− Alzheimer's disease is a chronic neurodegenerative disorder with no curative treatment. The commercially available drugs, which target acetylcholinesterase, are not satisfactory. The aim of this study was to investigate the cholinesterase inhibitory activity of Solenostemma argel aerial part. Eight compounds were isolated and identified by NMR: kaempferol-3-O-glucopyranoside (1), kaempferol (2), kaempferol-3-glucopyranosyl(1→6)rhamnopyranose (3) p-hydroxybenzoic acid (4), dehydrovomifoliol (5), 14,15-dihydroxypregn-4-ene-3,20-dione (6), 14,15-dihydroxy-pregn-4-ene-3,20-dione-15β-D-glucopyranoside (7) and solargin I (8). Two of them (compounds 2 and 3) could inhibit over 50 % of butyrylcholinesterase activity at 100 µM. Compound (2) displayed the highest inhibitory effect against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with a slight selectivity towards the latter. Molecular docking studies supported the in vitro results and revealed that (2) had made several hydrogen and π-π stacking interactions which could explain the compound potency to inhibit AChE and BChE.

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Transmembrane serine protease 2 (TMPRSS2) is a human protease which plays an important role in the viral life cycle. This enzyme cleaves the spike protein required for Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) viral entry at the host cell. TMPRSS2 inhibitors might limit SARS-CoV-2 infection in the respiratory tract. This work aims at identifying new potent TMPRSS2 inhibitors for anti-SARS CoV-2 drug research. Indeed, Structure-Based Virtual Screening (SBVS) of 13 521 analog compounds to 4-carbamimidamidobenzoic acid,a potent TMPRSS2 inhibitor, was undertaken using FlexX program. Then, the top ranked 1000 compounds were re-scored using Glide Extra Precision (XP) and their binding mode into TMPRSS2 binding site was further analyzed in order to eliminate false positive ones. Finally, drug likeness and toxicity properties of the most promising inhibitors were predicted. Out of these, compounds S1 and S2 showed a higher TMPRSS2 inhibitory potency than that of GBS, the reference molecule. They also were predicted to occupy the entire TMPRSS2 binding site making a rational number of interactions. Still more remarkably, these two compounds were also predicted to have satisfying drug likeness properties, indicating that they might be promising lead compounds for further anti-SARS CoV-2 drug research.

Cancer is a real public health problem that figures among the main causes of morbidity and mortality in the world. The Colchicine Binding Site (CBS) is an important pocket for potential tubulin polymerization destabilizers. Colchicine binding site inhibitors (CBSI) exhibit their biological effects by inhibiting tubulin assembly and suppressing microtubule formation. In order to identify new potent CBSI, molecular docking and drug likeness prediction were performed. In this context, a collection of 850 similar compounds to combretastatinA-4from PubChem database was docked into the CBS. Out of these, compounds S1 and S2 were found to have highest negative binding energy of -9.462 and -9.017 Kcal/mol respectively. Furthermore, these two compounds were predicted to have satisfying drug likeness properties, indicating that they might be promising lead compounds for further antitumor drug research.