Studies on some biologically active substituted 4(3H)-quinazolinones. Part 1. Synthesis, characterization and anti-inflammatory-antimicrobial activity of 6,8-disubstituted 2-phenyl-3-[substituted-benzothiazol-2-yl]-4(3H)-quinazolinones

Abstract

Two series of 6,8-disubstituted 2-phenyl-3-[substituted benzothiazol-2-yl]-4(3H)-quinazolinones [3a-m and 4a-m] have been synthesized and characterized by elemental analysis and spectral data. The anti-inflammatory activity of the title compounds (3a-m and 4a-m) was evaluated and the most active compounds were evaluated for COX-1 and COX-2 inhibitory activity and ulcerogenic activity. All the test compounds were administered orally/intraperitoneally at a dose 50 mg/Kg body weight and percentage inhibitions were determined. Further more all the compounds were also tested against Gram negative, Gram positive bacteria and fungi. Among the compounds tested in this study, compounds 2-phenyl-3-(4-methoxybenzothiazol-2-yl)-4(3H)quinazolinone (3e), 2-phenyl-3-(5-methylbenzothiazol-2-yl)-4(3H)-quinazolinone (3f) and 2phenyl-3-(4-6-dimethylbenzothiazol-2-yl)-4(3H)-quinazolinone (3l) showed most prominent anti-inflammatory activity with low gastric ulceration incidence compare to reference standard Indomethacin. Further compounds, 3e, 3f and 3l revealed superior inhibitory profile against COX-2 enzyme, when compared with reference standard Indomethacin. Among all the compounds, compounds 4g and 4j posses a broad spectrum of antibacterial activities against both Gram positive and Gram negative bacteria but insignificant antifungal and anti-inflammatory activity.