Synthesis, evaluation and docking of novel pyrazolo pyrimidines as potent p38α MAP kinase inhibitors with improved anti-inflammatory, ulcerogenic and TNF-α inhibitory properties.

A series of nine new N-substituted-4-((1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl)amino)benzamides (6a-i) derivatives was synthesized. All the compounds were screened in-vitro for BSA anti-denaturation property, antioxidant assay and p38α MAP kinase inhibition. The in vitro anti-inflammatory assay results revealed that the compounds (6f-i) showed better activity than the compounds 6a-e. Compound 6f bearing the 4-chlorophenyl group showed in vitro anti-inflammatory activity (82.35 ±â€¯4.04) comparable to standard drug diclofenac sodium (84.13 ±â€¯1.63) and better p38α MAP kinase inhibitory activity (IC50 = 0.032 ±â€¯1.63 µM) than the prototypic inhibitor SB203580 (IC50 = 0.041 ±â€¯1.75 µM). The selected active compounds (6f-i) were further studied in animal models for anti-inflammatory activity, ulcerogenic liability, lipid peroxidation and TNF-α inhibition potential. Compound 6f showed promising anti-inflammatory potential with a percentage inhibition of 83.73% when compared to the standard, diclofenac sodium (78.05%). Compound 6f was also found to show reduced ulcerogenic liability and lipid peroxidation in comparison to the standard. This compound also potently inhibited the lipopolysaccharide (LPS)-induced TNF-α production in mice model (ID50 = 8.23 mg/kg) in comparison to SB 203580 (ID50 = 26.38 mg/kg). The molecular docking of compounds 6a-i against p38α MAP kinase receptor was also performed to understand ligand receptor interaction. Amongst all synthesized molecules compound 6f displayed highest docking score of -9.824. It showed hydrogen bonding interactions with Asn115 and pi-cation interaction with Lys53.

Synthesis, characterization and pharmacological evaluation of pyrazolyl urea derivatives as potential anti-inflammatory agents.

p38α mitogen activated protein kinase (MAPK) inhibitors provide a novel approach for the treatment of inflammatory disorders. A series of fifteen pyrazolyl urea derivatives (3a-o) were synthesized and evaluated for their p38α MAPK inhibition and antioxidant potential. Compounds 3a-e, 3g and 3h showed low micromolar range potency (IC50 values ranging from 0.037 ± 1.56 to 0.069 ± 0.07 µmol/L) compared to the standard inhibitor SB 203580 (IC50 = 0.043 ± 3.62 µmol/L) when evaluated for p38α MAPK inhibition by an immunosorbent-based assay. Antioxidant activity was measured by a 2,2'-diphenyl-1-picryl hydrazyl radical (DPPH) free radical scavenging method and one of the compounds, 3c, showed better percentage antioxidant activity (75.06%) compared to butylated hydroxy anisole (71.53%) at 1 mmol/L concentration. Compounds 3a-e, 3g and 3h showed promising in vivo anti-inflammatory activity (ranging from 62.25% to 80.93%) in comparison to diclofenac sodium (81.62%). The ulcerogenic liability and lipid peroxidation activity of these compounds were observed to be less in comparison to diclofenac sodium. These compounds also potently inhibited the lipopolysaccharide (LPS)-induced TNF-α release in mice (ID50 of 3a-c = 19.98, 11.32 and 9.67 mg/kg, respectively). Among the screened compounds, derivative 3c was found to be the most potent and its binding mode within the p38α MAPK is also reported.