Synthesis and Cytotoxic Activity of the Products of Addition of Thiophenol to Sesquiterpene Lactones

Abstract

—Derivatives of sesquiterpene lactones modified at the lactone ring with a thiophenol residue have been synthesized. The resulting conjugates with thiophenol have capacity for the oxidation–elimination reaction by the action of ROS of a tumor cell with the release of initial cytotoxic lactones. It has been proposed to use the resulting sulfur-containing conjugates as ROS-activated prodrugs of sesquiterpene lactones. The antiproliferative properties of the conjugates have been examined on tumor and pseudonormal cell lines. The cytotoxicity of the conjugates is lower than that of parent lactones; however, in some cases, as with the conjugates of alantolactone with artemisiten, it remains moderate in all tumor cell lines tested.