Effectiveness of the sleep enhancement by green romaine lettuce (Lactuca sativa) in a rodent model

Hyo Won Kim, Hyung Joo Suh, Hyeon Son Choi, Ki Bae Hong, Kyungae Jo

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


This study was conducted to investigate the effects of the extracts of green romaine lettuce (GRE) on sleep enhancement. GRE contains 1071.7 and 199.2 μg/g of extracts of lactucin and lactucopicrin, respectively, known as sleep enhancement substances. When 100 mg/kg of GRE was administered orally, sleep latency and duration time were significantly increased compared to controls (p < 0.05). Rapid eye movement (REM) sleep decreased with 100 mg/kg of GRE administration and non-REM (NREM) sleep also increased. There was no significant difference between REM and NREM among the oral GRE administration groups receiving 100, 120, and 160 mg/kg GRE. In the caffeine-induced insomnia model, total sleep time was significantly increased by 100 mg/kg GRE administration compared to the caffeine-treated group (p < 0.05). In addition, GRE inhibited the binding of [3H]-flumazenil in a concentration-dependent manner, and affinity of both lactucin and lactucopicrin to gamma-aminobutyric acid (GABA)A-benzodiazepine (BDZ) receptor was 80.7% and 55.9%, respectively. Finally, in the pentobarbital-induced sleep mouse model, the sleep enhancement effect of GRE was inhibited by flumazenil, an antagonist of BDZ. Thus, these results demonstrate that GRE acts via a GABAergic mechanism to promote sleep in a rodent model.

Original languageEnglish
Pages (from-to)1726-1732
Number of pages7
JournalBiological and Pharmaceutical Bulletin
Issue number10
Publication statusPublished - 2019


  • Electroencephalogram
  • Lactone
  • Lactuca sativa
  • Pentobarbital
  • Rodent model
  • Sleep

ASJC Scopus subject areas

  • Pharmacology
  • Pharmaceutical Science


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