Virtual Screening-Accelerated Discovery of a Phosphodiesterase 9 Inhibitor with Neuroprotective Effects in the Kainate Toxicity In Vitro Model

In the central nervous system, some specific phosphodiesterase (PDE) isoforms modulate pathways involved in neuronal plasticity. Accumulating evidence suggests that PDE9 may be a promising therapeutic target for neurodegenerative diseases. In the current study, computational techniques were used to identify a nature-inspired PDE9 inhibitor bearing the scaffold of an isoflavone, starting from a database of synthetic small molecules using a ligand-based approach. Furthermore, docking studies supported by molecular dynamics investigations allowed us to evaluate the features of the ligand-target complex. In vitro assays confirmed the computational results, showing that the selected compound inhibits the enzyme in the nanomolar range. Additionally, we evaluated the expression of gene and protein levels of PDE9 in organotypic hippocampal slices, observing an increase following exposure to kainate (KA). Importantly, the PDE9 inhibitor reduced CA3 damage induced by KA in a dose-dependent manner in organotypic hippocampal slices. Taken together, these observations strongly support the potential of the identified nature-inspired PDE9 inhibitor and suggest that such a molecule could represent a promising lead compound to develop novel therapeutic tools against neurological diseases..

Interaction of imidazolium-based ionic liquids with supported phospholipid bilayers as model biomembranes

The cytotoxicity of ionic liquids (ILs) is receiving increasing attention due to their potential biological and environmental impact. We have used atomic force microscopy to investigate the interaction of ILs with supported phospholipid bilayers, as models of biomembranes.

Synthesis and photophysical evaluation of polarity sensitive push-pull isoquinolines and their alkynyl precursors

Two sets of unprecedented push-pull isoquinolines, characterized by an opposite "dipolar moment" with respect to the longitudinal axis of the molecule, have been prepared. The key step of the approach is the microwave-promoted domino imination/cycloisomerization of 2-alkynyl benzaldehydes in the presence of methanolic ammonia. Absorption spectra and emission spectra of the D-π-A isoquinolines and their alkynyl precursors in nine different solvents have been recorded. The absolute QYs of all compounds have been recorded in three solvents with different polarities, i.e. toluene, DMSO and ethanol. Among the D-π-A isoquinolines prepared - nicknamed QuinaChroms - two compounds characterized by opposite dipolar moments, i.e. 3-(4-methoxyphenyl)-7-nitroisoquinoline 1a and N,N-diethyl-3-(4-(methylsulfonyl)phenyl)isoquinolin-7-amine 2b displayed more interesting photophysical profiles, whereas 5-(diethylamino)-2-(A)arylethynylbenzaldehydes precursors 8a-c - having a free aldehyde group that is suitable for possible conjugation - exhibited strong fluorescence and wide Stokes shifts. These products are interesting for potential use as polarity-sensitive fluorescent probes or advanced functional materials.

Gold-catalyzed cascade reactions of 4H-furo[3,2-b]indoles with propargyl esters: synthesis of 2-alkenylidene-3-oxoindolines

2-Trienyliden-indolin-3-ones were synthesised in high yields via a gold catalysed cascade reaction between 4H-furo[3,2-b]indoles and propargyl esters.

Inhibition of tumor necrosis factor-alpha (TNF-alpha)/TNF-alpha receptor binding by structural analogues of suramin

Suramin, a symmetrical polysulfonated urea derivative, promotes the dissociation of trimeric human tumor necrosis factor-alpha (TNF-alpha) into biologically inactive subunits and prevents the interaction of TNF-alpha with its cellular receptors. The aim of this work was to identify compounds structurally related to suramin which inhibit the binding of TNF-alpha to its receptor. Molecular modeling studies were performed on suramin and TNF-alpha molecules and likely interaction sites were identified in the docked complex. On this basis, Evans blue, trypan blue, sulfonazo III, beryllon II, and 1,3,6-naphthalenetrisulfonic acid trisodium salt were identified as polysulfonated compounds endowed, to various extents, with the structural characteristics responsible for interaction with TNF-alpha. N,N-bis(3,5-di-tert-butylphenyl)-3,4,9,10-perylenedicarboximide was used as an unrelated structure. The capacity of these molecules to inhibit the binding of TNF-alpha with its receptor p55 was tested in vitro by means of a specific immunoenzymatic assay using suramin as reference compound. Evans blue and trypan blue inhibited TNF-alpha/p55 binding with an IC50 of 0.75 and 1.00 mM, respectively (suramin IC50: 0.65 mM); no effect was observed with the other molecules. Molecular modeling analyses on Evans blue and trypan blue docked into the TNF-alpha molecule support these experimental results by demonstrating that these compounds share with suramin a similar binding mode to TNF-alpha. The results of this work provide a new insight into and useful hints for the design of new chemical entities endowed with a potent and selective activity on TNF-alpha.

Effect of modifications of the alkylpiperazine moiety of trazodone on 5HT2A and alpha1 receptor binding affinity

A series of triazolopyridine derivatives (compounds 2a-l) were synthesized in order to explore the effect of modifications of the alkylpiperazine moiety of trazodone (fragment A) on binding affinity for 5HT2A and alpha1 receptors. All of the synthesized compounds show a decrease of affinity for both 5HT2A and alpha1 receptors, as compared to trazodone, with the exception of compounds 2b,c which bear a methyl group in an alpha position to the aliphatic nitrogen atom N1. These compounds showed a decrease of affinity only for the alpha1 receptor. The stereochemical influence of the piperazine moiety of compound 2c was also evaluated. Enantiomer (S)-2c showed the most significant differences between 5HT2A and alpha1 receptor affinity (IC50 values) and among the corresponding functional properties (pA2 values). Since (S)-2c cannot generate the metabolite 4-(3-chlorophenyl)piperazine this product was selected for further pharmacological studies.

Synthesis and antimicrobial activity of some new derivatives of 6,12-dihydroindolo[2,1-b]quinazolin-6,12-dione

Some derivatives of tryptantrine were prepared in order either to increase solubility and to study structure-activity relationship. All synthesized compounds were tested for antimicrobial activity.

Synthesis and antimicrobial activity of some new indolo[2,1-b]quinazolin-6(12H)ones

A series of indolo[2,1-b]quinazolin-6(12H)ones 4a-i was prepared and tested for the antimicrobial activity. The synthesis of the new compounds and the results of the antimicrobial screening are reported.