Ninjin-yoei-to (Ren-Shen-Yang-Rong-Tang) and Polygalae radix improves scopolamine-induced impairment of passive avoidance response in mice

Ninjin'yoeito Modulates Baseline and Reperfusion-Induced Changes in the Arteriole Diameter and Blood Flow in the Cerebral Cortex of Anesthetized Mice

OBJECTIVE

Intragastric administration of ninjin'yoeito (NYT), a traditional Japanese herbal medicine, reportedly prevents the decrease in baseline cerebral blood flow (CBF) in the cortex following gastric administration of water. We investigated the effect of NYT on baseline and dynamic changes in cerebral cortical arteriole diameter.

METHODS

Urethane-anesthetized mice were intragastrically administered 1 g/kg NYT or distilled water (DW). The artery in the left parietal cortex was imaged using two-photon microscopy. The baseline diameter of penetrating arterioles was measured before and 50-60 min after administration. Dynamic CBF and arteriole diameter changes before, during, and after transient occlusion of the left common carotid artery were measured approximately 10 min after administration.

RESULTS

DW decreased the baseline diameter of the penetrating arterioles, whereas NYT did not. During occlusion, the increase in penetrating arteriole diameter was comparable for DW and NYT; however, during reperfusion, the return to preocclusion diameter was slower for NYT than DW. Laser-speckle contrast imaging confirmed that CBF, although comparable during occlusion, was higher during reperfusion for NYT than DW.

CONCLUSIONS

These results suggest that NYT attenuates vasoconstriction in penetrating arterioles after intragastric administration and during cerebral reperfusion, contributing to CBF regulation.

The Effects of Ninjinyoeito on Impaired Spatial Memory and Prefrontal Cortical Synaptic Plasticity through α-Amino-3-hydroxy-5-4-isoxazole Propionic Acid Receptor Subunit in a Rat Model with Cerebral Ischemia and β-Amyloid Injection

Ninjinyoeito (NYT), a traditional Japanese medicine, is effective for improving physical strength and treating fatigue and anorexia. Recently, a clinical report revealed that NYT ameliorates cognitive dysfunction in Alzheimer's disease (AD) patients, although the mechanisms remain unclear. AD is a neurodegenerative disorder accompanied by a progressive deficit in memory. Current therapeutic agents are largely ineffective in treating cognitive dysfunction in AD patients. In this study, we investigated the effects of NYT on spatial memory impairment in a rat model of dementia. Rats were prepared with transient cerebral ischemia and intraventricular injection of β-amyloid1-42 for 7 days (CI + Aβ). NYT was orally administered for 7 days after cerebral ischemia. We evaluated spatial memory using the Morris water maze and investigated the expression of α-amino-3-hydroxy-5-4-isoxazole propionic acid receptor subunits, the phosphorylation level of glutamate receptor A (GluA)1 at serine sites S831 and S845, and the Ca2+/calmodulin-dependent protein kinase II (CaMKII) in the hippocampus and prefrontal cortex of CI + Aβ rats. In the CI + Aβ rats, NYT treatment shortened the extended time to reach the platform. However, NYT did not restore the decrease in the hippocampal GluA1, GluA2, or CaMKII expression but increased prefrontal cortical phosphorylation levels of S845-GluA1 and CaMKII. Therefore, NYT may alleviate spatial memory impairment by promoting glutamatergic transmission involved in the phosphorylation of S845-GluA1 and CaMKII in the prefrontal cortex of CI + Aβ rats. Our results suggest that NYT is a valuable treatment for AD patients.

Influence of Intragastric Administration of Traditional Japanese Medicine, Ninjin'Yoeito, on Cerebral Blood Flow via Muscarinic Acetylcholine Receptors

Ninjin'yoeito (NYT) is a traditional medicine that has been used for mitigating physical frailty, such as fatigue and anorexia, as well as for cognitive dysfunction. Maintenance of adequate cerebral blood flow (CBF) is important for preventing cognitive dysfunction. The present study aimed to examine the effect of NYT on CBF. Male C57BL/6 J mice were anesthetized with urethane and were artificially ventilated. We measured CBF in the neocortex with laser-speckle contrast imaging for 10 min before administration and 60 min after administration. We administered NYT solution (0.25, 0.5, 1, and 2 g/kg) or vehicle (distilled water; DW) over 5 min via an intragastric catheter. We surgically transected the vagus nerve to investigate its contribution as a neural pathway and intraperitoneally injected atropine to block muscarinic acetylcholine receptors. Finally, we tested the CBF response to cutaneous brushing stimulation applied to the left hind paw (30 sec). CBF decreased after DW administration, starting from 30 min onward, whereas CBF did not change after NYT. The averaged CBF change following DW administration differed from that following NYT (1 g/kg) but not from those following the other doses of NYT. Arterial pressure was not affected by either solution. CBF after NYT (1 g/kg) was not affected by vagotomy but was lower following additional atropine. In response to brushing stimulation, CBF in the right (contralateral) parietal cortex increased. The magnitude of CBF increase following NYT was greater than that following DW. These results suggest that NYT prevents CBF decrease via cholinergic activation independent of vagal activity and enhances the CBF response to somatosensory stimulation.

Preventive effect of Ninjin-yoei-to, a Kampo medicine, on amyloid β1-42-induced neurodegeneration via intracellular Zn2+ toxicity in the dentate gyrus

Ninjin-yoei-to (NYT), a Kampo medicine, has ameliorative effects on cognitive dysfunction via enhancing cholinergic neuron activity. To explore an efficacy of NYT administration for prevention and cure of Alzheimer’s disease, here we examined the effect of NYT on amyloid β_1-42 (Aβ_1-42)-induced neurodegeneration in the dentate gyrus. A diet containing 3% NYT was administered to mice for 2 weeks and human Aβ_1-42 was intracerebroventricularly injected. Neurodegeneration in the dentate granule cell layer of the hippocampus, which was determined 2 weeks after the injection, was rescued by administration of the diet for 4 weeks. Aβ staining (uptake) was not modified in the dentate granule cell layer by pre-administration of the diet for 2 weeks, while Aβ_1-42-induced increase in intracellular Zn²⁺ was reduced, suggesting that pre-administration of NYT prior to Aβ injection is effective for reducing Aβ_1-42-induced Zn²⁺ toxicity in the dentate gyrus. As a matter of fact, Aβ_1-42-induced neurodegeneration in the dentate gyrus was rescued by pre-administration of NYT. Interestingly, the level of metallothioneins, intracellular Zn²⁺-binding proteins, which can capture Zn²⁺ from Zn-Aβ_1-42 complexes, was elevated in the dentate granule cell layer by pre-administration of NYT. The present study suggests that pre-administration of NYT prevents Aβ_1-42-mediated neurodegeneration in the dentate gyurs by induced synthesis of metallothioneins, which reduces intracellular Zn²⁺ toxicity induced by Aβ_1-42.

A silk peptide fraction restores cognitive function in AF64A-induced Alzheimer disease model rats by increasing expression of choline acetyltransferase gene

This study investigated the effects of a silk peptide fraction obtained by incubating silk proteins with Protease N and Neutrase (SP-NN) on cognitive dysfunction of Alzheimer disease model rats. In order to elucidate underlying mechanisms, the effect of SP-NN on the expression of choline acetyltransferase (ChAT) mRNA was assessed in F3.ChAT neural stem cells and Neuro2a neuroblastoma cells; active amino acid sequence was identified using HPLC-MS. The expression of ChAT mRNA in F3.ChAT cells increased by 3.79-fold of the control level by treatment with SP-NN fraction. The active peptide in SP-NN was identified as tyrosine-glycine with 238.1 of molecular weight. Male rats were orally administered with SP-NN (50 or 300mg/kg) and challenged with a cholinotoxin AF64A. As a result of brain injury and decreased brain acetylcholine level, AF64A induced astrocytic activation, resulting in impairment of learning and memory function. Treatment with SP-NN exerted recovering activities on acetylcholine depletion and brain injury, as well as cognitive deficit induced by AF64A. The results indicate that, in addition to a neuroprotective activity, the SP-NN preparation restores cognitive function of Alzheimer disease model rats by increasing the release of acetylcholine.

Safety assessment of Guibi-tang: Subchronic toxicity study in Crl:CD SD rats

Guibi-tang (Kihi-To in Japanese and Qui-Pi-Tang in Chinese) is a multiherbal traditional Korean medicinal formula used for treatment of amnesia, fatigue, poor memory or forgetfulness, anemia, insomnia, and necrosis. The aim of the present study was to investigate potential safety, if any, of subchronic administration of Guibi-tang aqueous extract (GBT) in laboratory animals. For this study, 0, 1000, 2000, and 5000 mg/kg/day of GBT was administered to Crl:CD Sprague Dawley rats (10/sex/group) for 13 weeks via oral gavage. Administration of the GBT did not result in any mortality, body weight, food consumption, hematology, serum biochemistry, clinical or ophthalmological signs or changes in urinalysis, gross findings, or organ weight. However, histopathology revealed forestomach hyperplasia and duodenum mucosal hyperplasia in rats of both sexes at the highest dose of GBT, 5000 mg/kg/day. Therefore, the no-observed-adverse-effect level in rats was established for GBT at 2000 mg/kg/day under the conditions of this study.

Effect of nigranoic acid on Ca²⁺ influx and its downstream signal mechanism in NGF-differentiated PC12 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Schisandra chinensis has a long history of use as a famous traditional Chinese medicine. The plants of genus Schisandra, especially Schisandra neglecta, Schisandra rubriflora, and Schisandra sphaerandra are used in the same way as Schisandra chinensis in the folk medicine to treat insomnia, fatigue, increasing intelligence, and tranquilizing. Many studies showed that lignans were the major active components of Schisandra genus, whereas the bioactivity of abundant triterpenoids in Schisandra genus, such as nigranoic acid (SBB1, 3,4-secocycloartene triterpenoid), has not been examined yet in neuropathology.

MATERIALS AND METHODS

After treating with SBB1, intracellular Ca(2+) concentration was analyzed by Ca(2+) fluorescent indicator (Fluo-4 AM) in NGF-differentiated PC12 cells. Intracellular nitric oxide (NO) level was analyzed using NO fluorescent indicator (DAF-FM). The expression of extracellular signal regulated kinase 1 and 2 (ERK1/2) was analyzed by western blotting, and the temporal mRNA for BDNF and c-fos was analyzed using reverse transcription quantitative PCR.

RESULT

We found that SBB1 induced Ca(2+) influx in a time- and concentration-dependent manner, which was significantly attenuated in Ca(2+) free media. SBB1 promoted the intracellular NO production which depended on increasing cytoplasmic Ca(2+) level. Moreover, SBB1 stimulated activation of ERK1/2 through Ca(2+)-CaMKII pathway. In addition, we found that SBB1 increased the expression of BDNF and c-fos mRNA.

CONCLUSION

These results suggest that SBB1 is able to promote NO production and stimulate phosphorylation of ERK1/2 through Ca(2+) influx, further impact expression of BDNF and c-fos, which provides evidence for the effects of SBB1 that may be benefit to enhance mental and intellectual functions.

Ginseng in traditional herbal prescriptions

Panax ginseng Meyer has been widely used as a tonic in traditional Korean, Chinese, and Japanese herbal medicines and in Western herbal preparations for thousands of years. In the past, ginseng was very rare and was considered to have mysterious powers. Today, the efficacy of drugs must be tested through well-designed clinical trials or meta-analyses, and ginseng is no exception. In the present review, we discuss the functions of ginseng described in historical documents and describe how these functions are taken into account in herbal prescriptions. We also discuss the findings of experimental pharmacological research on the functions of ginseng in ginseng-containing prescriptions and how these prescriptions have been applied in modern therapeutic interventions. The present review on the functions of ginseng in traditional prescriptions helps to demystify ginseng and, as a result, may contribute to expanding the use of ginseng or ginseng-containing prescriptions.

Tenuigenin protects dopaminergic neurons from inflammation-mediated damage induced by the lipopolysaccharide

BACKGROUND

Parkinson's disease (PD) is a neurodegenerative disorder characterized by progressive death of dopaminergic neurons in the substantia nigra pars compacta (SNpc).

AIMS

To study if tenuigenin (TEN), the main active component of Polygala tenuifolia, can protect dopaminergic neurons from inflammation-mediated damage in vivo.

METHODS

We observed the effects of TEN on lipopolysaccharide (LPS) induced PD model by behavioral analysis, high-performance liquid chromatography, immunohistochemistry and enzyme-linked immunoadsorbent assay, etc.

RESULTS

We showed that a single intranigral dose of LPSs (10 μg) induced microglial activation, reduced the survival ratio of tyrosine hydroxylase-immunoreactive (TH-ir) neurons in the SNpc and reduced dopamine (DA) content in the striatum. Treatment with 300 mg/kg TEN once per day over 14 weeks improved the survival rate of TH-ir neurons in the SNpc to 75%, on the non-injected side. Treatment with 200 or 300 mg/kg TEN once per day over 14 weeks significantly improved DA levels in the striatum to 73% and 81% on the non-injected side, respectively. The excessive production of cytokines, such as tumor necrosis factor (TNF)-α and interleukin (IL)-1β, was abolished by TEN administration.

CONCLUSION

Our results suggest that TEN may play a role in protecting dopaminergic neurons against inflammatory challenge.

Cognitive-enhancing effects of polygalasaponin hydrolysate in aβ(25-35)-induced amnesic mice

Polygalasaponins are the major active constituents of Polygala tenuifolia exhibiting antiamnesic activity, but their applications are limited due to their toxicities. Evidence showed that the toxicities can be attenuated by hydrolysis. Herein, effects of a hydrolysate of polygalasaponins (HPS) on cognitive impairment induced by Aβ₂₅₋₃₅ were assessed by Morris water maze and step-through passive avoidance tests. The impaired spatial reference memory was improved by HPS (50 and 100 mg/kg). In the acquisition trial of step-through test, HPS (50 and 100 mg/kg) increased the latency into the dark chamber and decreased the error frequency significantly (P < .05). However, no significant change was observed during the retention trial. Additionally, HPS increased the corresponding SOD activities (62.34%, 22.09%) and decreased MDA levels (28.21%, 32.35%) in both cortex and hippocampus as compared to model animals. These results show that HPS may be a useful treatment against amnesia probably via its antioxidant properties.

Schizandrin reverses memory impairment in rats

The present study investigated the effect of schizandrin, a component of the fruit of Schizandra chinesis Baill (Fructus Schizandrae), on memory impairment in rats. Scopolamine (0.5 mg/kg, i.p.), a non-selective muscarinic receptor antagonist, markedly impaired spatial memory in an eight-arm radial maze. A higher dose of scopolamine (3 mg/kg, i.p.) also impaired the passive avoidance response. Schizandrin (1 and 10 mg/kg, p.o.) significantly reversed the scopolamine-induced impairment of spatial memory. Similarly, schizandrin (1 mg/kg, p.o.) significantly reversed the scopolamine-induced impairment of the passive avoidance response. Moreover, in mice, schizandrin (1 and 10 mg/kg, p.o.) enhanced tremors induced by oxotremorine, a muscarinic M(1) receptor agonist. Taken together these findings suggest that schizandrin reverses scopolamine-induced memory impairment, in part, by enhancing cholinergic function, and that schizandrin might be useful for treating memory deficits.

Effect of Polygala tenuifolia root extract on scopolamine-induced impairment of rat spatial cognition in an eight-arm radial maze task

The effects of Polygala tenuifolia root fractions and the acyl groups of its constituents on the retrieval process of spatial cognition in rats were studied using an eight-arm radial maze task. Oral administration of a precipitate fraction (PTB) obtained by concentration of the n-BuOH-soluble portion from the extract of the roots significantly decreased the number of total errors (TEs) and that of working memory errors (WMEs) at doses of 100 mg/kg and 200 mg/kg. However, it caused no significant decrease in the number of reference memory errors (RMEs). In addition, the saponin-rich fraction (PTBM) obtained by purification of PTB also showed significant decreases in TEs and WMEs at a dose of 100 mg/kg. Among the cinnamic acid derivatives present as the acyl groups in the P. tenuifolia constituents, sinapic acid (SNPA) significantly decreased TEs and WMEs at doses of 10 to 100 mg/kg. These results indicated that P. tenuifolia extracts, PTB and PTBM, and SNPA had a beneficial effect on the memory impairment induced by dysfunction of the cholinergic system in the brain. The memory improvement in the scopolamine-induced memory impairment seen in the radial maze performance was due to improvement in the short-term memory. A contribution of some constituents other than SNPA to the memory improvement was also suggested.

Cerebral protective and cognition-improving effects of sinapic acid in rodents

We previously demonstrated that tenuifoliside B and 3,6'-disinapoylsucrose in Polygalae Radix, the root of Polygala tenuifolia WILLDENOW, inhibited potassium cyanide (KCN)-induced hypoxia and scopolamine-induced memory impairment in mice. Because both ingredients have a common sinapoyl moiety in their structure, we inferred that the sinapoyl moiety could inhibit hypoxia and memory impairment. In the present study to clarify the hypothesis, sinapic acid inhibited KCN-induced hypoxia and scopolamine-induced memory impairment as well as tenuifoliside B and 3,6'-disinapoylsucrose did. In addition, sinapic acid inhibited decompression- or bilateral carotid artery ligation-induced hypoxia (or mortality) and CO2-induced impairment in mice, and basal forebrain lesion-induced cerebral cholinergic dysfunction (decreases in acetylcholine concentration and choline acetyltransferase activity) in rats. These results, taken together, suggest the possibilities that sinapic acid is not only a very important moiety in the pharmacological activities of tenuifoliside B and 3,6'-disinapoylsucrose but also a candidate for a cerebral protective and cognition-improving medicine.

Kamikihi-to, a Kampo medicine, ameliorates impairment of spatial memory in rats

The present study investigated the effects of Kamikihi-to (KKT), a Kampo medicine, on impairment of spatial memory in rats using an eight-arm radial maze task. Scopolamine (0.5 mg/kg, i.p.), a non-selective muscarinic receptor antagonist, and Delta(9)-tetrahydrocannabinol (THC; 6 mg/kg, i.p.), a principal psychoactive component of marihuana, each markedly impaired the spatial memory. KKT (1 and 3 mg/kg, p.o.) significantly improved the scopolamine-induced impairment of spatial memory. KKT (30 mg/kg, p.o.) also improved significantly the THC-induced impairment of spatial memory. Moreover, KKT (3 and 30 mg/kg, p.o.) enhanced tremors induced by oxotremorine, a muscarinic M(1) receptor agonist. Taken together these findings suggest that KKT is a useful drug for treating memory deficits.

Restoration of FcRγ/Fyn signaling repairs central nervous system demyelination

Disruption of myelin causes severe neurological diseases. An understanding of the mechanisms that control myelination and remyelination is needed to develop therapeutic strategies for demyelinating diseases such as multiple sclerosis (MS). Our previous finding indicating the critical involvement of the gamma chain of immunogloblin Fc receptors (FcRgamma) and Fyn signaling in oligodendrocyte differentiaion and myelination demands a fundamental revision of the strategies used for MS therapy, because antigen-antibody complexes in MS patients may induce the direct dysregulation of myelination process as well as the inflammatory destruction of myelin sheath. Here we show that the FcRgamma/Fyn signaling cascade is critically involved in cuprizone-induced demyelination/remyelination, with no lymphocytic response. The levels of phosphorylated myelin basic proteins (p-MBPs), especially the 21.5-kDa isoform, but not the levels of total MBPs, decreased markedly during demyelination induced by aging, cuprizone treatment, and double knockout of FcRgamma/Fyn genes. We also showed that the recovery from demyelination in cuprizone-treated and aged mice is achieved after administration of the herbal medicine Ninjin'yoeito, an effective therapy targeting the FcRgamma/Fyn-Rho (Rac1)-MAPK (P38 MAPK)-p-MBPs signaling cascade. These results suggest that the restoration of FcRgamma/Fyn signaling represents a new approach for the treatment of demyelinating diseases.

The Effects of BR003 on Memory and Cell Proliferation in the Dentate Gyrus of Rat Hippocampus

BR003 is a multi-herbal formula that contains twelve medicinal herbs. We investigated the effects of oral administration of BR003 to Wistar rats on (a) learning and memory using a passive avoidance test and (b) cell proliferation in the dentate gyrus (DG) of the hippocampus using immunohistochemical analysis of 5-bromo-2-deoxyuridine (BrdU) expression. In the passive avoidance test, the retention time of the BR003-treated group was significantly longer than that of the control group (182.64+/-39.88 vs. 73.08+/-29.30 s, respectively; n=11; p<0.05). There were significantly more BrdU-immunoreactive cells in the DG in the BR003-treated group than in the control group (1281.07+/-151.16 vs. 818.01+/-132.98 cells per DG, respectively; n=11; p<0.05). These results suggest that the administration of BR003 not only improves learning and memory but also increases cell proliferation in the DG of the rat hippocampus.

Low dose citalopram reverses memory impairment and electroconvulsive shock-induced immobilization

Citalopram, a selective serotonin reuptake inhibitor (SSRI), is one of the most widely used antidepressants. Recently, citalopram has been reported to improve working memory in patients with depression, and psychotic symptoms and behavioral disturbances in patients with dementia. However, the possibility of using citalopram in the treatment of cognitive disorders has not received much attention. The present study investigated the effects of citalopram on scopolamine- and Delta9-tetrahydrocannabinol (THC)-induced impairment of spatial memory using an eight-arm radial maze and electroconvulsive shock (ECS)-induced immobilization (a behavioral model for the disturbance of consciousness). Low dose citalopram reversed both scopolamine- and THC-induced impairment of spatial memory, suppressed ECS-induced immobilization reversed the THC-induced decrease of acetylcholine (ACh) release in the dorsal hippocampus in vivo microdialysis, and enhanced tremors induced by oxotremorine, a muscarinic M1 receptor agonist. Taken together these findings suggest that low dose citalopram is useful for the treatment of memory deficits and consciousness disturbance.

The multi-herbal formula Guibi-tang enhances memory and increases cell proliferation in the rat hippocampus

Guibi-tang (GBT) is a multi-herbal medicinal formula that has been used to treat amnesia in the traditional Korean medicine system for hundreds of years. In this study, we investigated the effects of GBT on learning and memory function in Wistar rats by using the foot shock passive avoidance test. In addition, cell proliferation was examined using 5-bromo-2-deoxyuridine (BrdU) uptake and immunostaining in the dentate gyrus of the rat hippocampus after oral administration of GBT. In the passive avoidance test, the retention time of the GBT-treated group was significantly longer (almost 2.5-fold) than that of the control group. The number of BrdU-immunoreactive cells in the dentate gyrus was significantly higher in the GBT-treated group (almost twofold) than in the control group. These results suggest that administration of GBT to rats not only improves learning and memory but also increases the proliferation of cells in the dentate gyrus of the hippocampus.

Effect of a Nutritive-Tonic Drink on Scopolamine-Induced Memory Impairment in Mice

The effects of a liquid nutritive and tonic drug (NTD) selected from a modification of the "Kai-xin-shou-yu-shen-qi-wan" prescription, on scopolamine-induced amnesia in mice were investigated using the passive avoidance and water-maze tasks. A popular NTD in Japan that contains 17 crude (natural) drug extracts together with synthetic drugs such as taurine, caffeine, various vitamins and ethanol, and the natural drug extracts is based on a prescription of "Kampo" origin in Chinese medicine. Scopolamine (0.4 mg/kg, i.p.) reduces the step-through latency of the passive avoidance test and fear reaction behavior at 24 and 48 h after treatment. A single oral administration of the NTD (10 ml/kg) increased the step-through latency and the fear reaction behavior score in scopolamine-treated mice. Administration of the natural drug extracts found in the NTD tended to extend the step-through latency in the retention test at 48 h, but not 24 h after the initial scopolamine trial. However, administration of the synthetic drugs found in the NTD did not improve either the step-through latency or the behavioral score. The NTD and the natural drug extracts also improved the scopolamine-induced spatial memory impairment as assessed using the Morris water-maze test. In contrast, the synthetic drugs did not affect the escape latencies. Both NTD and the synthetic drugs increased the locomotor activity in scopolamine-treated mice, whereas the natural drug extracts did not. These results suggest that NTD improves scopolamine-induced amnesia, and that this action is attributable to the natural drug extracts in the NTD.

Therapeutic effects of herbal extracts and constituents in animal models of psychiatric disorders

A search for novel pharmacotherapy from medicinal plants for psychiatric illnesses has progressed significantly in the past decade. This is reflected in the large number of herbal preparations for which psychotherapeutic potential has been evaluated in a variety of animal models. The objective of this review is to provide an overview of herbal extracts and constituents that have significant therapeutic effects in animal models of psychiatric illnesses. Eighty five individual herbs reviewed were classified as anxiolytic, antidepressant, neuroleptic, antidementia, or anti-substance abuse herbs. The full scientific name of each herb, herbal part used, active constituent, extract, dose range and route, animal model, possible mechanisms of action, and pertinent references are presented via synoptic tables. The herbal mixtures were also mentioned. A considerable number of herbal constituents whose behavioral effects and pharmacological actions have been well characterized may be good candidates for further investigations that may ultimately result in clinical use. The investigation of a large portion of the herbal extracts and herbal mixtures is in its infancy. Herbal remedies that have demonstrable psychotherapeutic activities have provided a potential to psychiatric pharmaceuticals and deserve increased attention in future studies.

Cognitive Improving and Cerebral Protective Effects of Acylated Oligosaccharides in Polygala tenuifolia

We studied the cognitive improving and cerebral protective constituents in the roots of Polygala tenuifolia Willdenow, a well-known Chinese traditional medicine prescribed for amnesia, neurasthenia, palpitation, noctural emission and insomnia. Tenuifoliside B (1), which is one of the acylated oligosaccharides in the roots of P. tenuifolia, showed the cerebral protective effect on potassium cyanide (KCN)-induced anoxia in mice, widely used as an animal model for cerebrovascular disease, and also had an ameliorative effect on the scopolamine-induced impairment of performance in passive avoidance task in rats. Compound 1 significantly enhanced oxotremorine-induced tremors in mice, suggesting that it ameliorated the scopolamine-induced impairment of passive avoidance response by enhancing the cholinergic system. These findings show that compound 1 has cognitive improving and cerebral protective effects.