Investigation of the salicylaldehyde thiosemicarbazone scaffold for inhibition of influenza virus PA endonuclease
作者:Dominga Rogolino、Alessia Bacchi、Laura De Luca、Gabriele Rispoli、Mario Sechi、Annelies Stevaert、Lieve Naesens、Mauro Carcelli
DOI:10.1007/s00775-015-1292-0
日期:2015.10
The influenza virus PA endonuclease is an attractive target for the development of novel anti-influenza virus therapeutics, which are urgently needed because of the emergence of drug-resistant viral strains. Reported PA inhibitors are assumed to chelate the divalent metal ion(s) (Mg2+ or Mn2+) in the enzyme's catalytic site, which is located in the N-terminal part of PA (PA-Nter). In the present work, a series of salicylaldehyde thiosemicarbazone derivatives have been synthesized and evaluated for their ability to inhibit the PA-Nter catalytic activity. Compounds 1-6 have been evaluated against influenza virus, both in enzymatic assays with influenza virus PA-Nter and in virus yield assays in MDCK cells. In order to establish a structure-activity relationship, the hydrazone analogue of the most active thiosemicarbazone has also been evaluated. Since chelation may represent a mode of action of such class of molecules, we studied the interaction of two of them, one with and one without biological activity versus the PA enzyme, towards Mg2+, the ion that is probably involved in the endonuclease activity of the heterotrimeric influenza polymerase complex. The crystal structure of the magnesium complex of the o-vanillin thiosemicarbazone ligand 1 is also described. Moreover, docking studies of PA endonuclease with compounds 1 and 2 were performed, to further analyse the possible mechanism of action of this class of inhibitors.
New thiosemicarbazone Schiff base ligands: Synthesis, characterization, catecholase study and hemolytic activity
and cobalt acetate and ligands (L/Cu: 1/1, 1/2, 2/1). The results show that all complexes were able to catalyze the oxidation of 3,5-DTBC. Acetate complexes have the highest activity. CuL1 and CoL1 complexes act as a catalyst and inhibitor. While copper and cobalt complexes obtained from ligand L2 illustrate concentration-independent oxidation activation. The hemolysis study performed by L1 increases