Ammonium glycyrrhizinate protects gastric epithelial cells from hydrogen peroxide-induced cell death.

Glycyrrhiza uralensis has a potential for preventing or ameliorating gastric mucosal ulceration. To understand the molecular mechanism about the medicinal effect of G. uralensis, we isolated four single compounds from G. uralensis and one related compound and screened for the cellular protective effect against H2O2-induced damage in gastric epithelial AGS cells. Interestingly, we found that ammonium glycyrrhizinate (AG) prepared from glycyrrhizin dramatically protects AGS cells from H2O2-induced damage as measured by the integrity of actin cytoskeleton. AG also inhibited FeSO4-induced reactive oxygen radicals in a dose-dependent manner, suggesting the role for AG as a free radical scavenger. To better understand the protective role of AG at the transcriptional level, we performed genome-wide expression profiling using high-density oligonucleotide microarrays, followed by validation using RT-PCR. Among the 33,096 genes that were screened in the microarray, 936 genes were found to be differentially expresse...