Virtual design of novel Plasmodium falciparum cysteine protease falcipain-2 hybrid lactone-chalcone and isatin-chalcone inhibitors probing the S2 active site pocket

• Published in: Journal of enzyme inhibition and medicinal chemistry 2019-01, Vol.34 (1), p.547-561
• Main Authors: Allangba, Koffi N'Guessan Placide Gabin, Keita, Mélalie, Kre N'Guessan, Raymond, Megnassan, Eugene, Frecer, Vladimir, Miertus, Stanislav
• Format: Article
• Language: English
• Subjects: Falcipain-2; molecular modelling; pharmacokinetics; pharmacophore; Plasmodium falciparum; QSAR model; Research Paper; virtual library
• ISSN: 1475-6366; 1475-6374
• DOI: 10.1080/14756366.2018.1564288

We report computer-aided design of new lactone-chalcone and isatin-chalcone (HLCIC) inhibitors of the falcipain-2 (PfFP-2). 3D models of 15 FP-2:HLCIC1-15 complexes with known observed activity (IC 50 exp ) were prepared to establish a quantitative structure-activity (QSAR) model and linear correlation between relative Gibbs free energy of enzyme:inhibitor complex formation (ΔΔG com ) and IC 50 exp : pIC 50 exp  = −0.0236 × ΔΔG com +5.082(#); R 2  = 0.93. A 3D pharmacophore model (PH4) derived from the QSAR directed our effort to design novel HLCIC analogues. During the design, an initial virtual library of 2621440 HLCIC was focused down to 18288 drug-like compounds and finally, PH4 screened to identify 81 promising compounds. Thirty-three others were added from an intuitive substitution approach intended to fill better the enzyme S2 pocket. One hundred and fourteen theoretical IC 50 (IC 50 pre) values were predicted by means of (#) and their pharmacokinetics (ADME) profiles. More than 30 putative HLCICs display IC 50 pre 100 times superior to that of the published most active training set inhibitor HLCIC1.