Resumo em Inglês:

Leishmaniasis is an infectious disease caused by protozoan parasites of the Leishmania genus and affects more than 90 countries, especially in tropical and subtropical regions. The first treatment for these diseases involves pentavalent antimonial derivatives, which are very toxic and cause severe side effects. The other chemotherapeutic drugs used as second-line agents include different organic compound classes, such as pentamidine, which also cause severe side effects. Thus, new, safer, and efficient antileishmaniasis agents are urgently needed to control and treat these diseases. This mini review, which considered the last two decades of related research, highlighted the principal synthetic methodologies used to access amidine derivatives, focusing on more eco-friendly methods. Furthermore, the results obtained from evaluations of the anti-Leishmania activity and several molecular targets of the amidine derivatives are highlighted.

Resumo em Inglês:

Nitroaromatic drugs represent an important class of therapeutic agents, endowed with different pharmacological properties such as antibacterial, antiprotozoal, anti-Parkinson, anticancer, etc. However, the nitroheterocycle and nitroarene fragments are considered potentially toxic, with reports of mutagenicity and genotoxicity. The bioreduction process of the nitro group plays a central role in the antimicrobial and toxicological mechanism of action of nitroaromatic drugs. This article will review the nitroaromatic drugs approved by the Food and Drug Administration (FDA) in the last 30 years, the mechanisms of bioactivation, metabolism and toxicity and, finally, it will revisit the main methodologies for obtaining the nitroaromatic fragment from aromatic nitration reaction and oxidation of arylamines and/or heteroarylamines.

Resumo em Inglês:

In this review, the works carried out in Brazil with multicomponent reactions over a period of 30 years were mapped through search in the literature (PubMed, Scopus, and Web of Science). A significant increase in papers with multicomponent reactions in Brazil was identified. In total, 243 articles with 6,672 citations (average of 27.46 citations per article) were found. Biginelli, Ugi, Mannich, Passerini and Hantzsch are the most employed reactions, and the articles were classified in medicinal chemistry, catalyst, mechanism, green chemistry, asymmetric synthesis and fluorescent. A bibliometric analysis with the 243 articles was performed, including the number of publications, citations, predominant journals, Brazilian universities with the highest number of publications on the subject, and international collaborations.

Resumo em Inglês:

Natural products have long been explored in the history of most cultures worldwide. They have been mainly applied in the therapy of some diseases and for food preservation due to the antimicrobial properties of some condiments. Most of this knowledge was empirically discovered and passed from generation to generation. Over the last few years, the evolution of organic chemistry and the techniques of analysis and purification of compounds from complex matrices enabled a significant increase in research to identify bioactive products isolated from plants. In this paper, we briefly discuss the relevance of natural products on drug development, mainly focusing on amide piperine, the main chemical constituent of black pepper (Piper nigrum). Its antiparasitic activities and the knowledge of possible mechanisms of action against different parasites provide essential information for drug development. Furthermore, its compatibility with medicinal and synthetic chemistry techniques allows the development of more effective drug candidates.

Resumo em Inglês:

The concept of privileged structures in medicinal chemistry refers to commonly found substructures in approved drugs and lead small molecules, presenting a broad profile of pharmacological action, i.e., participating in the recognition by several classes of pharmacological targets or by modulating physicochemical properties. Privileged structures are also related to nontoxic effects, which make their use in the design of new drug candidates very attractive. In contrast, another concept also refers to structures or substructures capable of presenting a pleiotropic profile for several pharmacological targets, referred to as promiscuous compounds. Worth mentioning, more recently, a great majority of promiscuous compounds have been classified as Pan Assay Interference Compounds (PAINS). In its great majority, PAINS are electrophilic in nature, capable of covalently reacting indiscriminately with several pharmacological targets, and are associated with specific substructures, which are, in turn, used as an exclusion filter during screening campaigns. This work aims to critically discuss the thin line that separates the two concepts, clarifying their differences from a molecular and pharmacological point of view. Moreover, special considerations regarding PAINS and exclusion filters will be made.

Resumo em Inglês:

Modified flavonoids of the sub-group of pterocarpans, 5-carba-pterocarpans, 5-carbapterocarpens, 1-carba-isoflavanones, coumestans, and aurones were synthesized and evaluated as antiproliferative, antileishmanial and antiviral. A new scaffold, called pterocarpanquinone, was discovered and LQB-118, the prototypical scaffold of its series, showed consistent antileishmanial (mice and hamster in vivo) and antineoplastic (respectively, human and mice tumors ex vivo and in vivo) activity. 5-Carpa-pterocarpan LQB-485 is potent towards SF-295 cancer cells (CNS). LQB-262 and LQB-34 are new inhibitors of NB5S RdRp polymerase of hepatitis C virus (HCV) while LQB-314 and LQB-360 demonstrated potent activity and selectivity against HCV replicon reporter cells. LQB-454 and LQB-501 were evaluated for their in vitro anti-proliferative effects against human breast cancer and leukemia cell lines with diverse profiles of drug resistance. In breast cancer they present higher toxicity on multidrug resistant cells (collateral sensitivity). Aurone LQB-814, featuring a “lipophilic phenol” at A-ring”, was a very potent and selective inhibitor of SARS-CoV-2 in Calu-3 cells. Other four aurones bearing EC50 (concentration required to inhibit 50% of cell growth) < 1 were also discovered.

Resumo em Inglês:

This account describes the analysis of the Laboratory of Evaluation and Synthesis of Bioactive Substances (LASSBio) chemical library as a valuable resource for early drug discovery studies. LASSBio has been using medicinal chemistry strategies for almost 30 years to design new prototype compounds with a focus on pharmacological activity. The LASSBio Chemical Library (LCL) is a collection of more than 2000 compounds, and the aim of this work was to characterize its chemical diversity and to perform a molecular repositioning study to identify ligands of feline McDonough sarcoma (FMS)-like tyrosine kinase 3 (FLT3), a validated target for leukemia treatment. To achieve this, cheminformatic tools were utilized to analyze the chemical diversity of the LCL. The analysis allowed the identification of the most representative compounds of this collection, showing that the N-acylhydrazone chemotype is present in approximately 50% of the compounds. Furthermore, the compounds in this chemical library demonstrated remarkable compliance with both the Lipinski’s (93% of the compounds) and Veber’s (96% of the compounds) rules. In the study on molecular repositioning, 10 compounds were selected through virtual screening to test their enzymatic inhibition of FLT3 kinase. Among them, 4-((6,7-dimethoxyquinazolin-4-yl)amino) benzamide (LASSBio-2166) (31) showed a half-maximal inhibitory concentration (IC50) = 194 nM. Optimization of the identified hit and further studies to compare the diversity of the LCL with other libraries are perspectives of this work.

Resumo em Inglês:

The interactive profile between four 1,4-naphthoquinone derivatives (1-4) and human serum albumin (HSA) was studied by spectroscopic techniques and in silico calculations. The bimolecular quenching rate constant (kq ca. 1012 L mol-1 s-1) and the time-resolved fluorescence decays indicated a static fluorescence quenching mechanism. Thus, there is a spontaneous ground-state association, and based on both Stern-Volmer, modified Stern-Volmer, and van’t Hoff approaches, the association is moderate mainly driven by hydrophobic forces. The circular dichroism (CD) analysis indicated that until the proportion albumin:compound of 1:8 there is a weak perturbation on the structural content of albumin, while molecular docking results suggested subdomain IIA (site I), a positive electrostatic pocket, as the main binding site. Overall, even though the hydrogen atom replacement by methyl, fluorine, or chlorine atoms in the para position of the aromatic ring in the benzo[g]chromene-5,10-dione moiety changes the lipophilicity, it does not change the binding profile to HSA.