Geissoschizine Methyl Ether Research Articles

Natural Corynanthe-Type Cholinesterase Inhibitors from Malaysian Uncaria attenuata Korth.: Isolation, Characterization, In Vitro and In Silico Studies.

The Uncaria genus is notable for its therapeutic potential in treating age-related dementia, such as Alzheimer's disease. A phytochemical study of the leaves of Malaysian Uncaria attenuata Korth., afforded an undescribed natural corynanthe-type oxindole alkaloid, isovillocarine D (1) together with two known indole alkaloids, villocarine A (2) and geissoschizine methyl ether (3), and their structural identification was performed with extensive mono- and bidimensional NMR and MS spectroscopic methods. The isolated alkaloids were evaluated for their acetylcholinesterase (AChE)- and butyrylcholinesterase (BChE)-inhibitory activity. The results indicated that compound (2) was the most potent inhibitor against both AChE and BChE, with IC50 values of 14.45 and 13.95 µM, respectively, whereas compounds (1) and (3) were selective BChE inhibitors with IC50 values of 35.28 and 17.65 µM, respectively. In addition, molecular docking studies revealed that compound (2) interacts with the five main regions of AChE via both hydrogen and hydrophobic bonding. In contrast to AChE, the interactions of (2) with the enzymatic site of BChE are established only through hydrophobic bonding. The current finding suggests that U. attenuata could be a good source of bioactive alkaloids for treating age-related dementia.

Protection against H2O2-evoked toxicity in HT22 hippocampal neuronal cells by geissoschizine methyl ether via inhibiting ERK pathway.

Oxidative stress is considered as an important mechanism underlying the pathology of neurodegenerative disorders. In this study, we utilized an in vitro model where oxidative stress process was evoked by exogenous hydrogen peroxide (H2O2) in HT22 murine hippocampal neurons and evaluated the neuroprotective effects of geissoschizine methyl ether (GME), a naturally occurring alkaloid from the hooks of Uncaria rhynchophylla (Miq.) Jacks. After a 24 h H2O2 (350 μM) insult, a significant decrease in cell survival and a sharp increase in intracellular reactive oxygen species were observed in HT22 cells. Encouragingly, GME (10–200 μM) effectively reversed these abnormal cellular changes induced by H2O2. Moreover, mechanistic studies using Western blot revealed that GME inhibited the increase of phospho-ERK protein expression, but not phospho-p38, caused by H2O2. Molecular docking simulation further revealed a possible binding mode that GME inhibited ERK protein, showing that GME favorably bound to ERK via multiple hydrophobic and hydrogen bond interactions. These findings indicate that GME provide effective neuroprotection via inhibiting ERK pathway and also encourage further ex vivo and in vivo pharmacological investigations of GME in treating oxidative stress-mediated neurological disorders.

Network Pharmacology and Molecular Docking to Explore the Mechanism of Kangxian Decoction for Epilepsy.

Purpose Kangxian decoction (KXD) has been used in clinical practice to treat epilepsy. The purpose of this study was to explore the active components of KXD and clarify its antiepileptic mechanism through network pharmacology and molecular docking. Methods The components of KXD were collected from the Encyclopedia of Traditional Chinese Medicine (ETCM) database and the literature was searched. Then, active ingredients were screened by SwissADME and potential targets were predicted by the SwissTargetPrediction database. Epilepsy-related differentially expressed genes were downloaded from the Gene Expression Omnibus database. A component-target-pathway network was constructed with Cytoscape. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis and protein‒protein interaction network analysis revealed the potential mechanism and critical targets. Receiver operating characteristic (ROC) curves and box plots in microarray data validated the good diagnostic value and significant differential expression of these critical genes. Molecular docking verified the association between active ingredients and essential target proteins. Results In our study, we screened the important compounds of KXD for epilepsy, including quercetin, baicalin, kaempferol, yohimbine, geissoschizine methyl ether, baicalein, etc. KXD may exert its therapeutic effect on epilepsy through the following targets: PTGS2, MMP9, CXCL8, ERBB2, and ARG1, acting on the following pathways: neuroactive ligand-receptor interactions, arachidonic acid metabolism, IL-17, TNF, NF-kappa B, and MAPK signaling pathways. The molecular docking results showed that the active ingredients in KXD exhibited good binding ability to the key targets. Conclusion In this study, we explored the possibility that KXD for epilepsy may act on multiple targets through multiple active ingredients, involving neurotransmitters and neuroinflammatory pathways, providing a theoretical basis for subsequent clinical and experimental studies that will help develop effective new drugs to treat epilepsy.

Properties, Pharmacology, and Pharmacokinetics of Active Indole and Oxindole Alkaloids in Uncaria Hook.

Uncaria Hook (UH) is a dry stem with hook of Ucaria plant and is contained in Traditional Japanese and Chinese medicine such as yokukansan, yokukansankachimpihange, chotosan, Gouteng-Baitouweng, and Tianma-Gouteng Yin. UH contains active indole and oxindole alkaloids and has the therapeutic effects on ailments of the cardiovascular and central nervous systems. The recent advances of analytical technology led to reports of detailed pharmacokinetics of UH alkaloids. These observations of pharmacokinetics are extremely important for understanding the treatment’s pharmacological activity, efficacy, and safety. This review describes properties, pharmacology, and the recently accumulated pharmacokinetic findings of UH alkaloids, and discusses challenges and future prospects. UH contains major indole and oxindole alkaloids such as corynoxeine, isocorynoxeine, rhynchophylline, isorhynchophylline, hirsuteine, hirsutine, and geissoschizine methyl ether (GM). These alkaloids exert neuroprotective effects against Alzheimer’s disease, Parkinson’s disease, and depression, and the mechanisms of these effects include anti-oxidant, anti-inflammatory, and neuromodulatory activities. Among the UH alkaloids, GM exhibits comparatively potent pharmacological activity (e.g., agonist activity at 5-HT1A receptors). UH alkaloids are absorbed into the blood circulation and rapidly eliminated when orally administered. UH alkaloids are predominantly metabolized by Cytochrome P450 (CYP) and converted into various metabolites, including oxidized and demethylated forms. Regarding GM metabolism by CYPs, a gender-dependent difference is observed in rats but not in humans. Several alkaloids are detected in the brain after passing through the blood–brain barrier in rats upon orally administered. GM is uniformly distributed in the brain and binds to various channels and receptors such as the 5-HT receptor. By reviewing the pharmacokinetics of UH alkaloids, challenges were found, such as differences in pharmacokinetics between pure drug and crude drug products administration, food-influenced absorption, metabolite excretion profile, and intestinal tissue metabolism of UH alkaloids. This review will provide readers with a better understanding of the pharmacokinetics of UH alkaloids and their future challenges, and will be helpful for further research on UH alkaloids and crude drug products containing UH.

Gender differences in plasma pharmacokinetics and hepatic metabolism of geissoschizine methyl ether from Uncaria hook in rats

Ethnopharmacological relevanceGeissoschizine methyl ether (GM), an indole alkaloid from Uncaria hook, is an active ingredient in the traditional Japanese Kampo medicine yokukansan, which is used to treat neurosis, insomnia, irritability, and night crying in children. Aim of the studyRecent our pharmacokinetic studies suggested that there may be gender differences in the plasma concentrations of GM in rats, but not in humans. However, the details of this difference remain unverified. The purpose of this study was to clarify the reasons for the gender differences in rats. Materials and methodsGM plasma pharmacokinetics was compared in male and female rats orally administered yokukansan (4 g/kg). To confirm the involvement of cytochrome P450 (CYP) in GM liver metabolism, GM was incubated with male and female rat liver S9 fraction in the absence or presence of 1-aminobenzotriazole (a nonspecific CYP inhibitor). CYP isoforms involved in GM metabolism were estimated using recombinant rat CYP isoforms and anti-rat CYP antibodies. ResultsThe maximum GM plasma concentrations were significantly higher in female than in male rats. When GM was incubated with rat liver S9 fractions, GM reduction was more striking in male S9 (69.3%) than that in female S9 (10.0%) and was completely blocked with nonspecific CYP inhibitor 1-aminobenzotriazole. Screening experiments using recombinant rat cytochrome P450 (CYP) isoforms showed that CYP1A1, CYP2C6, CYP2C11, CYP2D1, and CYP3A2 were involved in GM metabolism. Of these CYP isoforms, the use of anti-rat CYP antibodies indicated that male-dependent CYP2C11 and CYP3A2 were predominantly involved in the liver microsomal GM metabolism with gender differences. ConclusionsThese results suggest that the cause of gender differences in plasma GM pharmacokinetics in rats is most likely because of male-dependent CYP2C11 and CYP3A2, and provide also useful information to further evaluate the pharmacological and toxicological effects in future. This study is the first to demonstrate that the gender differences in plasma GM pharmacokinetics in rats are caused by the gender-dependent metabolism of GM.

Brain distribution of geissoschizine methyl ether in rats using mass spectrometry imaging analysis

Geissoschizine methyl ether (GM) is one of the main active ingredients responsible for ameliorating the behavioral and psychological symptoms of dementia (BPSD) in Kampo medicine yokukansan. GM is mainly metabolized into hydroxylated forms (HM-1/2). However, the brain distributions of GM and HM has not been reported in vivo. In this study, therefore, the plasma concentrations and brain distribution of these compounds were examined in vivo using rats injected intravenously with GM. Plasma concentrations were analyzed using liquid chromatography-tandem mass spectrometry analysis and brain distribution using mass spectrometry imaging analysis. Plasma GM and HM-1 concentrations decreased in the 4 h after injection, whereas the concentration of plasma HM-2 increased at 4 h. In the 0.25 h-brain, GM signals were diffusely observed throughout the brain, including the cerebral cortex, hippocampus, striatum, thalamus, amygdala, cerebellum, and cerebral ventricle. HM signals were detected only in the ventricles of the brain at 4 h. These results suggest that plasma GM enters the brain and distributes in the parenchyma of various brain regions involved in BPSD, while plasma HM does not enter the brain parenchyma. This study is also the first to visually demonstrate the brain distribution of GM and its metabolite in vivo.

Lipidomics-based study on the neuroprotective effect of geissoschizine methyl ether against oxidative stress-induced cytotoxicity

Ethnopharmacological relevanceLipid homoeostasis is important for neurodevelopment, cell signaling and neurotransmission. Alteration of lipid metabolism has been demonstrated in many neurological disorders and neurodegenerative diseases. Geissoschizine methyl ether (GM) is an active alkaloid ingredient in the traditional Chinese medicine Uncaria hook. It has been shown that GM has strong potency in neuroprotective activity and GM reduces the production of reactive oxygen species by regulating glucose metabolism, which protects neurons against oxidative stress-induced cell death. However, it is unknown whether GM could regulate neuronal lipid metabolism during oxidative challenge. Aim of the studyThe current study aimed to explore whether GM regulates lipid metabolism in oxidative damaged neurons and to determine the underlying mechanism involved in this neuro-protection. Materials and methodsUsing a glutamate-induced oxidative toxicity model in mouse hippocampal neuronal cell line (HT-22 cells), we investigated the effect of GM on glutamate-induced lipid peroxidation, lipotoxicity and mitochondrial dysfunction. In order to clarify the mechanism underlying the neuroprotection by GM, lipid metabolomics was performed to investigate whether GM prevent oxidative stress-induced lipid metabolism disruption. Furthermore, the expression of lipid metabolism-related genes was measured. ResultsThe results show the protective effect of GM against oxidative stress through blocking glutamate-induced lipid peroxidation and lipotoxicity. Overall, lipidomics analysis revealed that glutamate treatment resulted in different extents of changes in a wide range of lipid classes such as fatty acids (FA), triacylglycerol (TG), sphingomyelin (SM), cardiolipin (CL), lysophosphatidylcholines (LPC). However, GM treatment can significantly reverse glutamate-induced lipids disorder to the homeostasis level. GM prevented the disruption of lipid metabolism by regulating the expression of lipid homeostasis related genes, which contributes to preserve mitochondrial function under oxidative damage. ConclusionThese findings clearly demonstrated a novel protective mechanism of GM against glutamate-induced oxidative toxicity in neurons via regulating lipid metabolism. GM may provide an effective approach for the prevention and treatment of oxidative damaged neurons.

Antiepileptic geissoschizine methyl ether is an inhibitor of multiple neuronal channels.

Geissoschizine methyl ether (GM) is an indole alkaloid isolated from Uncaria rhynchophyll (UR) that has been used for the treatment of epilepsy in traditional Chinese medicine. An early study in a glutamate-induced mouse seizure model demonstrated that GM was one of the active ingredients of UR. In this study, electrophysiological technique was used to explore the mechanism underlying the antiepileptic activity of GM. We first showed that GM (1−30 μmol/L) dose-dependently suppressed the spontaneous firing and prolonged the action potential duration in cultured mouse and rat hippocampal neurons. Given the pivotal roles of ion channels in regulating neuronal excitability, we then examined the effects of GM on both voltage-gated and ligand-gated channels in rat hippocampal neurons. We found that GM is an inhibitor of multiple neuronal channels: GM potently inhibited the voltage-gated sodium (NaV), calcium (CaV), and delayed rectifier potassium (IK) currents, and the ligand-gated nicotinic acetylcholine (nACh) currents with IC50 values in the range of 1.3−13.3 μmol/L. In contrast, GM had little effect on the voltage-gated transient outward potassium currents (IA) and four types of ligand-gated channels (γ-amino butyric acid (GABA), N-methyl-D-aspartate (NMDA), α-amino-3-hydroxy-5-methylisoxazole-4-propionate/kainite (AMPA/KA receptors)). The in vivo antiepileptic activity of GM was validated in two electricity-induced seizure models. In the maximal electroshock (MES)-induced mouse seizure model, oral administration of GM (50−100 mg/kg) dose-dependently suppressed generalized tonic-clonic seizures. In 6-Hz-induced mouse seizure model, oral administration of GM (100 mg/kg) reduced treatment-resistant seizures. Thus, we conclude that GM is a promising antiepileptic candidate that inhibits multiple neuronal channels.

LC-MS/MS detection of citrus unshiu peel-derived flavonoids in the plasma and brain after oral administration of yokukansankachimpihange in rats

1. Yokukansankachimpihange (YKSCH), a Kampo formulation combining Citrus unshiu peel (CUP) and Pinellia tuber (PT) with yokukansan (YKS), has been recently used to treat the behavioral and psychological symptoms of dementia. Several flavonoids derived from CUP and PT reportedly exhibit psychopharmacological activity, but it remains unclear whether these flavonoids reach the brain after oral administration of YKSCH.2. In this study, we first measured eight target flavonoids in the plasma and brain in rats orally administered YKSCH. Among these flavonoids, hesperidin, narirutin, nobiletin, and heptamethoxyflavone (HMF) were detected in the plasma, and nobiletin and HMF were detected in the brain.3. Next, to clarify whether CUP and PT affect the pharmacokinetics of YKS ingredients in YKSCH, the plasma pharmacokinetics of geissoschizine methyl ether (GM) as a representative active ingredient in YKS was examined in rats orally administered YKSCH or YKS. There was no significant difference between the two groups, inferring that the pharmacokinetics of GM may not be affected by the two additional crude drugs.4. Taken together, this study suggests that the CUP-derived flavonoids nobiletin and HMF may be responsible for the psychopharmacological effects of YKSCH in addition to YKS ingredients.

Identification of the absorbed components and their metabolites of Tianma-Gouteng granule in rat plasma and bile using ultra-high-performance liquid chromatography combined with quadrupole time-of-flight mass spectrometry.

Tianma-Gouteng granule (TGG), a Chinese herbal formula preparation, is clinically used for the treatment of cardio-cerebrovascular diseases such as hypertension, cerebral ischaemia, acute ischaemic stroke and Parkinson's disease. Although few reports have been published concerning the absorbed prototype components of TGG, the possible metabolic pathways of TGG in vivo remain largely unclear. In this study, a method using UPLC-Q/TOF MS was established for the detection and identification of the absorbed prototype components and related metabolites in rat plasma and bile after oral administration of TGG at high and normal clinical dosages. A total of 68 components were identified or tentatively identified in plasma and bile samples, including absorbed prototypes and their metabolites. The major absorbed components were gastrodin, isorhynchophylline, rhynchophylline, isocorynoxeine, corynoxeine, geissoschizine methyl ether baicalin, baicalein, wogonoside, wogonin, geniposidic acid, leonurine, 2,3,5,4'-tetrahydroxystilbene-2-O-β-d-glucoside and emodin. The main metabolic pathways of these components involved phase I (isomerization, hydrolysis and reduction) and phase II (glucuronidation and sulfation) reaction, and the phase II biotransformation pathway was predominant. The present study provides rich information on the in vivo absorption and metabolism of TGG, and the results will be helpful for further studies on the pharmacokinetics and pharmacodynamics of TGG.

Basic Study of Drug-Drug Interaction between Memantine and the Traditional Japanese Kampo Medicine Yokukansan.

Several basic pharmacokinetic and pharmacological studies were conducted as part of a group of studies to clarify the drug-drug interaction (DDI) between memantine (MEM), a drug used to treat Alzheimer’s disease, and yokukansan (YKS), a traditional Japanese Kampo medicine used to treat behavioral and psychological symptoms of dementia. The pharmacokinetic studies showed that there were no statistically significant differences in MEM concentrations in the plasma, brain, and urine between mice treated with MEM alone and with MEM plus YKS. Regarding candidate active ingredients of YKS, there were also no statistically significant differences in concentrations of geissoschizine methyl ether in the plasma and brain, urine, glycyrrhetinic acid in the plasma, and isoliquiritigenin in the urine, in mice treated with YKS alone or with MEM plus YKS. The pharmacological studies showed that isoliquiritigenin, which has an N-methyl-d-aspartic acid (NMDA) receptor antagonistic effect, did not affect the inhibitory effect of MEM on NMDA-induced intracellular Ca2+ influx in primary cultured rat cortical neurons. Moreover, YKS did not affect either the ameliorative effects of MEM on NMDA-induced learning and memory impairment, or the MEM-induced decrease in locomotor activities in mice. These results suggest that there is probably no pharmacokinetic or pharmacological interaction between MEM and YKS in mice, but more detailed studies are needed in the future. Our findings provide important information for future studies, to clarify the DDI more regarding the efficacy and safety of combined use of these drugs in a clinical situation.

Yokukansan contains compounds that antagonize the 5-HT3 receptor

BackgroundWe recently focused on alkaloids in Uncaria hook (a constituent of the Kampo medicine, yokukansan) and identified the pharmacological action of geissoschizine methyl ether on several G protein-coupled receptors. However, the functions of other identified alkaloids in Uncaria hook, including hirsutine, hirsuteine, rhynchophylline, isorhynchophylline, corynoxeine, isocorynoxeine, are not clear. PurposeTo evaluate the effect of seven alkaloids in Uncaria hook (hirsutine, hirsuteine, rhynchophylline, isorhynchophylline, corynoxeine, isocorynoxeine and geissoschizine methyl ether) on the hydroxytryptamine type-3 (5-HT3) receptor ion channel. Study designWe examined the effect of these alkaloids on the current of human 5-HT3 receptors expressed in Xenopus laevis oocytes. MethodsThe human 5-HT3A subunit alone for the 5-HT3A receptor, or 5-HT3A and 5-HT3B subunits for the 5-HT3AB receptor, were expressed in Xenopus laevis oocytes. The 5-HT current was measured with or without alkaloid application using a two-electrode voltage clamp. ResultsEach alkaloid, except for geissoschizine methyl ether, weakly inhibited the 5-HT-mediated 5-HT3A and/or 5-HT3AB receptor current, but co-application of these seven alkaloids inhibited the current strongly. ConclusionEach alkaloid contributes to antagonism of the 5-HT3 receptor.

Simultaneous determination of eight bioactive compounds by LC-MS/MS and its application to the pharmacokinetics, liver first-pass effect, liver and brain distribution of orally administrated Gouteng-Baitouweng (GB) in rats

Only focusing on the circulating levels is insufficient for the comprehensive understanding of the physiological disposition of herbal medicine in vivo. Therefore, we conducted the comprehensive investigation on the in vivo dynamic process of orally administrated Gouteng-Baitouweng (GB), a classical herb pair with anti-Parkinson potentials. Serving as the technical base, a sensitive and selective liquid chromatography–tandem mass spectrometry method was established and validated in the plasma, liver and brain, for simultaneous determination of five alkaloids (rhynchophylline, isorhynchophylline, corynoxeine, isocorynoxeine and geissoschizine methyl ether) and three saponins (anemoside B4, anemoside A3 and 23-hydroxybetulinic acid). Following liquid-liquid extraction, favorable chromatographic behaviors of eight analytes were obtained on Waters Xbrigde C18 column within 13 min. This method elicited good linearity for the analytes at the concentration range of 0.3–1000 or 1.8–6000 ng/mL with favorable precision, accuracy and stability. Following oral administration of GB (25 g/kg) in rats, this method was applied to the quantitative analysis in the portal vein plasma, liver, systemic plasma, and brain. Consequently, anemoside B4 was of the highest exposure, followed by 23-hydroxybetulinic acid, anemoside A3, rhynchophylline and isocorynoxeine in vivo. Notably, three saponins were all observed with certain exposure in the brain, along with rhynchophylline at low levels. Besides, five alkaloids and 23-hydroxybetulinic acid underwent serious liver first-pass effect. Hence, the pharmacokinetics, liver first-pass effect, liver and brain distribution of ingredients in GB were clarified, which laid a solid foundation for interpreting its efficacy and safety.

Serotonin Receptor Binding Characteristics of Geissoschizine Methyl Ether, an Indole Alkaloid in Uncaria Hook.

Background: Geissoschizine methyl ether (GM) is one of the indole alkaloids in Uncaria hook, and an active ingredient of yokukansan (YKS) that improves behavioral and psychological symp-toms of dementia (BPSD) in patients with several types of dementia. The pharmacological action of GM has been related to various serotonin (5-HT) receptor subtypes.Objective: The aim of this article is to review the binding characteristics of GM to the 5-HT receptor sub-types in the brains using our own data and previous findings.Methods: Competitive receptor-binding and agonist/antagonist activity assays for several 5-HT receptor subtypes were performed. Moreover, the articles describing pharmacokinetics and brain distribution of GM were searched in PubMed.Results: GM bound the following 5-HT receptor subtypes: 5-HT1A, 5-HT1B, 5-HT2A, 5-HT2B, 5-HT2C, 5-HT4, 5-HT5A, 5-HT6, and 5-HT7. Among these receptors, GM had partial agonistic activity for 5-HT1A receptors and antagonistic activity for 5-HT2A, 5-HT2B, 5-HT2C, and 5-HT7 receptors. Also, GM was me-tabolized by various CYP isoforms, mainly CYP3A4. Parent/unchanged GM was detected in both the blood and brain of rats after oral administration of YKS. In the brains, GM was presumed to bind to 5-HT1A, 5-HT2A, 5-HT2B, 5-HT2C, and 5-HT7 receptors on neuron-like large cells mainly in the frontal cor-tex.Conclusion: These results suggest that GM is a pharmacologically important alkaloid that regulates vari-ous serotonergic activities or functions by binding to multiple 5-HT receptor subtypes. Thus, this review provides recent 5-HT receptor-related evidence that GM is partly responsible for pharmacological effects of YKS.

Characteristic Chromatogram: A Method of Discriminate and Quantitative Analysis for Quality Evaluation of Uncaria Stem with Hooks.

It remains a challenge to establish new monographs for herbal drugs derived from multiple botanical sources. Specifically, the difficulty involves discriminating and quantifying these herbs with components whose levels vary markedly among different samples. Using Uncaria stem with hooks as an example, a characteristic chromatogram was proposed to discriminate its five botanical origins and to quantify its characteristic components in the chromatogram. The characteristic chromatogram with respect to the components of Uncaria stem with hooks with the five botanical origins was established using 0.02% diethylamine and acetonitrile as the mobile phase. The total analysis time was 50 min and the detection wavelength was 245 nm. Using the same chromatogram parameters, the single standard to determine multicomponents method was validated to simultaneously quantify nine indole alkaloids, including vincosamide, 3α-dihydrocadambine, isocorynoxeine, corynoxeine, isorhynchophylline, rhynchophylline, hirsuteine, hirsutine, and geissoschizine methyl ether. The results showed that only the Uncaria stem with hooks from Uncaria rhynchophylla, the most widely used in the herbal market, showed the presence of these nine alkaloids. The conversion factors were 1.27, 2.32, 0.98, 1.04, 1.00, 1.02, 1.26, 1.33, and 1.25, respectively. The limits of quantitation were lower than 700 ng/mL. The total contents of 31 batches of Uncaria stem with hooks were in the range of 0.1 - 0.6%, except for Uncaria hirsuta Havil and Uncaria sinensis (Oliv.) Havil. The results also showed that the total content of indole alkaloids tended to decrease with an increase in the hook diameter. This showed that the characteristic chromatogram is practical for controlling the quality of traditional Chinese medicines with multiple botanical origins.

Multiple Psychopharmacological Effects of the Traditional Japanese Kampo Medicine Yokukansan, and the Brain Regions it Affects.

Yokukansan (YKS), a traditional Japanese Kampo medicine, has indications for use in night crying and irritability in children, as well as neurosis and insomnia. It is currently also used for the remedy of the behavioral and psychological symptoms of dementia (BPSD), such as aggressiveness, agitation, and hallucinations. In parallel with clinical evidence, a significant amount of fundamental researches have been undertaken to clarify the neuropsychopharmacological efficacies of YKS, with approximately 70 articles, including our own, being published to date. Recently, we reviewed the neuropharmacological mechanisms of YKS, including its effects on glutamatergic, serotonergic, and dopaminergic neurotransmission, and pharmacokinetics of the ingredients responsible for the effects. This review is aimed to integrate the information regarding the psychopharmacological effects of YKS with the brain regions known to be affected, to facilitate our understanding of the clinical efficacy of YKS. In this review, we first show that YKS has several effects that act to improve symptoms that are similar to BPSDs, like aggressiveness, hallucinations, anxiety, and sleep disturbance, as well as symptoms like tardive dyskinesia and cognitive deficits. We next provide the evidence showing that YKS can interact with various brain regions, including the cerebral cortex, hippocampus, striatum, and spinal cord, dysfunctions of which are related to psychiatric symptoms, cognitive deficits, abnormal behaviors, and dysesthesia. In addition, the major active ingredients of YKS, geissoschizine methyl ether and 18β-glycyrrhetinic acid, are shown to predominantly bind to the frontal cortex and hippocampus, respectively. Our findings suggest that YKS has multiple psychopharmacological effects, and that these are probably mediated by interactions among several brain regions. In this review, we summarize the available information about the valuable effects of a multicomponent medicine YKS on complex neural networks.

Neuropharmacological efficacy of the traditional Japanese Kampo medicine yokukansan and its active ingredients.

Dementia is a progressive neurodegenerative disorder with cognitive dysfunction, and is often complicated by behavioral and psychological symptoms of dementia (BPSD) including excitement, aggression, and hallucinations. Typical and atypical antipsychotics are used for the treatment of BPSD, but induce adverse events. The traditional Japanese Kampo medicine yokukansan (YKS), which had been originated from the traditional Chinese medicine Yi-Gan-San, has been reported to improve BPSD without severe adverse effects. In the preclinical basic studies, there are over 70 research articles indicating the neuropharmacological efficacies of YKS. In this review, we first describe the neuropharmacological actions of YKS and its bioactive ingredients. Multiple potential actions for YKS were identified, which include effects on serotonergic, glutamatergic, cholinergic, dopaminergic, adrenergic, and GABAergic neurotransmissions as well as neuroprotection, anti-stress effect, promotion of neuroplasticity, and anti-inflammatory effect. Geissoschizine methyl ether (GM) in Uncaria hook and 18β-glycyrrhetinic acid (GA) in Glycyrrhiza were responsible for several pharmacological actions of YKS. Subsequently, we describe the pharmacokinetics of GM and GA in rats. These ingredients were absorbed into the blood, crossed the blood-brain barrier, and reached the brain, in rats orally administered YKS. Moreover, autoradiography showed that [(3)H]GM predominantly distributed in the frontal cortex and [(3)H]GA in the hippocampus. Thus, YKS is a versatile herbal remedy with a variety of neuropharmacological effects, and may operate as a multicomponent drug including various active ingredients.

Geissoschizine methyl ether protects oxidative stress-mediated cytotoxicity in neurons through the ‘Neuronal Warburg Effect’

Ethnopharmacological relevanceThe rate of production of reactive oxygen species (ROS) is determined by mitochondrial metabolic rate. In turn, excessive ROS damage mitochondrial function, which is linked to aging and neurodegenerative conditions. One possible path to prevent oxidative stress could be achieved by reducing mitochondrial respiration in favor of less efficient ATP production via glycolysis. Such a shift in energy metabolism is known as the ‘Warburg effect’. Geissoschizine methyl ether (GM) is one of the active components responsible for the psychotropic effects of Yokukansan, an herbal preparation widely used in China and Japan. Aim of the studyGM protects neurons from glutamate-induced oxidative cytotoxicity through regulating mitochondrial function and suppressing ROS generation. We investigated the protective mechanism of GM against glutamate-induced oxidative stress in neuronal cells. Materials and methodsThe current study was performed on primary neurons and HT22 cells, a hippocampus neuronal cell line. Cell viability was measured by Calcein AM assay. H2DCFDA staining was used for intracellular ROS measurement. GSH level was measured using the GSH-Glo™ luminescence-based assay. Mitochondrial respiration and glycolysis were measured by the Seahorse Bioscience XFe 96 Extracellular Flux Analyzer. Protein levels were analyzed by western blot analysis. ResultsGM prevented glutamate-induced cytotoxicity in an HT-22 neuronal cell line even with a 9-hour exposure delay. GM blocked glutamate-induced intracellular ROS accumulation through suppressing mitochondrial respiration. Further, we found that GM up-regulated glycolysis and the pentose-phosphate pathway, which is involved in the production of intracellular reducing agent, NADPH. In addition, GM protected primary cortical neurons from both glutamate and buthioninesulfoximine toxicity. ConclusionGM prevents glutamate-induced oxidative damage through reducing mitochondrial respiration, which further suppresses ROS generation. In addition, GM up-regulates glycolysis which compensate for the energy depletion induced by mitochondrial respiration inhibition. Overall, our study is the first to report that GM protects neurons from oxidative toxicity by shifting energy metabolism from mitochondrial respiration to glycolysis.

Yokukansan improves behavioral and psychological symptoms of dementia by suppressing dopaminergic function.

Although three drugs, risperidone, yokukansan, and fluvoxamine, have shown equal efficacy in treating behavioral and psychological symptoms of dementia (BPSD) in our previous study, their mechanisms of action are different from one another. Monoamines have attracted attention for their key roles in mediating several behavioral symptoms or psychological symptoms through synaptic signaling. We aimed to clarify the monoamines changed by treatment with each drug in patients with BPSD. The main purpose of this study was to determine whether plasma levels of catecholamine metabolites are correlated with pharmacological treatments. This was an 8-week, rater-blinded, randomized, flexible-dose, triple-group trial. In total, 90 subjects were recruited and subsequently three different drugs were allocated to 82 inpatients with BPSD. We examined BPSD data from patients who completed 8 weeks of treatment. Eventually, we analyzed 42 patients (yokukansan: 17; risperidone: 9; fluvoxamine: 16). Homovanillic acid, a metabolite of dopamine, and 3-methoxy-4-hydroxyphenylglycol, a metabolite of noradrenaline, in their plasma were analyzed by high-performance liquid chromatography with electrochemical detection. All three drugs showed equal significant efficacy between baseline and study endpoint. By contrast, biomarkers showed mutually different changes. Patients in the yokukansan group had significantly decreased plasma homovanillic acid levels from baseline. Conversely, patients in the risperidone and fluvoxamine groups exhibited no significant changes in plasma homovanillic acid levels from baseline. Yokukansan contains geissoschizine methyl ether, which is known to have a partial agonist effect on dopamine D2 receptors. An improvement in BPSD condition with the intake of yokukansan is suggested to occur through a suppressed dopaminergic function, which is similar to the effect of aripiprazole.

Yokukansan, a Traditional Japanese Medicine, Enhances the L-DOPA-Induced Rotational Response in 6-Hydroxydopamine-Lesioned Rats: Possible Inhibition of COMT.

The aim of the present study was to investigate the effects of the traditional Japanese medicine yokukansan (YKS) on the function of dopamine (DA) in the rat nigrostriatal system. Unilateral 6-hydroxydopamine lesions were produced in the rat nigrostriatal system. Despite a marked loss in the striatal immunoreactivity of tyrosine hydroxylase on the lesion side, striatal serotonin (5-HT) immunoreactivity was not affected. Treatment using L-3,4-dihydroxyphenylalanine (L-DOPA) in conjunction with benserazide for 15 d induced abnormal involuntary movements (AIMs) such as locomotive (rotational response), axial, forelimb, and orolingual movements in the lesioned rats. The L-DOPA-induced locomotive and axial, but not forelimb and orolingual, AIMs were significantly increased and prolonged by the pre-administration of YKS. We next investigated the effects of YKS on the production of DA from L-DOPA in 5-HT synthetic RIN 14B cells. RIN 14B cells produced DA and its metabolite, 3-methoxytyramine (3-MT), following L-DOPA treatment. YKS significantly augmented DA production and inhibited its metabolism to 3-MT in a manner similar to the catechol-O-methyltransferase (COMT) inhibitor entacapone. YKS and some alkaloids (corynoxeine: CX, geissoschizine methyl ether: GM) in Uncaria hook, a constituent herb of YKS, also inhibited COMT activity, indicating that the augmenting effect of YKS on L-DOPA-induced DA production in 5-HT synthetic cells was due to the inhibition of COMT by CX and GM. Our results suggest that YKS facilitates the DA supplemental effect of L-DOPA, and that COMT inhibition by CX and GM contributes, at least in part, to the effects of YKS.