3,4,5-Trimethoxycinnamic acid (TMCA), one of the constituents of Polygalae Radix enhances pentobarbital-induced sleeping behaviors via GABAAergic systems in mice

Tenuigenin promotes non-rapid eye movement sleep via the GABAA receptor and exerts somnogenic effect in a MPTP mouse model of Parkinson's disease

Sleep disturbances are commonly non-motor symptoms in Parkinson's diseases (PD). However, standard dopamine replacement therapies for the treatment of motor symptoms often prove inadequate in combating sleep disturbances. Previous studies conducted by our research group have reported the neuroprotective effects of tenuigenin, a natural extract from Polygala tenuifolia root, which has been traditionally employed in treating insomnia. The objective of this study was to investigate the potential of tenuigenin in modulating sleep-wake behaviors and elucidate the underlying mechanisms. We employed EEG/EMG recordings to evaluate the impact of tenuigenin on sleep-wake profiles. Furthermore, we utilized c-Fos immunostaining, whole-cell patch clamping and local field potentials (LFP) recording to explore the mechanisms involved in sleep-promoting effects of tenuigenin. Additionally, we examined the effects of tenuigenin on sleep-promoting in MPTP PD mice. Here, we found tenuigenin demonstrated a significant increase in NREM sleep and a reduction in sleep latency in mice, without altering the EEG power density. Moreover, tenuigenin increased c-Fos expression in the ventrolateral preoptic area (VLPO) and stimulated sleep-promoting neurons in VLPO. The sleep-promoting effects of tenuigenin were abolished when mice were pretreated with flumazenil, an antagonist at the benzodiazepine site of the GABAA receptor. Furthermore, tenuigenin was found to ameliorate sleep disturbances in MPTP-induced mice. The results suggesting that tenuigenin facilitated a type of NREM sleep comparable to physiological NREM sleep through interaction with the GABAA receptor. Additionally, tenuigenin demonstrated improvements in sleep disturbances in MPTP-induced PD mice, suggesting its potential as a sleep-promoting substance, particularly for PD patients experiencing sleep disturbances.

Derivatives of 3, 4, 5-Trimethoxycinnamic Acid Ameliorate Stress-Induced Anxiety in Mice and Rats

Stress is an overwhelming problem associated with neuronal damage leading to anxiety and depression. The compound 3, 4, 5-trimethoxycinnamic acid (TMCA) has shown anti-stress effects; however, its derivatives remained unknown for their anxiolytic properties. Here, therefore, we investigated derivatives of TMCA (dTMCA) for their anxiolytic effects using immobilization and electric shock-induced stress in rats. Derivatives of TMCA ameliorated anxiety in mice and rats revealed by extended period of time spent in the open arms of elevated plus maze. Stress-mediated repression of tyrosine hydroxylase (TH) protein expression in the amygdala regions of rat brain and dopamine levels in the PC12 cells was restored by two selected derivatives (TMCA#5 and TMCA#9). Unlike TH expression, stress-induced protein expression of phospho-extracellular signal-regulated kinase (pERK) was unaffected by both derivatives in rats. Given the preferential inhibitory activity of dTMCA on dopamine and serotonin receptors, serotonergic road map of cellular signaling could be their target for anxiolytic effects. Thus, dTMCA would be promising agents to prevent neuronal damage associated with rampant stressful conditions.

Anxiolytic effects, metabolism and plasma pharmacokinetics of 3, 6' -disinapoylsucrose

3,6'-disinapoylsucrose (DISS) is a bioactive oligosaccharide ester derived from Polygalae Radix. This study aims to explore the anxiolytic effects of DISS and further reveal the material basis by establishing the pharmacokinetics of DISS and its metabolites. Behavioral experiments such as the open field test (OFT) and elevated plus maze test (EPM) were performed to evaluate the anxiolytic effects of DISS in mice after oral administration. By UPLC-MS/MS analysis, DISS and its metabolites both in blood and cerebrospinal fluid were identified, and the pharmacokinetics of DISS and its metabolites were characterized in SD rats after oral administration of DISS (100 mg·kg^-1). Oral DISS could increase the time and frequency of mice entering the central area of the field in OFT and open arm in EPM, which indicated DISS has good anxiolytic effects. We also identified DISS and its metabolites (sinapic acid (SA), 3,4,5-trimethoxycinnamic acid (TMCA), methyl-3,4,5-trimethoxycinnamate (TMCA-CH₂), p-Coumaric acid (CA) and p-methoxycinnamic acid (MA)) in rat plasma and cerebrospinal fluid. The pharmacokinetic results showed that DISS was rapidly absorbed after administration and reached its highest concentration at 12 min, SA had the highest exposure level in vivo and was probably the main active form of DISS action, TMCA could maintain at a low concentration for a long time. In brief, we reported the anxiolytic effect of DISS firstly, revealed the cerebrospinal fluid distribution and pharmacokinetics of DISS and its metabolites. Our findings provide the basis for further insight into the mechanisms involved in the anxiolytic effects of DISS.

Protective Effect of Natural Products against Huntington's Disease: An Overview of Scientific Evidence and Understanding Their Mechanism of Action

Huntington's disease (HD), a neurodegenerative disease, normally starts in the prime of adult life, followed by a gradual occurrence of characteristic psychiatric disturbances and cognitive and motor dysfunction. To the best of our knowledge, there is no treatment available to completely mitigate the progression of HD. Among various therapeutic approaches, exhaustive literature reports have confirmed the medicinal benefits of natural products in HD experimental models. Building on this information, this review presents a brief overview of the neuroprotective mechanism(s) of natural products against in vitro/in vivo models of HD. Relevant studies were identified from several scientific databases, including PubMed, ScienceDirect, Scopus, and Google Scholar. After screening through literature from 2005 to the present, a total of 14 medicinal plant species and 30 naturally isolated compounds investigated against HD based on either in vitro or in vivo models were included in the present review. Behavioral outcomes in the HD in vivo model showed that natural compounds significantly attenuated 3-nitropropionic acid (3-NP) induced memory loss and motor incoordination. The biochemical alteration has been markedly alleviated with reduced lipid peroxidation, increased endogenous enzymatic antioxidants, reduced acetylcholinesterase activity, and increased mitochondrial energy production. Interestingly, following treatment with certain natural products, 3-NP-induced damage in the striatum was ameliorated, as seen histologically. Overall, natural products afforded varying degrees of neuroprotection in preclinical studies of HD via antioxidant and anti-inflammatory properties, preservation of mitochondrial function, inhibition of apoptosis, and induction of autophagy.

Revealing the sedative-hypnotic effect of the extracts of herb pair Semen Ziziphi spinosae and Radix Polygalae and related mechanisms through experiments and metabolomics approach

BACKGROUND

Semen Ziziphi spinosae and Radix Polygalae, two herbs commonly used together in Traditional Chinese Medicine for the treatment of insomnia and anxiety. The study aims to study the sedative-hypnotic effect of the active components of the herbal pair, the possible mechanisms of such effect, and related metabolic pathways in vivo.

METHODS

The sedative and hypnotic effect of the active components (EI30) of the herbal pair was studied by recording influence on the proportion of sleeping within 30 min, sleep latency and sleep length of pentobarbital sodium-induced sleeping on mice. Possible mechanisms of the sedative-hypnotic effect of the active components were investigated by measuring the content of neurotransmitters in the total protein of mice brain tissue. The main chemical compounds of the herbal pair were identified by Liquid Chromatography-Mass Spectrometry (LC-MS). Serum samples of mice were studied, and related differential metabolites between the normal group and model group, and between model group and treatment group were identified by Gas Chromatography Time-Of-Flight Mass Spectrometry (GC-TOF-MS), Principal Components Analysis (PCA), and Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA).

RESULTS

Compared with the control group, high dose EI30 group and the Clonazepam group were with significantly higher proportions of sleep within 30 min (P = 0.027 and 0.005 respectively). Compared with the control group, all of the high, medium and low dose of EI30 groups were with significantly shorter sleep latency (P < 0.01) and prolonged sleeping time (P < 0.01). The herbal pair has good sedative-hypnotic effects, although it is weaker than the effect of Clonazepam. The sedative-hypnotic effect of EI30 is possibly related to the adjustment of neurotransmitters 5-hydroxytryptamine (5-HT), norepinephrine (NE), and dopamine (DA) in the total protein of mice brain tissue. There are five metabolic pathways in vivo most related to the sedative-hypnotic effect of EI30, and they are biosynthesis of valine, leucine, and isoleucine, metabolism of glyceride, metabolism of alanine, aspartic acid and glutamic acid, metabolism of phenylalanine, and metabolism of cysteine and methionine.

CONCLUSIONS

This study reveals the mechanisms of sedative and hypnotic effects of herbal pair Semen Ziziphi spinosae and Radix Polygalae by using metabolomics methods. This study provides a basis for further development and utilization of this herbal pair.

Sedative and Hypnotic Effects and Transcriptome Analysis of Polygala tenuifolia in Aged Insomnia Rats

OBJECTIVE

To study the sedative and hypnotic effects and underlying mechanisms of Polygala tenuifolia (PT) on treating aged insomnia rats.

METHODS

Sixty Sprague-Dawley male rats were divided into 6 groups by a random number table, including control group, model group, diazepam group (0.92 mg/kg), as well as PT low-, medium- and high-dose groups (0.0875, 0.175, 0.35 g/kg, respectively), 10 rats in each group. Aged insomnia rat model was established with subcutaneous injection of D-galactose for 42 days and then intraperitoneal injection of para-chlorophenylalanine for 3 days. PT and diazepam were respectively given to aged insomnia rats by intragastric administration for 7 days after model establishment. Then the rats were investigated by body weight, Morris water maze test, pentobarbital test, enzyme-linked immunosorbent assay, and transcriptome sequencing.

RESULTS

Compared with the model group, PT increased the body weight, improved memory ability, and prolonged pentobarbital-induced sleep time of aged insomnia rats (P<0.01 or P<0.05). The medium dose of PT also increased the neurotransmitter levels of 5-hydroxytryptamine (5-HT) and gamma-aminobutyric acid (GABA), and decreased the level of Glu in the hippocampus of aged insomnia rats (P<0.05 or P<0.01). Twenty-four differentially expressed genes (DEGs) were overlapped among model group, medium-dose PT group, and diazepam group in transcriptome analysis. Fuom and Pcp2 were down-regulated by the treatment of medium-dose PT (P<0.01 or P<0.05). The metabolic pathways of PT were relatively less than diazepam (91 vs. 104).

CONCLUSIONS

The sedative and hypnotic effects of PT in aged insomnia rats might be related to neuro, metabolism pathways, especially through GABAergic signaling pathway. It provided more effective herb choice for the treatment of senile insomnia.

Effects of tenuifolin on rest/wake behaviour in zebrafish

Insomnia is a common sleep disorder with a high prevalence and substantial adverse consequences. There is growing interest in identifying novel therapeutics from herbal medicine. Tenuifolin is a major constituent of the well-known anti-insomnia herb Radix Polygala. The present study investigated the neural activity in response to tenuifolin during rest/wake behaviour in zebrafish and identified the potential biological signalling pathways involved. An automatic video tracking system was used to monitor the behavioural response of zebrafish larvae for 24 h after treatment with tenuifolin. In total, six rest/wake parameters were measured and visualized with a behavioural fingerprint. Time series analysis was conducted by averaging the total rest and waking activity in 10 min intervals. A correlation analysis was performed between tenuifolin and well-known compounds to analyse the underlying biological signalling pathways. Reverse transcription-quantitative PCR was also performed to detect the effects of tenuifolin on the transcription of interesting genes associated with the signalling pathways that were potentially involved. The present results suggested tenuifolin significantly increased the total rest time during the dark phase, with a slight effect on the waking activity in zebrafish larvae. This behavioural phenotype induced by tenuifolin is similar to that of selective serotonin reuptake inhibitors and gamma-aminobutyric acid (GABA) agonists. Furthermore, the expression levels of GABA transporter 1 were significantly increased after tenuifolin treatment. No significant difference was determined in other associated genes in untreated control and tenuifolin-treated larvae. The present results suggested that tenuifolin caused sleep-promoting activity in zebrafish and that these effects may be mediated by the serotoninergic systems and the GABAergic systems.

Research progress in the biological activities of 3,4,5-trimethoxycinnamic acid (TMCA) derivatives

TMCA (3,4,5-trimethoxycinnamic acid) ester and amide are privileged structural scaffolds in drug discovery which are widely distributed in natural products and consequently produced diverse therapeutically relevant pharmacological functions. Owing to the potential of TMCA ester and amide analogues as therapeutic agents, researches on chemical syntheses and modifications have been carried out to drug-like candidates with broad range of medicinal properties such as antitumor, antiviral, CNS (central nervous system) agents, antimicrobial, anti-inflammatory and hematologic agents for a long time. At the same time, SAR (structure-activity relationship) studies have draw greater attention among medicinal chemists, and many of the lead compounds were derived for various disease targets. However, there is an urgent need for the medicinal chemists to further exploit the precursor in developing chemical entities with promising bioactivity and druggability. This review concisely summarizes the synthesis and biological activity for TMCA ester and amide analogues. It also comprehensively reveals the relationship of significant biological activities along with SAR studies.

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3,4,5-Trimethoxycinnamic acid (TMCA) derivatives show applications in different pathophysiological conditions due to its privileged structural scaffolds.

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Natural derived TMCA analogues and chemically modified TMCA ester and amide analogues and their bioactivities are focused in this review. Additionally, it also comprehensively summarized the relationship of significant biological activities along with SAR studies of synthetic TMCA derivatives.

Study on the safety of Polygala tenuifolia Willdenow root extract powder (BT-11) in young person aged from 9 to 19 years old

ETHNOPHARMACOLOGICAL RELEVANCE

Polygala tenuifolia Willdenow root extract (BT-11) has beneficial effects on central nervous system disorders in human. The safety of BT-11 should be elucidated in younger person further.

AIM OF THE STUDY

To evaluate the safety of BT-11 in human aged from 9 to 19 years old.

MATERIAL AND METHODS

The safety was evaluated in randomly assigned subjects who received the test products (61 subjects in BT-11 300 mg daily or 60 subjects in matching placebo) for 12 weeks. Adverse reactions were analyzed by the incidence rate, type, and severity. The clinical examination included hematology and blood chemistry tests, urinalysis, vital signs, body weight, and electrocardiogram (ECG).

RESULTS

Eleven adverse reactions were observed in ten subjects receiving BT-11 while seven adverse reactions in six subjects receiving placebo. There were no statistical differences in the incidence of adverse reactions between the two groups. Serious adverse reactions such as acute appendicitis and acute viral gastroenteritis were observed in the BT-11 group4 and the placebo group, respectively. However, it was confirmed that they were not associated with the test product. All other adverse reactions observed during the test period were resolved completely without special treatment. No statistical difference was also observed in safety laboratory tests, vital signs, and ECG between two groups.

CONCLUSIONS

This study demonstrates the safety of BT-11 in the adolescent by showing no apparent adverse reactions related to it.

Comprehensive characterization of in vivo metabolic profile of Polygalae radix based on ultra-high-performance liquid chromatography-tandem mass spectrometry

In this study, a novel analysis strategy for progressively targeted screening and characterization of drug ingredients from in vitro to in vivo was proposed based on ultra-high performance liquid chromatography-tandem mass spectrometry for comprehensive characterization of in vivo metabolic profile of Polygalae radix (PR). First, an in vitro chemical profile of PR was described with the assistance of UNIFI™ software. The characteristic neutral small molecule losses were summarized to distinguish different chemical structures in the PR extract. Second, the in vitro intestinal microflora metabolism model was applied to describe an in vitro metabolic profile of the main ingredients of PR. The metabolic rule and metabolites were integrated for subsequent targeted screening of metabolites in vivo. Finally, an integrated strategy was established and applied to screen and characterize the major absorbed components in vivo, including blood, urine, brain, feces, and liver, based on the prototypes and metabolic rules obtained in vitro. As a result, in vitro and in vivo metabolic profiles of PR were effectively depicted. A total of 136 compounds were isolated and identified from the crude extract in vitro, and 12 compounds were reported for the first time based on the proposed fragmentations. A total of 13, 32, and 3 compounds were identified and characterized in the dosed plasma, liver, and brain, respectively. A total of 40 and 73 compounds were identified in urine and feces, respectively. This strategy not only provided a comprehensive insight into the chemical and metabolic profiles of PR but also presented a new perspective for the discovery of new drugs for medicinal application.

UHPLC-MS/MS method for simultaneous determination of Radix Polygalae glycolipids and organic acids in rat plasma and application in a pharmacokinetic study

Radix Polygala (Yuanzhi in Chinese) is well-known in traditional Chinese medicine (TCM) and has been used for treatment of depression, brain protection, and memory improvement for thousands of years. This plant medicine is rich in saponins, glycolipids, and organic acids. The purpose of the current study was to develop a rapid, accurate, and sensitive ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for the simultaneous determination of the following seven active components of Radix Polygala extracts in rat plasma: sibiricose A5 (A5); sibiricose A6 (A6); 3,6'-disinapoyl sucrose (DSS); tenuifoliside A (TFSA); tenuifoliside B (TFSB); tenuifoliside C (TFSC); and 3,4,5-trimethoxycinnamic acid (TMCA). Then, the pharmacokinetics were studied following oral administration. Plasma samples were precipitated with methanol. Chromatographic separation was successfully performed on a thermo C₁₈ column (100 × 3.0 mm, 3 μm) with a mobile phase consisting of acetonitrile and 10 mmol/L of an ammonium acetate aqueous solution. Seven analytes were detected by multiple reaction monitoring (MRM) with an electrospray ionization source in the positive mode. The transitions of m/z were 517.1/174.9, 547.0/204.9, 753.2/205.2, 681.3/443.3, 667.2/205.1, 767.4/529.2, 236.8/103.2, and 136.9/92.9 for A5, A6, DSS, TFSA, TFSB, TFSC, TMCA, and salicylic acid (IS), respectively. The method validation showed good linearity in the range of 1-2000 ng/mL and LLOQs of 1 ng/mL for the 7 components in plasma. The accuracy, precision, and stability of QC samples were all within allowable ranges. In addition, no significant matrix effect was observed using this method. For the first time, the validated method has been successfully applied to the pharmacokinetic study of the seven components of Radix Polygala extracts in rat plasma. Moreover, this method may be applied for detecting prescriptions that contain Radix Polygala or other plant medicines that include one or more components above. The results of the pharmacokinetic study of the seven ingredients will provide important guidance to clinical medicine regarding Radix Polygala and prescriptions include Radix Polygala.

Sleep-Aids Derived from Natural Products

Although drugs such as barbiturates and benzodiazepines are often used for the treatment of insomnia, they are associated with various side effects such as habituations, tolerance and addiction. Alternatively, natural products with minimal unwanted effects have been preferred for the treatment of acute and/or mild insomnia, with additional benefits of overall health-promotion. Basic and clinical researches on the mechanisms of action of natural products have been carried out so far in insomnia treatments. Recent studies have been focusing on diverse chemical components available in natural products, with an interest of developing drugs that can improve sleep duration and quality. In the last 15 years, our co-workers have been actively looking for candidate substances from natural products that can relieve insomnia. This review is, therefore, intended to bring pharmacological data regarding to the effects of natural products on sleep duration and quality, mainly through the activation of GABA_A receptors. It is imperative that phytochemicals will provide useful information during electroencephalography (EEG) analysis and serve as an alternative medications for insomnia patients who are reluctant to use conventional drugs.

1,3,7-Trihydroxyxanthone, derived from Polygalae Radix, a herbal medicine, stimulates the expression of neurotrophic factors in rat astrocyte primary cultures via cAMP- and ERK-dependent pathways

1,3,7-Trihydroxyxanthone is a compound isolated from Polygalae Radix, a medicinal herb frequently applied for treatment of psychiatric disordres with symptoms of forgetfulness and depression in ancient China. In current research, this compound was applied onto rat astrocyte primary cultures in exploring the action mechanisms of 1,3,7-trihydroxyxanthone on regulating synthesis of neurotrophic factors. It was found that 1,3,7-trihydroxyxanthone could significantly stimulate the expression of NGF and BDNF in dose-dependent manners: the stimulation was both in mRNA and protein levels. Furthermore, 1,3,7-trihydroxyxanthone might fulfill this effect by regulating critical enzymes, such as plasminogen, tissue plasminogen activator, neuroserpin and tissue inhibitor of metalloproteinases in metabolic pathway of neurotrophic factors. Besides, inhibitors of cAMP- and ERK-dependent pathways, which implied the possible signaling pathway, could reverse this inducing effect. These results might support the potentiality of 1,3,7-trihydroxyxanthone in drug development in treating psychiatric disorders.

Treatment of Insomnia With Traditional Chinese Herbal Medicine

Insomnia is a condition with sleep problems and many people suffered from it. Chronic insomnia can last for long time and it will severely affect people's health and the quality of life. In conventional medicine, the most commonly used the medicine is benzodiazepine. It is effective but also has significant side effects. Patients try to use some kinds of alternative medicines. Chinese medicinal herbs and formulas have been used in the treatment of insomnia for more than 2000 years in China. In recent decades, Chinese herbal medicine has been widely used in the Western countries. Many clinical studies including randomized controlled clinical trials and research on pharmacological action mechanisms of the herbs for treatment of insomnia have been conducted. It is very important and very helpful to review the published research papers to gather the available information for a critical analysis. This chapter evaluated the data from both of clinical studies and pharmacological researches on the therapeutic formulas and on some key herbs used in the treatment of insomnia. Clinical studies showed a very wide spectrum of herbs that were used in clinical treatment of insomnia. This was due to different syndrome patterns happened with insomnia. This brought complexity and difficulties to identify which are the essential key herbs or formulas. It was found Suanzaoren decoction (Ziziphus spinose decoction ) is the most frequently used formula for the treatment of insomnia. Based on the clinical data, several herbs were identified as most frequently used sedative and hypnotic herbs in Chinese herbal medicine including Suanzaoren (Ziziphus spinose ), Fuling (Poria cocos ), and Gancao (Glycyrrhiza uralensis ). The underlying pharmacological action mechanisms discovered in the studies on some key herbs used in the treatment of insomnia were evaluated. The major pharmacological action mechanisms shared by most of the sedative herbs are to act through the neurotransmitter gamma-aminobutyric acid (GABA) or via stimulation of GABAA_A receptor. Some herbs exert sedative activities via inhibition of 5-hydroxytryptamine 1A receptor. Another mechanism shown by some herbs is to upregulate the expression of orexin-A, leptin, orexin receptor-1, and leptin receptor in the brain, reducing insomnia-induced negative consequences, and thus indirectly help improvement of insomnia.

Tenuifolin, a saponin derived from Radix Polygalae, exhibits sleep-enhancing effects in mice

BACKGROUND

Radix Polygalae, the dried root of Polygala tenuifolia, has been extensively used as a traditional Chinese medicine for promoting intelligence and tranquilization. Polygalasaponins extracted from the root of P. tenuifolia possess evident anxiolytic and sedative-hypnotic activities. Previous studies have reported that tenuifolin was a major constituent of polygalasaponins.

PURPOSE

The currently study aims to investigate the hypnotic effect and possible mechanism of tenuifolin in freely moving mice.

DESIGN/METHODS

The hypnotic effects of tenuifolin (20, 40 and 80mg/kg, p.o.) were assessed by electroencephalographic (EEG) and electromyographic (EMG) analysis. Double-staining immunohistochemistry test was performed to evaluate the neuronal activity of sleep-wake regulating brain areas. High performance liquid chromatograph- electrochemical detection (HPLC-ECD) and ultrafast liquid chromatography-mass spectrometry (UFLC-MS) were used for the detection of neurotransmitters. Locomotor activity was measured by Open-field Test.

RESULTS

Tenuifolin at doses of 40 and 80mg/kg (p.o.) significantly prolonged the total sleep time by increasing the amount of non-rapid eye movement (NREM) and rapid eye movement (REM) sleep, associated with the significant increase in the bouts of episodes respectively. After administration of tenuifolin, the cortical EEG power spectral densities during NREM and REM sleep were similar to that of natural sleep (vehicle) and thus compatible with physiological sleep. Double-immunohistochemistry staining test showed that tenuifolin increased the c-Fos positive ratios of GABAergic NREM sleep-promoting neurons in ventrolateral preoptic area (VLPO), cholinergic REM sleep-promoting neurons in laterodorsal tegmental area (LDT) and pontomesencephalic tegmental area (PPT) and decreased the c-Fos positive ratios in wake-promoting neurons (locus coeruleus (LC) and perifornical area (Pef)). Neurotransmitter detections revealed that tenuifolin significantly reduced the noradrenaline (NA) levels in LC, VLPO, PPT and LDT, elevated the GABA levels in VLPO, LC and Pef and increased the acetylcholine (Ach) levels in LDT and PPT. In addition, tenuifolin did not cause any change to locomotor activity.

CONCLUSION

Taken together, these results provide the first experimental evidence of the significant sleep-enhancing effect of tenuifolin in mice. This effect appears to be mediated, at least in part, by the activation of GABAergic systems and/or by the inhibition of noradrenergic systems. Moreover, this study adds new scientific evidence and highlights the therapeutic potential of the medicinal plant P. tenuifolia in the development of phytomedicines with hypnotic properties.

3,4,5-Trimethoxycinnamic acid, one of the constituents of Polygalae Radix exerts anti-seizure effects by modulating GABAAergic systems in mice

Polygalae Radix is an important medicinal plant that is widely used in most of Africa. 3,4,5-Trimethoxycinnamic acid (TMCA) is one of the constituents of Polygalae Radix. Until now, the mechanisms involved in the anti-seizure property of TMCA are still unclear. We examined the anti-seizure effect of TMCA. TMCA administered at doses of 5, 10 and 20 mg/kg and evaluated anti-seizure effects by maximal electroshock (MES) and pentylenetetrazol (PTZ) models in mice. TMCA administered at doses of 10 and 20 mg/kg significantly reduced the incidence of MES-induced tonic hindlimb extension (THE). TMCA significantly delayed the onset of myoclonic jerks (MJ), and decreased the seizure severity and mortality compared with the vehicle-treated animals in PTZ seizure model. TMCA 10 and 20 mg/kg treated groups also did not determined generalized clonic seizures (GCS). Pretreatment with a GABAA/benzodiazepine (BZ) receptor antagonist flumazenil blocked the anti-seizure effects of TMCA. These data support the further investigation of TMCA as a GABAA/BZ receptor agonist for anti-seizure therapy.

The gastrointestinal irritation of polygala saponins and its potential mechanism in vitro and in vivo

Processing alters the pharmacological activity and reduces the gastrointestinal toxicity of the polygalae. To investigate the effect of processing, different glycosyl substituent products were tested. Hypnotic and subhypnotic doses of pentobarbital-induced sleep tests on mice were used to evaluate the sedative activity of polygala saponins with different glycosyl substituents; isolated gut motility experiment was employed to study excitatory effects of different polygala saponins; the gastrointestinal irritation effects of different polygala saponins were compared by measuring the levels of gastric PGE2 and intestinal TNF-α on mice. When compared with control, Onjisaponin B (OJB) and tenuifolin (TEN), but not senegenin (SNG), significantly increased the number of sleeping mice and prolonged the sleeping time (P < 0.05); 80, 40, and 20 mg/L of OJB and 80 mg/L of TEN, but not SNG, obviously changed the amplitude and frequency of isolated jejunum (P < 0.05); all the three compounds significantly decreased the level of gastric PGE2 but had no obvious influences on the reduction of intestinal TNF-α level. For sedative and hypnotic effects, OJB > TEN > SNG; for the protection form gastrointestinal irritation and damages, OJB > TEN > SNG. Therefore, in processing Polygala, glycosyl breaking may be related to the decline of pharmacological activity and gastrointestinal toxicity of polygala saponins.

Comparison of Two Old Phytochemicals versus Two Newly Researched Plant-Derived Compounds: Potential for Brain and Other Relevant Ailments

Among hundreds of formulae of Chinese herbal prescriptions and recently extracted active components from the herbs, some of which had demonstrated their functions on nervous system. For the last decade or more, Gingko biloba and Polygala tenuifolia were widely studied for their beneficial effects against damage to the brain. Two compounds extracted from Apium graveolens and Rhizoma coptidis, butylphthalide and berberine, respectively, received much attention recently as potential neuroprotective agents. In this review, the two traditionally used herbs and the two relatively new compounds will be discussed with regard to their potential advantages in alleviating brain and other relevant ailments.