Dihydroxylated 2,4-diphenyl-6-aryl pyridine derivatives were simply achieved using Claisen-Schmidt condensation reaction and modified Kröhnke pyridine synthetic method. Total forty-five compounds were designed and synthesized which contain hydroxyl groups at ortho, meta or para position of 2- and 4-phenyl rings attached to the central pyridine. They were evaluated for topoisomerase I and II inhibitory activity, and cytotoxicity against several human cancer cell lines for the development of novel antitumor agents. Most of the prepared compounds exhibited significant antiproliferative activity on human cancer cell lines, HCT15 and K562, as well as potent topo II inhibitory activity comparable to or stronger than etoposide. The structure-activity relationship demonstrated that compounds with hydroxyl group at meta or para position of 2-phenyl ring in combination with hydroxyl at ortho, meta or para position of 4-phenyl ring displayed the most potent topoisomerase II inhibitory activity and cytotoxicity. Positive correlation between topoisomerase II inhibition and cytotoxicity was obtained for several compounds (30, 35, 36, 40-45, 49, 54, 56). Compound 56 showed the most potent topoisomerase II inhibitory activity at low concentration and functioned as a topoisomerase poison like the mode of action of etoposide.
Keywords: Antitumor agents; Cytotoxicity; Dihydroxylated 2,4-diphenyl-6-aryl pyridine; Terpyridine bioisosteres; Topoisomerase poison.
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