Anticarcinogenic effects of products of heat-processed ginsenoside Re, a major constituent of ginseng berry, on human gastric cancer cells.

Ginsenoside Re is a triol type triterpene glycoside and is abundantly present in ginseng berry. In the present study, we verified that ginsenoside Re can be transformed into less-polar ginsenosides, namely, Rg2, Rg6, and F4, by heat-processing. The products of heat-processed ginsenoside Re inhibited phosphorylation of CDK2 at Thr160 by upregulation of p21 level, resulting in S phase arrest. The products of heat-processed ginsenoside Re also activated caspase-8, caspase-9, and caspase-3, followed by cleavage of PARP, a substrate of caspase-3, in a dose-dependent manner. Concurrently, alteration of mitochondrial factors such as Bcl-2 and Bax was also observed. Moreover, pretreatment with Z-VAD-fmk abrogated caspase-8, -9, and -3 activations by the products of heat-processed ginsenoside Re. We further confirmed that the anticancer effects of the products of heat-processed ginsenoside Re in AGS cells are mainly mediated via generation of less-polar ginsenosides Rg6 and F4.