Background: Pyrazolones have identified as significant antioxidant agents and many
marketed and clinically prescribed NSAIDs have pyrazolone ring as main scaffold.
Method: Keeping in consideration the antioxidant potential of pyrazolone scaffold, new bispyrazolones
3-30 were synthesized by a green and enviroment friendly reaction route, in which
two equivalents of 1-(4-chlorophenyl)-3-methyl-1H-pyrazol-5-ol were treated with one equivalent
of benzaldehyde derivatives without any catalyst. All compounds were structurally characterzied
by 1H-NMR and FAB analysis. 13C-NMR of selected compounds was also recorded. All compounds
gave satisfactory elemental analyses and found in good agreement with calculated values.
Results: Synthetic bis-pyrazolones 3-30 were evaluated for their oxidative burst inhibitory effect
of zymosan stimulated whole blood phagocytes by using luminol enhanced chemilluminescence
technique. All molecules demonstrated the potent ROS inhibition activity in the range of IC50 = 1.2
± 0.1-48.8 ± 3.9 µM as compared to the standard ibuprofen (IC50 = 54.2 ± 9.2 μM). The purity of
active compounds was checked by HPLC.
Conclusion: This study has identified a number of non-acidic lead molecules for future research
on ROS inhibitors.