Synthesis and in vitro antitumor evaluation of dihydroartemisinin-cinnamic acid ester derivatives.

To explore novel high efficiency and low toxicity antitumor agents, a series of dihydroartemisinin-cinnamic acid ester derivatives modified on C-12 and/or C-9 position (s) were synthesized and the in vitro antitumor activities against PC-3, SGC-7901, A549 and MDA-MB-435s cancer cell lines were assessed. The hybrids (3-36) were prepared by esterification of 9α-hydroxyl-dihydroartemisinin (9α-OH DHA), the biotransformation product of dihydroartemisinin (DHA), and cinnamic acid derivatives. Compound 17 (IC50 = 0.20 μM) was the most potent anti-proliferative agent against the human lung carcinoma A549 cells, although it displayed low cytotoxicity on normal hepatic L-02 cells. The mechanism of action of compound 17 was further investigated by analysis of cell apoptosis and intracellular ROS generation. The results indicated that both ROS and ferrous ion contributed to the compound 17-induced cell death. Meanwhile, high intracellular ferrous ion and endogenous oxidative stress in A549 cells made them easier to suffer to compound 17-induced apoptosis. Our promising findings indicated the compound 17 could stand as drug candidate against lung cancer for further investigation.