Natural Products from Single Plants as Sleep Aids: A Systematic Review

Lactuca sativa L. Extract Enhances Sleep Duration Through Upregulation of Adenosine A1 Receptor and GABAA Receptors Subunits in Pentobarbital-Injected Mice

We investigated the effects of Lactuca sativa L. extracts (Lactuc) on pentobarbital-induced sleep in mice to elucidate the mechanisms underlying its impact on sleep quality. Mice were randomly assigned to five groups: control, positive control (diazepam 2 mg/kg b.w.), and three groups orally administered with Lactuc (50, 100, and 200 mg/kg b.w.). After 2 weeks of oral administration and intraperitoneal injections, the mice were killed. We found that the Lactuc-administered groups had significantly reduced sleep latency and increased sleep duration compared with the control group. Furthermore, the oral administration of Lactuc induced a significant increase in mRNA expression and protein expression of adenosine A1 receptor in the brains compared with the expressions in the control group. In addition, the Lactuc-administered groups exhibited significantly higher levels of mRNA expressions of GABAA receptors subunits α2, β2, γ1, and, γ2 in the brain tissue. Therefore, we suggest that Lactuc could be used to develop natural products that effectively improve sleep quality and duration.

Protocol for a randomized controlled trial evaluating the effect of Hibiscus syriacus L. flower extract on sleep quality

Introduction

Hibiscus syriacus L. flower (HSF) is a food ingredient commonly used for tea, and previous animal studies have reported its sleep-promoting effect. This study aims to test the potential of HSF extract as functional food that improves sleep in humans.

Methods and analysis

Eighty participants with sleep disturbances who meet the inclusion/exclusion criteria will be enrolled in this study. Since the effect of HSF extract on sleep is considered to be that of a functional food rather than a medicine, participants with severe insomnia will be excluded from the study. The enrolled participants will be randomly assigned to the HSF extract or placebo groups in a 1:1 ratio. The HSF extract and placebo capsules will look identical, and participants, investigators, and outcome assessors will be blinded to the allocation. Four capsules of HSF extract or placebo will be orally administered 30-60 min before bedtime for 4 weeks. The primary outcome of this study will be the change in the Pittsburgh Sleep Quality Index (PSQI) global score from the baseline after 4 weeks. The subjective and objective changes in the participants' sleep will be evaluated using the Insomnia Severity Index (ISI), Epworth Sleep Scale (ESS), sleep diary, and polysomnography (PSG). The occurrence of adverse events will be closely monitored.

Discussion

The results of this trial will provide data on the efficacy and safety of HSF extract in enhancing sleep quality. Based on the results, the potential of HSF extract as a functional food that improves sleep in humans will be evaluated, and the findings of the trial will be submitted to the Korean Ministry of Food and Drug Safety for consideration as a new functional ingredient that may help to improve sleep quality.

Clinical trial registration

: Clinical Research Information Service: KCT0007314; Registered 19 May 2022, https://cris.nih.go.kr/cris/search/detailSearch.do/21497.

Sleep-promoting activity of lotus (Nelumbo nucifera) rhizome water extract via GABAA receptors

CONTEXT

The sleep-promoting activity of Nelumbo nucifera Gaertn. (Nymphaeaceae) alkaloids in leaves or seeds are well known. However, the sleep-promoting activity of the lotus rhizome (LE), which is used mainly as food, has not yet been evaluated.

OBJECTIVE

We investigated the sleep-promoting activity of LE water extract.

MATERIALS AND METHODS

Institute of Cancer Research (ICR) mice (n = 8) were subject to a pentobarbital-induced sleep test to assess changes in sleep latency and duration following the administration of LE (80-150 mg/kg). In addition, electroencephalography analysis was performed to determine the sleep quality after LE treatment as well as the sleep recovery effect of LE using a caffeine-induced insomnia SD rat model. Real-time PCR and western blot analysis were performed to investigate the expression of neurotransmitter receptors, and the GABA_A receptor antagonists were used for receptor binding analysis.

RESULTS

An oral administration of 150 mg/kg LE significantly increased sleep duration by 24% compared to the control. Furthermore, LE increased nonrapid eye movement (NREM) sleep by increasing theta and delta powers. In the insomnia model, LE increased sleep time by increasing NREM sleep. Moreover, treatment with picrotoxin and flumazenil decreased the sleep time by 33% and 23%, respectively, indicating an involvement of the GABA_A receptor in the sleep-enhancing activity of LE. The expression of GABA_A receptors and the concentration of GABA in the brain were increased by LE.

DISCUSSION AND CONCLUSIONS

The results suggest that the sleep-promoting activity of LE was via the GABA_A receptor. Collectively, these data show that LE may promote sleep.

Dietary Supplement Ingredients for Optimizing Cognitive Performance Among Healthy Adults: A Systematic Review

Background: Dietary supplements promoted for brain health and enhanced cognitive performance are widely available. Claims made for these products are directed not only to the elderly wishing to prevent or mitigate cognitive decline, but also young healthy populations looking to boost their cognitive performance. It is unclear whether these claims made on product bottles and through advertising match the science. Objectives: To explore the evidence on the efficacy and safety of single dietary supplement ingredients frequently marketed with claims of enhanced cognitive performance among healthy adults. Design: A systematic review. Results: Nine of 54 dietary supplement ingredients identified through a scoping review met the eligibility criteria with at least 3 published studies identified per ingredient, yielding 69 unique publications. Ingredients evaluated included Bacopa monnieri, choline, creatine, omega-3 fatty acids, Ginkgo biloba, ginseng, Rhodiola rosea, tyrosine, and valerian root, all in supplement form and compared with a placebo, at various serving sizes and durations of use. Conclusions: The low level of certainty in the state of the science, coupled with not always knowing what is in a dietary supplement product, make weighing risks and benefits difficult; these data hinder the ability to develop recommendations about using such ingredients for consumers interested in boosting their cognitive performance. Whereas certain trends regarding promising serving sizes or duration for use, are pointed to in this synthesis, when combined, studies are inconsistent and imprecise, and many are methodologically flawed. Potential solutions to address research gaps are offered, for future research next steps, which is needed to strengthen the evidence and inform decisions.

Study on the Sleep-Improvement Effects of Hemerocallis citrina Baroni in Drosophila melanogaster and Targeted Screening to Identify Its Active Components and Mechanism

Hemerocallis citrina Baroni (HC) is an edible plant in Asia, and it has been traditionally used for sleep-improvement. However, the bioactive components and mechanism of HC in sleep-improvement are still unclear. In this study, the sleep-improvement effect of HC hydroalcoholic extract was investigated based on a caffeine-induced insomnia model in Drosophila melanogaster (D. melanogaster), and the ultrahigh-performance liquid chromatography coupled with electrospray ionization quadrupole Orbitrap high-resolution mass spectrometry (UHPLC-ESI-Orbitrap-MS) and network pharmacology strategy were further combined to screen systematically the active constituents and mechanism of HC in sleep-improvement. The results suggested HC effectively regulated the number of nighttime activities and total sleep time of D. melanogaster in a dose-dependent manner and positively regulated the sleep bouts and sleep duration of D. melanogaster. The target screening suggested that quercetin, luteolin, kaempferol, caffeic acid, and nicotinic acid were the main bioactive components of HC in sleep-improvements. Moreover, the core targets (Akt1, Cat, Ple, and Sod) affected by HC were verified by the expression of the mRNA of D. melanogaster. In summary, this study showed that HC could effectively regulate the sleep of D. melanogaster and further clarifies the multi-component and multi-target features of HC in sleep-improvement, which provides a new insight for the research and utilization of HC.

Use of Plant-Derived Natural Products in Sleep Disturbances

Sleep disorders have a high prevalence both in the general population and especially in specific populations such older adults and oncologic patients. Impacting on quality of life, they often translate in drug prescription, with consequent increased risk of drug-drug interactions and adverse drug reactions. In the last years several products derived from plants have been developed with the aim of treating insomnia with lower risk of side effects. Despite several studies have been performed with this aim, the available evidence is inconclusive, and reviews summarizing the most recent evidences on the effectiveness of plant-derived products in treating insomnia are lacking.This narrative review aims at summarizing the evidences of the mechanism of action, effectiveness and safety of the most commonly used plant-derived products for the treatment of sleep disorders (Valerian, Lemon balm, Passionflower, Chamomile, Hops, and Jujube).

Optimisation and Validation of a Nutritional Intervention to Enhance Sleep Quality and Quantity

Background: Disturbed sleep may negatively influence physical health, cognitive performance, metabolism, and general wellbeing. Nutritional interventions represent a potential non-pharmacological means to increase sleep quality and quantity. Objective: (1) Identify an optimal suite of nutritional ingredients and (2) validate the effects of this suite utilising polysomnography, and cognitive and balance tests. Methods: The optimal and least optimal combinations of six ingredients were identified utilising 55 male participants and a Box–Behnken predictive model. To validate the model, 18 healthy, male, normal sleepers underwent three trials in a randomised, counterbalanced design: (1) optimal drink, (2) least optimal drink, or (3) placebo were provided before bed in a double-blinded manner. Polysomnography was utilised to measure sleep architecture. Cognitive performance, postural sway, and subjective sleep quality, were assessed 30 min after waking. Results: The optimal drink resulted in a significantly shorter sleep onset latency (9.9 ± 12.3 min) when compared to both the least optimal drink (26.1 ± 37.4 min) and the placebo drink (19.6 ± 32.0 min). No other measures of sleep, cognitive performance, postural sway, and subjective sleep quality were different between trials. Conclusion: A combination of ingredients, optimised to enhance sleep, significantly reduced sleep onset latency. No detrimental effects on sleep architecture, subjective sleep quality or next day performance were observed.

Update on Research and Practices in Major Sleep Disorders: Part II-Insomnia, Willis-Ekbom Disease (Restless Leg Syndrome), and Narcolepsy

PURPOSE

This review (Part II of a series on sleep disorders) presents an update of the characteristics, epidemiology, assessment, and latest management of insomnia, restless legs syndrome (Willis-Ekbom disease; RLS/WED), and narcolepsy. Insomnia, the most common sleep disorder and most prevalent of all psychological health disorders, is a problem of difficulty initiating and maintaining sleep and early morning awakenings. RLS/WED is characterized by a crawling sensation or urge to move the legs in the evening and nighttime. Narcolepsy is a sleep disorder that commonly results in chronic daytime sleepiness and cataplexy. Nonpharmacological management, which includes education, cognitive behavioral therapy, and complementary therapy, is used as primary or adjunctive to pharmacotherapy for the treatment of these disorders.

METHODS

This narrative review utilized medical databases such as PubMed to identify relevant English-language original and systematic review articles predominantly from peer-reviewed journals from 2012 to 2019. However, as background, findings from classic articles prior to 2012 were also included.

CLINICAL RELEVANCE

Assessment of sleep problems, excessive sleepiness, and difficulty performing activities or being productive should be routine in the care of all patients. Utilization of behavioral interventions, including cognitive behavioral therapy, in addition to education and sleep hygiene, can promote sleep quality. Management of insomnia, RLS/WED, and narcolepsy should include helping patients adjust to treatment, managing cataplexy triggers in narcolepsy, and initiating strategies to live with chronic illness to improve quality of life.