-yl)-3,6-dimethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2))-dione (9) (EC₅₀ = 21.5 µmol·L⁻¹, SI = 15.8) was selected for mechanism of action assays. The substance was able to reduce viral activity by approximately 70% in both pre-treatment and post-treatment assays.