Antioxidant and Lifespan Extending Property of Quercetin-3-O-dirhamnoside from Curcuma longa L. in Caenorhabditis elegans

Quercetin-3-O-alpha-L-rhamnopyranosyl(1 -> 2)-O-alpha-L-rhamnopyranoside (QDR) was isolated from the remaining underground parts of Curcuma longa after harvesting the medicinal parts, and the antioxidant activities in vitro and lifespan-extending effect of QDR were elucidated using the Caenorhabditis elegans model system. The 1,1-diphenyl-2-picrythydrazyl (DPPH) radical scavenging effect of QDR showed similar potent activities in comparison with vitamin C. QDR also showed strong superoxide quenching activities as measured by the riboflavin- and xanthine-originated superoxide quenching activities. QDR demonstrated potent lifespan extension of worms under normal culture condition. Subsequently, the protective effect of QDR on the stress conditions such as thermal and oxidative stresses was determined. In the case of heat stress, QDR-treated worms exhibited enhanced survival rate, as compared to control worms. In addition, QDR-fed worms lived longer than control worms under oxidative stress induced by paraquat. To verify the possible mechanism of QDR-mediated increased lifespan and stress resistance of worms, we investigated whether QDR might alter superoxide dismutase (SOD) activity and intracellular reactive oxygen species (ROS) levels. Our results showed that QDR was able to elevate SOD activity of worms and reduce intracellular ROS accumulation in a dose-dependent manner.