The result shows that NAC treatment completely blocks ginsenoside-Rh2-induced AMPK activation

(Fig. 5B) in HepG2 cells. These results indicate that AMPK activation is mediated by ginsenoside-Rh2-induced ROS generation. MAPKs are known to correlate with the pharmacological effects of ginsenosides. Ginsenoside-Rh2-induced late-phase activation of JNK is associated with the induction of apoptosis via the proteolytic dissociation of p21WAF/CIP1 from JNK1-containing complexes [29]. ERK activation inhibits ginseng metabolite, IH-901-induced apoptosis and cell cycle arrest, via COX-2 induction [30]. The antiproliferative effect of ginsenoside-Rg1 is involved in the inhibition of ERK in cultured human arterial vascular smooth muscle cell [31]. Thus, we next examined whether the MAPK pathway is associated with ginsenoside-Rh2-induced www.selleckchem.com/screening/epigenetics-compound-library.html apoptosis

Selleck BIBW2992 and the antiapoptotic effects of AMPK in HepG2 cells. As shown in Fig. 6A, ginsenoside-Rh2 induces the activation of three MAPKs in a time-dependent manner. To determine whether the activity of the three MAPKs was involved in ginsenoside-Rh2-induced apoptosis, HepG2 cells were pretreated with 20 μM PD98059, SB203580, and SP600152, a selective inhibitor of ERK, p38 MAPK, and JNK, respectively. Cotreatment with ginsenoside-Rh2 and SB203580 (p38 MAPK inhibitor) causes cell death to increase from 20% to 50%, compared with ginsenoside-Rh2 treatment alone, suggesting that the inhibition of p38 MAPK can enhance ginsenoside-Rh2-induced apoptosis in HepG2 cells. However, there was no observed effect of ERK or JNK inhibition on cell death. To examine whether there was a correlation between AMPK and p38 MAPK activity, we investigated AMPK and p38 MAPK activation following each kinase inhibition by compound C or SB203580. As shown in Fig. 6C, inhibition of AMPK did not affect p38

MAPK activity, and inhibition of p38 MAPK did not affect AMPK activity, either. Therefore, it is likely that AMPK and p38 MAPK transmit its signal in an independent manner. Ginseng, the root of P. ginseng, is a medicinal herb that has been reported to have various biological effects, including anticarcinogenic activities. Ginseng extracts induce apoptosis, and decrease telomerase activity and cyclooxygenase-2 Gefitinib (COX-2) expression in human leukemia cells [32]. In addition, ginseng extracts suppress colon carcinogenesis induced by 1,2-dimethylhydrazine with inhibition of cell proliferation [33]. Among them, ginsenoside-Rh2 is recognized as a major active anticancer saponin [34]. Ginsenoside-Rg3 is known to metabolize to ginsenoside-Rh2 by human intestinal bacteria [35]. In this regard, the anticancer activity of two compounds has been compared in many reports. In the case of Hep3B cells, these two compounds induce apoptosis through a mitochondrial pathway [36].