Some benzoxazoles and benzimidazoles as DNA topoisomerase I and II inhibitors.
Some novel fused heterocyclic compounds of 2, 5-disubstituted-benzoxazole and benzimidazole derivatives, which were previously synthesized by our group, were investigated for their inhibitory activity on both eukaryotic DNA topoisomerase I and II in a cell free system. 2-Phenoxymethylbenzimidazole (17), 5-amino-2-(p-fluorophenyl)benzoxazole (3), 5-amino-2-(p-bromophenyl)benzoxazole (5), 5-nitro-2-phenoxymethyl-benzimidazole (18), 2-(p-chlorobenzyl)benzoxazole (10) and 5-amino-2-phenylbenzoxazole (2) were found to be more potent as eukaryotic DNA topoisomerase I poisons than the reference drug camptothecin having IC(50) values of 14.1, 132.3, 134.1, 248, 443.5, and 495 microM, respectively. 5-Chloro-2-(p-methylphenyl)benzoxazole (4), 2-(p-nitrobenzyl)benzoxazole (6) and 5-nitro-2-(p-nitrobenzyl)benzoxazole (8) exhibited significant activity as eukaryotic DNA topoisomerase II inhibitors, having IC(50) values of 22.3, 17.4, 91.41 microM, respectively, showing higher potency than the reference drug etoposide.
Oksuzoglu
Emine
E
Molecular Biology Department, Hacettepe University, Ankara, Beytepe, Turkey.
Tekiner-Gulbas
Betul
B
Alper
Sabiha
S
Temiz-Arpaci
Ozlem
O
Ertan
Tugba
T
Yildiz
Ilkay
I
Diril
Nuran
N
Sener-Aki
Esin
E
Yalcin
Ismail
I
D001562:Benzimidazoles / Q000494:pharmacology*; D001583:Benzoxazoles / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005047:Etoposide / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D013329:Structure-Activity Relationship; D059004:Topoisomerase I Inhibitors; D059005:Topoisomerase II Inhibitors
D001562:Benzimidazoles; D001583:Benzoxazoles; D004791:Enzyme Inhibitors; D059004:Topoisomerase I Inhibitors; D059005:Topoisomerase II Inhibitors; D005047:Etoposide