New pyrazole derivatives: Synthesis, anti-inflammatory activity, cycloxygenase inhibition assay and evaluation of mPGES.

New pyrazole derivatives 2-5 were synthesized and evaluated for their COX-1 and COX-2 inhibitory activity in vitro. All compounds showed good inhibitory activity at a nanomolar level and most compounds exhibited selectivity towards COX-2 inhibition. Compounds 2a, 3b, 4a, 5b and 5e exhibited IC50 towards COX-2 enzyme of 19.87, 39.43, 61.24, 38.73 and 39.14 nM, respectively. Furthermore, compounds 3b, 4a, 5b and 5e exhibited a selectivity index of 22.21, 14.35, 17.47 and 13.10, respectively. The most active compounds were further subjected to in vivo anti-inflammatory assay. The tested compounds showed better or comparable activity to celecoxib as positive control. In order to explore their binding mode and selectivity behaviour, molecular docking in the active site of COX-2 was carried out for these derivatives. Analysis of the docked poses of the compounds showed that they adopt similar conformations to the highly selective COX-2 inhibitor, SC-558. The docking pose of compound 3b was confirmed by molecular dynamics. All the tested compounds exhibited potent inhibitory effect on the production of PGE2, in addition to their inhibition of COX-2 enzyme.

Novel pyrazolopyrimidines: Synthesis, in vitro cytotoxic activity and mechanistic investigation.

A series of novel pyrazolo[3,4-d]pyrimidines bearing benzenesulfonamide moiety 5a-f, 6 and 7 were synthesized. Cytotoxic screening was conducted against MCF-7 and HepG2. 6-(4-Methoxyphenyl)-4-oxopyrazolopyrimidine derivative 5e and 4-imino-6-oxopyrazolopyrimidine derivative 6 revealed potent cytotoxic activity with IC50 1.4 µM (MCF-7) and 0.4 µM (HepG2), respectively compared to that of doxorubicin, (IC50 = 1.02 µM and 0.9 µM, respectively). Compounds 5e and 6 were subjected to cell cycle analysis and apoptosis assay after 24 h and 48 h treatment. Compound 5e arrested cell at G1 phase, while 6 arrested cell at S and G2/M phases, respectively. The apoptotic effect of both compounds were evidenced by pre G1 apoptosis as its percentage increased by time (7.38%, 11.61%) and (13.92%, 16.71%), respectively. Apoptosis induction capability was confirmed by the effect on early and late apoptosis and augmentation of caspase-3 level. Furthermore, compound 6 inhibited CDK2 enzyme with IC50 = 0.19 µM and increased levels of its regulators, P21 and P27 by 10.06% and 8.5%, respectively. Moreover, a molecular docking study of compound 6 on CDK2 enzyme was adopted to explore binding interaction with amino acid residues of its active site.