Cytotoxicity and DNA binding property of phenanthrene imidazole with polyglycol side chains

A series of phenanthrene imidazole with polyglycol side chain (2a-2c and 3a-3c) were synthesized and characterized by IR, NMR and MS. The cytotoxicity of 2a-2c and 3a-3c against cancer cell lines (HL-60, BGC-823, Bel-7402 and KB) in vitro were measured using MTT method. The DNA binding properties of 3a-3c were investigated by UV, fluorescence, CD spectroscopies and thermal denaturation. The results indicate that 2a exhibits higher cytotoxicity than cisplatin against BGC-823 and Bel-7402 cell lines, 3b and 3c exhibit higher cytotoxicity than 2b and 2c against BGC-823, Bel-7402 and KB cell lines. The cytotoxic effect of 2a-2c decrease with the increase of side chains length, the cytotoxic effect of 3a-3c increased with the increasing length of side chains against BGC-823, Bel-7402 and KB cell lines. Compounds 3a-3c intercalated DNA with a vertical orientation in the intercalation pocket. The binding constants of 3a-3c with Ct-DNA are 1.68 x 10(6), 1.51 x 10(6) and 0.709 x 10(6)M (1), respectively. The binding affinity of 3a-3c with Ct-DNA trended to decrease with the increasing length of polyglycol side chains. (c) 2012 Elsevier Ltd. All rights reserved.