Alpha-Asarone, a Major Component of Acorus gramineus, Attenuates Corticosterone-Induced Anxiety-Like Behaviours via Modulating TrkB Signaling Process

Improvement in Testosterone Production by Acorus gramineus for the Alleviation of Andropause Symptoms

Acorus gramineus has a number of beneficial effects, including protective effects against age-related disorders. In this study, the effects of A. gramineus on testosterone production and andropause symptoms were evaluated. We first treated TM3 mouse Leydig cells, responsible for testosterone production, with A. gramineus aqueous extract at different concentrations. In TM3 cells, the testosterone concentration increased in a concentration-dependent manner compared with those in the control. In addition, at 400 μg/mL extract, the mRNA expression level of the steroidogenic enzyme CYP11A1 was increased. Subsequently, 23-week-old Sprague-Dawley (SD) rats exhibiting an age-related reduction in serum testosterone (approximately 80% lower than that in 7-week-old SD rats) were administered A. gramineus aqueous extract for 8 weeks. Serum total testosterone and free testosterone levels were higher and serum estradiol, prostate-specific antigen levels, and total cholesterol levels were lower in the AG50 group (A. gramineus aqueous extract 50 mg/kg of body weight/day) than in the OLD (control group). The AG50 group also showed significant elevations in sperm count, grip strength, and mRNA expression of StAR, CYP11A1, 17β-HSD, and CYP17A1 compared with those in the OLD group. In conclusion, A. gramineus aqueous extract facilitated steroidogenesis in Leydig cells, elevated testosterone levels, lowered serum estradiol and total cholesterol levels, and increased muscle strength and sperm count, thus alleviating the symptoms of andropause. These findings suggest that A. gramineus aqueous extract is a potentially effective therapeutic agent against various symptoms associated with andropause.

Corticosterone effects on postnatal cerebellar development in mice

Glucocorticoids administered early in infancy can affect the architectonic organization of brain structures, particularly those with a postnatal development and resulting in long-term deficits of neuromotor function and cognition. The present study was undertaken to study the effects of daily corticosterone (CORT) injections at a pharmacological dose from postnatal days 8-15 on cerebellar and hippocampal development in mouse pups. Gene expression status for trophic factors involved in synaptic development and function as well as measures of layer thickness associated with cytochrome oxidase labelling were analyzed in the hippocampus, hypothalamus, and specific cerebellar lobules involved in motor control. Repeated CORT injections dysregulated the HPA axis with increased Crh and Nr3c1 mRNA levels in the hypothalamus and a resulting higher serum corticosterone level. The CORT treatment altered the morphology of the hippocampus and down-regulated gene transcription for corticotropin-releasing hormone (Crh) and its type-1 receptor (Crhr1), glucocorticoid receptor (Nr3c1), and brain-derived neurotrophic factor Bdnf and its receptor Ntrk2 (neurotrophic receptor tyrosine kinase 2). Similar mRNA expression decreases were found in the cerebellum for Crhr1, Crhr2, Nr3c1, and Grid2 (glutamatergic δ2 receptor). Morphological alterations and metabolic activity variations were observed in specific cerebellar lobules involved in motor control. The paramedian lobule, normally characterized by mitotic activity in the external germinative layer during the second postnatal week, was atrophic but metabolically hyperactive in its granule cell and molecular layers. On the contrary, lobules with an earlier cell proliferation displayed neurogenesis but a hypoactivated granule cell layer, suggesting a developmental delay in synaptogenesis. The results indicate that glucocorticoid, administered daily during the second postnatal week modulated the developmental programming of the hippocampus and cerebellum. These growth and metabolic alterations may lead possibly to morphological and functional changes later in life.

β-asarone prolongs sleep via regulating the level of glutamate in the PVN

People of all ages could suffer from sleep disorders, which are increasingly recognized as common manifestations of neurologic disease. Acorus tatarinowii is a herb that has been used in traditional medicine to promote sleep. β-asarone, as the main component of volatile oil obtained from Acorus tatarinowii, may be the main contributor to the sleeping-promoting efficacy of Acorus tatarinowii. In the study, adult male C57BL/6 mice were administered β-asarone at 12.5 mg/kg, 25 mg/kg, and 50 mg/kg. Behavioral experiments showed that β-asarone at 25 mg/kg could significantly improve sleep duration. It was also observed that the proportion of NREM (Non-Rapid Eye Movement) sleep increased considerably after administration of β-asarone. In the PVN (paraventricular nucleus of hypothalamus) region of the hypothalamus, it was observed that the glutamate content decreased after β-asarone treatment. At the same time, the expression of VGLUT2 (vesicular glutamate transporters 2) decreased while the expression of GAD65 (glutamic acid decarboxylase 65) and GABARAP (GABA Type A Receptor-Associated Protein) increased in the hypothalamus, suggesting that β-asarone may suppress arousal by reducing glutamate and promoting transformation of glutamate to the inhibitory neurotransmitter GABA (γ-aminobutyric acid). This study is the first to focus on the association between β-asarone and sleep, shedding perspectives for pharmacological applications of β-asarone and providing a new direction for future research.

Sedative-hypnotic effects of Boropinol-B on mice via activation of GABAA receptors

OBJECTIVES

Boropinol-B is a phenylpropanoid compound originally isolated from Boronia pinnata Sm. (Rutaceae). This study aimed to evaluate the sedative-hypnotic effects of Boropinol-B and explore the underlying mechanisms.

METHODS

Pentobarbital sodium-induced sleep mouse model and caffeine-induced insomnia mouse model were used to investigate the sedative effects of Boropinol-B. Pharmacokinetics profiles of Boropinol-B in rats were evaluated by high-performance liquid chromatography. The effects of Boropinol-B on the γ-aminobutyric acid (GABA)ergic system were investigated using ELISA assay and patch-clamp technique. Immunohistochemistry and immunofluorescence were carried out to assess the effects of Boropinol-B on sleep-related brain nucleus.

KEY FINDINGS

Boropinol-B showed significant sedative effects, including reduced sleep latency, increased sleep duration in pentobarbital sodium-treated mice and decreased locomotor activity in insomnia mice. Pharmacokinetics studies demonstrated that Boropinol-B had a rapid onset of action, a short half-life and no accumulation. It increased the GABA level in mice's brain, and promoted chloride ions influx mediated by the γ-aminobutyric acid type A (GABAA) receptors in neurons. Also, it increased the c-Fos positive ratio of GABAergic neurons in ventrolateral preoptic nucleus and decreased c-Fos expression in tuberomammillary nucleus.

CONCLUSION

Boropinol-B showed significant sedative-hypnotic effects in mice by activating the GABAA receptors and stimulating the sleep-related brain nucleus.

Therapeutic Potential of Active Components from Acorus gramineus and Acorus tatarinowii in Neurological Disorders and Their Application in Korean Medicine

Neurological disorders represent a substantial healthcare burden worldwide due to population aging. Acorus gramineus Solander (AG) and Acorus tatarinowii Schott (AT), whose major component is asarone, have been shown to be effective in neurological disorders. This review summarized current information from preclinical and clinical studies regarding the effects of extracts and active components of AG and AT (e.g., α-asarone and β-asarone) on neurological disorders and biomedical targets, as well as the mechanisms involved. Databases, including PubMed, Embase, and RISS, were searched using the following keywords: asarone, AG, AT, and neurological disorders, including Alzheimer's disease, Parkinson's disease, depression and anxiety, epilepsy, and stroke. Meta-analyses and reviews were excluded. A total of 873 studies were collected. A total of 89 studies were selected after eliminating studies that did not meet the inclusion criteria. Research on neurological disorders widely reported that extracts or active components of AG and AT showed therapeutic efficacy in treating neurological disorders. These components also possessed a wide array of neuroprotective effects, including reduction of pathogenic protein aggregates, antiapoptotic activity, modulation of autophagy, anti-inflammatory and antioxidant activities, regulation of neurotransmitters, activation of neurogenesis, and stimulation of neurotrophic factors. Most of the included studies were preclinical studies that used in vitro and in vivo models, and only a few clinical studies have been performed. Therefore, this review summarizes the current knowledge on AG and AT therapeutic effects as a basis for further clinical studies, and clinical trials are required before these findings can be applied to human neurological disorders.

Advances in extraction methods, chemical constituents, pharmacological activities, molecular targets and toxicology of volatile oil from Acorus calamus var. angustatus Besser

Acorus calamus var. angustatus Besser (ATT) is a traditional herb with a long medicinal history. The volatile oil of ATT (VOA) does possess many pharmacological activities. It can restore the vitality of the brain, nervous system and myocardial cells. It is used to treat various central system, cardiovascular and cerebrovascular diseases. It also showed antibacterial and antioxidant activity. Many studies have explored the benefits of VOA scientifically. This paper reviews the extraction methods, chemical components, pharmacological activities and toxicology of VOA. The molecular mechanism of VOA was elucidated. This paper will serve as a comprehensive resource for further carrying the VOA on improving its medicinal value and clinical use.

Molecular Mechanisms and Therapeutic Potential of α- and β-Asarone in the Treatment of Neurological Disorders

Neurological disorders are important causes of morbidity and mortality around the world. The increasing prevalence of neurological disorders, associated with an aging population, has intensified the societal burden associated with these diseases, for which no effective treatment strategies currently exist. Therefore, the identification and development of novel therapeutic approaches, able to halt or reverse neuronal loss by targeting the underlying causal factors that lead to neurodegeneration and neuronal cell death, are urgently necessary. Plants and other natural products have been explored as sources of safe, naturally occurring secondary metabolites with potential neuroprotective properties. The secondary metabolites α- and β-asarone can be found in high levels in the rhizomes of the medicinal plant Acorus calamus (L.). α- and β-asarone exhibit multiple pharmacological properties including antioxidant, anti-inflammatory, antiapoptotic, anticancer, and neuroprotective effects. This paper aims to provide an overview of the current research on the therapeutic potential of α- and β-asarone in the treatment of neurological disorders, particularly neurodegenerative diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), as well as cerebral ischemic disease, and epilepsy. Current research indicates that α- and β-asarone exert neuroprotective effects by mitigating oxidative stress, abnormal protein accumulation, neuroinflammation, neurotrophic factor deficit, and promoting neuronal cell survival, as well as activating various neuroprotective signalling pathways. Although the beneficial effects exerted by α- and β-asarone have been demonstrated through in vitro and in vivo animal studies, additional research is required to translate laboratory results into safe and effective therapies for patients with AD, PD, and other neurological and neurodegenerative diseases.

Anti-inflammatory and central and peripheral anti-nociceptive activities of α-asarone through the inhibition of TNF-α production, leukocyte recruitment and iNOS expression, and participation of the adenosinergic and opioidergic systems

Alpha-asarone has been found to possess many pharmacological activities, which can improve cognitive function and exert anti-oxidant, anxiolytic, anti-epileptic and protective effects against endothelial cell injury. The anti-inflammatory activity of α-asarone was evaluated using lipopolysaccharide (LPS)-induced paw oedema. Moreover, leukocyte migration, inducible nitric oxide synthase (iNOS) expression and tumour necrosis factor-alpha (TNF-α) levels were quantified in footpads. Formalin and LPS-induced thermal hyperalgesia models were generated using adenosinergic, opioidergic, serotonergic and muscarinic receptor antagonists. The effects on motor coordination were evaluated by means of the rota-rod test. Oral treatment (p.o.) with α-asarone (3 mg/kg) significantly inhibited paw oedema by 62.12 and 72.22%, 2 and 4 h post LPS injection, respectively. Alpha-asarone (3 mg/kg, p.o.) attenuated the inflammatory infiltrate 1, 3 and 6 h after LPS injection. Furthermore, α-asarone (3 mg/kg, p.o.) suppressed iNOS expression and TNF-α production, 6 and 1 h after inflammatory stimulus, respectively. Alpha-asarone (3, 10 and 30 mg/kg, p.o.) inhibited both phases of formalin-induced licking. In the hot-plate test, α-asarone (10 and 30 mg/kg, p.o.) increased the latency to response 3 and 5 h post LPS stimulus. Caffeine and naloxone abolished the central anti-nociceptive effect of α-asarone (neurogenic phase of formalin and hot plate tests), suggesting the participation of the adenosinergic and opioidergic systems. Furthermore, naloxone reversed the peripheral activity of α-asarone (inflammatory phase of formalin test), indicating the possible involvement of the opioidergic pathway. In the rota-rod test, α-asarone did not change motor coordination. These findings suggest that α-asarone has anti-inflammatory, peripheral and central anti-nociceptive effects and could represent a promising agent for future research.

Anxiolytic Effect of Essential Oils and Their Constituents: A Review

Essential oils are usually used in aromatherapy to alleviate anxiety symptoms. In comparison to traditional drugs, essential oils have fewer side effects and more diversified application ways, including inhalation. This review provides a comprehensive overview of studies on anxiolytic effects of essential oils in preclinical and clinical trials. Most of the essential oils used in clinical studies have been proven to be anxiolytic in animal models. Inhalation and oral administration were two common methods for essential oil administration in preclinical and clinical trials. Massage was only used in the clinical trials, while intraperitoneal injection was only used in the preclinical trails. In addition to essential oils that are commonly used in aromatherapy, essential oils from many folk medicinal plants have also been reported to be anxiolytic. More than 20 compounds derived from essential oils have shown an anxiolytic effect in rodents, while two-thirds of them are alcohols and terpenes. Monoamine neurotransmitters, amino acid neurotransmitters, and the hypothalamic-pituitary-adrenal axis are thought to play important roles in the anxiolytic effects of essential oils.

Anti-Amyloidogenic Effects of Asarone Derivatives From Perilla frutescens Leaves against Beta-Amyloid Aggregation and Nitric Oxide Production

Alzheimer's disease (AD) is a progressive, neurodegenerative brain disorder associated with loss of memory and cognitive function. Beta-amyloid (Aβ) aggregates, in particular, are known to be highly neurotoxic and lead to neurodegeneration. Therefore, blockade or reduction of Aβ aggregation is a promising therapeutic approach in AD. We have previously reported an inhibitory effect of the methanol extract of Perilla frutescens (L.) Britton (Lamiaceae) and its hexane fraction on Aβ aggregation. Here, the hexane fraction of P. frutescens was subjected to diverse column chromatography based on activity-guided isolation methodology. This approach identified five asarone derivatives including 2,3-dimethoxy-5-(1E)-1-propen-1-yl-phenol (1), β-asarone (2), 3-(2,4,5-trimethoxyphenyl)-(2E)-2-propen-1-ol (3), asaronealdehyde (4), and α-asarone (5). All five asarone derivatives efficiently reduced the aggregation of Aβ and disaggregated preformed Aβ aggregates in a dose-dependent manner as determined by a Thioflavin T (ThT) fluorescence assay. Furthermore, asarone derivatives protected PC12 cells from Aβ aggregate-induced toxicity by reducing the aggregation of Aβ, and significantly reduced NO production from LPS-stimulated BV2 microglial cells. Taken together, these results suggest that asarone derivatives derived from P. frutescens are neuroprotective and have the prophylactic and therapeutic potential in AD.

Asarones from Acori Tatarinowii Rhizoma stimulate expression and secretion of neurotrophic factors in cultured astrocytes

Acori Tatarinowii Rhizoma (ATR, the dried rhizome of Acorus tatarinowii Schott.) is a traditional Chinese medicine widely used to treat brain diseases, e.g. depression, forgetfulness, anxiety and epilepsy. Several lines of evidence support that ATR has neuronal beneficial functions in animal models, but its action mechanism in cellular level is unknown. Here, we identified α-asarone and β-asarone could be the major active ingredients of ATR, which, when applied onto cultured rat astrocytes, significantly stimulated the expression and secretion of neurotrophic factors, i.e. nerve growth factor (NGF), brain derived neurotrophic factor (BDNF) and glial derived neurotrophic factor (GDNF), in dose-dependent manners. These results suggested that the neuronal action of ATR, triggered by asarone, might be mediated by an increase of expression of neurotrophic factors in astrocytes, which therefore could support the clinical usage of ATR. In addition, application of PKA inhibitor, H89, in cultured astrocytes partially blocked the asarone-induced neurotrophic factor expression, suggesting the involvement of PKA signaling. The results proposed that α-asarone and β-asarone from ATR could serve as potential candidates for drug development in neurodegenerative diseases.

The immunomodulatory tellurium compound ammonium trichloro (dioxoethylene-O,O') tellurate reduces anxiety-like behavior and corticosterone levels of submissive mice

Ammonium trichloro (dioxoethylene-O,O') tellurate (AS101) is a synthetic organotellurium compound with potent immunomodulatory and neuroprotective properties shown to inhibit the function of integrin αvβ3, a presynaptic cell-surface-adhesion receptor. As partial deletion of αvβ3 downregulated reuptake of serotonin by the serotonin transporter, we hypothesized that AS101 may influence pathways regulating anxiety. AS101 was tested in the modulation of anxiety-like behavior using the selectively bred Submissive (Sub) mouse strain that develop anxiety-like behavior in response to an i.p. injection. Mice were treated daily with AS101 (i.p., 125 or 200 μg/kg) or vehicle for 3 weeks, after which their anxiety-like behavior was measured in the elevated plus maze. Animals were then culled for the measurement of serum corticosterone levels by ELISA and hippocampal expression of brain-derived neurotrophic factor (BDNF) by RT-PCR. Chronic administration of AS101 significantly reduced anxiety-like behavior of Sub mice in the elevated plus maze, according to both time spent and entries to open arms, relative to vehicle-treated controls. AS101 also markedly reduced serum corticosterone levels of the treated mice and increased their hippocampal BDNF expression. Anxiolytic-like effects of AS101 may be attributed to the modulation of the regulatory influence integrin of αvβ3 upon the serotonin transporter, suggesting a multifaceted mechanism by which AS101 buffers the hypothalamic-pituitary-adrenal axis response to injection stress, enabling recovery of hippocampal BDNF expression and anxiety-like behavior in Sub mice. Further studies should advance the potential of AS101 in the context of anxiety-related disorders.

Pharmacology and toxicology of α- and β-Asarone: A review of preclinical evidence

BACKGROUND

Asarone is one of the most researched phytochemicals and is mainly present in the Acorus species and Guatteria gaumeri Greenman. In preclinical studies, both α- and β-asarone have been reported to have numerous pharmacological activities and at the same time, many studies have also revealed the toxicity of α- and β-asarone.

PURPOSE

The purpose of this comprehensive review is to compile and analyze the information related to the pharmacokinetic, pharmacological, and toxicological studies reported on α- and β-asarone using preclinical in vitro and in vivo models. Besides, the molecular targets and mechanism(s) involved in the biological activities of α- and β-asarone were discussed.

METHODS

Databases including PubMed, ScienceDirect and Google scholar were searched and the literature from the year 1960 to January 2017 was retrieved using keywords such as α-asarone, β-asarone, pharmacokinetics, toxicology, pharmacological activities (e.g. depression, anxiety).

RESULTS

Based on the data obtained from the literature search, the pharmacokinetic studies of α- and β-asarone revealed that their oral bioavailability in rodents is poor with a short plasma half-life. Moreover, the metabolism of α- and β-asarone occurs mainly through cytochrome-P450 pathways. Besides, both α- and/or β-asarone possess a wide range of pharmacological activities such as antidepressant, antianxiety, anti-Alzheimer's, anti-Parkinson's, antiepileptic, anticancer, antihyperlipidemic, antithrombotic, anticholestatic and radioprotective activities through its interaction with multiple molecular targets. Importantly, the toxicological studies revealed that both α- and β-asarone can cause hepatomas and might possess mutagenicity, genotoxicity, and teratogenicity.

CONCLUSIONS

Taken together, further preclinical studies are required to confirm the pharmacological properties of α-asarone against depression, anxiety, Parkinson's disease, psychosis, drug dependence, pain, inflammation, cholestasis and thrombosis. Besides, the anticancer effect of β-asarone should be further studied in different types of cancers using in vivo models. Moreover, further dose-dependent in vivo studies are required to confirm the toxicity of α- and β-asarone. Overall, this extensive review provides a detailed information on the preclinical pharmacological and toxicological activities of α-and β-asarone and this could be very useful for researchers who wish to conduct further preclinical studies using α- and β-asarone.

Dissolution and bioavailability enhancement of alpha-asarone by solid dispersions via oral administration

Alpha (α)-asarone (1-propenyl-2,4,5-methoxybenzol) (ARE) has been extensively used to treat chronic obstructive pulmonary diseases (COPD), bronchial asthma, pneumonia, and epilepsy. Due to its poor solubility and bioavailability, ARE was clinically administered via intravenous injection. However, severe allergies were often reported due to the presence of solublizers in the injection formulation. In our study, we sought to explore the biopharmaceutical classification of ARE, elucidate the mechanisms behind ARE absorption, and to develop a viable formulation to improve the oral bioavailability of ARE. ARE was not a P-glycoprotein substrate, which was absorbed in the passive mode without site specificity in the gastrointestinal tract. Solid dispersions prepared using hydrophilic matrix materials such as Pluronic F68, and polyethylene glycol (PEG) of varying molecular weights (PEG4K, PEG10K, and PEG20K) were proven to significantly improve the dissolution of ARE in vitro and the oral bioavailability of ARE in rats, which represent a promising strategy for the oral administration of ARE and other BCS II compounds.

Biological Properties of Some Volatile Phenylpropanoids

Plants and their extracts are the new field of interest for many scientists and also of some pharmaceutical industries. In order to provide more information for their usage in the prevention and treatment of diseases many clinical trials and researches are being carried out. In this review the biological activities and the mechanism of action of volatile phenylpropanoids (PPs) found in essential oils (EOs) are presented. The aim of this overview is to show that volatile PPs found in EOs can exert many of the biological activities which are generally attributed to EOs. Almost all of the PPs possess antimicrobial, anti-inflammatory and anticancer activities. These are related to the different substitution of the phenylpropane molecule. For each isolated group not only one, but more pharmacological activities can be credited.

Alterations in the corticotropin-releasing hormone (CRH) neurocircuitry: Insights into post stroke functional impairments

Although it is well accepted that changes in the regulation of the hypothalamic-pituitary adrenal (HPA) axis may increase susceptibility to affective disorders in the general population, this link has been less examined in stroke patients. Yet, the bidirectional association between depression and cardiovascular disease is strong, and stress increases vulnerability to stroke. Corticotropin-releasing hormone (CRH) is the central stress hormone of the HPA axis pathway and acts by binding to CRH receptors (CRHR) 1 and 2, which are located in several stress-related brain regions. Evidence from clinical and animal studies suggests a role for CRH in the neurobiological basis of depression and ischemic brain injury. Given its importance in the regulation of the neuroendocrine, autonomic, and behavioral correlates of adaptation and maladaptation to stress, CRH is likely associated in the pathophysiology of post stroke emotional impairments. The goals of this review article are to examine the clinical and experimental data describing (1) that CRH regulates the molecular signaling brain circuit underlying anxiety- and depression-like behaviors, (2) the influence of CRH and other stress markers in the pathophysiology of post stroke emotional and cognitive impairments, and (3) context and site specific interactions of CRH and BDNF as a basis for the development of novel therapeutic targets. This review addresses how the production and release of the neuropeptide CRH within the various regions of the mesocorticolimbic system influences emotional and cognitive behaviors with a look into its role in psychiatric disorders post stroke.

Neuroprotective effect of β-asarone against Alzheimer's disease: regulation of synaptic plasticity by increased expression of SYP and GluR1

Aim

β-asarone, an active component of Acori graminei rhizome, has been reported to have neuroprotective effects in Alzheimer’s disease. As the underlying mechanism is not known, we investigated the neuroprotective effects of β-asarone in an APP/PS1 double transgenic mouse model and in NG108 cells.

Materials and methods

APPswe/PS1dE9 double transgenic male mice were randomly assigned to a model group, β-asarone treatment groups (21.2, 42.4, or 84.8 mg/kg/d), or donepezil treatment group (2 mg/kg/d). Donepezil treatment was a positive control, and background- and age-matched wild-type B6 mice were an external control group. β-asarone (95.6% purity) was dissolved in 0.8% Tween 80 and administered by gavage once daily for 2.5 months. Control and model animals received an equal volume of vehicle. After 2.5 months of treatment, behavior of all animals was evaluated in a Morris water maze. Expression of synaptophysin (SYP) and glutamatergic receptor 1 (G1uR1) in the hippocampus and cortex of the double transgenic mice was assayed by Western blotting. The antagonistic effects of β-asarone against amyloid-β peptide (Aβ) were investigated in vitro in the NG108-15 cell line. After 24 hours of incubation, cells were treated with 10 μm Aβ with or without β-asarone at different concentrations (6.25, 12.5, or 25 μM) for an additional 36 hours. The cytotoxicity of β-asarone was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay of cell viability, and cell morphology was evaluated by bright-field microscopy after 24 hours of treatment. The expression of SYP and GluR1 in cells was detected by Western blot assay in the hippocampus and brain cortex tissues of mice.

Results

β-asarone at a high dose reduced escape latency and upregulated SYP and GluR1 expression at both medium and high doses. Cell morphology evaluation showed that β-asarone treatment did not result in obvious cell surface spots and cytoplasmic granularity. β-asarone had a dose-dependent effect on cell proliferation.

Conclusion

β-asarone antagonized the Aβ neurotoxicity in vivo, improved the learning and memory ability of APP/PS1 mice, and increased the expression of SYP and GluR1 both in vivo and in vitro. Thus, β-asarone may be a potential drug for the treatment of Alzheimer’s disease.

Decreased Interleukin-4 Release from the Neurons of the Locus Coeruleus in Response to Immobilization Stress

It has been demonstrated that immobilization (IMO) stress affects neuroimmune systems followed by alterations of physiology and behavior. Interleukin-4 (IL-4), an anti-inflammatory cytokine, is known to regulate inflammation caused by immune challenge but the effect of IMO on modulation of IL-4 expression in the brain has not been assessed yet. Here, it was demonstrated that IL-4 was produced by noradrenergic neurons in the locus coeruleus (LC) of the brain and release of IL-4 was reduced in response to IMO. It was observed that IMO groups were more anxious than nontreated groups. Acute IMO (2 h/day, once) stimulated secretion of plasma corticosterone and tyrosine hydroxylase (TH) in the LC whereas these increments were diminished in exposure to chronic stress (2 h/day, 21 consecutive days). Glucocorticoid receptor (GR), TH, and IL-4-expressing cells were localized in identical neurons of the LC, indicating that hypothalamic-pituitary-adrenal- (HPA-) axis and sympathetic-adrenal-medullary- (SAM-) axis might be involved in IL-4 secretion in the stress response. Accordingly, it was concluded that stress-induced decline of IL-4 concentration from LC neurons may be related to anxiety-like behavior and an inverse relationship exists between IL-4 secretion and HPA/SAM-axes activation.

Pretreatment with Resveratrol Prevents Neuronal Injury and Cognitive Deficits Induced by Perinatal Hypoxia-Ischemia in Rats

Despite advances in neonatal care, hypoxic-ischemic brain injury is still a serious clinical problem, which is responsible for many cases of perinatal mortality, cerebral palsy, motor impairment and cognitive deficits. Resveratrol, a natural polyphenol with important anti-oxidant and anti-inflammatory properties, is present in grapevines, peanuts and pomegranates. The aim of the present work was to evaluate the possible neuroprotective effect of resveratrol when administered before or immediately after a hypoxic-ischemic brain event in neonatal rats by analyzing brain damage, the mitochondrial status and long-term cognitive impairment. Our results indicate that pretreatment with resveratrol protects against brain damage, reducing infarct volume, preserving myelination and minimizing the astroglial reactive response. Moreover its neuroprotective effect was found to be long lasting, as behavioral outcomes were significantly improved at adulthood. We speculate that one of the mechanisms for this neuroprotection may be related to the maintenance of the mitochondrial inner membrane integrity and potential, and to the reduction of reactive oxygen species. Curiously, none of these protective features was observed when resveratrol was administered immediately after hypoxia-ischemia.

A Systematic Review of the Anxiolytic-Like Effects of Essential Oils in Animal Models

The clinical efficacy of standardized essential oils (such as Lavender officinalis), in treating anxiety disorders strongly suggests that these natural products are an important candidate source for new anxiolytic drugs. A systematic review of essential oils, their bioactive constituents, and anxiolytic-like activity is conducted. The essential oil with the best profile is Lavendula angustifolia, which has already been tested in controlled clinical trials with positive results. Citrus aurantium using different routes of administration also showed significant effects in several animal models, and was corroborated by different research groups. Other promising essential oils are Citrus sinensis and bergamot oil, which showed certain clinical anxiolytic actions; along with Achillea wilhemsii, Alpinia zerumbet, Citrus aurantium, and Spiranthera odoratissima, which, like Lavendula angustifolia, appear to exert anxiolytic-like effects without GABA/benzodiazepine activity, thus differing in their mechanisms of action from the benzodiazepines. The anxiolytic activity of 25 compounds commonly found in essential oils is also discussed.

β-Asarone Mitigates Amyloidosis and Downregulates RAGE in a Transgenic Mouse Model of Alzheimer's Disease

Elevated β-amyloid (Aβ) is a hallmark of Alzheimer's disease (AD). Recent evidence has suggested that the receptor of advanced glycation end products (RAGE) is a key target for Aβ-induced perturbation in AD, and blockade of RAGE significantly alleviates synaptic injury. Our previous study has suggested that β-asarone could reduce neuronal apoptosis and improve memory deficits in β-amyloid precursor protein and presenilin-1 (APP/PS1) double transgenic AD-model mice. In the present study, we evaluated the effects of β-asarone on amyloidosis in APP/PS1 mice. We found that the survival of neurons of APP/PS1 mice was improved by β-asarone, meanwhile, β-asarone decreased Aβ deposition and down-regulated Aβ1-42 levels in cortex and hippocampus of APP/PS1 mice brain. Interestingly, the level of RAGE was also significantly down-regulated by β-asarone. Our findings suggest that β-asarone might be effective for the treatment of AD, and the decreasing effects of β-asarone on Aβ might associate with its down-regulation of RAGE.

A novel 2-decenoic acid thioester ameliorates corticosterone-induced depression- and anxiety-like behaviors and normalizes reduced hippocampal signal transduction in treated mice

We characterized mice administered corticosterone (CORT) at a dose of 20 mg/kg for 3 weeks to determine their suitability as a model of mood disorders and found that the time immobilized in the tail suspension test was longer and the time spent in the open arms of the elevated plus-maze test was shorter than those of the vehicle-treated group, findings demonstrating that chronic CORT induced both depression-like and anxiety-like behaviors. Furthermore, the levels of phosphorylated extracellular signal-regulated kinase (pERK) 1/2 in the hippocampus and cerebral cortex were reduced in the CORT-treated group. Using this model, we investigated the protective effect of the ester, thioester, and amide compounds of 2-decenoic acid derivatives (termed compounds A, B, and C, respectively). The potency of the protective activity against the CORT-induced depression-like or anxiety-like behaviors and the reduction in pERK1/2 level were found to be in the following order: compound B > compound C > compound A. Therefore, we further investigated the therapeutic activity of only compound B, and its effect on depression-like behavior was observed after oral administration for 1 or 2 weeks, and its effect on anxiety-like behavior was observed after oral administration for 3 weeks. The ratios of phosphorylated ERK1/2, Akt, and cAMP-response element-binding protein to their respective nonphosphorylated forms were smaller in the CORT-treated group than in the vehicle-treated group; however, subsequent treatment with compound B at either 0.3 or 1.5 mg/kg significantly ameliorated this reduction. Compound B appeared to elicit intracellular signaling, similar to that elicited by brain-derived neurotrophic factor, and its mode of action was shown to be novel and different from that of fluvoxamine, a currently prescribed drug for mood disorders.