Dereplication of 4-Quinolone Alkaloids from Waltheria Indica (Malvaceae) Tissues Using Molecular Network Tools.

Waltheria indica (Malvaceae) is a plant popularly used in folk medicine by traditional African and indigenous communities, and in various countries worldwide, to treat general inflammation. Several biological activities of this plant have been reported, including acetylcholinesterase inhibition and potential anti-human immunodeficiency virus (HIV), antinociceptive, analgesic, antifungal, anticancer, anti-inflammatory, leishmanicidal, trypanocidal, antioxidant, and antibacterial activities. The chemical profile of Waltheria indica was assessed by dereplication analysis using UPLC-MS/MS, and data acquisition was performed using chemoinformatics tools, such as Mass Spectrometry-Data Independent AnaLysis (MS-DIAL) and MS-FINDER softwares. The preprocessed data were sent to the GNPS to build a feature-based molecular network (FBMN). Thirty-three 4-quinolone alkaloids were annotated in the extracts and fractions of stems and roots, whereas 12 were annotated in the extracts and fractions of flowers and leaves. This represents an inaugural chemical investigation study employing UPLC-Q-TOF-MS/MS analysis, along with a molecular network approach, within this species and genus.

Design, synthesis, in vitro and in silico studies of novel 4-oxoquinoline ribonucleoside derivatives as HIV-1 reverse transcriptase inhibitors.

Human immunodeficiency virus type 1 (HIV-1) is a public health problem that affects over 38 million people worldwide. Although there are highly active antiretroviral therapies, emergence of antiviral resistant strains is a problem which leads to almost a million death annually. Thus, the development of new drugs is necessary. The viral enzyme reverse transcriptase (RT) represents a validated therapeutic target. Because the oxoquinolinic scaffold has substantial biological activities, including antiretroviral, a new series of 4-oxoquinoline ribonucleoside derivatives obtained by molecular hybridization were studied here. All synthesized compounds were tested against human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT), and 9a and 9d displayed the highest antiviral activities, with IC50 values of 1.4 and 1.6 µM, respectively. These compounds were less cytotoxic than AZT and showed CC50 values of 1486 and 1394 µM, respectively. Molecular docking studies showed that the most active compounds bound to the allosteric site of the enzyme, suggesting a low susceptibility to the development of antiviral resistance. In silico pharmacokinetic and toxicological evaluations reinforced the potential of the active compounds as anti-HIV candidates for further exploration. Overall, this work showed that compounds 9a and 9d are promising scaffold for future anti-HIV-1 RT drug design.

4-Oxoquinoline Derivatives as Antivirals: A Ten Years Overview.

4-Oxoquinoline derivatives constitute an important family of biologically important substances, associated with different bioactivities, which can be synthesized by different synthetic methods, allowing the design and preparation of libraries of substances with specific structural variations capable of modulating their pharmacological action. Over the last years, these substances have been extensively explored by the scientific community in efforts to develop new biologically active agents, with greater efficiency for the treatment of a variety of diseases. Viral infections have been one of the targets of these studies, although to a lesser extent than other diseases such as cancer and bacterial infections. Nevertheless, the literature provides examples that corroborate with the fact that these substances may act on different pharmacological targets in different viral pathogens. This review provides a compilation of some of the major studies published in recent years showing the discovery and/or development of new antiviral oxoquinoline agents, highlighting, whenever possible, their mechanisms of action.

Synthesis, In Silico, and In Vitro Evaluation of Long Chain Alkyl Amides from 2-Amino-4-Quinolone Derivatives as Biofilm Inhibitors.

Infection from multidrug resistant bacteria has become a growing health concern worldwide, increasing the need for developing new antibacterial agents. Among the strategies that have been studied, biofilm inhibitors have acquired relevance as a potential source of drugs that could act as a complement for current and new antibacterial therapies. Based on the structure of 2-alkyl-3-hydroxy-4-quinolone and N-acylhomoserine lactone, molecules that act as mediators of quorum sensing and biofilm formation in Pseudomonas aeruginosa, we designed, prepared, and evaluated the biofilm inhibition properties of long chain amide derivatives of 2-amino-4-quinolone in Staphylococcus aureus and P. aeruginosa. All compounds had higher biofilm inhibition activity in P. aeruginosa than in S. aureus. Particularly, compounds with an alkyl chain of 12 carbons exhibited the highest inhibition of biofilm formation. Docking scores and molecular dynamics simulations of the complexes of the tested compounds within the active sites of proteins related to quorum sensing had good correlation with the experimental results, suggesting the diminution of biofilm formation induced by these compounds could be related to the inhibition of these proteins.

Molecular design, synthesis and biological evaluation of 1,4-dihydro-4-oxoquinoline ribonucleosides as TcGAPDH inhibitors with trypanocidal activity.

The 1,4-dihydro-4-oxoquinoline ribonucleoside, Neq135, is the first low micromolar trypanosomatidae inhibitor to show good ligand efficiency (0.28 kcal mol(-1)atom(-1)) and good ligand lipophilicity efficiency (0.37 kcal mol(-1)atom(-1)) when acting against Trypanosoma cruzi glyceraldehyde 3-phosphate dehydrogenase (TcGAPDH). This and other six ribonucleosides were synthesized using our in-house technology, and assayed against the GAPDH NAD(+) site using isothermal titration calorimetry (ITC). Compound Neq135 had acceptable in vitro cytotoxicity, inhibited TcGAPDH with a Ki(app) value of 16 µM and killed the trypomastigote form of Trypanosoma cruzi Tulahuen strain with a concentration similar to that displayed by the control drug benznidazole. Neq135 is tenfold lower kinetic affinity against hGAPDH and does not kill Balb-c fibroblast nor spleen mouse cells. These results emphasize the possibility of integrating ligand- and target-based designs to uncover potent and selective TcGAPDH inhibitors that expands the opportunity for further medicinal chemistry endeavor towards NAD(+) TcGAPDH site.

Evaluation of synthetic acridones and 4-quinolinones as potent inhibitors of cathepsins L and V.

Cathepsins, also known as lysosomal cysteine peptidases, are members of the papain-like peptidase family, involved in different physiological processes. In addition, cathepsins are implicated in many pathological conditions. This report describes the synthesis and evaluation of a series of N-arylanthranilic acids, acridones, and 4-quinolinones as inhibitors of cathepsins V and L. The kinetics revealed that compounds of the classes of acridones are reversible competitive inhibitors of the target enzyme with affinities in the low micromolar range. They represent promising lead candidates for the discovery of novel competitive cathepsin inhibitors with enhanced selectivity and potency. On the other hand, 4-quinolinones were noncompetitive inhibitors and N-arylanthranilic acids were uncompetitive inhibitors.