Irene Briguglio

Quinoline tricyclic derivatives. Design, synthesis and evaluation of the antiviral activity of three new classes of RNA-dependent RNA polymerase inhibitors

In this study three new classes of linear N-tricyclic compounds, derived by condensation of the quinoline nucleus with 1,2,3-triazole, imidazole or pyrazine, were synthesized, obtaining triazolo[4,5-g]quinolines, imidazo[4,5-g]quinolines and pyrido[2,3-g]quinoxalines, respectively. Title compounds were tested in cell-based assays for cytotoxicity and antiviral activity against RNA viruses representative of the three genera of the Flaviviridae family, that is BVDV (Pestivirus), YFV (Flavivirus) and HCV (Hepacivirus). Quinoline derivatives were also tested against representatives of other RNA virus families containing single-stranded, either positive-sense (ssRNA(+)) or negative-sense (RNA(-)), and double-stranded genomes (dsRNA), as well as against representatives of two DNA virus families. Some quinolines showed moderate, although selective activity against CVB-5, Reo-1 and RSV. However, derivatives belonging to all classes showed activity against BVDV. Among the most potent were the bis-triazoloquinoline 1m, the imidazoquinolines 2e and 2h, and the pyridoquinoxalines 4h, 4j and 5n (EC(50) range 1-5 μM). When tested in a replicon assay, compound 2h was the sole derivative to also display anti-HCV activity (EC(50)=3.1 μM). In enzyme assays, 1m, 2h, 5m and 5n proved to be potent inhibitors of the BVDV RNA-dependent RNA polymerase (RdRp), while only 2h also inhibited the recombinant HCV enzyme.

3-Aryl-2-[1H-benzotriazol-1-yl]acrylonitriles: a novel class of potent tubulin inhibitors

During a screening for compounds that could act against Mycobacterium tuberculosis, a series of new cellular antiproliferative agents was identified. The most cytotoxic molecules were evaluated against a panel of human cell lines derived from hematological and solid human tumors. In particular, (E)-2-(1H-benzo[d] [1,2,3]triazol-1-yl)-3-(4-methoxyphenyl)acrylonitrile (1) was found to be of a potency comparable to etoposide and greater than 6-mercaptopurine in all cell lines tested. Accordingly, a synthesis of a new series of (E)-2-(5,6-dichloro-1H-benzo[d] [1,2,3]triazol-1-yl)-3-(4-R-phenyl)acrylonitriles was conducted in order to extend the studies of structure-activity relationship (SAR) for this class of molecules. With the aim to evaluate if 3-aryl-2-[1H-benzotriazol-1-yl]acrylonitriles were able to act like tubulin binding agents, the effects on cell cycle distribution of the most active compounds (1, 2a, 3 and 4) were analyzed in K562 cells. A detailed molecular modeling study of the putative binding mode of this series of compounds on tubulin is also reported.

Synthesis and anti-mycobacterial activities of triazoloquinolones

A number of quinolone derivatives have been reported to possess anti-mycobacterial activity. Generally. Mycobacterium tuberculosis isolates expressing resistance to both isoniazid and rifampin are susceptible to fluoroquinolones. Benzotriazole is a hetero-bicyclic aromatic ring endowed with interesting chemical and biological properties and pharmacological activities. In a preliminary study we have recently reported the activity of triazolo[4,5-h]quinolone-carboxylic acids, a new class of benzotriazole derivatives active against multi-drug resistant M. tuberculosis (MDR-Mtb). In this study we confirm that this novel class of quinolones is endowed with a selective anti-mycobacterial activity, coupled with absence of cytotoxicity. The SAR analysis of the new derivatives in comparison with the previous series shows that the methyl group is the most effective substituent in both N-3 and N-9 positions of the ring system.

Enantiomeric Separation of 13 New Amphetamine-Like Designer Drugs by Capillary Electrophoresis, Using Modified--Cyclodextrins

An easy-to-prepare chiral CE method for the enantiomeric separation of 13 new amphetamine-like designer drugs, using CDs as chiral selectors, was developed. Sulfated-β-CD was found to be the best chiral selector among the three used (sulfated-β-CD, caroboxymethyl-β-CD, dimethyl-β-CD). The separation of the analytes was achieved in a fused-silica gel capillary at 20 °C using an applied voltage of +25 kV. The optimized background electrolyte consisted of 63.5 mM H3 PO4 and 46.9 mM NaOH in water. Several electrophoretic parameters such as CD type, CD concentration (1 - 40 mg/mL), buffer pH (2.6, 3.6, 5.0, 6.0), length of the capillary (70 - 40 cm total length), amount of the organic solvent (methanol and acetonitrile) were investigated and optimized.

Inhibition of RNA Helicases of ssRNA(+) Virus Belonging to Flaviviridae, Coronaviridae and Picornaviridae Families.

Many viral pathogens encode the motor proteins named RNA helicases which display various functions in genome replication. General strategies to design specific and selective drugs targeting helicase for the treatment of viral infections could act via one or more of the following mechanisms: inhibition of the NTPase activity, by interferences with ATP binding and therefore by limiting the energy required for the unwinding and translocation, or by allosteric mechanism and therefore by stabilizing the conformation of the enzyme in low helicase activity state; inhibition of nucleic acids binding to the helicase; inhibition of coupling of ATP hydrolysis to unwinding; inhibition of unwinding by sterically blocking helicase translocation. Recently, by in vitro screening studies, it has been reported that several benzotriazole, imidazole, imidazodiazepine, phenothiazine, quinoline, anthracycline, triphenylmethane, tropolone, pyrrole, acridone, small peptide, and Bananin derivatives are endowed with helicase inhibition of pathogen viruses belonging to Flaviviridae, Coronaviridae, and Picornaviridae families.

ELISA Detection of 30 New Amphetamine Designer Drugs in Whole Blood, Urine and Oral Fluid using Neogen® "Amphetamine" and "Methamphetamine/MDMA" Kits.

Amphetamine designer drugs are central nervous system stimulants that are widely disseminated in the illegal market. Generally, in forensic laboratories, immunoassay methods are the first line of screening for these types of drugs in a biological specimen (typically blood, urine or oral fluid). In this article, we describe the cross-reactivity profiles of 30 new amphetamine designer drugs, using the Neogen(®) [Amphetamine Specific and Methamphetamine/3,4-Methylenedioxymethamphetamine (MDMA) assays] drug tests. To assess the potential matrix influence on the response, each assay was tested on whole blood, urine and oral fluid. Concentrations of 10,000 ng/mL were not sufficient to produce a positive response for the majority of the analyzed amphetamines. This clearly demonstrates that, although these kits are extremely effective for the target drugs for which they are intended (amphetamine, methamphetamine and MDMA), they cannot be used to reliably identify the tested designer drugs in real cases, as these concentrations greatly exceed those expected to be found in forensic samples.

2-[ N -Alkyl( R -phenyl)-aminomethyl]-3-phenyl-7-trifluoromethylquinoxalines as anticancer agents inhibitors of folate enzymes

Based on our previous results on the ascertained potent growth inhibition effect against a panel of 60 human tumors cell lines at National Cancer Institute of Bethesda (NCI), we have synthesized a novel series of thirty-one 2-[N-methyl(R-phenyl)-aminomethyl]-3-phenyl-7-trifluoromethylquinoxalines (1-31). The lead compound 1 was previously reported to be endowed with significant inhibition against hDHFR enzyme, with a Ki of 0.2 μM. Docking studies were performed on compound 1 and here reported to predict its binding conformation to human dihydrofolate reductase (hDHFR). All compounds (1-31) were assayed versus hDHFR and human thymidylate synthase (hTS). From the screening emerged that all compounds inhibited hDHFR with Ki values included between 0.2 and 11 μM, while only a few (6, 21, 24, 27, 29) showed great activity and selectivity towards hTS. Evaluation of the anticancer activity was performed by NCI, first against the three cell line panel, and only the most active compounds (17, 21, 24, 26, 27) were evaluated on a panel of 60 human tumor cell lines. Compound 21 was the most active against all cell lines with log GI50 equal to -5.49 and log LC50 equal to -4.19 and maintained significant percent of growth inhibition on seven cancer cell lines at the concentration of 1 μM. Compound 17 was the second most active and moreover showed interesting selectivity against some cell lines (Lung cancer: A549/ATCC, Melanoma: UACC-257, Ovarian Cancer: ovcar-8 and Renal cancer: RXF 393) at all concentration examined (100-0.01 μM).

Quinoxaline derivatives as new inhibitors of coxsackievirus B5

Enteroviruses are among the most common and important human pathogens for which there are no specific antiviral agents approved by the US Food and Drug Administration so far. Particularly, coxsackievirus infections have a worldwide distribution and can cause many important diseases. We here report the synthesis of new 14 quinoxaline derivatives and the evaluation of their cytotoxicity and antiviral activity against representatives of ssRNA, dsRNA and dsDNA viruses. Promisingly, three compounds showed a very potent and selective antiviral activity against coxsackievirus B5, with EC50 in the sub-micromolar range (0.3-0.06 μM). A combination of experimental techniques (i.e. virucidal activity, time of drug addition and adsorption assays) and in silico modeling studies were further performed, aiming to understand the mode of action of the most active, selective and not cytotoxic compound, the ethyl 4-[(2,3-dimethoxyquinoxalin-6-yl)methylthio]benzoate (6).