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Cancer rates are increasing dramatically, and there is currently a strong emphasis on identifying biologically active substances with anti-cancer activity from traditional herbs, as these are thought to have less adverse side-effects than conventional chemotherapy. Here, we examined the effects of extracts of Orostachys japonicus A. BERGER (O. japonicus) on cancer cell proliferation and apoptosis, and investigated the underlying signaling pathways. Dried powdered O. japonicus was extracted with 95% ethyl alcohol and fractionated with a series of organic solvents, including n-hexane (hexane), dichloromethane (DCM), ethylacetate (EtOAc), n-butanol (BuOH), and water (H 2 O). These extracts were tested for anti-cancer activity on a range of cancer cells; of all these, the EtOAc soluble fraction showed the highest anti-cancer activity, which was most marked in AGS human gastric cancer cells. The EtOAc fraction inhibited the proliferation of AGS cells in a dose-dependent and time-dependent manner, by inducing apoptosis and cell cycle arrest, as evidenced by 4,6-diamidino-2-phenylindole (DAPI) staining, annexin V-fluorescein isothiocyanate staining, propidium iodide-labeling, and DNA fragmentation assays. Western blot analysis revealed that p53 and cleaved caspase-3 proteins were up-regulated, and B cell lymphoma-2 (bcl-2) protein and pro-caspase-3 were down-regulated, but bcl-2 associated x protein (bax) protein was not regulated, in response to treatment of AGS cells with the EtOAc fraction. However, the changes of pro-caspase-3 and cleaved caspase-3 could be abolished by the pancaspase inhibitor Z-VAD-FMK. These results suggest the EtOAc fraction from O. japonicus has substantial anti-cancer activity in human gastric cancer cells.

Orostachys japonicus shows various biological activities. However, the molecular mechanisms remain unknown in LPS-stimulated macrophages. Here, we investigated the anti-oxidizing effect of the dichloromethane (DCM) and hexane fractions from O. japonicus (OJD and OJH) against oxidative stress in RAW 264.7 cells stimulated by LPS. OJD and OJH significantly increased the expression of heme oxygenase-1 (HO-1) in a dose- and time-dependent manner. Additionally, it was found that the expression of HO-1 was stimulated by Nrf2 activated via degradation of Keap1. ERK and p38 inhibitors repressed HO-1 induced by OJD and OJH in LPS-stimulated cells, respectively. In conclusion, these results suggest that OJD and OJH may block oxidative damage stimulated by LPS, via increasing the expression of HO-1 and Nrf2, and MAPK signaling pathway. [BMB Reports 2014; 47(2): 98-103]

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