Eui-Su Kim

Potential mechanism of kaempferol against Cu2+-induced oxidative stress through chelating activity and regulation of nuclear factorerythroid-2-related factor 2 signaling

Metal ions play important roles in various biological processes of living systems. However, the generation of reactive oxygen species (ROS) is also closely linked with the participation of redox-active metal ions such as copper, iron, chromium, and cobalt ions. Excessive production of ROS by redox-active metal ions can cause oxidative stress and further oxidative stress-related diseases. This study shows the results of the antioxidant activity of kaempferol in both ORACOH· and Cu2+-treated HepG2 cells. Preventive mechanism of kaempferol in Cu2+-treated HepG2 cells is also elucidated. These results suggest that both cellular Cu2+-chelating activity and expression of phase II detoxifying enzymes such as HO-1 and GSTA2 through activating Nrf2 are required for cellular antioxidant activity of kaempferol in Cu2+-treated HepG2 cells. Our findings provide the scientific evidence for the development of Nrf2 targeting dietary antioxidant to prevent oxidative stressrelated conditions.

Antimicrobial activity of epigallocatechin gallate from green tea (Camellia sinensis) on pathogenic Salmonella Enteritidis in braised quail eggs

The inhibitory effect of epigallocatechin gallate (EGCG), one of the antioxidants in green tea (Camellia sinensis), against Salmonella Enteritidis was evaluated in commercial braised quail eggs at two temperatures (4 and 25oC). Although S. Enteritidis was dose-dependently suppressed by EGCG in pure culture at 25oC, it was not inhibited in the sauce or eggs at this temperature. At low temperature (4oC), S. Enteritidis was inhibited in both the sauce and eggs by 400 μg/mL EGCG. Thus, EGCG at an appropriate concentration could be a useful food additive for inhibiting S. Enteritidis in braised quail eggs at low temperatures.