Design, syntheses and biological evaluation of natural product aiphanol derivatives and analogues: Discovery of potent anticancer agents

The natural product aiphanol (1) is one of the substances with anticancer biological activity isolated from traditional Chinese medicines (TCM) Smilax glabra Roxb. (Tufuling). Our recent research found that aiphanol could suppress angiogenesis and tumor growth by dual-blocking VEGF/VEGFRs and COX2 signal pathway. In this study, four series of 40 aiphanol derivatives and analogues were designed, synthesized and evaluated for their anticancer activity. Among them, the analogues 10j and 14c exhibited the most potent inhibition and broad-spectrum antiproliferative activity toward nine tumor cell lines. The IC50 values of the analogues 10j and 14c range from 0.81 to 10 μmol/L which up to 80-fold vs. parent compound aiphanol. The structure–activity relationship (SAR) studies indicated that the substrate at 7-position of benzo 1,4-dioxane is very crucial for anticancer activity. Molecular docking indicated that the compound 14c (ent-14c) tightly binds to VEGFR2 and COX2, respectively. Therefore, compounds 10j and 14c could be promising candidates for the development of anticancer agents in the future.