Design, synthesis and molecular docking studies of novel N-arylsulfonyl-benzimidazoles with anti Trypanosoma cruzi activity.

Currently, only two drugs (i.e. benznidazole (BZN) and nifurtimox (NFX)) have been approved for the treatment of Trypanosoma cruzi (Tc) infection, the etiological agent causing Chagas disease. Since both drugs exhibit severe side effects, patients frequently abandon therapy, resulting in an inefficient pharmacotherapeutic treatment. In this context, there is an urgent need to develop new, safer and optimised anti-Tc agents. In this report, we present the synthesis and biological activity of 11 novel and 3 already reported N-arylsulfonyl-benzimidazole derivatives (NBSBZD,1-14) currently in development as potential anti-Tc compounds. These compounds were designed as part of a library of synthetic arylsulfonyl heterocycle derivatives constructed from privileged structures exhibiting drug-like properties. Based on bioactivity assays against Tc, (in both the extracellular and intracellular forms), we observed that 10 compounds exhibited bioactivity against the epimastigote form, while six of them exhibited activity against the amastigote counterpart. Also, the compounds showed less cytotoxicity compared to the reference drug BZN as measured in Vero cell culture. In order to elucidate the potential mechanism of action, metabolite excretion profiles studies were performed, and complemented with molecular modeling studies performed over known Tc druggable targets. Consistency was observed between experimental and theoretical findings, with metabolic profiles showing that compounds 1, 2, 9, 12 and 14 interfered with the normal glycolysis cycle of Tc, while molecular modeling studies were able to establish a solid structure-activity relationship towards the inhibition of 6-phospho-1-fructokinase, a key enzyme involved in the parasite glycolytic cascade. Overall, the present study constitutes a multidisciplinary contribution to the development of new anti-Chagas compounds.

Synthesis and in vitro anti-HIV-1 evaluation of some N-arylsulfonyl-3-formylindoles

As our ongoing work on research of anti-HIV-1 inhibitors, fifteen N-arylsulfonyl-3-formylindoles (3a-o) were designed and prepared through two step synthetic route. Firstly, 3-formylindoles (2a-c) were synthesized via the Vilsmeier-Haack reaction. Subsequently, treatment of 2a-c with the appropriate arylsulfonyl chlorides led to the corresponding target compounds in excellent yields. All analogues were also preliminary evaluated in vitro for their inhibitory activity against HIV-1 replication. Among of all the reported analogues, three compounds 3c, 3g and 3i displayed significant anti-HIV-1 activity, with EC50 values of 9.57, 11.04 and 5.02 µM, and TI values of 31.89, 13.79 and 81.69, respectively. N-m-nitrophenylsulfonyl-3-formylindole (3c) and N-m-nitrophenylsulfonyl-6-methyl-3-formylindole (3i) especially exhibited the best promising anti-HIV-1 activity. In addition, it demonstrated that insertion of a methyl group at the C-6 position of the indolyl ring and a nitro group at the meta position of the arylsulfonyl ring, as in compound 3i, resulted in both low cytotoxicity (CC50= 410.41 µM) and good antiviral activity

Interaction between bioactive compound 11a-N-tosyl-5-deoxi-pterocarpan (LQB-223) and Calf thymus DNA: Spectroscopic approach, electrophoresis and theoretical studies.

The interaction of small molecules with DNA has been quite important, since this biomolecule is currently the major target for a wide range of drugs in clinical use or advanced clinical research phase. Thus, the present work aimed to assess the interaction process between the bioactive compound 11a-N-tosyl-5-carba-pterocarpan, (LQB-223), that presents antitumor activity, with DNA, employing spectroscopic techniques, electrophoresis, viscosity and theoretical studies. Through UV-vis and molecular fluorescence spectroscopy, it was possible to infer that the preferential quenching mechanism was static, characterized by non-fluorescent supramolecular complex formation between the LQB-223 and DNA. The binding constant was 1.94∙103Lmol-1 (30°C) and, according to the thermodynamic parameters, the main forces involved in the interaction process are hydrophobic. Potassium iodide assay, competition with ethidium bromide, fluorescence contact energy transfer and melting temperature profile of DNA were employed to evaluate the binding mode. Except for KI assay, all results obtained indicated minor groove as the preferential binding mode of LQB-223 to DNA. These observations were supported by ionic strength assay, viscosity and molecular dynamics and docking studies. Finally, electrophoresis analysis demonstrated that the interaction does not promote DNA fragmentation, but it leads to variation in the migration profile after increasing the ligand concentration.