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The ethylacetate fraction of Empetrum nigrum var. japonicum (ENE) was shown to reduce intracellular reactive oxygen species (ROS) generated by γ-radiation and activate antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), and gluthathion peroxidase (GPx). ENE protected cells against radiation-induced cellular DNA damage, membrane lipid peroxidation, and protein modification, which are the main points of radiation-induced damage. In addition, ENE recovered cell viability by inhibiting apoptosis after cells were treated with radiation. ENE treatment also reduced γ-radiation induced Bax, and caspase 9 and 3 expression in irradiated cells. However, irradiated cells with ENE recovered Bcl-2 expression, which was reduced by radiation. This anti-apoptotic effect of ENE was due to the inhibition of mitogen-activated protein kinase kinase-4 (MKK4/SEK1)-c-Jun NH2-terminal kinase (JNK) cascades induced by γ-radiation. In summary, these results suggest that ENE protects cells against γ-radiation-induced oxidative stress via the reduction of ROS and attenuation of apoptosis. [ABSTRACT FROM AUTHOR]

We investigated the molecular effects of 3,4,2',4'-tetrahydroxychalcone (butein) treatment in two human hepatoma cancer cell lines-HepG2 and Hep3B. Butein treatment inhibited cancer cell growth by inducing G(2)/M phase arrest and apoptosis. Butein-induced G(2)/M phase arrest was associated with increased ATM, Chk1, and Chk2 phosphorylations and reduced cdc25C levels. Additionally, butein treatment enhanced inactivated phospho-Cdc2 levels, reduced Cdc2 kinase activity, and generated reactive oxygen species (ROS) that was accompanied by JNK activation. The extent of butein-induced G(2)/M phase arrest significantly decreased following pretreatment with N-acetyl-l-cysteine or glutathione and following JNK phosphorylation reduction by SP600125. Both N-acetyl-l-cysteine and glutathione also decreased butein-mediated apoptosis. Taken together, these results imply a critical role of ROS and JNK in the anticancer effects of butein. [ABSTRACT FROM AUTHOR]