Synthesis and Cytotoxicity Studies of Stilbene Long-Chain Fatty Acid Conjugates.

A series of 16 conjugates of the tubulin polymerization inhibitor combretastatin A4 (CA-4) and other functionally related stilbene with four 18-carbon fatty acids, namely, stearic, oleic, linoleic, and linolenic acids, have been synthesized in good yields. These new derivatives have been evaluated against the KB-3-1 (human epidermoid carcinoma), NCI-H460 (human lung cancer), HEK293 (human embryonic kidney), and MCF-7 (human breast adenocarcinoma) cell lines for antiproliferative activity, with the exhibited cytotoxic activities comparable with those of CA-4 and colchicine. Compounds 22 and 23, CA-4 conjugates of linoleic and linolenic acids, respectively, were determined to have exhibited the most active in vitro assays, with compound 23 exhibiting very similar activity to the parent compound against the NCI-H460 cell line. Our studies further delineated the structurally required Z-geometry of the stilbene moiety and that conjugation of the less active E-stilbenes with the most active fatty acid had minimal or no improvement in their respective activities.