Synthesis and Biological Evaluation of Novel 2-(4-acetyl-3-methyl- 5-(arylamino) thiophen-2-yl)-3-arylquinazolin-4(3H)-one Derivatives as Potential Anti-inflammatory and Antioxidant Agents.

Abstract

A new series of 2-(4-acetyl-3-methyl-5-(arylamino) thiophen-2- yl)-3-arylquinazolin-4(3H)-one derivatives (11a-11j) were synthesized from acetyl acetone, phenyl isothiocyanate and 2-chloromethyl quinazolinone. Due to side effects of Non Steroidal Anti-Inflammatory Drugs (NSAID), an attempt was made to identify the novel tetrasubstituted thiophene lead compound as potential anti-inflammatory and antioxidant agent. Then newly synthesized compounds were characterized by IR spectroscopy, 1H NMR and mass spectrometry. The synthesized compounds were screened for their in vivo anti-inflammatory activity in carrageenan-induced rat hind paw edema model at dose 20mg/kg body weight using diclofenac sodium as a standard drug. The compounds were also evaluated for their in vitro DPPH free radical-scavenging activity and nitric oxide radical scavenging activity at the concentrations of 10, 20, 40, 60, 80 and 100 µg/mL using ascorbic acid as standard drug. The results from carrageenan-induced rat hind paw edema showed that compounds 11e, 11f and 11b show a significant anti-inflammatory activity of 46.61%, 48.94% and 47.04 % protection respectively to inflamed paw but less than diclofenac sodium. Compounds 11h and 11e show good DPPH free radical scavenging and nitric oxide radical scavenging activity, respectively. From results, it was observed that highly substituted thiophene scaffold exhibits anti-inflammatory and antioxidant activity.