Cytotoxic effects of new geranyl chalcone derivatives isolated from the leaves of Artocarpus communis in SW 872 human liposarcoma cells

Breadfruit (Artocarpus communis Moraceae) is cultivated in tropical and subtropical regions as a traditional starch crop and also has potential medicinal properties. The aim of this work was to study the in vitro anticancer activity of compounds isolated from the leaves of Artocarpus communis. Three new geranyl chalcone derivatives including isolespeol (1), 5′-geranyl- 2′,4′,4-trihydroxychalcone (2), and 3,4,2′,4′- tetrahydroxy-3′-geranyldihydrochalcone (3), together with two known compounds lespeol (4) and xanthoangelol (5), were isolated from the leaves of Artocarpus communis. The structures of 1-5 were elucidated by spectroscopy and through comparison with data reported in the literature. The effects of geranyl chalcone derivatives (1-5) on the viability of human cancer cells (including SW 872, HT-29, COLO 205, Hep3B, PLC5, Huh7, and HepG2 cells) were investigated. The results indicate that isolespeol (1) showed the highest inhibitory activity with an IC50 value of 3.8 μM in SW 872 human liposarcoma cells. Treatment of SW 872 human liposarcoma cells with isolespeol (1) caused the loss of mitochondrial membrane potential (ΔΨm). Western blotting revealed that isolespeol (1) stimulated increased protein expression of Fas, FasL, and p53. The expression ratios of pro- and antiapoptotic Bcl-2 family members were also changed by isolespeol (1) treatment to subsequently induce the activation of caspase-9 and caspase-3, which was followed by cleavage of poly (ADP-ribose) polymerase (PARP). These results demonstrate that isolespeol (1) induces apoptosis in SW 872 cells through Fas- and mitochondria-mediated pathways.