Rare Ginsenoside 20(R)-Rg3 Inhibits D-Galactose-Induced Liver and Kidney Injury by Regulating Oxidative Stress-Induced Apoptosis

Oxidative stress is considered as a major factor in aging and exacerbates aging process through a variety of molecular mechanisms. D-galactose, a normal reducing sugar with high dose can cause the accumulation of reactive oxygen species (ROS) or stimulate free radical production indirectly by the formation of advanced glycation end products in tissues, finally resulting in oxidative stress. 20(R)-ginsenoside Rg3 (20(R)-Rg3), a major and representative component isolated from red ginseng (Panax ginseng C.A Meyer), has been shown to observably have an anti-oxidative effect. We thereby investigated the beneficial effects of 20(R)-Rg3 on D-galactose-induced oxidative stress injury and its underlying mechanisms. Our results showed that continuous injection of D-galactose with 800 mg/kg/ day for 8 weeks increased the levels of alanine aminotransferase (ALT) and blood urea nitrogen (BUN). However, such increases were attenuated by the treatment of 20(R)-Rg3 for 4 weeks. Meanwhile, 20(R)-Rg3 markedly inhibited D-galactose-caused oxidative stress in liver and kidney. The anti-oxidants, including catalase (CAT) and superoxide dismutase (SOD), were elevated in the mice from 20(R)-Rg3-treated group compared with that from D-galactose group. In contrast, a significant decrease in levels of cytochrome P450 E1 (CYP2E1) and the lipid peroxidation product malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) were observed in the 20(R)-Rg3-treated group. These effects were associated with a significant increase of AGEs. More importantly, 20(R)-Rg3 effectively attenuated D-galactose induced apoptosis in liver and kidney via restoring the upstream PI3K/AKT signaling pathway. Taken together, our study suggests that 20(R)-Rg3 may be a novel and promising anti-oxidative therapeutic agent to prevent aging-related injuries in liver and kidney.