Effect of Valerian/Hop Mixture on Sleep-Related Behaviors in Drosophila melanogaster

Biol Pharm Bull. 2017;40(7):1101-1110. doi: 10.1248/bpb.b17-00262.


The aim of this study was to investigate the sleep-promoting effect of a Valerian/Hops mixture in fruit flies. The HPLC analysis showed that Valerenic acid (1260.53 µg/g of extract) and Xanthohumol (Cascade: 827.49 µg/g, Hallertau: 763.60 µg/g, Saaz: 186.93 µg/g) were contained in Valerian and Hop, respectively. The sleep patterns of fruit flies on the Valerian/Hops were examined in both baseline and caffeine-treated conditions. Total activities of flies significantly decreased in 20 mg/mL Valerian (74%), 10 mg/mL Cascade (25%), and 5 mg/mL Hallertau (11%) during nighttime or daytime compared with the control. Valerian/Cascade mixture showed longer sleeping time (ca. 20%) than control group. This mixture-mediated effect was partly observed in caffeine-treated flies. Valerian/Cascade mixture upregulated mRNA expressions of gamma-aminobutyric acid (GABA) receptors and serotonin receptor, and GABA receptors were more strongly regulated than serotonin receptor. In competitive GABA receptor binding assay, Valerian/Cascade mixture extract showed a higher binding ability on GABA receptor than Valerenic acid or/and Xanthohumol which are estimated to be active compounds in the extract. This study demonstrates that a Valerian/Cascade mixture extract improves sleep-related behaviors, including sleeping time, by modulating GABAergic/serotonergic signaling.

Keywords: Drosophila melanogaster; Hop; Valerian; insomnia; sleep-promotion.

MeSH terms

  • Animals
  • Drosophila melanogaster / physiology*
  • Humulus*
  • Protein Binding
  • RNA, Messenger / genetics
  • Receptors, GABA / genetics
  • Receptors, GABA / metabolism
  • Receptors, Serotonin / genetics
  • Receptors, Serotonin / metabolism
  • Sleep*
  • Up-Regulation
  • Valerian*


  • RNA, Messenger
  • Receptors, GABA
  • Receptors, Serotonin