Antioxidant and Cellular Protective Effects against Oxidative Stress of Calendula officinalis Flowers Extracts in Human Skin Cells

In this study, we investigated the total phenolic and flavonoid contents, antioxidant activity and cellular protective effects against oxidative stress on human skin cells in 50% ethanol extract and its fractions of Calendula officinalis (C. officinalis) flowers. We measured the antioxidant effects of 50% ethanol extract and its fractions of C. officinalis flowers on the free radical scavenging activity (FSC50), the reactive oxygen species (ROS) scavenging activities (OSC50) and the inhibition of intracellular ROS generation in human skin cells. These results showed that the antioxidant effect of the ethyl acetate and aglycone fraction was more than the 50% ethanol extract of C. officinalis flowers. We also investigated the cellular protective activity and the results showed that treatment of the ethyl acetate fraction (0.05-3.13 mu g/mL) protects human skin cells in a concentration-dependent manner when the skin cell damages were induced by treating them with H2O2. In addition, the aglycone fraction (1.56-3.13 mu g/mL) shows cellular protective effects on the UV-induced cell damages in a dose-dependent manner. These results suggest that the fractions of C. officinalis flowers can function as a natural antioxidant agent of cosmetics in human skin cells exposed to oxidative stress by ROS scavenging effects.