Synthesis of gibberellin derivatives with anti-tumor bioactivities.

A series of gibberellin based molecules were designed and synthesized. Gibberellin derivatives bearing two alpha,beta-unsaturated ketone units showed strong anticancer activities in MTT assay towards a number of human cancer cell lines including HT29, A549, HepG2 and MKN28. The most potent gibberellin derivative (compound 10, IC(50)=2.9 microM against HT29) inhibited completely the topoisomerase I activity at 8 microg/mL level.