Effects of kava-kava extract on the sleep-wake cycle in sleep-disturbed rats

The potential of Valeriana as a traditional Chinese medicine: traditional clinical applications, bioactivities, and phytochemistry

Valeriana plants are members of the Caprifoliaceae family, which include more than 200 species worldwide. We summarized previous reports on traditional clinical applications, bioactivities, and phytochemistry of Valeriana by searching electronic databases of Science Direct, Web of Science, PubMed, and some books. Some Valeriana species have been used as traditional medicines, demonstrating calming fright and tranquilizing mind, promoting Qi and blood, activating blood circulation and regulating menstruation, dispelling wind and eliminating dampness, regulating Qi-flowing to relieve pain, and promoting digestion and checking diarrhea, and treating diseases of the nervous, cardiovascular, and digestive systems, inflammation, gynecology, and others. Pharmacology studies revealed the effects of Valeriana, including sedative, hypnotic, antispasmodic, analgesic, antidepressant, anxiolytic, anticonvulsant, antiepileptic, neuroprotective, antibacterial, antiviral, cytotoxic, and antitumor effects as well as cardiovascular and cerebrovascular system improvements. More than 800 compounds have been isolated or identified from Valeriana, including iridoids, lignans, flavonoids, sesquiterpenoids, alkaloids, and essential oils. Constituents with neuroprotective, anti-inflammatory, cytotoxic, and sedative activities were also identified. However, at present, the developed drugs from Valeriana are far from sufficient. We further discussed the pharmacological effects, effective constituents, and mechanisms directly related to the traditional clinical applications of Valeriana, revealing that only several species and their essential oils were well developed to treat insomnia. To effectively promote the utilization of resources, more Valeriana species as well as their different medicinal parts should be the focus of future related studies. Clinical studies should be performed based on the traditional efficacies of Valeriana to facilitate their use in treating diseases of nervous, cardiovascular, and digestive systems, inflammation, and gynecology. Future studies should also focus on developing effective fractions or active compounds of Valeriana into new drugs to treat diseases associated with neurodegeneration, cardiovascular, and cerebrovascular, inflammation and tumors. Our review will promote the development and utilization of potential drugs in Valeriana and avoid wasting their medicinal resources.

Medicinal Plants for Insomnia Related to Anxiety: An Updated Review

Sleep disorders are common among the general population and can generate health problems such as insomnia and anxiety. In addition to standard drugs and psychological interventions, there are different complementary plant-based therapies used to treat insomnia and anxiety. This review aimed to find and examine the most recent research on the use of herbal medicines for treating anxiety and insomnia as compiled from clinical trials, as well as to assess the safety and efficacy of these medicines and to elucidate their possible mechanisms of action. The process entailed a search of PubMed, Scopus, and the Cochrane Library databases from 2010 to 2020. The search terms included "sleep disorder", "insomnia", "sedative", "hypnotic", "anxiety", "anxiolytic", and "clinical trial", combined with the search terms "herbs" and "medicinal plants", in addition to individual herbal medicines by both their common and scientific names. This updated review, which focuses mainly on clinical trials, includes research on 23 medicinal plants and their combinations. Essential oils and their associations have also been reviewed. The efficacy of medicinal plants depends on treatment duration, types of study subjects, administration route, and treatment method. More clinical trials with an adequate, standardized design are necessary, as are more preclinical studies to continue studying the mechanisms of action. As a result of our work, we can conclude that the 3 plants with the most potential are valerian, passionflower, and ashwagandha, with the combination of valerian with hops and passionflower giving the best results in the clinical tests.

Herbal Remedies and Their Possible Effect on the GABAergic System and Sleep

Sleep is an essential component of physical and emotional well-being, and lack, or disruption, of sleep due to insomnia is a highly prevalent problem. The interest in complementary and alternative medicines for treating or preventing insomnia has increased recently. Centuries-old herbal treatments, popular for their safety and effectiveness, include valerian, passionflower, lemon balm, lavender, and Californian poppy. These herbal medicines have been shown to reduce sleep latency and increase subjective and objective measures of sleep quality. Research into their molecular components revealed that their sedative and sleep-promoting properties rely on interactions with various neurotransmitter systems in the brain. Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter that plays a major role in controlling different vigilance states. GABA receptors are the targets of many pharmacological treatments for insomnia, such as benzodiazepines. Here, we perform a systematic analysis of studies assessing the mechanisms of action of various herbal medicines on different subtypes of GABA receptors in the context of sleep control. Currently available evidence suggests that herbal extracts may exert some of their hypnotic and anxiolytic activity through interacting with GABA receptors and modulating GABAergic signaling in the brain, but their mechanism of action in the treatment of insomnia is not completely understood.

Pharmacology of Herbal Sexual Enhancers: A Review of Psychiatric and Neurological Adverse Effects

Sexual enhancers increase sexual potency, sexual pleasure, or libido. Substances increasing libido alter the concentrations of specific neurotransmitters or sex hormones in the central nervous system. Interestingly, the same pathways are involved in the mechanisms underlying many psychiatric and neurological disorders, and adverse reactions associated with the use of aphrodisiacs are strongly expected. However, sexual enhancers of plant origin have gained popularity over recent years, as natural substances are often regarded as a safer alternative to modern medications and are easily acquired without prescription. We reviewed the psychiatric and neurological adverse effects associated with the consumption of herbal aphrodisiacs Areca catechu L., Argemone Mexicana L., Citrus aurantium L., Eurycoma longifolia Jack., Lepidium meyenii Walp., Mitragyna speciosa Korth., Panax ginseng C. A. Mey, Panax quinquefolius L., Pausinystalia johimbe (K. Schum.) Pierre ex Beille, Piper methysticum G. Forst., Ptychopetalum olacoides Benth., Sceletium tortuosum (L.) N. E. Brown, Turnera diffusa Willd. ex. Schult., Voacanga africana Stapf ex Scott-Elliot, and Withania somnifera (L.) Dunal. A literature search was conducted on the PubMed, Scopus, and Web of Science databases with the aim of identifying all the relevant articles published on the issue up to June 2020. Most of the selected sexual enhancers appeared to be safe at therapeutic doses, although mild to severe adverse effects may occur in cases of overdosing or self-medication with unstandardized products. Drug interactions are more concerning, considering that herbal aphrodisiacs are likely used together with other plant extracts and/or pharmaceuticals. However, few data are available on the side effects of several plants included in this review, and more clinical studies with controlled administrations should be conducted to address this issue.

Behavioral and physiological effects of acute and chronic kava exposure in adult zebrafish

Kava kava (Piper methysticum) is a medicinal plant containing kavalactones that exert potent sedative, analgesic and anti-stress action. However, their pharmacological effects and molecular targets remain poorly understood. The zebrafish (Danio rerio) has recently emerged as a powerful new model organism for neuroscience research and drug discovery. Here, we evaluate the effects of acute and chronic exposure to kava and kavalactones on adult zebrafish anxiety, aggression and sociality, as well as on their neurochemical, neuroendocrine and genomic responses. Supporting evolutionarily conserved molecular targets, acute kava and kavalactones evoked dose-dependent behavioral inhibition, upregulated brain expression of early protooncogenes c-fos and c-jun, elevated brain monoamines and lowered whole-body cortisol. Chronic 7-day kava exposure evoked similar behavioral effects, did not alter cortisol levels, and failed to evoke withdrawal-like states upon discontinuation. However, chronic kava upregulated several microglial (iNOS, Egr-2, CD11b), astrocytal (C3, C4B, S100a), epigenetic (ncoa-1) and pro-inflammatory (IL-1β, IL-6, TNFa) biomarker genes, downregulated CD206 and IL-4, and did not affect major apoptotic genes in the brain. Collectively, this study supports robust, evolutionarily conserved behavioral and physiological effects of kava and kavalactones in zebrafish, implicates brain monoamines in their acute effects, and provides novel important insights into potential role of neuroglial and epigenetic mechanisms in long-term kava use.

Medicinal Plants for Management of Insomnia: A Systematic Review of Animal and Human Studies

Insomnia is one of the most troubling sleep disorders and can be characterized by an inability to fall asleep and/or inadequate sleep duration and/or waking up multiple times during the night. Herbal medicine has been used to treat a range of sleep disorders for centuries. This study aimed to review medicinal plants investigated experimentally or clinically for sleep disorders, as well as their potential mechanisms of action and active components. Electronic databases and literature were systematically investigated to assess all in vitro and in vivo trials and clinical evidence of the efficacy and potential mechanisms of actions playing major roles in sleep induction or insomnia treatment. Among many herbal studies and trials on insomnia, some showed no significant difference between herbal remedies and placebos. While others showed improvements in sleep parameters (sleep latency, total sleep, non-rapid eye movement (NREM) and rapid eye movement (REM) sleep duration, delta activity in NREM sleep, wakefulness anxiety-associated insomnia). In this study, in vitro, animal, and clinical studies investigating a variety of herbal treatments for insomnia were systematically reviewed. The mechanisms of action of herbal medicines in treating insomnia are mainly related to gamma-aminobutyric acid (GABA)-synthesizing and GABA-metabolizing enzymes that influenced sleep outcomes. Overall, herbal remedies were not associated with more benefits than nonbenzodiazepines, although side effects were less. The results suggest that herbs have some benefits in improving the quantity and quality of sleep and could be a promising alternative therapy.

Effects of the 5-HT(1A) Receptor Agonist Tandospirone on ACTH-Induced Sleep Disturbance in Rats

The aim of this study was to compare the effect of the serotonin (5-HT)1A receptor agonist tandospirone versus that of the benzodiazepine hypnotic flunitrazepam in a rat model of long-term adrenocorticotropic hormone (ACTH)-induced sleep disturbance. Rats implanted with electrodes for recording electroencephalogram and electromyogram were injected with ACTH once daily at a dose of 100 µg/rat. Administration of ACTH for 10 d caused a significant increase in sleep latency, decrease in non-rapid eye movement (non-REM) sleep time, and increase in wake time. Tandospirone caused a significant decrease in sleep latency and increase in non-REM sleep time in rats treated with ACTH. The effect of tandospirone on sleep patterns was antagonized by the 5-HT1A receptor antagonist WAY-100635. In contrast, flunitrazepam had no significant effect on sleep parameters in ACTH-treated rats. These results clearly indicate that long-term administration of ACTH causes sleep disturbance, and stimulating the 5-HT1A receptor by tandospirone may be efficacious for improving sleep in cases in which benzodiazepine hypnotics are ineffective.

Marine polyphenol phlorotannins promote non-rapid eye movement sleep in mice via the benzodiazepine site of the GABAA receptor

RATIONALE

In psychopharmacology, researchers have been interested in the hypnotic effects of terrestrial plant polyphenols and their synthetic derivatives. Phlorotannins, a marine plant polyphenol, could have potential as a source of novel hypnotic drugs.

OBJECTIVES

The effects of phlorotannins and major phlorotannin constituent eckstolonol on sleep-wake profiles in mice were evaluated in comparison with diazepam, and their hypnotic mechanism was also investigated.

METHODS

The effects of phlorotannin preparation (PRT) and eckstolonol orally given on sleep-wake profiles were measured by recording electroencephalograms (EEG) and electromyograms in C57BL/6N mice. Flumazenil, a GABAA-benzodiazepine (BZD) receptor antagonist, was injected 15 min before PRT and eckstolonol to reveal its hypnotic mechanism.

RESULTS

PRT administration (>250 mg/kg) produced a significant decrease in sleep latency and an increase in the amount of non-rapid eye movement sleep (NREMS). Eckstolonol significantly decreased sleep latency (>12.5 mg/kg) and increased the amount of NREMS (50 mg/kg). PRT and eckstolonol had no effect on EEG power density of NREMS. The hypnotic effects of PRT or eckstolonol were completely abolished by pretreatment with flumazenil.

CONCLUSIONS

We demonstrated that phlorotannins promote NREMS by modulating the BZD site of the GABAA receptor. These results suggest that phlorotannins can be potentially used as an herbal medicine for insomnia and as a promising structure for developing novel sedative-hypnotics.

Herbal Insomnia Medications that Target GABAergic Systems: A Review of the Psychopharmacological Evidence

Insomnia is a common sleep disorder which is prevalent in women and the elderly. Current insomnia drugs mainly target the γ-aminobutyric acid (GABA) receptor, melatonin receptor, histamine receptor, orexin, and serotonin receptor. GABA_A receptor modulators are ordinarily used to manage insomnia, but they are known to affect sleep maintenance, including residual effects, tolerance, and dependence. In an effort to discover new drugs that relieve insomnia symptoms while avoiding side effects, numerous studies focusing on the neurotransmitter GABA and herbal medicines have been conducted. Traditional herbal medicines, such as Piper methysticum and the seed of Zizyphus jujuba Mill var. spinosa, have been widely reported to improve sleep and other mental disorders. These herbal medicines have been applied for many years in folk medicine, and extracts of these medicines have been used to study their pharmacological actions and mechanisms. Although effective and relatively safe, natural plant products have some side effects, such as hepatotoxicity and skin reactions effects of Piper methysticum. In addition, there are insufficient evidences to certify the safety of most traditional herbal medicine. In this review, we provide an overview of the current state of knowledge regarding a variety of natural plant products that are commonly used to treat insomnia to facilitate future studies.

Neurobehavioral and toxicological activities of two potentially CNS-acting medicinal plants of Piper genus

Plants from the genus Piper are economically useful and some species have been indicated because of their medicinal properties in the central nervous system. However, few studies about toxicity and neurobehavioral effects have been conducted. In this study, two Piper species, P. amalago and P. mikanianum were investigated in rats to determine acute toxicity and to evaluate the ansiogenic/ansiolytic properties in the elevated plus-maze and the effects on locomotion and exploration in an open field. Additionally, genotoxic activities were evaluated, using the comet assay in several tissues and the micronucleus assay in bone marrow. The phytochemical analysis of both Piper species leaves suggests the presence of amide, essential oils, flavonoids and phenolic compounds. The LD(50) of P. amalago and P. mikanianum were estimated as 2,545 and 1,661 mg/kg, respectively. The behavioral and genotoxic parameters were determined after an intraperitoneal administration of P. amalago (250 or 420 mg/kg) or P. mikanianum (160 or 270 mg/kg). Both plants decreased the number of entries and time spent in the open arms in the plus-maze test, indicating an anxiogenic effect. Only P. mikanianum affected locomotion and exploration in the open field behavior test. No genotoxic or mutagenic effect was observed. Our results suggest that these Piper species act on the central nervous system, without induce genetic toxicity.

Hypnotic and sleep quality-enhancing properties of kavain in sleep-disturbed rats

The present study was performed to investigate the effects of kavain on the sleep-wake cycle in comparison with that of rilmazafone and diphenhydramine using sleep-disturbed rats. Electrodes for the electroencephalogram (EEG) and electromyogram (EMG) were implanted into Wistar rats. Total awake time, non-rapid eye movement (non-REM) sleep and rapid eye movement (REM) sleep were measured for 6 h. Kavain and rilmazafone showed a significant shortening in sleep latency, decreased awake time, and increased non-REM sleep time. On the other hand, significant shortening of the sleep latency was observed following the administration of diphenhydramine, while no effects were observed on the awake and non-REM sleep time. Moreover, kavain showed a significant increase in delta activity during non-REM sleep in sleep-disturbed rats, whereas a significant decrease in delta power during non-REM sleep was observed with rilmazafone. These results clearly indicate that kavain is a compound with not only hypnotic effects, but also sleep quality-enhancement effects.

Effects of histamine H1-antagonists on sleep-awake state in rats placed on a grid suspended over water or on sawdust

The present study was performed to investigate the effects of histamine H(1)-antagonists on the sleep-awake state in rats placed on a grid suspended over water in comparison with rats placed on sawdust. When rats were placed on the grid suspended over water, significant increases in the awake time and decreases in non-rapid eye movement (non-REM) sleep time were observed compared with in rats on sawdust, even when measured hourly for 6 h. Diphenhydramine, chlorpheniramine and promethazine caused a significant decrease in the awake time and increase in non-REM sleep time in rats placed on the grid suspended over water for 1-2 h and/or 2-3 h after administration. On the other hand, in rats placed on sawdust, no significant differences were observed in the awake time and non-REM sleep time with diphenhydramine and chlorpheniramine compared with the control. Different from these two drugs, promethazine caused a significant decrease in the awake time and increase in non-REM sleep time 1-2 h and 2-3 h after administration even when rats were placed on sawdust at a relatively high dose. These results clearly indicate that histamine H(1)-antagonists had potent effects on decreasing the awake time and increasing non-REM sleep time under the conditions of an activated histaminergic system.

Potential medicinal plants for CNS disorders: an overview

Although very few drugs are currently approved by regulatory authorities for treating multi-factorial ailments and disorders of cognition such as Alzheimer's disease, certain plant-derived agents, including, for example, galantamine and rivastigmine (a semi-synthetic derivative of physostigmine) are finding an application in modern medicine. However, in Ayurveda, the Indian traditional system of medicine which is more than 5000 years old, selected plants have long been classified as 'medhya rasayanas', from the Sanskrit words 'medhya', meaning intellect or cognition, and 'rasayana', meaning 'rejuvenation'. These plants are used both in herbal and conventional medicine and offer benefits that pharmaceutical drugs lack. In the present article, an attempt has been made to review the most important medicinal plants, including Ginkgo biloba, St John's wort, Kava-kava, Valerian, Bacopa monniera and Convolvulus pluricaulis, which are widely used for their reputed effectiveness in CNS disorders.

Effects of some H1-antagonists on the sleep-wake cycle in sleep-disturbed rats

The present study was undertaken to investigate the effects of some H(1)-antagonists on the sleep-wake cycle in sleep-disturbed rats in comparison with those of nitrazepam. Electrodes were chronically implanted into the frontal cortex and the dorsal neck muscle of rats for the electroencephalogram (EEG) and electromyogram (EMG), respectively. EEG and EMG were recorded with an electroencephalograph. SleepSign ver. 2.0 was used for EEG and EMG analysis. The total times of waking, non-rapid eye movement (non-REM), and rapid eye movement (REM) sleep were measured from 10:00 to 16:00. Nitrazepam showed a significant decrease in sleep latency, total waking time, and delta activity and an increase in the total non-REM sleep time. A significant decrease in the sleep latency was observed with diphenhydramine, chlorpheniramine, and cyproheptadine. Cyproheptadine also caused a significant decrease in the total waking time and increases in total non-REM sleep time, REM sleep time, slow wave sleep, and delta activity, although no remarkable effects were observed with diphenhydramine and chlorpheniramine. In conclusion, cyproheptadine can be useful as a hypnotic, having not only sleep inducing-effects, but also sleep quantity- and quality-increasing effects.