Abstract
The perennial herb, Humulus japonicus, has been previously described as possessing potential antituberculosis and anti-inflammatory properties. In the present study, the anti-aging activity of ethanol extracts from the leaves of H. japonicus (HJE) was evaluated in yeast and human fibroblast cells. In addition, the antioxidant activity of HJE was analyzed using free radical scavenging assays. Furthermore, the mechanism underlying the hypothesized HJE-associated extension of lifespan was investigated, and the results indicated that HJE was able to extend the lifespan of yeast cells. Further experiments demonstrated that HJE upregulated the longevity-associated proteins, sirtuin 1 and AMP-activated protein kinase, and effectively inhibited the generation of reactive oxygen species (ROS). In addition, the antioxidative potential of the active constituents of HJE, including luteolin, luteolin 7-glycoside, quercetin and quercitrin, was evaluated and the results demonstrated that these flavonoids were able to scavenge ROS in cell-free and intracellular systems. In summary, the results revealed that HJE possessed the potential for antioxidative activity; however, further in vivo investigations are required with the aim of developing safe, high-efficacy anti-aging agents.