This study investigated the effect of ethanol-extracted green lettuce leaf (GLE) on sleep behavior in physical stress-induced invertebrate and vertebrate models. In Drosophila melanogaster, the group that experienced vibration stress showed decreased sleep time compared to the no-vibration-stress control group, but the GLE treatment group recovered this lost sleep time. The GLE group also recovered the gene expression of downregulated superoxide dismutase induced by vibration stress conditions. According to electroencephalography analysis of rats, non-rapid eye movement (NREM) sleep significantly decreased with a decrease in sleep time for the group in which immobilization stress was induced. In the GLE group (120 mg/kg), the change in sleep pattern caused by stress was restored, and NREM sleep increased by 68.8%, improving overall sleep quality. In addition, GLE upregulated the expression levels of oxidation-related factors and γ-aminobutyric acid (GABAA) receptor. Quercetin-3-glucuronide (Q3G) was evaluated as a sleep-promoting active substance contained in GLE using the pentobarbital-induced sleep test and showed the effect of prolonged sleep time. Q3G inhibited [3 H]-flumazenil binding in a concentration-dependent manner with GLE. Taken together, the results indicate that GLE effectively binds to the GABAA receptor to promote sleep, demonstrating the potential of Q3G as an active substance.
Bibliographical noteFunding Information:
Funding: This work was supported by the Korea Institute of Planning and Evaluation for Technology in Food, Agriculture and Forestry (IPET) through the Useful Agricultural Life Resources Industry Technology Development Program, funded by the Ministry of Agriculture, Food and Rural Affairs (MAFRA) (121038-2).
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
- Drosophila melanogaster
- GABA receptor
- Green lettuce leaf extract
- Oxidative stress
ASJC Scopus subject areas
- Molecular Biology
- Clinical Biochemistry
- Cell Biology