Antioxidative stress effects of Humulus japonicus extracts on neuronal PC12 cells

The objective of the current study was to assess the antioxidant activity of different solvents containing Humulus japonicus extract (HJE) and their antioxidant effects on neurons. H. japonicus ethanol extracts (HEEs) together with H. japonicus water extracts (HWEs) were generated via extraction of H. japonicus leaves with 30%, 50%, and 80% ethanol solutions under a hot water temperature of 121 degrees C. HEEs showed higher levels of bioactive compounds, such as total flavonoids and polyphenols, with stronger antioxidant activities in contrast to HWEs. HEE (80%) showed the highest content of bioactive compounds and antioxidant activity. Next, we used a H2O2-induced rat model of pheochromocytoma PC12 cells to investigate the antioxidant activity and cellular signal regulation of 80% HEEs. The results showed that HJEs resisted oxidative stress via MAPK and/or AKT-NRF2 and NF-kappa B signaling pathways and upregulated antioxidant enzymes such as SOD, catalase, HO-1, and OGG1, thereby reducing intracellular ROS levels. Further, HJE promoted neuronal survival by upregulating sirtuin 1 expression. This study provides evidence supporting the potential benefits of HJE in preventing oxidative stress in PC12 cells, suggesting its application as a promising functional food additive or therapeutic agent for the prevention and the treatment of oxidative stress-related neurodegenerative diseases.