Studies on imidazo[2,1-b][1,3]benzothiazole derivatives as new radiosensitizers

The synthesis and characterization of potent 7-substituted-2-(4-substitutedphenyl)imidazo[2,1- b ][1,3]benzothiazoles as effective radiosensitizers and anticarcinogenic compound is reported. The activity is determined against human liver cancer Hep G2 cell line, two parental melanoma cell lines (human melanoma cell line, A375C and mouse melanoma cell line, A375C). The compounds 7-sulfonamide-2-(4-fluorophenyl)imidazo[2,1- b ][1,3]benzothiazole ( 3f , IC 50 = 0.097 μM) and 7-sulfonamide-2-(4-methylphenyl)imidazo[2,1- b ][1,3]benzothiazole ( 3g , IC 50 = 0.114 μM) exhibited considerable in vitro anticancer activity against Hep G2 cell line while 7-bromo-2-(4-fluorophenyl)imidazo[2,1- b ][1,3]benzothiazole showed effectiveness against both parental melanoma cell lines ( 3c , IC 50 = 0.04 and 0.052 μM). Further the active molecules 3f, 3g and 3h are tested for radiosensitizing activity over Hep G2 cell line at 4 Gy, with the comet formed at 0.054 μM . Similarly, 3c tested against two parental melanoma cell lines, it has proven to be more potent when combined with 2 Gy ϒ-radiation. The present study reveals that presence of sulfonamide in combination with methoxy substitution enhanced DNA fragmentation and there by acting as effective derivative for Hepatocellular carcinoma.