NHBA isolated from Gastrodia elata exerts sedative and hypnotic effects in sodium pentobarbital-treated mice

Experimental study on the detection of Gastrodia elata by enzymatic recombinase amplification and immunochromatography

OBJECTIVE

The objective of this research is to develop two methodologies, Enzymatic recombinase amplification (ERA) and Polymerase Chain Reaction (PCR) coupled with Lateral Flow Dipstick (LFD), for the swift authentication of Gastrodia elata.

METHODOLOGY

Primers and nfo probes for the ERA of Gastrodia elata were developed based on the ITS2 genome sequences of Gastrodia elata and its counterfeits. Specific primers for the PCR analysis of Gastrodia elata were generated using the NCBI (National Center for Biotechnology Information) online platform. Through experimental validation, the optimal reaction system and conditions for both methodologies were established, and their efficacy was assessed.

RESULTS

The methodologies developed herein are applicable for the targeted analysis of the medicinal species, Gastrodia elata. The sensitivity of the ERA-LFD detection method matched that of the conventional PCR-LFD approach, recorded at 1 ng μL-1. Consistency was observed in the results across three replicates of visualization test strips for both techniques. Upon evaluation, both the PCR-LFD and ERA-LFD methods demonstrated a total compliance rate of 100 %.

CONCLUSION

The ERA-LFD and PCR-LFD methods facilitate reduced detection times and offer visual results. These techniques are particularly effective for on-site detection and quality control in the authentication of Gastrodia elata within traditional Chinese medicine markets and at the primary level of healthcare provision.

Sleep promoting and omics exploration on probiotics fermented Gastrodia elata Blume

Fermenting Chinese medicinal herbs could enhance their bioactivities. We hypothesized probiotic-fermented gastrodia elata Blume (GE) with better potential to alleviate insomnia than that of unfermented, thus the changes in chemical composition and the insomnia-alleviating effects and mechanisms of fermented GE on pentylenetetrazole (PTZ)-induced insomnia zebrafish were explored via high-performance liquid chromatography (HPLC) and mass spectroscopy-coupled HPLC (HPLC-MS), phenotypic, transcriptomic, and metabolomics analysis. The results demonstrated that probiotic fermented GE performed better than unfermented GE in increasing the content of chemical composition, reducing the displacement, average speed, and number of apoptotic cells in zebrafish with insomnia. Metabolomic investigation showed that the anti-insomnia effect was related to regulating the pathways of actin cytoskeleton and neuroactive ligand-receptor interactions. Transcriptomic and reverse transcription qPCR (RT-qPCR) analysis revealed that secondary fermentation liquid (SFL) significantly modulated the expression levels of neurod1, msh2, msh3, recql4, ercc5, rad5lc, and rev3l, which are mainly involved in neuron differentiation and DNA repair. Collectively, as a functional food, fermented GE possessed potential for insomnia alleviation.

Functions and mechanisms of adenosine and its receptors in sleep regulation

Sleep is a natural and recurring state of life. Long-term insomnia can lead to physical and mental fatigue, inattention, memory loss, anxiety, depression and other symptoms, imposing immense public health and economic burden worldwide. The sleep and awakening regulation system is composed of many nerve nuclei and neurotransmitters in the brain, and it forms a neural network that interacts and restricts each other to regulate the occurrence and maintenance of sleep-wake. Adenosine (AD) is a neurotransmitter in the central nervous system and a driver of sleep. Meanwhile, the functions and mechanisms underlying sleep-promoting effects of adenosine and its receptors are still not entirely clear. However, in recent years, the increasing evidence indicated that adenosine can promote sleep through inhibiting arousal system and activating sleep-promoting system. At the same time, astrocyte-derived adenosine in modulating sleep homeostasis and sleep loss-induced related cognitive and memory deficits plays an important role. This review, therefore, summarizes the current research on the functions and possible mechanisms of adenosine and its receptors in the regulation of sleep and homeostatic control of sleep. Understanding these aspects will provide us better ideas on clinical problems such as insomnia, hypersomnia and other sleep disorders.

Adenosine A2A receptors and sleep

Adenosine, a known endogenous somnogen, induces sleep via A1 and A2A receptors. In this chapter, we review the current knowledge regarding the role of the adenosine A2A receptor and its agonists, antagonists, and allosteric modulators in sleep-wake regulation. Although many adenosine A2A receptor agonists, antagonists, and allosteric modulators have been identified, only a few have been tested to see if they can promote sleep or wakefulness. In addition, the growing popularity of natural sleep aids has led to an investigation of natural compounds that may improve sleep by activating the adenosine A2A receptor. Finally, we discuss the potential therapeutic advantage of allosteric modulators of adenosine A2A receptors over classic agonists and antagonists for treating sleep and neurologic disorders.

Gymnadenia conopsea (L.) R. Br.: Comprehensive review of propagation and breeding, traditional uses, chemical composition, pharmacology, quality control, and processing

ETHNOPHARMACOLOGICAL RELEVANCE

Gymnadenia conopsea, a perennial herbaceous flowering plant that belongs to the family of Orchidaceae, sporadic distributed in the altitudes of 200-4700 m across northern Europe and, temperate and subtropical Asia region. The dried tubers of G. conopsea have been used to treat cough, asthma, and their syndromes, and also as a tonic in China and surrounding countries for a long history. G. conopsea is often processed deeply processed before use to enhance its efficacy. In recent years, because of its remarkable pharmacological activity and health care function, G. conopsea has been used more and more widely. Due to its extensive application and bad growth environment, the wild distribution of G. conopsea is decreasing and it has been listed as an endangered plant.

AIM OF THE REVIEW

This review aims to summarize the propagation and breeding, traditional uses, chemical composition, pharmacology, quality control, and processing of G. conopsea. Moreover, it also provides suggestions for the future high-value utilization of G. conopsea.

MATERIALS AND METHODS

A literature search on Gymnadenia genus and G. conopsea was performed using scientific databases including SciFinder, ACS, Web of Science, Springer, ScienceDirect, PubMed, and CNKI. Information was also collected from classic books of Chinese herbal medicine, official websites, Ph.D. and M.Sc. Dissertations, and so on. Structures of chemical compounds were drawn by ChemDraw software.

RESULTS

As of submission date of this manuscript, total 170 natural compounds have been isolated and characterized from G. conopsea, and all of the compounds were isolated from the tubers. The isolated compounds including benzylester glucosides, dihydrostilbenes, phenanthrenes, phenolic compounds, alkaloids, polysaccharide, lignans, flavones, triterpenoids, steroids, and other compounds. Some of these compounds and active extracts exhibited a wide range of pharmacological activities, in which, the tonifying, anti-fatigue, anti-oxidant, anti-viral, sedative and hypnotic activities are consistent with the traditional uses for the treatment of diseases. In addition, a variety of new pharmacological activities, such as preventing and treating gastric ulcers, immunoregulatory, anti-hyperlipidemia, anti-anaphylaxis, anti-silicosis, anti-cancer and neuroprotective activities have also been reported. However, the bioactive compounds responsible for most of the above pharmacological effects have not been well summarised till now. In this manuscript, analysis, speculation and summary of compounds that responsible for pharmacological effects were conducted.

CONCLUSIONS

The chemical constituents and pharmacological activities studies of G. conopsea extract have been summarised in this context, the isolated compounds responsible for the pharmacological activities were also analyzed and deduced according to the publications, all above led to suggestions for the future high-value utilization of G. conopsea.

Inhibition of α-synuclein aggregation by MT101-5 is neuroprotective in mouse models of Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disease, after Alzheimer's disease, and becomes increasingly prevalent with age. α-Synuclein (α-syn) forms the major filamentous component of Lewy bodies, which are pathological hallmarks of α-synucleinopathies such as PD. We evaluated the neuroprotective effects of MT101-5, a standardized herbal formula that consists of an ethanolic extract of Genkwae Flos, Clematidis Radix, and Gastrodiae Rhizoma, against α-synuclein-induced cytotoxicity in vivo. MT101-5 protected against behavioral deficits and loss of dopaminergic neurons in human α-syn-overexpressing transgenic mice after treatment with 30 mg/kg/day for 5 months. We investigated transcriptomic changes within MT101-5 mechanisms of action (MOA) suppressing α-syn aggregation in an α-synuclein preformed fibril (α-syn PFF) mouse model of sporadic PD. We found that inhibition of α-syn fibril formation was associated with changes in transcripts in mitochondrial biogenesis, electron transport, chaperones, and proteasomes following treatment with MT101-5. These results suggest that the mixed herbal formula MT101-5 may be used as a pharmaceutical agent for preventing or improving PD.

The effects of fresh Gastrodia elata Blume on the cognitive deficits induced by chronic restraint stress

Chronic restraint stress (CRS) is a classic animal model of stress that can lead to various physiological and psychological dysfunctions, including systemic neuroinflammation and memory deficits. Fresh Gastrodia elata Blume (FG), the unprocessed raw tuber of Gastrodia elata Blume, has been reported to alleviate the symptoms of headache, convulsions, and neurodegenerative diseases, while the protective effects of FG on CRS-induced cognitive deficits remain unclear. This work aimed to evaluate the effects of FG on CRS-induced cognitive deficits through multiplex animal behavior tests and to further explore the related mechanism by observing the expression of mitochondrial apoptosis-related proteins in the mouse hippocampus. In in vivo experiments, mice were subjected to the object location recognition test (OLRT), new object recognition test (NORT), Morris water maze test (MWMT), and passive avoidance test (PAT) to evaluate the learning and memory ability. In in vitro experiments, the expression of the AKT/CREB pathway, the fission- and apoptosis-related proteins (Drp1, Cyt C, and BAX), and the proinflammatory cytokines’ (TNF‐α and IL‐1β) level in the hippocampus was examined. Our results demonstrated that in spontaneous behavior experiments, FG significantly improved the cognitive performance of CRS model mice in OLRT (p < 0.05) and NORT (p < 0.05). In punitive behavior experiments, FG shortened the escape latency in long-term spatial memory test (MWMT, p < 0.01) and prolonged the latency into the dark chamber in non-spatial memory test (PAT, p < 0.01). Biochemical analysis showed that FG treatment significantly suppressed CRS‐induced Cyt C, Drp1, and BAX activation (p < 0.001, p < 0.01 and p < 0.05), promoted the CREB, p-CREB, AKT, and p-AKT level (p < 0.05, p < 0.01 and p < 0.001), and inhibited the CRS‐induced proinflammatory cytokines (TNF‐α and IL‐1β, p < 0.05 and p < 0.001) level in the hippocampus. Taken together, these results suggested that FG could attenuate cognitive deficits induced by CRS on multiple learning and memory behavioral tests.

Gastrodia elata blume ameliorates circadian rhythm disorder-induced mice memory impairment

Circadian rhythm disorder (CRD) in space flight can lead to memory impairment, performance decrements and adverse health outcomes, the main manifestations of which are circadian desynchronization, sleep loss and insomnia. Sleep deprivation (SD) provide the means to evaluate these effects and the risks associated with CRD on ground. Gastrodia elata Blume (GEB) has beneficial effects on the treatment of sleep disturbances and memory loss. Fresh GEB (FG), an unprocessed raw tuber of GEB, has been used as functional health food in Asian countries for a long time. However, the research report of FG to ameliorate memory impairment caused by insomnia or lack of sleep is meager. In this study, ICR male mice were sleep-deprived continuously and water extract of FG (WFG) was orally administrated (3 and 9 g/kg/d, i.g) during the SD process lasted for 25 days, except control and model groups gavage administration with water, positive control group with modafinil (MOD, 0.1 g/kg/d, i.g). We studied the effect of WFG on CRD-induced learning and memory impairment using a set of behavioral analyses including the object location recognition test (OLRT), novel object recognition test (NORT), and the passive avoidance test (PAT). In addition, oxidative stress parameters were assessed by measuring the malondialdehyde (MDA) and superoxide dismutase (SOD) reactivity in serum and hippocampus. Our results revealed that SD decreased discrimination index (DI) in OLRT and NORT, with shorter latency into the dark chamber in PAT. Both WFG and MOD treatment can reverse these changes (P < 0.05). We concluded that WFG treatment improve CRD-induced learning and memory impairment and oxidative stress damage which makes FG a promising candidate as herbal health product of memory decline in CRD.

Insight into Medicinal Chemistry Behind Traditional Chinese Medicines: p-Hydroxybenzyl Alcohol-Derived Dimers and Trimers from Gastrodia elata

From an aqueous extract of "tian ma" (the steamed and dried rhizomes of Gastrodia elata), ten new compounds gastrodibenzins A-D (1-4) and gastrotribenzins A-F (5-10), along with known analogues (11-20), having structure features coupling between two and three p-hydroxybenzyl-derived units via carbon- and/or ether-bonds, were isolated and characterized by spectroscopic data analysis. Meanwhile, the new compounds 5a, 6a, 8a, 22, and 23, as well as the known derivatives 13a, 14a, 15, 17-21, 24, 25, and p-hydroxybenzyl aldehyde were isolated and identified from a refluxed aqueous solution of p-hydroxybenzyl alcohol. Methylation of 5a and 6a in methanol and ethylation of 6a, 8a, 13a, and 14a in ethanol produced 5 and 6 and 7, 8, 13, and 14, respectively. using ultra-performance liquid chromatography high-resolution electrospray ionization mass spectrometry (UPLC-HRESIMS) analysis of the refluxed solutions of p-hydroxybenzyl alcohol and the refluxed extracts of the fresh G. elata rhizome and "tian ma" extracts indicated consistent production and variation of the dimeric and trimeric derivatives of p-hydroxybenzyl alcohol upon extracting solvents and refluxing time. In various assays, the dimeric and trimeric derivatives showed more potent activities than p-hydroxybenzyl alcohol itself and gastrodin, which are the main known active constituents of "tian ma". These results revealed for the first time that the more effective dimers and trimers can be produced through condensation of the co-occurring p-hydroxybenzyl alcohol during processing and decocting of the G. elata rhizomes, demonstrating insights into medicinal chemistry behind application protocols of traditional Chinese medicines.

Glial Nrf2 signaling mediates the neuroprotection exerted by Gastrodia elata Blume in Lrrk2-G2019S Parkinson's disease

The most frequent missense mutations in familial Parkinson's disease (PD) occur in the highly conserved LRRK2/PARK8 gene with G2019S mutation. We previously established a fly model of PD carrying the LRRK2-G2019S mutation that exhibited the parkinsonism-like phenotypes. An herbal medicine, Gastrodia elata Blume (GE), has been reported to have neuroprotective effects in toxin-induced PD models. However, the underpinning molecular mechanisms of GE beneficiary to G2019S-induced PD remain unclear. Here, we show that these G2019S flies treated with water extracts of GE (WGE) and its bioactive compounds, gastrodin and 4-HBA, displayed locomotion improvement and dopaminergic neuron protection. WGE suppressed the accumulation and hyperactivation of G2019S proteins in dopaminergic neurons and activated the antioxidation and detoxification factor Nrf2 mostly in the astrocyte-like and ensheathing glia. Glial activation of Nrf2 antagonizes G2019S-induced Mad/Smad signaling. Moreover, we treated LRRK2-G2019S transgenic mice with WGE and found that the locomotion declines, the loss of dopaminergic neurons, and the number of hyperactive microglia were restored. WGE also suppressed the hyperactivation of G2019S proteins and regulated the Smad2/3 pathways in the mice brains. We conclude that WGE prevents locomotion defects and the neuronal loss induced by G2019S mutation via glial Nrf2/Mad signaling, unveiling a potential therapeutic avenue for PD.

Simultaneous determination of YZG-331 and its metabolites in monkey blood by liquid chromatography-tandem mass spectrometry

N6-[(S)-1- (phenyl)-propyl]-adenine riboside (YZG-331) is being developed as a novel sedative and hypnotic agent. The hydroxylated metabolites of YZG-331 have the same mass transition ion pair, making their determination in blood challenging. In this study, a rapid and sensitive liquid chromatography-tandem mass spectrometry method was developed for the simultaneous determination of YZG-331 and its metabolites M1 (hydrolysis), M2 and M4 (hydrolysis and hydroxylation), M3, M5 and M6 (hydroxylation) in monkey blood. Propranolol was used as the internal standard (IS). Blood samples were prepared using a simple protein precipitation with acetonitrile. The chromatographic separation was performed on an Eclipse Plus C18 column (2.1 × 50 mm, 3.5 μm) at a flow rate of 0.3 mL/min with a gradient mobile phase of methanol/water containing 0.5 % formic acid (v/v). Detection was carried out on a triple quadrupole mass spectrometer in positive ion multiple reaction monitoring mode. The optimized mass transition ion pairs for quantitation were 386→254 for YZG-331, 254→136 for M1, 270→136 for M2 and M4, 402→136 for M3, M5 and M6 and 260→183 for IS. Acceptable linearity was obtained for the analytes over the range of 15-2000 ng/mL for YZG-331, 3-400 ng/mL for M1-M6. The lower limits of the quantification were 15 ng/mL for YZG-331, 3 ng/mL for M1-M6. The intra- and inter-day precisions wre within 10.5 % for all analytes, while the accuracy ranged from -8.3 %-8.8 %. There was no obvious matrix effect and the recoveries of the analytes were 90.6 %-118.2 %. The analytes were proved to be stable during all sample storage, preparation and analytic procedures. The sensitive and rapid LC-MS/MS method for YZG-331 in monkey blood has been applied to pharmacokinetic studies of YZG-331 in monkeys. The oral bioavailability of YZG-331 in monkeys is 74.1 %.

KLF4 Exerts Sedative Effects in Pentobarbital-Treated Mice

KLF4 is a zinc-finger transcription factor that plays an essential role in many biological processes, including neuroinflammation, neuron regeneration, cell proliferation, and apoptosis. Through effects on these processes, KLF4 has likely roles in Alzheimer's disease, Parkinson's disease, and traumatic brain injury. However, little is known about the role of KLF4 in more immediate behavioral processes that similarly depend upon broad changes in brain excitability, such as the sleep process. Here, behavioral approaches, western blot, and immunohistochemical experiments were used to explore the role of KLF4 on sedation and the potential mechanisms of those effects. The results showed that overexpression of KLF4 prolonged loss of righting reflex (LORR) duration in pentobarbital-treated mice and increased c-Fos expression in the lateral hypothalamus (LH) and the ventrolateral preoptic nucleus (VLPO), while it decreased c-Fos expression in the tuberomammillary nucleus (TMN). Moreover, overexpression of KLF4 reduced the expression of p53 in the hypothalamus and increased the expression of STAT3 in the hypothalamus. Therefore, these results suggest that KLF4 exerts sedative effects through the regulation of p53 and STAT3 expression, and it indicates a role of KLF4 ligands in the treatment of sleep disorders.

Sleep Promoting Effect of Luteolin in Mice via Adenosine A1 and A2A Receptors

Luteolin, a widespread flavonoid, has been known to have neuroprotective activity against various neurologic diseases such as epilepsy, and Alzheimer’s disease. However, little information is available regarding the hypnotic effect of luteolin. In this study, we evaluated the hypnotic effect of luteolin and its underlying mechanism. In pentobarbital-induced sleeping mice model, luteolin (1, and 3 mg/kg, p.o.) decreased sleep latency and increased the total sleep time. Through electroencephalogram (EEG) and electromyogram (EMG) recording, we demonstrated that luteolin increased non-rapid eye movement (NREM) sleep time and decreased wake time. To evaluate the underlying mechanism, we examined the effects of various pharmacological antagonists on the hypnotic effect of luteolin. The hypnotic effect of 3 mg/kg of luteolin was not affected by flumazenil, a GABAA receptor-benzodiazepine (GABAAR-BDZ) binding site antagonist, and bicuculine, a GABAAR-GABA binding site antagonist. On the other hand, the hypnotic effect of 3 mg/kg of luteolin was almost completely blocked by caffeine, an antagonist for both adenosine A1 and A2A receptor (A1R and A2AR), 8-Cyclopentyl-1,3-dipropylxanthine (DPCPX), an A1R antagonist, and SCH-58261, an A2AR antagonist. From the binding affinity assay, we have found that luteolin significantly binds to not only A1R but also A2AR with IC₅₀ of 1.19, 0.84 μg/kg, respectively. However, luteolin did not bind to either BDZ-receptor or GABAAR. From these results, it has been suggested that luteolin has hypnotic efficacy through A1R and A2AR binding.

Transformation Mechanisms of Chemical Ingredients in Steaming Process of Gastrodia elata Blume

To explore the transformation mechanisms of free gastrodin and combined gastrodin before and after steaming of Gastrodia elata (G. elata), a fresh G. elata sample was processed by the traditional steaming method prescribed by Chinese Pharmacopoeia (2015 version), and HPLC-ESI-TOF/MS method was used to identify the chemical composition in steamed and fresh G. elata. Finally, 25 components were identified in G. elata based on the characteristic fragments of the compounds and the changes of the 25 components of fresh and steamed G. elata were compared by the relative content. Hydrolysis experiments and enzymatic hydrolysis experiments of 10 monomer compounds simulating the G. elata steaming process were carried out for the first time. As a result, hydrolysis experiments proved that free gastrodin or p-hydroxybenzyl alcohol could be obtained by breaking ester bond or ether bond during the steaming process of G. elata. Enzymatic experiments showed that steaming played an important role in the protection of gastrodin, confirming the hypothesis that steaming can promote the conversion of chemical constituents of G. elata—inhibiting enzymatic degradation. This experiment clarified the scientific mechanism of the traditional steaming method of G. elata and provided reference for how to apply G. elata decoction to some extent.

Novel Adenosine Analog, N6-(4-Hydroxybenzyl)-Adenosine, Dampens Alcohol Drinking and Seeking Behaviors

Adenosine signaling is associated with ethanol-related behaviors. We previously found that adenosine A_2A receptor (A_2AR) activation dampens ethanol drinking behaviors in equilibrative nucleoside transporter 1 (ENT1) knockout mice, and A_2AR inhibition augments reward-seeking behavior in wild-type mice. The novel adenosine analog N6-(4-hydroxybenzyl)-adenosine (NHBA), which is isolated from the rhizomes of Gastrodia elata, activates A_2AR and inhibits ENT1. Here, we examined the effects of NHBA on ethanol drinking in the two-bottle choice test and operant ethanol seeking behaviors. We selected mice exhibiting high ethanol drinking behavior in the two-bottle choice test. NHBA (0.1 mg/kg, i.p.) reduced ethanol drinking behavior in a limited-access 3-hour drinking session in high-consumption ethanol drinking mice, and NHBA (0.1 mg/kg, i.p.) did not alter locomotor activity in the open-field test. Operant conditioning with 10% ethanol and 10% sucrose (10E10S) reward increased zone entries and time spent in the ethanol zone, while NHBA (0.1 mg/kg, i.p.) dampened ethanol zone preference in the Y-maze. Furthermore, NHBA (0.1 mg/kg, i.p.) devalued 10E10S and 10% ethanol (10E) reward after operant conditioning with 10E10S and 10E. Taken together, NHBA through A_2AR activation and ENT1 modulation may dampen ethanol drinking and seeking behaviors, suggesting that NHBA is a potential therapeutic agent for treating alcohol use disorder. SIGNIFICANCE STATEMENT: Our work highlights that A_2AR activation and ENT1 inhibition by a novel adenosine analog isolated from Gastrodia elata, N6-(4-hydroxybenzyl)-adenosine, decreases ethanol drinking and seeking behaviors. We suggest that NHBA is a potential therapeutic agent to treat alcohol use disorder.

Polybenzyls from Gastrodia elata, their agonistic effects on melatonin receptors and structure-activity relationships

Gastrodia elata is a famous traditional Chinese herb with medicinal and edible application. In this study, nine polybenzyls (1-9), including six new ones (2-5, 7 and 9), were isolated from the EtOAc extract of G. elata. Five compounds 1, 3, 4, 6 and 8 were found to activate melatonin receptors. Especially, compound 1 showed agonistic effects on MT₁ and MT₂ receptors with EC₅₀ values of 237 and 244 μM. For better understanding their structure-activity relationships (SARs), ten polybenzyl analogs were further synthesized and assayed for their activities on melatonin receptors. Preliminary SARs study suggested that two para-hydroxy groups were the key pharmacophore for maintaining activity. Molecular docking simulations verified that compound 1 could strongly interact with MT₂ receptor by bonding to Phe 118, Gly 121, His 208, Try 294 and Ala 297 residues.

Melatonin Receptors Agonistic Activities of Phenols from Gastrodia elata

Gastrodia elata is a famous traditional Chinese herb with medicinal and edible application. In this study, three new polybenzyls, gastropolybenzylols G-I (1-3) were isolated from the EtOAc extract of G. elata. Their structures were identified by extensive spectroscopic analyses involving HRESIMS, UV, IR, 1D and 2D NMR. Compound 1 showed agonistic effects on MT1 and MT2 receptors with agonistic rates of 55.91±4.84% and 165.13±5.65% at the concentration of 0.5 mM, respectively, and an EC50 value of 76.24 μM on MT2 receptor.

Whole-body spatially-resolved metabolomics method for profiling the metabolic differences of epimer drug candidates using ambient mass spectrometry imaging

Investigation of the in vivo drug action and metabolic differences of epimer drugs is challenging. Whole-body MSI analysis can visually present the stereoscopic distribution of molecules related to the interaction of drugs and organisms, and can provide more comprehensive organ-specific profiling information. Herein, we developed a whole-body spatially-resolved imaging metabolomics method based on an air flow-assisted ionisation desorption electrospray ionisation (AFADESI)-MSI system coupled with a high-resolution mass spectrometer and highly discriminating imaging software. The epimeric sedative-hypnotic drug candidates YZG-331 and YZG-330 were selected as examples, and rats administered normal or high oral doses were used. By performing multivariate statistical data-mining on the combined MSI data, organ-specific differential ions were screened. By comparing the variations in the relative contents of the drugs, their metabolites, and endogenous neurotransmitters throughout whole-body tissue sections of the rats, rich information that could potentially explain the more significant sedative-hypnotic effects of YZG-330 compared to YZG-331 was obtained. Such as the increased ratio of gamma-aminobutyric acid in the brain and stomach of the rats (0.25, 0.47, 0.68, 0.30, and 0.89 for the control and YZG-331-H, YZG-330-H, YZG-331-L, and YZG-330-L, respectively) were interesting. This study provided a convenient and visual method to investigate in vivo molecular metabolic differences and provide insight towards a better understanding of the pharmacodynamic mechanisms of these sedative-hypnotic drug-candidates.

Optimal Extraction Study of Gastrodin-Type Components from Gastrodia Elata Tubers by Response Surface Design with Integrated Phytochemical and Bioactivity Evaluation

Gastrodia elata tuber (GET) is a popular traditional Chinese medicines (TCMs). In this study, response surface methodology (RSM) with a Box–Behnken design (BBD) was performed to optimize the extraction parameters of gastrodin-type components (gastrodin, gastrodigenin, parishin A, parishin B, parishin C and parishin E). Different from the conventional studies that merely focused on the contents of phytochemical, we gave consideration to both quantitative analysis of the above six components by HPLC and representative bioactivities of GET, including antioxidation and protection of human umbilical vein endothelial cells (HUVEC). Four independent variables (ethanol concentration, liquid-material ratio, soaking time and extraction time) were investigated with the integrated evaluation index of phytochemical contents. With the validation experiments, the optimal extraction parameters were as follows: ethanol concentration of 41%, liquid–solid ratio of 28.58 mL/g, soaking time of 23.91 h and extraction time of 46.60 min. Under the optimum conditions, the actual standardized comprehensive score was 1.8134 ± 0.0110, which was in accordance with the predicted score of 1.8100. This firstly established method was proved to be feasible and reliable to optimize the extraction parameters of the bioactive components from GET. Furthermore, it provides some reference for the quality control and extraction optimization of TCMs.

Novel Strategies Using Total Gastrodin and Gastrodigenin, or Total Gastrodigenin for Quality Control of Gastrodia elata

Gastrodia elata Blume (G. elata), a traditional Chinese medicine, is widely used for treatment of various neuro dysfunctions. However, its quality control is still limited to the determination of gastrodin. In the present study, two novel strategies based on quantitative evaluation of total gastrodin and gastrodigenin with base hydrolysis and total gastrodigenin with base-enzymatic hydrolysis followed by HPLC-FLD were put forward and successfully applied to evaluate the quality of 47 batches of G. elata from eight localities. Meanwhile, a systematic comparison of the novel strategy with the multiple markers and the Pharmacopeia method was performed. The results showed that the parishins category could be completely hydrolyzed to gastrodin by sodium hydroxide solution, and gastrodin could further utterly hydrolyze to gastrodigenin with β-d-glucosidase buffer solution. The contents of total gastrodin and gastrodigenin ranged from 1.311% to 2.034%, and total gastrodigenin from 0.748% to 1.120% at the eight localities. From the comparison, we can conclude that the two novel strategies can comprehensively reveal the characteristics of overall active ingredients in G. elata for quality control. The present study provides a feasible and credible strategy for the quality control of G. elata, suggesting a revision of the latest Chinese Pharmacopoeia or European Pharmacopoeia methods for the modernization of G. elata use.

4-Hydroxybenzyl alcohol derivatives and their sedative–hypnotic activities

4-Hydroxybenzyl alcohol (HBA), one of the characteristic active components of Gastrodia elata, exhibits obvious effects on the human central nervous system. In order to acquire compounds with superior bioactivity, 10 derivatives of HBA were synthesized from HBA and carboxylic acids. The sedative effects of the 10 HBA derivatives were evaluated using a spontaneous locomotor activity test (SLT) in mice, and their hypnotic effects were determined to be synergistic with pentobarbital-induced sleep. The results showed that 4-hydroxybenzyl alcohol 3-furancarboxylic acid diester (2FHBA, 10 mg kg⁻¹) exhibited the strongest sedative–hypnotic activity among HBA and its derivatives, and 2FHBA could reverse the insomnia caused by p-chlorophenylalanine (pCPA), flumazenil (FLU) and thiosemicarbazide (TSC). Meanwhile, 2FHBA and 5-hydroxytryptophan (5-HTP) showed a synergistic effect. The results suggested that 2FHBA might be a potential agent against insomnia, which might be mediated by the serotonergic and GABAergic systems.

2FHBA, a derivative of HBA, exerts sedative and hypnotic effects through the serotonergic and GABAergic systems.

Theacrine: A purine alkaloid from Camellia assamica var. kucha with a hypnotic property via the adenosine system

Theacrine (l,3,7,9-tetramethyluric acid), a purine alkaloid from Camellia assamica var. kucha, has diverse pharmacological properties, including sedative and hypnotic activities, anti-inflammatory and analgesic activities, antidepressant effects, and a protective effect against stress-provoked liver damage. The present study aims to investigate the possible mechanism of the hypnotic activity of theacrine. The results revealed that theacrine significantly enhanced pentobarbital-induced sleep at a dose of 3.0mg/kg (i.g.) in mice. Sleep parameter analysis by EEG and EMG showed that theacrine obviously shortened wake time and increased NREM sleep time and that theacrine almost had no effect on REM sleep. Meanwhile, theacrine markedly attenuated caffeine (a nonselective antagonist of adenosine receptor)-induced insomnia. In pretreatment with the adenosine A₁ receptor antagonist DPCPX and the A_2A receptor antagonist SCH 58261, theacrine significantly reversed the decrease in sleeping time in pentobarbital-treated mice. In addition, theacrine also markedly increased the adenosine content in the hippocampus of rats. These results suggested that theacrine might mediate the adenosine system to augment pentobarbital-induced sleep.

Interspecies Variation of In Vitro Stability and Metabolic Diversity of YZG-331, a Promising Sedative-Hypnotic Compound

YZG-331, a synthetic adenosine derivative, express the sedative and hypnotic effects via binding to the adenosine receptor. The current study was taken to investigate the metabolic pathway of YZG-331 as well as species-specific differences in vitro. YZG-331 was reduced by 14, 11, 6, 46, and 11% within 120 min incubation in human, monkey, dog, rat, and mouse liver microsomes (LMs), respectively. However, YZG-331 was stable in human, monkey, dog, rat, and mouse liver cytoplasm. In addition, YZG-331 was unstable in rat or mouse gut microbiota with more than 50% of prototype drug degraded within 120 min incubation. Interestingly, the systemic exposure of M2 and M3 in rats and mice treated with antibiotics were significantly decreased in the pseudo germ-free group. YZG-331 could be metabolized in rat and human liver under the catalysis of CYP enzymes, and the metabolism showed species variation. In addition, 3 phase I metabolites were identified via hydroxyl (M1), hydrolysis (M2), or hydrolysis/ hydroxyl (M3) pathway. Flavin-containing monooxygenase 1 (FMO1) and FMO3 participated in the conversion of YZG-331 in rat LMs. Nevertheless, YZG-331 expressed stability with recombinant human FMOs, which further confirmed the species variation in the metabolism. Overall, these studies suggested that YZG-331 is not stable in LMs and gut microbiota. CYP450 enzymes and FMOs mediated the metabolism of YZG-331, and the metabolic pathway showed species difference. Special attention must be paid when extrapolating data from other species to humans.

Analytical Techniques and Pharmacokinetics of Gastrodia elata Blume and Its Constituents

Gastrodia elata Blume (G. elata), commonly called Tianma in Chinese, is an important and notable traditional Chinese medicine (TCM), which has been used in China as an anticonvulsant, analgesic, sedative, anti-asthma, anti-immune drug since ancient times. The aim of this review is to provide an overview of the abundant efforts of scientists in developing analytical techniques and performing pharmacokinetic studies of G. elata and its constituents, including sample pretreatment methods, analytical techniques, absorption, distribution, metabolism, excretion (ADME) and influence factors to its pharmacokinetics. Based on the reported pharmacokinetic property data of G. elata and its constituents, it is hoped that more studies will focus on the development of rapid and sensitive analytical techniques, discovering new therapeutic uses and understanding the specific in vivo mechanisms of action of G. elata and its constituents from the pharmacokinetic viewpoint in the near future. The present review discusses analytical techniques and pharmacokinetics of G. elata and its constituents reported from 1985 onwards.

Gastrodia elata and epilepsy: Rationale and therapeutic potential

BACKGROUND

Gastrodia elata Blume (G. elata) is a traditional Chinese herb used for centuries in folk medicine. Due to the claimed anticonvulsant properties of G. elata, it is expected that this herb continues to be a target of research, aiming to deepen the available knowledge on its biological activity and safety.

PURPOSE

The current review aims to discuss the most recent advances on the elucidation of the phytochemical composition and anticonvulsant potential of G. elata.

METHODS

Available literature was reviewed from PubMed, ISI Web of Knowledge and Science Direct, using combinations of the following keywords: Gastrodia elata, tianma, epilepsy, anticonvulsant and pharmacokinetics. Abstracts and full texts were evaluated for their clarity and scientific merit.

RESULTS

G. elata rhizome, as well as specific phenolic compounds isolated from this herb, have demonstrated anticonvulsant potential in a variety of in vitro and in vivo models. The pharmacological mechanisms potentially involved in the anticonvulsant activity have been extensively studied, being similar to the known mechanisms claimed for the available antiepileptic drugs. In addition, the pharmacokinetics of the main bioactive component of G. elata (gastrodin) has also been studied.

CONCLUSION

Due to its recognised therapeutic properties, G. elata has gained an increasing interest within the scientific community and, therefore, new medicinal preparations containing G. elata rhizome itself or its bioactive components are expected to be developed in the coming years. Moreover, specific phytochemical constituents isolated from G. elata may also be considered to integrate programs of discovery and development of new anticonvulsant drug candidates.

The rhizome of Gastrodia elata Blume - An ethnopharmacological review

ETHNOPHARMACOLOGICAL RELEVANCE

Gastrodia elata Blume (Orchidaceae) is commonly called Tian ma in Chinese and mainly distributed in the mountainous areas of eastern Asia, such as China, Korea, Japan and India. It is an extensively used traditional Chinese herbal medicine in the clinical practice of traditional Chinese medicine, to treat headache, migraine, dizziness, epilepsy, infantile convulsion, tetany and so on. The present paper reviews the advancements in investigation of botany and ethnopharmacology, phytochemistry, pharmacology, toxicology and quality control of Gastrodia elata Blume. Finally, the possible tendency and perspective for future investigation of this plant are also put forward.

MATERIALS AND METHODS

The information on Gastrodia elata Blume was collected via piles of resources including classic books about Chinese herbal medicine, and scientific databases including Pubmed, Google Scholar, ACS, Web of science, ScienceDirect databases, CNKI and others. Plant taxonomy was validated by the databases "The Plant List", and "Mansfeld's Encyclopedia".

RESULTS

Over 81 compounds from this plant have been isolated and identified, phenolics and polysaccharides are generally considered as the characteristic and active constituents of Gastrodia elata Blume. Its active compounds possess wide-reaching biological activities, including sedative, hypnotic, antiepileptic, anticonvulsive, antianxietic, antidepressant, neuroprotective, antipsychotic, anti-vertigo, circulatory system modulating, anti-inflammationary, analgesic, antioxidative, memory-improving and antiaging, antivirus and antitumor effects.

CONCLUSION

Despite the publication of various papers on Gastrodia elata Blume, there is still, however, the need for definitive research and clarification of other bioactive compounds using bioactivity-guided isolation strategies, and the possible mechanism of action as well as potential synergistic or antagonistic effects of multi-component mixtures derived from Gastrodia elata Blume need to be evaluated. It is also necessary and important to do more quality control and toxicological study on human subjects in order to maintain its efficacy stable in the body and validate its safety in clinical uses. In addition, more investigations on other parts of this plant beyond the tubers are needed. Further studies on Gastrodia elata Blume will lead to the development of new drugs and therapeutics for various diseases, and how to utilize it better should be paid more attention to.

Global profiling and rapid matching of natural products using diagnostic product ion network and in silico analogue database: Gastrodia elata as a case study

Rapid discovery of novel compounds of a traditional herbal medicine is of vital significance for pharmaceutical industry and plant metabolic pathway analysis. However, discovery of unknown or trace natural products is an ongoing challenge. This study presents a universal targeted data-independent acquisition and mining strategy to globally profile and effectively match novel natural product analogues from an herbal extract. The famous medical plant Gastrodia elata was selected as an example. This strategy consists of three steps: (i) acquisition of accurate parent and adduct ions (PAIs) and the product ions data of all eluting compounds by untargeted full-scan MS(E) mode; (ii) rapid compound screening using diagnostic product ions (DPIs) network and in silico analogue database with SUMPRODUCT function to find novel candidates; and (iii) identification and isomerism discrimination of multiple types of compounds using ClogP and ions fragment behavior analyses. Using above data mining methods, a total of 152 compounds were characterized, and 70 were discovered for the first time, including series of phospholipids and novel gastroxyl derivatives. Furthermore, a number of gastronucleosides and phase II metabolites of gastrodin and parishins were discovered, including glutathionylated, cysteinylglycinated and cysteinated compounds, and phosphatidylserine analogues. This study extended the application of classical DPIs filter strategy and developed a structure-based screening approach with the potential for significant increase of efficiency for discovery and identification of trace novel natural products.

Effect of Yajieshaba, a preparation of Dai indigenous medicine, on enhanced liver detoxification

OBJECTIVE

To explore the mechanistic effects of Yajieshaba (YJSB) on enhanced liver detoxification.

METHODS

The effects of YJSB on alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were assayed in five acute chemical liver injury models [carbon tetrachloride (CCl4), D-galactosamine (D-Glan), 4-acetamidophenol (AAP), thioacetamide (TAA) and 1-naphthyl isothiocyanate (ANIT)]. Sleep latency and sleep time of pentobarbital sodium were tested in control mice and CCl4 model miceafter oral YJSB administration. The effects of YJSB on drug metabolism enzymes of liver microsomes were tested in control rats and CCl4 model rats. The levels of cytochrome P450 (CYP450) and Cyt b5 in liver microsomes were assayed using the method by Omura and Sato, and activities of erythromycin N-demethylase (ERD) and aminopyrine N-demethyl (ADM) were evaluated by Nash colorimetry. Probe substrate-based high performance liquid chromatography (HPLC) methods were established for CYP3A4 and CYP1A2.

RESULTS

The level of serum ALT was reduced by YJSB at 3.51 g/kg in the five models as follows: CCl4 > D-Glan, AAP, ANIT > TAA. YJSB treatment did not reduce the level of serum AST. YJSB at 3.51 g/kg prolonged the sleep latency in control mice and shortened the sleep time of control mice and CCl4 model mice. For control rats, YJSB at 2.43 g/kg increased the levels of CYP450 and Cyt b5 and induced the activities of ERD and ADM; for liver injuries induced by CCl4 in rats, YJSB at 2.43 g/kg increased the levels of CYP450 and Cyt b5. These results suggest that YJSB at 2.43 g/kg induces CYP3A4 and CYP1A2.

CONCLUSION

These results suggest that YJSB enhanced liver detoxification and the mechanisms may be partially related to CYP3A4 and CYP1A2 induction.

4-Hydroxybenzyl-substituted amino acid derivatives from Gastrodia elata

Seven new 4-hydroxybenzyl-substituted amino acid derivatives (1−7), together with 11 known compounds, were isolated from an aqueous extract of the rhizomes of Gastrodia elata Blume. Their structures were determined by spectroscopic and chemical methods. Compounds 1−3 are pyroglutamate derivatives containing 4-hydroxybenzyl units at the N atom and 4−7 are the first examples of natural products with the 4-hydroxybenzyl unit linked via a thioether bond to 2-hydroxy-3-mercaptopropanoic acid (4−6) and 2-hydroxy-4-mercaptobutanoic acid (7), which would be biogenetically derived from cysteine and homocysteine, respectively. The structures of 1 and 2 were verified by synthesis, while the absolute configurations of 4, 5 and 7 were assigned using Mosher’s method based on the MPA determination rule of Δδ_RS values. The known compound 4-(hydroxymethyl)-5-nitrobenzene-1,2-diol (8) exhibited activity against Fe²⁺-cysteine induced rat liver microsomal lipid peroxidation with IC₅₀ values of 9.99×10⁻⁶ mol/L.

4-Hydroxybenzyl-substituted glutathione derivatives from Gastrodia elata

Seven new 4-hydroxybenzyl-substituted glutathione derivatives (2-8), together with a known analogue (1), were isolated from the aqueous extract of Gastrodia elata Blume rhizomes. Their structures were determined by using spectroscopic and chemical methods. The absolute configurations of 1-8 were assigned by using Marfey's method, combined with comparing the NMR and CD spectroscopic data of sulfoxide moieties in 3-6 with those of S-(4-hydroxybenzyl)cysteine sulfoxide stereoisomers (9-12) synthesized as authentic samples. The configurations of 9-12 were confirmed by electronic CD calculations based on the quantum-mechanical time-dependent density functional theory. Furthermore, the structures of 1, 3, 5, 7, and 8 were verified by synthesis. Compound 3 was active against serum deprivation-induced PC12 cell damage and synthetic 9-14 exhibited activity against Fe(2+)-cysteine induced rat liver microsomal lipid peroxidation.

Ambient mass spectrometry imaging metabolomics method provides novel insights into the action mechanism of drug candidates

Elucidation of the mechanism of action for drug candidates is fundamental to drug development, and it is strongly facilitated by metabolomics. Herein, we developed an imaging metabolomics method based on air-flow-assisted desorption electrospray ionization mass spectrometry imaging (AFADESI-MSI) under ambient conditions. This method was subsequently applied to simultaneously profile a novel anti-insomnia drug candidate, N(6)-(4-hydroxybenzyl)-adenosine (NHBA), and various endogenous metabolites in rat whole-body tissue sections after the administration of NHBA. The principal component analysis (PCA) represented by an intuitive color-coding scheme based on hyperspectral imaging revealed in situ molecular profiling alterations in response to stimulation of NHBA, which are in a very low intensity and hidden in massive interferential peaks. We found that the abundance of six endogenous metabolites changed after drug administration. The spatiotemporal distribution indicated that five altered molecules—including neurotransmitter γ-aminobutyric acid, neurotransmitter precursors choline and glycerophosphocholine, energy metabolism-related molecules adenosine (an endogenous sleep factor), and creatine—are closely associated with insomnia or other neurological disorders. These findings not only provide insights into a deep understanding on the mechanism of action of NHBA, but also demonstrate that the AFADESI-MSI-based imaging metabolomics is a powerful technique to investigate the molecular mechanism of drug action, especially for drug candidates with multitarget or undefined target in the preclinical study stage.

Evaluation of analgesic, sedative effects and antimigraine mechanism of Qilong Toutong Granule () in rodents

OBJECTIVE

To evaluate the analgesic and sedative effects of Qilong Toutong Granule (, QTG) and explore its possible mechanisms.

METHODS

Kunming mice were randomly divided into 6 groups: normal control group, Zhengtian Pill (, ZTP) group, Western medicine group, and high-dose (5.2 g/kg), medium-dose (2.6 g/kg) and low-dose (1.3 g/kg) of QTG groups. After completing the prophylactic treatment for 3 days, hot-plate test and acetic acid-induced writhing test were used to assess the analgesic effect, and spontaneous locomotor test and sodium pentobarbital-induced hypnosis activity were adopted to estimate the sedative effect. Sprague-Dawley rats were grouped into normal control group, model group, ZTP group, rizatriptan group, and high-dose (3.6 g/kg), medium-dose (1.8 g/kg), and low-dose (0.9 g/kg) of QTG groups. After gavage for continuous 7 days, rats were intraperitoneally injected nitroglycerin, and 4 h later, blood samples were collected from postcava for measuring the levels of plasma calcitonin gene-related peptide (CGRP) and beta-endorphin (β-EP) by radioimmunoassay. Subsequently, rats were perfused transcardially and the brain tissues containing the trigeminal nucleus caudalis (TNC) were achieved for detecting the number of Fos-immunoreactive cells by immunohistochemical method.

RESULTS

In the mice experiments, compared with the normal control group, high- and medium-dose of QTG groups significantly raised the pain threshold (P<0.01), reduced the number of writhing response (P<0.01) and spontaneous activity (P<0.01), but had no influence on the sleeping rate of mice (P>0.05), and low-dose of QTG group also raised the pain threshold at 120 min (P=0.007), as well as lowered locomotor activity of mice at 2 h (P=0.003). On the study of migraine model rats, high- and medium-dose of QTG groups remarkably down-regulated the levels of plasma CGRP (P<0.01), up-regulated the levels of plasma β-EP (P<0.01) and inhibited the expression of Fos protein in TNC (P<0.01), compared with the model group.

CONCLUSIONS

QTG has obvious analgesic and sedative action and its mechanism on relieving migraine may be through regulating the levels of neurotransmitters and/or neuropeptides, and inhibiting the activation of Fos pathway.

Sedative and hypnotic activity of N(6)-(3-methoxyl-4-hydroxybenzyl) adenine riboside (B2), an adenosine analog

N(6)-(3-methoxyl-4-hydroxybenzyl) adenine riboside (B2) is an N(6)-substitued adenosine analog. Previous studies have shown that B2 binds to the adenosine A1 and A2A receptors with moderate affinity and produces protective effects on serum deprivation-induced cell damage. However, central nervous system effects of B2 have not been studied. We aimed to investigate the sedative and hypnotic effects and the mechanism of action of B2 in mice. Our behavioral studies showed that oral administration of B2 decreased spontaneous locomotor activity and potentiated the hypnotic effect of pentobarbital in mice. Sleep architecture analyses revealed that B2 decreased wakefulness and increased non-rapid eye movement (NREM) sleep in both normal mice and mice with caffeine-induced insomnia. Using immunohistochemistry, we showed that B2 increased c-Fos expression, a cellular marker for neuronal activity, in the ventrolateral preoptic (VLPO) area, a sleep center in the anterior hypothalamus. Altogether, these results indicate that oral administration of B2 produces sedative and hypnotic effects. Furthermore, the activation of VLPO neurons may be involved in the central depressant effects of B2.

Determination of YZG-331 in mouse plasma using liquid chromatography-tandem mass spectrometry

A rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of YZG-331 in mouse plasma was developed. Plasma samples containing YZG-331 and YZG-441 (internal standard, IS) were prepared using a simple protein precipitation by the addition of acetonitrile. Thermo Scientific TSQ Quantum triple quadrupole system with multiple reaction monitoring (MRM) positive scanning mode was applied. The separation was performed on a ZorbaxSB-C18 column (3.5μm, 2.1mm×100mm) at a flow rate of 0.2mL/min, using acetonitrile/water containing 0.1% formic acid (v/v) as mobile phase. The MS/MS ion transit ions monitored were 386→254 for YZG-331 and 400→268 for IS. Linear detection responses were obtained for YZG-331 ranging from 25 to 5000ng/mL and the lower limits of quantitation (LLOQ) for the compound was 25ng/mL. The intra- and inter-day precisions (R.S.D.%) were within 12.6% for all analytes, while the deviation of assay accuracies was within ±6.9%. The average recoveries of analytes were greater than 94.3%. The analytes were proved to be stable during all sample storage, preparation and analytic procedures. The method was successfully applied to the pharmacokinetic studies of YZG-331 in mice.