Cinnamic acid derivatives can be found in plant material, and they possess a remarkable variety of biological
effects. In the present study, we have investigated the cytotoxic effects of representative cinnamic acid esters and amides.
The cytotoxicity was determined by MTT test on human cervix adenocarcinoma (HeLa), myelogenous leukemia (K562),
malignant melanoma (Fem-x), and estrogen-receptor-positive breast cancer (MCF-7) cells, versus peripheral blood mononuclear
cells (PBMCs) without or with the addition of the plant lectin phytohemaglutinin (PHA). The compounds tested
showed significant cytotoxicity (IC50s between 42 and 166 µM) and furthermore selectivity of these cytotoxic effects on
the malignant cell lines versus the PBMCs was also seen, especially when electron-withdrawing groups, such as a cyano
group (compound 5), were present on the aromatic rings of the alcohol or amine parts of the cinnamic acid derivatives.
The additional study on cell cycle phase distribution indicated that novel cinnamic acid derivatives inhibit cell growth by
induction of cell death. Thus, cinnamic acids derivatives represent important lead compounds for further development of