Potent, selective and reversible hMAO-B inhibition by benzalphthalides: Synthesis, enzymatic and cellular evaluations and virtual docking and predictive studies

Monoaminooxidases (MAOs) are important targets for drugs used in the treatment of neurological and psychiatric disorders and particularly on Parkinson's Disease (PD). Compounds containing a trans-stilbenoid skeleton have demonstrated good selective and reversible MAO-B inhibition. Here, twenty-two (Z)-3-benzylidenephthalides (benzalphthalides, BPHs) displaying a trans-stilbenoid skeleton have been synthesised and evaluated as inhibitors of the MAO-A and MAO-B isoforms. Some BPHs have selectively inhibited MAO-B, with IC50 values ranging from sub-nM to μM. The most potent compound with IC50 = 0.6 nM was the 3',4'-dichloro-BPH 16, which showed highly selective and reversible MAO-B inhibitory activity. Furthermore, the most selective BPHs displayed a significant protection against the apoptosis, and mitochondrial toxic effects induced by 6-hydroxydopamine (6OHDA) on SH-SY5Y cells, used as a cellular model of PD. The results of virtual binding studies on the most potent compounds docked in MAO-B and MAO-A were in agreement with the potencies and selectivity indexes found experimentally. Additionally, related to toxicity risks, drug-likeness and ADME properties, the predictions found for the most relevant BPHs in this research were within those ranges established for drug candidates.

Synthesis, bioevaluation and structural study of substituted phthalazin-1(2H)-ones acting as antifungal agents

Twenty-five polysubstituted phthalazinone derivatives were synthesized and tested for their antifungal activity against a panel of pathogenic and clinically important yeasts and filamentous fungi. Among them, the compound 4-(4-chlorobenzyl)-2-methylphthalazin-1(2H)-one (5) exhibited a remarkable antifungal activity against standardised strains of dermatophytes and Cryptococcus neoformans, as well as against some clinical isolates. A physicochemical study performed on compound 5 revealed its conformational and electronic characteristics, providing us with useful data for the future design of novel related antifungal analogues.

Antimalarial activity of imidazo[2,1-a]isoindol-5-ol derivatives and related compounds

The synthesis of several series of imidazo[2,1-a]isoindol-5-ol derivatives and the results of their evaluation against Plasmodium falciparum are presented and discussed. The effects of electron-withdrawing or-donating substituents on different parts of the molecule, as well as those produced by the incorporation of an additional fused ring, were analyzed. Several compounds showed significant antimalarial activity in vitro with IC(50) values as low as 60 nM and a certain efficacy in vivo by reducing parasitemia in Plasmodium berghei mouse models.

Anti-HIV activity of stilbene-related heterocyclic compounds

Viral transcription has not been routinely targeted in the development of new antiviral drugs. This crucial step of the viral cycle depends on the concerted action of cellular and viral proteins such as NF-kappaB and Tat. In the present study, stilbene-related heterocyclic compounds including benzalphthalide, phthalazinone, imidazoindole and pyrimidoisoindole derivatives are tested for their anti-HIV activity. Original assays based on recombinant viruses were used to evaluate HIV replication inhibition and stably transfected cell lines were used to evaluate inhibition of Tat and NF-kappaB proteins. Some of the stilbene-related heterocyclic compounds analysed displayed anti-HIV activity through interference with NF-kappaB and Tat function. Moreover, compounds inhibiting both targets displayed a stronger activity on viral replication.

Vasorelaxant activity of phthalazinones and related compounds

Several series of dihydrostilbenamide, imidazo[2,1-a]isoindole, pyrimido[2,1-a]isoindole and phthalazinone derivatives were obtained and their vasorelaxant activity was measured on isolated rat aorta rings pre-contracted with phenylephrine (10(-5)M). Some phthalazinones attained, practically, the total relaxation of the organ at micromolar concentrations. For the most potent compound 9h (EC(50)=0.43microM) the affinities for alpha(1A), alpha(1B) and alpha(1D) adrenergic sub-receptors were determined.