Maria Gabriella Vigorita

Synthesis and aldose reductase inhibitory activity of 5-arylidene-2,4-thiazolidinediones.

Several (Z)-5-arylidene-2,4-thiazolidinediones were synthesized and tested as aldose reductase inhibitors (ARIs). The most active of the N-unsubstituted derivatives (2) exerted the same inhibitory activity of Sorbinil. The introduction of an acetic side chain on N-3 of the thiazolidinedione moiety led to a marked increase in lending inhibitory activity, conducting to the discovery of a very potent ARI (4c), whose activity level (IC50=0.13 microM) was in the same range of Tolrestat. Moreover, the corresponding methyl esters (3), devoid of any acidic functionality, showed appreciable inhibitory activity similar to that of the N-unsubstituted compounds. It was also found that the substitution pattern on the 5-benzylidene moiety markedly influenced the activity of N-unsubstituted 2,4-thiazolidinediones 2, compounds with substituents at the meta position being generally more effective than the para-substituted ones; however, this SAR was not evidenced in acetates 3 and acids 4.

Isoniazid-related copper(II) and nickel(II) complexes with antimycobacterial in vitro activity. Part 9

Isonicotinoylhydrazones 1, obtained by the primary antituberculous agent Isoniazid, have been used as monoanionic ligands (L) to prepare copper(II) 2 and nickel(II) 3 octahedral complexes of stoichiometry [MeL2(H2O)2]. Their antimycobacterial in vitro activity was evaluated against Mycobacterium tuberculosis H37Rv in comparison with the ligands. Complexes 2a, 2b, 2f, 3b, 3d and 3g displayed MIC values < or = 0.2 microg/mL.

In Vitro Antimycobacterial Activities of 2′-Monosubstituted Isonicotinohydrazides and Their Cyanoborane Adducts

ABSTRACT As a result of our search for new isoniazid derivatives with extended spectra of activity, we evaluated the in vitro antimycobacterial activities of isonicotinohydrazides (compounds 2) and their cyanoborane adducts (compounds 3), both obtained by the reaction of isonicotinoylhydrazones (compounds 1) with sodium cyanoborohydride. Most of the tested compounds displayed moderate to high activity against Mycobacterium tuberculosis H37Rv, with MICs ranging from 0.2 to 12.5 μg/ml. In particular, some hydrazides showed activity similar to that of rifampin (MIC = 0.2 μg/ml) and rather low cytotoxicity, so that they were generally shown to possess high safety indices. In contrast, the coordination to a cyanoborane (BH2CN) group (compounds 3) in general brought about a decrease in antimycobacterial activity, while cytotoxicity increased. Interestingly, selected compounds 1 to 3, mostly hydrazides (compounds 2), were effective in killing M. tuberculosis growing within macrophages at concentrations in culture medium which were much lower than the corresponding MICs. These compounds also displayed good activity against drug-resistant M. tuberculosis strains.

Nickel(II) 2,6-diacetylpyridine bis(isonicotinoylhydrazonate) and bis(benzoylhydrazonate) complexes : Structure and antimycobacterial evaluation. Part XI

The reaction of 2,6-diacetylpyridine (dap) and isonicotinoyl- or benzoylhydrazide leads to bishydrazones H(2)dapin (1a) and H(2)dapb (1b), respectively. The condensation can either take place as a bimolecular kinetic process between the two reactants or as a monomolecular metal-templated synthesis in the presence of nickel(II) ions. In the latter case the reaction products are charged 2,6-diacetylpyridine bis(hydrazone) nickel(II) complexes, which can be easily deprotonated to neutral hydrazonates. Diffractometric analysis of one of these [Ni(dapb)](2) (8b) has shown a binuclear structure with two octahedral nickel(II) ions bridged by two helicoidal dap (bishydrazonates) in a spheroidal structure of C(2V) symmetry. The synthesized complexes 8 are promising as antimycobacterial agents against M. tuberculosis H37Rv. In particular, 8b displays significant activity (MIC=0.025 microg/mL) 10-fold higher than rifampin and equal to isoniazid, while its ligand is ineffective. Compound 8b is also capable of reducing HIV-induced cytopathogenic effect in human T(4 )lymphocytes.

Rational design, synthesis, biophysical and antiproliferative evaluation of fluorenone derivatives with DNA G-quadruplex binding properties.

Molecular modeling studies carried out with experimental DNA models with the sequence d[AG3(T2AG3)3] suggest that the introduction of a net positive charge onto the side chain of a series of fluorenone carboxamides can improve G‐quadruplex binding. The terminal morpholino moiety was replaced with a novel N‐methylmorpholinium cation starting from two 4‐carboxamide compounds. A different substitution on the fluorenone ring was also investigated and submitted to the same quaternarization process. All compounds were analyzed for their DNA binding properties by competition dialysis methods. In vitro antiproliferative tests were carried out against two different tumor cell lines. Docking experiments were conducted by including all four known human repeat unit G‐quadruplex DNA sequences (27 experimentally determined conformations) against the most active fluorenone derivatives. The results of theoretical, biophysical, and in vitro experiments indicate two novel derivatives as lead compounds for the development of a new generation of G‐quadruplex ligands with greater potency and selectivity.

Antimycobacterial in vitro activity of cobalt(ii) isonicotinoylhydrazone complexes. Part 10

Octahedral cobalt(II) complexes of isonicotinoylhydrazones, which were obtained from the primary antituberculous agent isoniazid, have been synthesised and characterised. Their antimycobacterial in vitro activity has been evaluated against Mycobacterium tuberculosis H37Rv: they exhibit MIC values ranging from < 0.1 to 0.39 microg/mL, showing them to be generally more active than previously reported analogous Cu(II) and Ni(II) complexes.

3,3′-Di [1,3-thiazolidine-4-one] system. II. Anti-inflammatory and anti-histaminic properties in new substituted derivatives

Abstract In pursuing our search on anti-inflammatory dl and meso 3,3′-di[1,3-thiazolidine-4-one] compounds, two series of derivatives have been prepared by modifying the substitution pattern at positions 1 and 2 of the heterocyclic rings and by introducing an ethylene chain between nitrogen atoms. The anti-inflammatory activity of these compounds has been preliminarily assayed against carrageenin-induced rat paw edema: those proven to be active were also tested for analgesic, anti-pyretic and anti-histamine properties. As a whole, the obtained results suggest that some of the new derivatives possess significant anti-histamine activity. The meso forms generally are more active than dl ones in agreement with the previously emphasized SAR of the chiral systems under study.

3,3′-Di(1,3-thiazolidine-4-one) system. V. Synthesis and pharmacological properties of 3,3′(1,2-ethanediyl)bis-(2-heteroaryl-1,3-thiazolidine-4-one) derivatives

A class of anti-inflammatory, analgesic and histamine H1- and H2-receptor antagonists the 2,2′-diheteroarylbisthiazolidinones and their 1,1′-disulfones, obtained as [RR, SS] and [RS, SR] isomers, is described. The heteroaryl substitution at 2 and 2′ carbons generally improves the pharmacological activities with respect to those of the previously studied 2,2′-diaryl analogues. In particular the 2,2′-dithienyl derivatives exhibit analgesic properties and, as [RS, SR] isomers 6b, 11b, 12b H2-histamine receptor antagonism as well. The most effective acute anti-inflammatory agents appear to be the 2,2′-di(3-pyridyl) compounds 8a, 8b, 14a, 14b which also display analgesic activity. Moreover, an H1-histamine receptor antagonism is almost selectively exerted by the 2,2′-di(2-pyridyl) derivatives 7a, 7b, 13a, 13b. The relationships between the assessed activities and the chirality and/or the sulfur oxidation state of the molecules are discussed. The anti-cancer potential was also evaluated against P 388 murine lymphocytic leukemia; however, the results were not significant.

2/4-Substituted-9-fluorenones and their O-glucosides as potential immunomodulators and anti-herpes simplex virus-2 agents. Part 5

In pursuing a research on the antiviral and immunomodulatory activity of tilorone congeners, two new series of compounds were prepared and pharmacologically explored: 9-fluorenone carboxyhydroxyesters, indicated as AG, and 9-fluorenone carboxyhydroxamides, indicated as MG. Two of them, AG17 and MG3, were used as sugar acceptors in the transglycosylation reactions performed by alpha- and beta-glucosidases extracted from the marine mollusc Aplysia fasciata providing different alpha- and beta-, mono- and oligosaccharides. Then aglycons and saccharides were assayed for cytotoxicity, for anti-herpes virus-2 properties on peripheral blood mononuclear cells (PBMC) and for their capability to trigger human cells to produce antiviral cytokines such as IFNalpha and TNFalpha. Some promising compounds were individuated whereas the utility of the biocatalytic procedures in the preparation of pure anomeric material was further focused.

Facile biocatalytic access to 9-fluorenylmethyl polyglycosides: evaluation of antiviral activity on immunocompetent cells.

The biological activities of a series of mono‐ and oligosaccharides (β‐xylosides and α‐glucosides) of 9‐fluorenylmethanol were investigated together with mono‐β‐galactoside and β‐glucoside of this aglycone, produced by biocatalytic routes. By using marine glycoside hydrolases and inexpensive donors such as maltose or xylan, access to mono‐α‐glucoside or mono‐β‐xyloside of 9‐fluorenylmethanol was obtained. Additionally, interesting polyglycoside derivatives were isolated. Biological testing indicated that in vitro treatment with these carbohydrate derivatives may influence the balance of cytokines in the environment of human peripheral blood mononuclear cells (PBMC), restricting the harmful effect of herpes simplex type 2 replication. In fact, these carbohydrate derivatives tested in WISH cells did not show any significant antiviral activity.