Marta Giorgis

Edaravone derivatives containing NO-donor functions.

A new series of polyvalent drugs obtained by joining edaravone with NO-donor moieties is described. All compounds display high antioxidant power together with NO-dependent vasodilator properties. The analysis of a number of molecular descriptors shows that the antioxidant activity, which is tightly linked to the presence of the edaravone substructure, is principally modulated by lipophilicity. These products are potentially useful in the treatment of cardiovascular disorders in which EDRF deficiency and ROS excess are involved.

Synthesis, Physicochemical Characterization, and Biological Activities of New Carnosine Derivatives Stable in Human Serum As Potential Neuroprotective Agents

The synthesis and the physicochemical and biological characterization of a series of carnosine amides bearing on the amido group alkyl substituents endowed with different lipophilicity are described. All synthesized products display carnosine-like properties differentiating from the lead for their high serum stability. They are able to complex Cu(2+) ions at physiological pH with the same stoichiometry as carnosine. The newly synthesized compounds display highly significant copper ion sequestering ability and are capable of protecting LDL from oxidation catalyzed by Cu(2+) ions, the most active compounds being the most hydrophilic ones. All the synthesized amides show quite potent carnosine-like HNE quenching activity; in particular, 7d, the member of the series selected for this kind of study, is able to cross the blood-brain barrier (BBB) and to protect primary mouse hippocampal neurons against HNE-induced death. These products can be considered metabolically stable analogues of carnosine and are worthy of additional investigation as potential neuroprotective agents.

Electrophilic warhead-based design of compounds preventing NLRP3 inflammasome-dependent pyroptosis.

Pyroptosis is a caspase-1-dependent pro-inflammatory form of programmed cell death implicated in the pathogenesis of autoinflammatory diseases as well as in disorders characterized by excessive cell death and inflammation. Activation of NLRP3 inflammasome is a key event in the pyroptotic cascade. In this study, we describe the synthesis and chemical tuning of α,β-unsaturated electrophilic warheads toward the development of antipyroptotic compounds. Their pharmacological evaluation and structure-activity relationships are also described. Compound 9 was selected as a model of this series, and it proved to be a reactive Michael acceptor, irreversibly trapping thiol nucleophiles, which prevented both ATP- and nigericin-triggered pyroptosis of human THP-1 cells in a time- and concentration-dependent manner. Moreover, 9 and other structurally related compounds, inhibited caspase-1 and NLRP3 ATPase activities. Our findings can contribute to the development of covalent, multitarget antipyroptotic compounds targeting molecular components of the NLRP3 inflammasome regulatory pathway.

Amodiaquine analogues containing NO-donor substructures: Synthesis and their preliminary evaluation as potential tools in the treatment of cerebral malaria

The synthesis and physico-chemical properties of novel compounds obtained by conjugation of amodiaquine with moieties containing either furoxan or nitrooxy NO-donor substructures are described. The synthesised compounds were tested in vitro against both the chloroquine sensitive, D10 and the chloroquine resistant, W-2 strains of Plasmodium falciparum (P. falciparum). Most of the compounds showed an antiplasmodial activity comparable to that of the parent drug. By comparing the activities of simple related structures devoid of the ability to release NO, it appears that the contribution of NO to the antiplasmodial action in vitro is marginal. All the compounds were able to relax rat aorta strips with a NO-dependent mechanism, thus showing their capacity to release NO in the vessels. A preliminary in vivo study using Plasmodium berghei ANKA-infected mice showed a trend for prolonged survival of mice with cerebral malaria treated with compound 40, which is potent and fast amodiaquine-derived NO-donor, when compared with amodiaquine alone or with compound 31, a milder NO-donor. The two compounds showed in vivo antiplasmodial activity similar to that of amodiaquine.

Development of an Acrylate Derivative Targeting the NLRP3 Inflammasome for the Treatment of Inflammatory Bowel Disease

Pharmacological inhibition of NLRP3 inflammasome activation may offer a new option in the treatment of inflammatory bowel disease. In this work, we report the design, synthesis, and biological screening of a series of acrylate derivatives as NLRP3 inhibitors. The in vitro determination of reactivity, cytotoxicity, NLRP3 ATPase inhibition, and antipyroptotic properties allowed the selection of 11 (INF39), a nontoxic, irreversible NLRP3 inhibitor able to decrease interleukin-1β release from macrophages. Bioluminescence resonance energy transfer experiments proved that this compound was able to directly interfere with NLRP3 activation in cells. In vivo studies confirmed the ability of the selected lead to alleviate the effects of colitis induced by 2,4-dinitrobenzenesulfonic acid in rats after oral administration.

Design, Synthesis, and Evaluation of Acrylamide Derivatives as Direct NLRP3 Inflammasome Inhibitors.

NLRP3 inflammasome plays a key role in the intracellular activation of caspase‐1, processing of pro‐inflammatory interleukin‐1β (IL‐1β), and pyroptotic cell death cascade. The overactivation of NLRP3 is implicated in the pathogenesis of autoinflammatory diseases, known as cryopyrin‐associated periodic syndromes (CAPS), and in the progression of several diseases, such as atherosclerosis, type‐2 diabetes, gout, and Alzheimers disease. In this study, the synthesis of acrylamide derivatives and their pharmaco‐toxicological evaluation as potential inhibitors of NLRP3‐dependent events was undertaken. Five hits were identified and evaluated for their efficiency in inhibiting IL‐1β release from different macrophage subtypes, including CAPS mutant macrophages. The most attractive hits were tested for their ability to inhibit NLRP3 ATPase activity on human recombinant NLRP3. This screening allowed the identification of 14, 2‐(2‐chlorobenzyl)‐N‐(4‐sulfamoylphenethyl)acrylamide, which was able to concentration‐dependently inhibit NLRP3 ATPase with an IC50 value of 74 μm. The putative binding pose of 14 in the ATPase domain of NLRP3 was also proposed.

New inhibitors of dihydroorotate dehydrogenase (DHODH) based on the 4-hydroxy-1,2,5-oxadiazol-3-yl (hydroxyfurazanyl) scaffold.

Based on some structural analogies with leflunomide and brequinar, two well-known inhibitors of dihydroorotate dehydrogenase (DHODH), a new series of products was designed, by joining the substituted biphenyl moiety to the 4-hydroxy-1,2,5-oxadiazol-3-yl scaffold through an amide bridge. The compounds were studied for their DHODH inhibitory activity on rat liver mitochondrial/microsomal membranes. The activity was found to be closely dependent on the substitution pattern at the biphenyl system; the most potent products were those bearing two or four fluorine atoms at the phenyl adjacent to the oxadiazole ring. A molecular modeling study suggested that these structures might have a brequinar-like binding mode. The greater potency of fluorinated analogs may depend partly on enhanced interactions with the hydrophobic ubiquinone channel, and partly on the role of fluorine in stabilizing the putative bioactive conformation.

Novel antioxidant agents deriving from molecular combination of Vitamin C and NO-donor moieties

In this paper, we describe a new class of products in which NO-donor moieties are linked to either the 3-OH (4a-f) or 2-OH group (7a-c) of ascorbic acid (ASA). Log Ps and pK(a)s of these products were experimentally evaluated. All the compounds were tested for their antioxidant activity on lipidic peroxidation induced by Fe(3+)-ADP/NADPH in lipids of microsomal membranes of rat hepatocytes. Only 3-O series displays antioxidant activity and it seems to be principally dependent on the lipophilicity. Both series trigger in vitro NO-dependent vasodilator properties.

1,2,5-Oxadiazole analogues of leflunomide and related compounds

A new series of compounds, structurally related to leflunomide, based on the 1,2,5-oxadiazole ring system (furazan) has been synthesised, and their ability to undergo ring scission at physiological pH to afford the corresponding cyano-oximes has been analyzed. The latter, together with the respective nitro derivatives obtained by oxidation, have been characterised as weak inhibitors of rat dihydroorotate dehydrogenase (DHODH).

Design and synthesis of N‐benzoyl amino acid derivatives as DNA methylation inhibitors

The inhibition of human DNA Methyl Transferases (DNMT) is a novel promising approach to address the epigenetic dysregulation of gene expression in different diseases. Inspired by the validated virtual screening hit NSC137546, a series of N‐benzoyl amino acid analogues was synthesized and obtained compounds were assessed for their ability to inhibit DNMT‐dependent DNA methylation in vitro. The biological screening allowed the definition of a set of preliminary structure–activity relationships and the identification of compounds promising for further development. Among the synthesized compounds, L‐glutamic acid derivatives 22, 23, and 24 showed the highest ability to prevent DNA methylation in a total cell lysate. Compound 22 inhibited DNMT1 and DNMT3A activity in a concentration‐dependent manner in the micromolar range. In addition, compound 22 proved to be stable in human serum and it was thus selected as a starting point for further biological studies.