Synthesis of macrocyclic bisbibenzyl derivatives and their anticancer effects as anti-tubulin agents

Based on the core skeleton of the total synthesized bisbibenzyl marchantin C, riccardin D and plagiochin E, a series of brominated and aminomethylated derivatives of above three bisbibenzyls have been synthesized and their cytotoxic activity against KB, MCF-7 and PC3 cell lines has been preliminary evaluated. The bio-test results revealed that the brominated derivatives 21, 22, 24, 25 and 28 exhibited excellent antiproliferative activity, with IC50 value lower than their parent compounds. As a most potent microtubule depolymerization agent, compound 28 was found to arrest cells at the G2/M phase of the cell cycle as determined by the flow cytometry assay in PC3 cell line. The remarkable biological profile and novel structure of these bisbibenzyl derivatives make them possible as promising candidates for clinical development as chemotherapeutic agents.