Geissoschizine methyl ether, an alkaloid in Uncaria hook, is a potent serotonin ₁A receptor agonist and candidate for amelioration of aggressiveness and sociality by yokukansan

Pharmacokinetic Profiles of Active Ingredients and Its Metabolites Derived from Rikkunshito, a Ghrelin Enhancer, in Healthy Japanese Volunteers: A Cross-Over, Randomized Study

Background

Rikkunshito, a traditional Japanese (Kampo) medicine, has been used to treat upper gastrointestinal disorders such as functional dyspepsia and gastroesophageal reflux. This study investigated the exposure and pharmacokinetics of the ingredients of rikkunshito in healthy volunteers.

Methods and Results

First, an exploratory nonrandomized, open-label, one-period, noncrossover study using four healthy Japanese volunteers to detect 32 typical ingredients of rikkunshito in plasma and urine. As a result, 18 or 21 of 32 ingredients was detected in plasma or urine samples after oral administration of rikkunshito (7.5 g/day). Furthermore, a randomized, open-label, three-arm, three-period, crossover study using 21 subjects was conducted to determine the amounts of exposure and pharmacokinetic parameters of nine ingredients derived from rikkunshito (atractylodin, atractylodin carboxylic acid, pachymic acid, 3,3′,4′,5,6,7,8-heptamethoxyflavone, naringenin, nobiletin, liquiritigenin, isoliquiritigenin, and 18β-glycyrrhetinic acid) after oral administration of rikkunshito at three different doses (2.5, 5.0, or 7.5 g/day) during each period. The pharmacokinetic profiles of the nine ingredients in plasma were characterized. The geometric means (95% confidence interval) for the Cmax of the ingredients at a dose of 7.5 g were 1570 (1210–2040), 14,300 (12,200–16,800), 91.0 (71.8–115), 105 (75.6–144), 1150 (802–1650), 35.9 (24.6–52.5), 800 (672–952), 42.8 (30.4–60.3), and 55,600 (39,600–78,100) pg/mL, respectively, and for the AUC_0–last were 1760 (1290–2390), 12700 (11,100–14,600), 1210 (882–1650), 225 (157–322), 4630 (2930–7320), 35.7 (20.4–62.7), 4040 (3260–5010), 122 (88.2–168), and 832,000 (628,000–1,100,000) pg·h/mL respectively.

Conclusions

We identified the ingredients of rikkunshito that are absorbed in humans. Furthermore, we determined the pharmacokinetics of nine ingredients derived from rikkunshito. This information will be useful for elucidating the pharmacological effects of rikkunshito.

Trial Registration

Japan Pharmaceutical Information Center #CTI-121801 and -142522

Pharmacokinetics of Active Components of Yokukansan, a Traditional Japanese Herbal Medicine after a Single Oral Administration to Healthy Japanese Volunteers: A Cross-Over, Randomized Study

Context

Yokukansan (YKS) is a traditional Japanese herbal medicine called kampo medicine in Japan. Its extract comprises seven crude drugs: Atractylodis lanceae rhizoma, Poria, Cnidii rhizoma, Uncariae uncis cum ramulus, Angelicae radix, Bupleuri radix, and Glycyrrhizae radix. YKS is used to treat neurosis, insomnia, as well as behavioral and psychological symptoms of dementia.

Objective

To confirm the exposure and pharmacokinetics of the active components of YKS in healthy volunteers.

Design, Setting, and Participants

A randomized, open-label, 3-arm, 3-period, crossover trial was conducted on 21 healthy Japanese volunteers at the Kochi Medical University between May 2012 and November 2012.

Interventions

Single oral administration of YKS (2.5 g, 5.0 g, or 7.5 g/day) during each period.

Main Outcome Measure

Plasma concentrations of three active compounds in YKS, namely 18β-glycyrrhetinic acid (GA), geissoschizine methyl ether (GM), and hirsuteine (HTE).

Results

The mean maximum plasma concentrations (C_max) of GM and HTE increased dose-dependently (ranges: 0.650–1.98 ng/mL and 0.138–0.450 ng/mL, respectively). The times to maximum plasma concentration after drug administration (t_max) were 0.500 h for GM and 0.975–1.00 h for HTE. The apparent elimination half-lives (t_1/2) were 1.72–1.95 h for GM and 2.47–3.03 h for HTE. These data indicate the rapid absorption and elimination of GM and HTE. On the other hand, the C_max, t_max, and t_1/2 of GA were 57.7–108 ng/mL, 8.00–8.01 h, and 9.39–12.3 h, respectively.

Conclusion

We demonstrated that pharmacologically active components of YKS are detected in humans. Further, we determined the pharmacokinetics of GM, HTE, and GA. This information will be useful to elucidate the pharmacological effects of YKS.

Trial Registration

Japan Pharmaceutical Information Center JAPIC CTI-121811

Yokukansan, a traditional Japanese medicine, decreases head-twitch behaviors and serotonin 2A receptors in the prefrontal cortex of isolation-stressed mice

ETHNOPHARMACOLOGICAL RELEVANCE

Yokukansan, a traditional Japanese (Kampo) medicine, has recently been used to treat the behavioral and psychological symptoms of dementia (BPSD), including aggressiveness, excitability, and hallucination. The present study was designed to investigate the mechanisms underlying the ameliorative effects of yokukansan on BPSD using animals exhibiting hallucination-like behaviors. For this purpose, we initially examined whether chronic isolation stress increases the frequency of hallucination in response to a psychedelic drug. Using this animal model, we next examined the effects of yokukansan on drug-induced hallucination-like behaviors. Finally, we examined the density and mRNA levels of serotonin 2A (5-HT2A) receptors.

MATERIALS AND METHODS

Male mice were subjected to isolation stress for six weeks. Yokukansan was incorporated into food pellets, and administered to the mice for six weeks. In some experiments, yokukansan and each of seven constituent herbs were administered orally to the mice for the last two weeks during the six-week period of isolation stress. A 5-HT2A receptor agonist, 2,5-dimethoxy-4-iodoamphetamine (DOI, 2.5mg/kg), was injected into the mice, and head-twitch behaviors were quantified. The binding sites of 5-HT2A receptors on the plasma membrane of the prefrontal cortex (PFC) were assessed by a receptor-binding assay using tritium-labeled ketanserin, and the density and affinity were calculated from a Scatchard plot. The level of mRNAs was measured by PCR analyses.

RESULTS

Isolation stress enhanced the frequency of the DOI-induced head-twitch response, and yokukansan treatment by feeding significantly reduced this enhancement. Isolation stress significantly increased the 5-HT2A receptor density in the PFC, and yokukansan treatment by feeding as well as administration significantly down-regulated this increase. Isolation stress and yokukansan did not affect the affinity. Among seven constituent herbs, Bupleurum Root, Uncaria Hook, Japanese Angelica Root, and Glycyrrhiza down-regulated the increase, but statistically not significant, in which their efficacies were over 50% relative to yokukansan. Neither isolation stress nor yokukansan affected mRNA levels of 5-HT2A receptors.

CONCLUSION

Yokukansan attenuated drug-induced hallucination-like behaviors in isolated mice, which is suggested to be mediated by 5-HT2A receptor down-regulation in the PFC. This mechanism may underlie the ameliorative effects of yokukansan on hallucination.

The Kampo Medicine Yokukansan Decreases MicroRNA-18 Expression and Recovers Glucocorticoid Receptors Protein Expression in the Hypothalamus of Stressed Mice

It is well known that glucocorticoid receptor (GR) signaling regulates the hypothalamic-pituitary-adrenal (HPA) axis, and GR expression level is associated with HPA axis activity. Recent studies revealed that microRNA- (miR-) 18 and/or 124a are candidate negative regulators of GR in the brain. The Kampo medicine Yokukansan (YKS) can affect psychological symptoms such as depression and anxiety that are associated with stress responses. In this study, we evaluated the effect of YKS on miR-18 and 124a and GR levels in mice exposed to stress. We found that YKS pretreatment normalized elevated plasma corticosterone levels in stress-exposed mice. In addition, GR mRNA levels were downregulated in the brain following stress exposure. While miR-124a expression levels were not altered in the hypothalamus of stress-exposed mice, miR-18 levels decreased in the hypothalamus of YKS-pretreated mice after stress exposure. Finally, GR protein levels in the paraventricular nucleus (PVN) of the hypothalamus after stress exposure recovered in YKS-pretreated mice. Collectively, these data suggest that YKS normalizes GR protein levels by regulating miR-18 expression in the hypothalamus, thus normalizing HPA axis activity following stress exposure.

Yokukansan normalizes glucocorticoid receptor protein expression in oligodendrocytes of the corpus callosum by regulating microRNA-124a expression after stress exposure

Stressful events are known to down-regulate expression levels of glucocorticoid receptors (GRs) in the brain. Recently, we reported that stressed mice with elevated plasma levels of corticosterone exhibit morphological changes in the oligodendrocytes of nerve fiber bundles, such as those in the corpus callosum. However, little is known about the molecular mechanism of GR expression regulation in oligodendrocytes after stress exposure. A previous report has suggested that GR protein levels might be regulated by microRNA (miR)-18 and/or -124a in the brain. In this study, we aimed to elucidate the GR regulation mechanism in oligodendrocytes and evaluate the effects of yokukansan (YKS), a Kampo medicine, on GR protein regulation. Acute exposure to stress increased plasma corticosterone levels, decreased GR protein expression, and increased miR-124a expression in the corpus callosum of adult male mice, though the GR mRNA and miR-18 expression levels were not significant changes. YKS normalized the stress-induced changes in the plasma corticosterone, GR protein, and miR124a expression levels. An oligodendrocyte primary culture study also showed that YKS down-regulated miR-124a, but not miR-18, expression levels in dexamethasone-treated cells. These results suggest that the down-regulation of miR124a expression might be involved in the normalization of stress-induced decreases in GR protein in oligodendrocytes by YKS. This effect may imply the molecular mechanisms underlying the ameliorative effects of YKS on psychological symptoms and stress-related behaviors.

Yokukansan Improves Mechanical Allodynia through the Regulation of Interleukin-6 Expression in the Spinal Cord in Mice with Neuropathic Pain

Neuropathic pain is caused by nerve injury. Yokukansan (Yi-Gan San), a traditional Japanese (Kampo) medicine, has been widely used for neuropathic pain control. However, the analgesic mechanisms remain unknown. In this study, we investigated the analgesic mechanisms of yokukansan in a mouse model of neuropathic pain. Partial sciatic nerve ligation (PSL) induced mechanical allodynia in mice. Repetitive oral administration of the extracts of yokukansan and the constituent herbal medicine Atractylodis Lanceae Rhizoma, but not Glycyrrhizae Radix, relieved mechanical allodynia in the PSL mice and inhibited the PSL-induced expression of interleukin- (IL-) 6 mRNA in the spinal cord. Yokukansan did not attenuate intrathecal IL-6-induced mechanical allodynia. IL-6 immunoreactivity was detected in microglia and astrocytes in the spinal dorsal horn. These results suggest that yokukansan relieves mechanical allodynia in PSL mice by regulating the expression of IL-6 in astrocytes and/or microglia in the spinal cord. In addition, the components of Atractylodis Lanceae Rhizoma, one of the constituent herbal medicines in yokukansan, may play an important role in the regulation of IL-6 expression and neuropathic pain control.

Metabolic profiling of the Uncaria hook alkaloid geissoschizine methyl ether in rat and human liver microsomes using high-performance liquid chromatography with tandem mass spectrometry

Geissoschizine methyl ether (GM) is an indole alkaloid found in Uncaria hook, which is a galenical constituent of yokukansan, a traditional Japanese medicine. GM has been identified as the active component responsible for anti-aggressive effects. In this study, the metabolic profiling of GM in rat and human liver microsomes was investigated. Thirteen metabolites of GM were elucidated and identified using a high-performance liquid chromatography with tandem mass spectrometry method, and their molecular structures were proposed on the basis of the characteristics of their precursor ions, product ions, and chromatographic retention times. There were no differences in the metabolites between the rat and human liver microsomes. Among the 13 identified metabolites, there were two demethylation metabolites, one dehydrogenation metabolite, three methylation metabolites, three oxidation metabolites, two water-adduct metabolites, one di-demethylation metabolite, and one water-adduct metabolite followed by oxidation. The metabolic pathways of GM were proposed on the basis of this study. This study will be helpful in understanding the metabolic routes of GM and related Uncaria hook alkaloids, and provide useful information on the pharmacokinetics and pharmacodynamics. This is the first report that describes the separation and identification of GM metabolites in rat and human liver microsomes.

Specific binding and characteristics of geissoschizine methyl ether, an indole alkaloid of Uncaria Hook, in the rat brain

ETHNOPHARMACOLOGICAL RELEVANCE

Geissoschizine methyl ether (GM) is an indole alkaloid that is a component of Uncaria Hook, and has been identified as the active component responsible for the anti-aggressive effects of the Uncaria Hook-containing traditional Japanese medicine, yokukansan. Recently, GM was shown to reach the brain by crossing the blood-brain barrier in rats following the oral administration of yokukansan. This finding suggested that there may be specific binding sites for GM in the brain. Here we show evidence that tritium-labeled GM ([(3)H]GM) binds specifically to several brain areas of rats.

MATERIALS AND METHODS

Male rats were used. [(3)H]GM was synthesized from a demethylated derivative of GM. Specific binding sites of [(3)H]GM on brain sections were determined by quantitative autoradiography, and maximum binding densities (Bmax) and dissociation constants (Kd) were calculated. Several chemical compounds were used to clarify the molecules that recognize [(3)H]GM in the completion-binding assay. Emulsion microautoradiography was also performed to identify the cells that bind [(3)H]GM.

RESULTS

Specific binding of [(3)H]GM was observed in the frontal cortex, including the prefrontal cortical region (e.g., prelimbic cortex (PrL)), hippocampus, caudate putamen, amygdala, central medial thalamic nucleus, dorsal raphe nucleus (DR), and cerebellum. Bmax ranged between 0.65 and 8.79pmol/mg tissue, and Kd was between 35.0 and 232.6nM. Specific binding with relatively high affinity (Kd less than 62nM) was dense in the frontal cortical region, moderate in the DR, and sparse in the cerebellum. The specific binding of [(3)H]GM in the PrL was significantly replaced by the serotonin 1A (5-HT1A) receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (DPAT), 5-HT2A receptor antagonist ketanserin, 5-HT2B receptor agonist BW 723C86, 5-HT2C receptor agonist RO60-0175, adrenergic α2A receptor antagonist yohimbine, L-type Ca(2+) channel blocker verapamil, and μ-opioid receptor antagonist naloxone. Similar results were obtained in the frontal cortex and DR, but not in the cerebellum. Microautoradiography revealed that [(3)H]GM signals were distributed throughout the frontal cortex, which included neuron-like large cells.

CONCLUSION

These results demonstrate that specific binding sites for GM exist in rat brain tissue, and suggest that the pharmacological actions of GM are mainly associated with 5-HT receptors in the frontal cortex and DR. These results provide an insight into the neuropharmacology of GM and GM-containing herbal medicines.

Mother/offspring co-administration of the traditional herbal remedy yokukansan during the nursing period influences grooming and cerebellar serotonin levels in a rat model of neurodevelopmental disorders

Neurodevelopmental impairment in the serotonergic system may be involved in autism spectrum disorder. Yokukansan is a traditional herbal remedy for restlessness and agitation in children, and mother-infant co-administration (MICA) to both the child and the nursing mother is one of the recommended treatment approaches. Recent studies have revealed the neuropharmacological properties of Yokukansan (YKS), including its 5-HT1A (serotonin) receptor agonistic effects. We investigated the influence of YKS treatment on behavior in a novel environment and on brain monoamine metabolism during the nursing period in an animal model of neurodevelopmental disorders, prenatally BrdU (5-bromo-2'-deoxyuridine)-treated rats (BrdU-rats). YKS treatment did not influence locomotor activity in BrdU-rats but reduced grooming in open-field tests. YKS treatment without MICA disrupted the correlation between locomotor behaviors and rearing and altered levels of serotonin and its metabolite in the cerebellum. These effects were not observed in the group receiving YKS treatment with MICA. These data indicate a direct pharmacological effect of YKS on the development of grooming behavior and profound effects on cerebellar serotonin metabolism, which is thought to be influenced by nursing conditions.

Yokukan-san: a review of the evidence for use of this Kampo herbal formula in dementia and psychiatric conditions

Japanese traditional herbal medicine (Kampo) has its origins in traditional Chinese medicine (TCM). It was introduced to Japan in the middle of the sixth century and has evolved over the past 1,400 years after combining with Japan's original folk remedies. While it retains some similarities to TCM, Kampo has evolved in Japan, resulting in a system of medicine that has many differences from TCM. Kampo medicine is considered to be very safe; in Japan, Kampo herbal formulas are manufactured by licensed pharmaceutical companies, prescribed by Western-trained medical doctors (usually as a freeze-dried extract), and have quality control standards similar to those of prescription drugs. The present study examined Yokukan-san (Yi-Gan San in TCM), a Kampo formula that has been used empirically in Japan for more than 400 years. Accumulating clinical trials have demonstrated Yokukan-san's efficacy in treating patients with behavioral and psychological symptoms of dementia, which has resulted in the Japanese Society of Neurology listing it in the Japanese Guidelines for the Management of Dementia 2010. Efficacy in other diseases and conditions, such as sleep disorders, tardive dyskinesia, aggression, and impulsivity has also been reported. This article reviews both clinical and basic studies of Yokukan-san, with the goal of clarifying its clinical indications.

Specific binding and characteristics of 18β-glycyrrhetinic acid in rat brain

18β-Glycyrrhetinic acid (GA) is the aglycone of glycyrrhizin that is a component of Glycyrrhiza, and has several pharmacological actions in the central nervous system. Recently, GA has been demonstrated to reach the brain by crossing the blood-brain barrier in rats after oral administration of a Glycyrrhiza-containing traditional Japanese medicine, yokukansan. These findings suggest that there are specific binding sites for GA in the brain. Here we show evidence that [³H]GA binds specifically to several brain areas by quantitative autoradiography; the density was higher in the hippocampus, moderate in the caudate putamen, nucleus accumbens, amygdala, olfactory bulb, cerebral cortex, thalamus, and mid brain, and lower in the brain stem and cerebellum. Several kinds of steroids, gap junction-blocking reagents, glutamate transporter-recognized compounds, and glutamate receptor agonists did not inhibit the [³H]GA binding. Microautoradiography showed that the [³H]GA signals in the hippocampus were distributed in small non-neuronal cells similar to astrocytes. Immunohistochemical analysis revealed that immunoreactivity of 11β-hydroxysteroid dehydrogenase type-1 (11β-HSD1), a defined molecule recognized by GA, was detected mainly in neurons, moderately in astrocytes, and very slightly in microglial cells, of the hippocampus. These results demonstrate that specific binding sites for GA exist in rat brain tissue, and suggest that the pharmacological actions of GA may be related to 11β-HSD1 in astrocytes. This finding provides important information to understand the pharmacology of GA in the brain.

Yokukansan, a traditional Japanese herbal medicine, alleviates the emotional abnormality induced by maladaptation to stress in mice

The aim of the present study was to examine the effect of yokukansan, a traditional Japanese herbal medicine that is composed of Atractylodis lanceae Rhizoma, Poria, Cnidii Rhizoma, Uncariae Uncis cum Ramulus, Angelicae Radix, Bupleuri Radix and Glycyrrhizae Radix, on the emotional abnormality induced by maladaptation to stress in mice. Mice were exposed to repeated restraint stress for 60 or 240 min/day for 14 days. From the 3rd day of stress exposure, mice were given yokukansan orally (p.o.) or the 5-HT1A receptor agonist flesinoxan intraperitoneally (i.p.) immediately after the daily exposure to restraint stress. After the final exposure to restraint stress, the emotionality of mice was evaluated using an automatic hole-board apparatus. A single exposure to restraint stress for 60 min induced a decrease in head-dipping behavior in the hole-board test. This emotional stress response disappeared in mice that had been exposed to repeated restraint stress for 60 min/day for 14 days, which confirmed the development of stress adaptation. In contrast, mice that were exposed to restraint stress for 240 min/day for 14 days did not develop this stress adaptation, and still showed a decrease in head-dipping behavior. The decreased emotionality observed in stress-maladaptive mice was significantly recovered by chronic treatment with yokukansan (1000 mg/kg, p.o.) as well as flesinoxan (0.25 and 0.5 mg/kg, i.p.) immediately after daily exposure to stress. These findings suggest that yokukansan may have a beneficial effect on stress adaptation and alleviate the emotional abnormality under conditions of excessive stress.

Yokukansan and its ingredients as possible treatment options for schizophrenia

Schizophrenia is a debilitating psychotic mental disorder that affects almost the entire range of human mental function. The devastating effect of the illness is usually long-lasting and requires lifelong treatment. Despite an evolved psychopharmacological understanding, the overall therapeutic effect of antipsychotics is still not satisfactory. The choice of proper medication presents a clinical dilemma between efficacy and safety. As a result, searching for comparable treatment options with safer profiles is very important. Yokukansan (TJ-54), also called yi-gan san in Chinese, is a traditional herbal medicine with evident therapeutic effect for neuropsychiatric disorders. There are several open-label clinical studies upholding the possibility of using yokukansan to treat schizophrenia or schizophrenia-like psychosis. Evidence from animal studies and neurobiology also sheds light on the antipsychotic implications of yokukansan and its ingredients. Nevertheless, correlations between the experimental environment and clinical settings may be complicated by a number of confounders. Clinical trials with more sophisticated designs are required to fill the gap between the experimental environment and clinical settings.

Yokukansan promotes hippocampal neurogenesis associated with the suppression of activated microglia in Gunn rat

BACKGROUND

The pathophysiology of schizophrenia (SCZ) remains unclear, and its treatment is far from ideal. We have previously reported that yokukansan (YKS), which is a traditional Japanese medicine, is effective as an adjunctive therapy for SCZ. However, the mechanisms underlying the action of YKS have not yet been completely elucidated. A recent meta-analysis study has shown that adjuvant anti-inflammatory drugs are effective for SCZ treatment, and it has been proposed that some of the cognitive deficits associated with inflammation may in part be related to inflammation-induced reductions in adult hippocampal neurogenesis. Although certain ingredients of YKS have potent anti-inflammatory activity, no study has determined if YKS has anti-inflammatory properties.

METHODS

Using the Gunn rat, which has been reported as a possible animal model of SCZ, we investigated whether YKS affects cognitive dysfunction in an object-location test and the suppression of microglial activation and neurogenesis in the hippocampus.

RESULTS

We found that YKS ameliorated spatial working memory in the Gunn rats. Furthermore, YKS inhibited microglial activation and promoted neurogenesis in the hippocampal dentate gyrus of these rats. These results suggest that the ameliorative effects of YKS on cognitive deficits may be mediated in part by the suppression of the inflammatory activation of microglia.

CONCLUSIONS

These findings shed light on the possible mechanism underlying the efficacy of YKS in treating SCZ.

Ameliorative effects of yokukansan on behavioral deficits in a gerbil model of global cerebral ischemia

The aim of this study was to investigate the neuroprotective effects of yokukansan, a traditional Kampo medicine, on the behavioral dysfunction induced by cerebral ischemia/reperfusion injury in gerbils. Gerbils were treated with yokukasan by oral gavage for 30 days, once per day, until the day before induction of ischemia, which was induced by occluding the bilateral common carotid artery for 5 min. The effects of yokukansan (50, 100 and 300 mg/kg) were examined by measuring neuronal damage and behavioral deficits (locomotor activity, 8-arm radial maze task). The anti-inflammatory and anti-oxidant properties of yokukansan were also examined. Administration of yokukansan at 300 mg/kg significantly reduced hippocampal neuronal death after brain ischemia, inhibited the ischemia-induced inflammatory response and DNA oxidative damage. Yokukansan also reduced ischemia-induced locomotor hyperactivity and improved memory impairment. These findings suggest that yokukansan can inhibit the inflammatory response, oxidative damage and subsequent neuronal death induced by cerebral ischemia/reperfusion injury, and also can contribute to improvement in neurological deficits following such injury.

Potential usefulness of the kampo medicine yokukansan, containing uncaria hook, for paediatric emotional and behavioural disorders: a case series

Background. Paediatric emotional and behavioural disorders (EBD) are relatively common diseases. Although nonpharmacologic and pharmacologic treatments are utilized in these cases, it is sometimes difficult to manage the symptoms of EBD. Historically, Uncaria hook has been used for treating nighttime crying and convulsions in children. Recent clinical studies have demonstrated that the Kampo medicine Yokukansan (YKS), which contains Uncaria hook, is efficacious for behaviour disorders in Alzheimer's disease patients. Herein, we investigated the clinical efficacy and safety of YKS in a series of cases with paediatric EBD. Patients and Methods. We retrospectively reviewed all paediatric patients who sought Japanese Kampo therapy at our outpatient clinics between April 1, 2012, and April 30, 2013; we selected patients who were diagnosed with paediatric EBD and were treated with YKS. Results. After screening all candidates, 3 patients were eligible for this analysis. Their average age was 11.6 years (range 10–13 years). All 3 patients responded very well to YKS within 1 month. No drug-related adverse events were observed during the course of YKS treatment. Conclusion. Yokukansan may be efficacious for paediatric EBD. We believe these results warrant further evaluation of the clinical efficacy and safety of Yokukansan for paediatric EBD in a carefully designed, double-blind, randomized clinical study.

Geissoschizine methyl ether, an alkaloid from the Uncaria hook, improves remyelination after cuprizone-induced demyelination in medial prefrontal cortex of adult mice

Accumulating evidence indicates that the medial prefrontal cortex (mPFC) is a site of myelin and oligodendrocyte abnormalities that contribute to psychotic symptoms of schizophrenia. The development of therapeutic approaches to enhance remyelination, a regenerative process in which new myelin sheaths are formed on demyelinated axons, may be an attractive remedial strategy. Geissoschizine methyl ether (GM) in the Uncaria hook, a galenical constituent of the traditional Japanese medicine yokukansan (Yi-gan san), is one of the active components responsible for the psychotropic effects of yokukansan, though little is known about the mechanisms underlying the effects of either that medicine or GM itself. In the present study, we employed a cuprizone (CPZ)-induced demyelination model and examined the cellular changes in response to GM administration during the remyelination phase in the mPFC of adult mice. Using the mitotic marker 5-bromo-2'-deoxyuridine (BrdU), we demonstrated that CPZ treatment significantly increased the number of BrdU-positive NG2 cells, as well as microglia and mature oligodendrocytes in the mPFC. Newly formed oligodendrocytes were increased by GM administration after CPZ exposure. In addition, GM attenuated a decrease in myelin basic protein immunoreactivity caused by CPZ administration. Taken together, our findings suggest that GM administration ameliorated the myelin deficit by mature oligodendrocyte formation and remyelination in the mPFC of CPZ-fed mice. The present findings provide experimental evidence supporting the role for GM and its possible use as a remedy for schizophrenia symptoms by promoting the differentiation of progenitor cells to and myelination by oligodendrocytes.

Effects of geissoschizine methyl ether, an indole alkaloid in Uncaria hook, a constituent of yokukansan, on human recombinant serotonin 7 receptor

Effects of seven alkaloids, geissoschizine methyl ether (GM), hirsutine, hirsuteine, rhynchophylline, isorhynchophylline, corynoxeine and isocorynoxeine, in Uncaria hook, a constituent of the kampo medicine yokukansan, on serotonin(7) (5-HT(7)) receptor were investigated using Chinese hamster ovary (CHO) cell membranes and human embryonic kidney 293 (HEK293) cells stably expressing the human recombinant 5-HT(7) receptor. A competitive binding assay using CHO membranes showed that GM (IC(50) = 0.034 μM) more strongly inhibited the binding of the radioligand [(3)H] LSD to 5-HT(7) receptor than the other alkaloids, suggesting that GM is bound to 5-HT(7) receptor. Agonistic/antagonistic effects of GM (1-50 μM) on the receptor were evaluated by measuring intracellular cAMP levels in HEK239 cells. GM (IC(50) = 6.0 μM) inhibited 5-HT-induced cAMP production in a concentration-dependent manner, as well as the specific 5-HT(7) receptor antagonist SB-269970 (0.1-1 μM). However, GM did not induce intracellular cAMP production as 5-HT did. These results suggest that GM has an antagonistic effect on 5-HT(7) receptor.

Yokukansan inhibits morphine tolerance and physical dependence in mice: the role of α₂A-adrenoceptor

Yokukansan (YKS) is a traditional Japanese medicine consisting of seven medicinal herbs that is used for the treatment of neurosis, insomnia, and the behavioral/psychological symptoms of dementia. This study examined the effects of YKS on morphine tolerance and physical dependence in mice. Daily oral administration of YKS (0.5 or 1.0 g/kg) for 3 weeks significantly attenuated morphine tolerance and naloxone-precipitated morphine withdrawal signs (jumps and body weight loss) without affecting the analgesic effect of morphine. The inhibitory effect of YKS on withdrawal jumps in morphine-dependent mice was blocked by a single pretreatment with an α(2)-adrenoceptor antagonist, yohimbine, but not by an α(1)-adrenoceptor antagonist, prazosin. A similar inhibitory effect on withdrawal jumps was observed by repeated administration of yohimbine. The membrane expression of α(2A)-adrenoceptors in the pons/medulla was decreased in morphine withdrawn animals; this reduction was prevented by repeated administration of YKS or yohimbine. Competitive radioligand and [(35)S]guanosine-5'-O-(3-thiotriphosphate) binding assays revealed that YKS and its constituent herbs, Glycyrrhiza (GR) and Uncaria hook (UH), had specific binding affinity for and antagonist activity against the α(2A)-adrenoceptor. Certain chemical constituents, including GR -derived glycyrrhizin and its metabolite, 18β-glycyrrhetinic acid, and UH-derived geissoschizine methyl ether (GME), shared such activities. Repeated administration of GR, UH, glycyrrhizin or GME significantly inhibited morphine withdrawal signs. These results suggest that YKS and its active constituents inhibit morphine tolerance and physical dependence, and that the latter is due at least in part to the prevention of the decreased membrane expression of the α(2A)-adrenoceptor in the brainstem by its prolonged blockade.

Ameliorative effect of yokukansan on vacuous chewing movement in haloperidol-induced rat tardive dyskinesia model and involvement of glutamatergic system

Effects of yokukansan (YKS) on vacuous chewing movement (VCM), which is an index for tardive dyskinesia, were investigated in haloperidol decanoate-treated rats. Haloperidol decanoate was injected to a thigh muscle once every four weeks for 18 weeks. The rats which exhibited VCM eight times or more in 3min were selected on the 12th week, and examined. A significant increase in VCM on the 12th week continued until the 18th week. Oral administration of YKS (0.1 and 0.5g/kg) once a day for three weeks (21 days) from the 12th week to 15th week ameliorated the haloperidol decanoate-induced increase in VCM in a dose-dependent manner. The significant ameliorative effect observed in 0.5g/kg YKS-treated rats was abolished by stopping administration for three weeks from the 15th week to the 18th week. The extracellular glutamate concentration and glutamate transporter mRNA expression in the striatum were evaluated by microdialysis and real-time reverse-transcription polymerase chain reaction assays at the 15th week. The striatal glutamate level increased in haloperidol-treated rats, and the increase was inhibited by treatment with YKS. The striatal GLT-1 mRNA level showed a tendency to decrease in the haloperidol-treated rats. The GLT-1 mRNA level after treatment with YKS (0.5g/kg) was greater than the control level. These results suggest the effect of YKS may be involved in the extracellular glutamate level and GLT-1 mRNA expression in the striatum.