Synthesis and in Vitro Bioactivity of Polyunsaturated Fatty Acid Conjugates of Combretastatin A-4.

Combretastatin A-4 (CA-4) (1) is a plant-derived anticancer agent binding to the tubulin colchicine site. Polyunsaturated fatty acids (PUFAs) are readily taken up by cancer cells and have been used to improve cell targeting. In the present study, four CA-4-PUFA conjugates were synthesized by coupling combretastatin A-4 (1) with several polyunsaturated fatty acids. The conjugates (2a-d) were characterized using spectroscopic methods. Their cytotoxicity was evaluated against human breast cancer cells (MCF-7), and the inhibition of tubulin polymerization was determined in vitro. All conjugates influenced tubulin polymerization, with the arachidonic acid conjugate (2c) displaying cytotoxicity similar in potency to the natural product CA-4 (1).