Compounds 4a–f, 5a–f and 6–9, showed significant growth inhibition activity against human tumor cell lines. Of these compounds, 1-(2-((Z)-6-(2-(trifluoromethyl)phenyl)hexa-3-en-1,5-diynyl)phenyl)piperidin-2-one (8) displayed the most potent growth inhibition activity. Compound 8 also arrested cancer cells in G2/M phase and induced apoptosis via activation of caspase-3 and -9. According to western-blotting