Aqueous and Ethanolic Valeriana officinalis Extracts Change the Binding of Ligands to Glutamate Receptors

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.

Valerian treatment during the postpartum period alters breast milk composition and impairs long-term memory in female rat offspring

Maternal anxiety symptoms in the perinatal period might have long-term health effects on both the mother and the developing child. Valerian is a phytotherapeutic agent that is widely used for the treatment of anxiety. This study investigated the effects of valerian treatment in postpartum rats on maternal care, toxicity, and milk composition. Postnatal development, memory, and anxiety behavior in the offspring were also assessed. Postpartum Wistar rats received the valerian (500, 1000, or 2000 mg·kg-1·day-1) by oral gavage. Clinical and biochemical toxicity was evaluated with commercial kits. Maternal behavior was observed daily. Milk composition was analyzed by colorimetric methods. Physical and neuromotor tests were used to analyze postnatal development. Anxiolytic activity was assessed by the elevated plus maze, and memory was evaluated by the step-down inhibitory avoidance task. Maternal toxicity and care behavior were not altered by the treatment, while only the highest dose promoted a significant increase of lactose, and the doses 1000 and 2000 mg·kg-1·day-1 promoted a reduction of protein contents in milk. Postnatal development was similar in all offspring. Adult offspring did not display altered anxiety behavior, while long-term memory was impaired in the female adult offspring by maternal treatment with 1000 mg·kg-1·day-1. These results suggested that high doses of valerian had significant effects on important maternal milk components and can cause long-term alterations of offspring memory; thus, treatment with high doses of valerian is not safe for breastfeeding Wistar rat mothers.

Effects of Zinc, Mercury, or Lead on [3H]MK-801 and [3H]Fluorowillardiine Binding to Rat Synaptic Membranes

Glutamate (Glu) is considered the most important excitatory amino acid neurotransmitter in the mammalian Central Nervous System. Zinc (Zn) is co-released with Glu during synaptic transmission and interacts with Glutamate receptors and transporters. We performed binding experiments using [³H]MK-801 (NMDA), and [³H]Fluorowillardine (AMPA) as ligands to study Zn-Glutamate interactions in rat cortical synaptic membranes. We also examined the effects of mercury and lead on NMDA or AMPA receptors. Zinc at 1 nM, significantly potentiates [³H]MK-801 binding. Lead inhibits [³H]MK-801 binding at micromolar concentrations. At millimolar concentrations, Hg also has a significant inhibitory effect. These effects are not reversed by Zn (1 nM). Zinc displaces the [³H]FW binding curve to the right. Lead (nM) and Hg (μM) inhibit [³H]FW binding. At certain concentrations, Zn reverses the effects of these metals on [³H]FW binding. These specific interactions serve to clarify the role of Zn, Hg, and Pb in physiological and pathological conditions.

Plant Species of Sub-Family Valerianaceae-A Review on Its Effect on the Central Nervous System

Valerianaceae, the sub-family of Caprifoliaceae, contains more than 300 species of annual and perennial herbs, worldwide distributed. Several species are used for their biological properties while some are used as food. Species from the genus Valeriana have been used for their antispasmodic, relaxing, and sedative properties, which have been mainly attributed to the presence of valepotriates, borneol derivatives, and isovalerenic acid. Among this genus, the most common and employed species is Valerianaofficinalis. Although valerian has been traditionally used as a mild sedative, research results are still controversial regarding the role of the different active compounds, the herbal preparations, and the dosage used. The present review is designed to summarize and critically describe the current knowledge on the different plant species belonging to Valerianaceae, their phytochemicals, their uses in the treatment of different diseases with particular emphasis on the effects on the central nervous system. The available information on this sub-family was collected from scientific databases up until year 2020. The following electronic databases were used: PubMed, Scopus, Sci Finder, Web of Science, Science Direct, NCBI, and Google Scholar. The search terms used for this review included Valerianaceae, Valeriana, Centranthus, Fedia, Patrinia, Nardostachys, Plectritis, and Valerianella, phytochemical composition, in vivo studies, Central Nervous System, neuroprotective, antidepressant, antinociceptive, anxiolytic, anxiety, preclinical and clinical studies.

Valeriana officinalis Root Extract Modulates Cortical Excitatory Circuits in Humans

BACKGROUND

Valeriana officinalis extract (VE) is a popular herbal medicine used for the treatment of anxiety and sleep disorders. Although the anxiolytic and sedative effects are mainly attributed to the modulation of GABA-ergic transmission, the mechanism of action has not been fully investigated in humans. Noninvasive brain stimulation protocols can be used to elucidate the mechanisms of action of psychoactive substances at the cortical level in humans. In this study, we investigated the effects of a single dose of VE on cortical excitability as assessed with transcranial magnetic stimulation (TMS).

METHODS

Fifteen healthy volunteers participated in a double-blind, randomized, cross-over, placebo-controlled study. Subjects were required to take either 900 mg of VE (valerenic acid 0.8%) or placebo (an equal dose of vitamin E). Motor cortex excitability was studied by single and paired TMS before and at 1 h and 6 h after the oral administration. Cortical excitability was assessed using different TMS parameters: resting motor threshold, motor-evoked potential amplitude, cortical silent period, short-interval intracortical inhibition, and intracortical facilitation. Furthermore, we assessed sensorimotor integration by short-latency and long-latency afferent inhibition.

RESULTS

We found a significant reduction in ICF, without any significant changes in other TMS measures of motor cortex excitability. The amount of ICF returned to baseline value 6 h after the intake of the VE.

CONCLUSION

A single oral dose of VE modulates intracortical facilitatory circuits. Our results in healthy subjects could be predictive markers of treatment response in patients and further support the use of pharmaco-TMS to investigate the neuropsychiatric effects of herbal therapies in humans.

Reversal of pentylenetetrazole-altered swimming and neural activity-regulated gene expression in zebrafish larvae by valproic acid and valerian extract

RATIONALE

Ethnopharmacology has documented hundreds of psychoactive plants awaiting exploitation for drug discovery. A robust and inexpensive in vivo system allowing systematic screening would be critical to exploiting this knowledge.

OBJECTIVE

The objective of this study was to establish a cheap and accurate screening method which can be used for testing psychoactive efficacy of complex mixtures of unknown composition, like plant crude extracts.

METHODS

We used automated recording of zebrafish larval swimming behavior during light vs. dark periods which we reproducibly altered with an anxiogenic compound, pentylenetetrazole (PTZ). First, we reversed this PTZ-altered swimming by co-treatment with a well-defined synthetic anxiolytic drug, valproic acid (VPA). Next, we aimed at reversing it by adding crude root extracts of Valeriana officinalis (Val) from which VPA was originally derived. Finally, we assessed how expression of neural activity-regulated genes (c-fos, npas4a, and bdnf) known to be upregulated by PTZ treatment was affected in the presence of Val.

RESULTS

Both VPA and Val significantly reversed the PTZ-altered swimming behaviors. Noticeably, Val at higher doses was affecting swimming independently of the presence of PTZ. A strong regulation of all three neural-activity genes was observed in Val-treated larvae which fully supported the behavioral results.

CONCLUSIONS

We demonstrated in a combined behavioral-molecular approach the strong psychoactivity of a natural extract of unknown composition made from V. officinalis. Our results highlight the efficacy and sensitivity of such an approach, therefore offering a novel in vivo screening system amenable to high-throughput testing of promising ethnobotanical candidates.

Valerenic acid and Valeriana officinalis extracts delay onset of Pentylenetetrazole (PTZ)-Induced seizures in adult Danio rerio (Zebrafish)

Background

Anticonvulsant properties have been attributed to extracts of the herbal medicine Valeriana officinalis. Our aims were to examine the anticonvulsant properties of valerenic acid and valerian extracts and to determine whether valerian preparations interact with the activity of other anti-epileptic drugs (phenytoin or clonazepam). To achieve these goals, we validated the adult zebrafish, Danio rerio, as an animal model for studying anticonvulsant drugs.

Methods

All drug treatments were administered by immersion in water containing the drug. For assays of anticonvulsant activity, zebrafish were pretreated with: anti-epileptic drugs, valerenic acid, aqueous or ethanolic valerian extracts, or mixtures (phenytoin or clonazepam with valerenic acid or valerian extracts). Seizures were then induced with pentylenetetrazole (PTZ). A behavioral scale was developed for scoring PTZ-induced seizures in adult zebrafish. The seizure latency was evaluated for all pretreatments and control, untreated fish. Valerenic acid and both aqueous and ethanolic extracts of valerian root were also evaluated for their ability to improve survival after pentylenetetrazole-challenge. The assay was validated by comparison with well-studied anticonvulsant drugs (phenytoin, clonazepam, gabapentin and valproate). One-way ANOVA followed by Tukey post-hoc test was performed, using a p < 0.05 level of significance. All treatments were compared with the untreated animals and with the other pretreatments.

Results

After exposure to pentylenetetrazole, zebrafish exhibited a series of stereotypical behaviors prior to the appearance of clonic-like movements—convulsions. Both valerenic acid and valerian extracts (aqueous and ethanolic) significantly extended the latency period to the onset of seizure (convulsion) in adult zebrafish. The ethanolic valerian extract was a more potent anticonvulsant than the aqueous extract. Valerenic acid and both valerian extracts interacted synergistically with clonazepam to extended the latency period to the onset of seizure. Phenytoin showed interaction only with the ethanolic valerian extracts.

Conclusions

Valerenic acid and valerian extracts have anticonvulsant properties in adult zebrafish. Valerian extracts markedly enhanced the anticonvulsant effect of both clonazepam and phenytoin, and could contribute to therapy of epileptic patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-015-0731-3) contains supplementary material, which is available to authorized users.

Valeriana officinalis root extract suppresses physical stress by electric shock and psychological stress by nociceptive stimulation-evoked responses by decreasing the ratio of monoamine neurotransmitters to their metabolites

Background

In this study, we investigate the effects of valerian root extracts (VE) on physical and psychological stress responses by utilizing a communication box.

Methods

Eight-week-old ICR mice received oral administration of VE (100 mg/kg/0.5 ml) or equal volume of distilled water in every day for 3 weeks prior to being subjected to physical or psychological stress for 3 days, which are induced by communication box developed for physical electric shock and psychological stress by nociceptive stimulation-evoked responses. The stress condition was assessed by forced swimming test and serum corticosterone levels. In addition, norepinephrine (NE), serotonin (5-HT), and their metabolites such as 3-methoxy-4-hydroxyphenylethyleneglycol sulfate (MHPG-SO₄) and 5-hydroxyindoleacetic acid (5-HIAA) were measured in the hippocampus and amygdala at 1 h after final stress condition, respectively.

Results

Immobility time and corticosterone levels were significantly increased in both the physical and psychological stress groups compared to the control group. The administration of VE significantly reduced these parameters in both the physical and psychological stress groups. In addition, compared to the control group, physical and psychological stress groups showed significantly increased levels of MHPG-SO₄ and 5-HIAA in the hippocampus and amygdala, respectively. The administration of VE significantly suppressed the increase of MHPG-SO₄ and 5-HIAA in the two stress groups.

Conclusion

These results suggest that VE can suppress physical and psychological stress responses by modulating the changes in 5-HT and NE turnover in the hippocampus and amygdala.