Design, Synthesis and Structure-Activity Relationship Studies of Glycosylated Derivatives of Marine Natural Product Lamellarin D

Lamellarin D, a marine natural product, acts as a potent inhibitor of DNA topoisomerase I (Topo I). To modify its physicochemical property and biological activity, a series of mono- and di-glycosylated derivatives were designed and synthesized through 22–26 multi-steps. Their inhibition of human Topo I was evaluated, and most of the glycosylated derivatives exhibited high potency in inhibiting Topo I activity as well as lamellarin D. All the 15 target compounds were evaluated for their cytotoxic activities against five human cancer cell lines. The typical lamellarin derivative ZL−3 exhibited the best activity with IC50 values of 3 nM, 10 nM, and 15 nM against human lung cancer A549 cells, human colon cancer HCT116 cells and human hepatocellular carcinoma HepG2 cells. Compound ZL−1 exhibited anti-cancer activity with IC50 of 14 nM and 24 nM against human colon cancer HCT116 cells and human hepatocellular carcinoma HepG2 cells, respectively. Cell cycle analysis in MDA-MB-231 suggested ZL−3 inhibited cell growth through arresting cells at the G2/M phase of the cell cycle. Further tests showed a significant improvement in aqueous solubility of ZL−1 and ZL−7. This study suggested that glycosylation could be utilized as a useful strategy to optimize lamellarin D derivatives as Topo I inhibitors and anticancer agents.