Challenges Based on Antiplasmodial and Antiviral Activities of 7-Chloro-4-aminoquinoline Derivatives

We report the structural functionalization of the terminal amino group of N¹-(7-chloroquinolin-4-yl) butane-1,4-diamine, leading to a series of 7-chloro-4-aminoquinoline derivatives, and their evaluation as potent anti-malarial and anti-viral agents. Some compounds exhibited promising anti-malarial effects against the Plasmodium falciparum 3D7 (chloroquine-sensitive) and Dd2 (chloroquine-resistant) strains. In addition, these compounds were assayed in vitro against influenza A virus (IAV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Compound 5 h , bearing an N-mesityl thiourea group, displayed pronounced anti-infectious effects against malaria, IAV, and SARS-CoV-2. These results provide new insights into drug discovery for the prevention or treatment of malaria and virus co-infection.     

Mechanisms of Radical Formation on Chemically Modified Graphene Oxide under Near Infrared Irradiation

In this work, the mechanisms of radical generation on different functionalized graphene oxide (GO) conjugates under near-infrared (NIR) light irradiation are investigated. The GO conjugates are designed to understand how chemical functionalization can influence the generation of radicals. Both pristine and functionalized GO are irradiated by a NIR laser, and the production of different reactive oxygen species (ROS) is investigated using fluorimetry and electron paramagnetic resonance to describe the type of radicals present on the surface of GO. The mechanism of ROS formation involves a charge transfer from the material to the oxygen present in the media, via the production of superoxide and singlet oxygen. Cytotoxicity and effects of ROS generation are then evaluated using breast cancer cells, evidencing a concentration dependent cell death associated to the heat and ROS. The study provides new hints to understand the photogeneration of radicals on the surface of GO upon near infrared irradiation, as well as, to assess the impact on these radicals in the context of a combined drug delivery system and phototherapeutic approach. These discoveries open the way for a better control of phototherapy-based treatments employing graphene-based materials.     

Coordination polymers as precursors of simple and complex oxides

Coordination polymers (CPs) are assembled from metal ions and organic linker molecules. Here, we demonstrate that CPs can be used as precursors for simple and complex oxide synthesis. First, we investigated the conditions for linker solutions in which CP was obtained as precipitate only by mixing and stirring the solutions for each of the 28 metal–ion aqueous solutions. Evaluation of the crystalline phase of the samples obtained by firing the precipitates revealed that CPs could be used as precursors of simple oxides for 21 metal ions. Next, we conducted experiments to prepare precursors of 10 complex oxides with an A_nB_nO_m composition containing equimolar amounts of metal ions. Seven complex oxides were successfully synthesized. Three of them were complex oxides that could not be synthesized by the spray coprecipitation method. The present method has a comparable precursor preparation capability to the spray coprecipitation method. Because of the much shorter time for the precursor synthesis, the present method should be useful for parallel and automated experiments.