Effectiveness of the Sleep Enhancement by Green Romaine Lettuce (<i>Lactuca sativa</i>) in a Rodent Model

Abstract

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 [ 3 H]-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.

Effects of Green Lettuce Leaf Extract on Sleep Disturbance Control in Oxidative Stress-Induced Invertebrate and Vertebrate Models

“…In previous studies, the sleep-enhancing activity of green romaine lettuce, a type of Lactuca sativa , was confirmed in a rat model [ 13 ]. In the pentobarbital-induced sleep test, romaine lettuce leaf extract reduced sleep latency and increased sleep time.…”

Sedative Effects of Latexes Obtained from Some Lactuca L. Species Growing in Turkey

“…The latexes were evaluated for lactucin-type guaianolides (lactucin, lactucopicrin, 11β,13-dihydrolactucin, and 11β,13-dihydrolactucopicrin), which are characteristic constituents of the Lactuca genus. According to the literature, these compounds have sedative effects, which have been shown in various studies and attempts have been made to prove this effect in both in vivo and in vitro experiments [4,15,16]. The constituents were separated using HPLC and quantified by a diode-array detector (DAD).…”

“…Sutrisna also reported significant analgesic, anti-inflammatory, antidepressant, and anti-coagulant properties and found that the 70% ethanolic extract of the leaves of L. sativa displayed a remarkable sedative effect [19]. Additionally, Kim et al showed that the 70% ethanolic extract of L. sativa enhanced sleeping time and acted via the GABAergic system [16].…”

“…In addition, the sleep-enhancing effects of lettuce were investigated, and the extracts of lettuce inhibited the binding of [3H]-flumazenil in a concentration-dependent manner and the affinity of both lactucin and lactucopicrin to gamma-aminobutyric acid (GABA)A-benzodiazepine (BDZ) receptor was 80.7% and 55.9%, respectively. Thus, lettuce extracts have been reported to act through a GABAergic mechanism to promote sleep [16].…”

“…Several studies on lactucin and its derivatives have confirmed that these compounds have sedative effects. In addition, it has been noted that lactucin and lactucopicrin are active substances that promote sleep, because they bind effectively to the GABA A receptor [15,16].…”