Gastrodin microinjection suppresses 6-OHDA-induced motor impairments in parkinsonian rats: insights into oxidative balance and microglial activation in SNc

The protective effects of gastrodin on neurological disorders: an update and future perspectives

Neurological disorders are characterized by high mortality and disability rates. Furthermore, the burden associated with disability and mortality resulting from neurological disorders has been increasing at an alarming rate. Botanical drugs and their bioactive components have emerged as a prominent area of research, offering a promising avenue for developing novel alternatives for treating neurological diseases. Gastrodin is the principal active component derived from the traditional Chinese medicinal plant Gastrodia elata Blume (GEB). Existing literature reveals that gastrodin exerts various pharmacological protective actions against neurological disorders. This review aimed to collate novel literature on gastrodin for treating neurological disorders from Web of Science, PubMed, Embase and CNKI. The pharmacokinetics of gastrodin, its therapeutic role in neurological disorders, the main mechanisms of action and clinical application were addressed. Furthermore, a detailed overview of gastrodin drug delivery systems and physical enhancement methods was presented, offering invaluable insights into potential research and the extensive applications of gastrodin.

The role of gastrodin in the management of CNS-related diseases: Underlying mechanisms to therapeutic perspectives

Central nervous system (CNS)-related diseases have a high mortality rate, are a serious threat to physical and mental health, and have always been an important area of research. Gastrodin, the main active metabolite of Gastrodia elata Blume, used in Chinese medicine and food, has a wide range of pharmacological effects, mostly related to CNS disorders. This review aims to systematically summarize and discuss the effects and underlying mechanisms of gastrodin in the treatment of CNS diseases, and to assess its potential for further development as a lead drug in both biomedicine and traditional Chinese medicine. Studies on the pharmacological effects of gastrodin on the CNS indicate that it may exert anti-neurodegenerative, cerebrovascular protective, and ameliorative effects on diabetic encephalopathy, perioperative neurocognitive dysfunction, epilepsy, Tourette's syndrome, depression and anxiety, and sleep disorders through various mechanisms. To date, 110 gastrodin products have been approved for clinical use, but further multicenter clinical case-control studies are relatively scarce. Preclinical studies have confirmed that gastrodin can be used to treat CNS-related disorders. However, important concerns need to be addressed in the context of likely non-specific, assay interfering effects when gastrodin is studied using in vitro and in silico approaches, calling for a systematic assessment of the evidence to date. High-quality clinical trials should have priority to evaluate the therapeutic safety and clinical efficacy of gastrodin. Further experimental research using appropriate in vivo models is also needed, focusing on neurodegenerative diseases, cerebral ischemic and hypoxic diseases, brain damage caused by methamphetamine or heavy metals, and epilepsy.

Gastrodin, a Promising Natural Small Molecule for the Treatment of Central Nervous System Disorders, and Its Recent Progress in Synthesis, Pharmacology and Pharmacokinetics

Gastrodia elata Blume is a traditional medicinal and food homology substance that has been used for thousands of years, is mainly distributed in China and other Asian countries, and has always been distinguished as a superior class of herbs. Gastrodin is the main active ingredient of G. elata Blume and has attracted increasing attention because of its extensive pharmacological activities. In addition to extraction and isolation from the original plant, gastrodin can also be obtained via chemical synthesis and biosynthesis. Gastrodin has significant pharmacological effects on the central nervous system, such as sedation and improvement of sleep. It can also improve epilepsy, neurodegenerative diseases, emotional disorders and cognitive impairment to a certain extent. Gastrodin is rapidly absorbed and widely distributed in the body and can also penetrate the blood-brain barrier. In brief, gastrodin is a promising natural small molecule with significant potential in the treatment of brain diseases. In this review, we summarised studies on the synthesis, pharmacological effects and pharmacokinetic characteristics of gastrodin, with emphasis on its effects on central nervous system disorders and the possible mechanisms, in order to find potential therapeutic applications and provide favourable information for the research and development of gastodin.

Herpotrichone A Exerts Neuroprotective Effects by Relieving Ferroptosis

Inhibition of oxidative stress and ferroptosis is currently considered to be a promising therapeutic approach for neurodegenerative diseases. Herpotrichones, a class of compounds derived from insect symbionts, have shown potential for neuroprotective activity with low toxicity. However, the specific mechanisms through which herpotrichones exert their neuroprotective effects remain to be fully elucidated. In this study, the natural [4 + 2] adducts herpotrichone A (He-A) and its new analogues were isolated from the isopod-associated fungus Herpotrichia sp. SF09 and exhibited significantly protective effects in H2O2-, 6-OHDA-, and RSL3-stimulated PC12 cells and LPS-stimulated BV-2 cells. Moreover, He-A was able to relieve ferroptotic cell death in RSL3-stimulated PC12 cells and 6-OHDA-induced zebrafish larvae. Interestingly, He-A can activate antioxidant elements and modulate the SLC7A11 pathway without capturing oxidic free radical and chelating iron. These findings highlight He-A as a novel hit that protects against ferroptosis-like neuronal damage in the treatment of neurodegenerative diseases.

Chemistry, Biological Activities, and Pharmacological Properties of Gastrodin: Mechanism Insights

Gastrodin, a bioactive compound derived from the rhizome of the orchid Gastrodia elata, exhibits a diverse range of biological activities. With documented neuroprotective, anti-inflammatory, antioxidant, anti-apoptotic, and anti-tumor effects, gastrodin stands out as a multifaceted therapeutic agent. Notably, it has demonstrated efficacy in protecting against neuronal damage and enhancing cognitive function in animal models of Alzheimer's disease, Parkinson's disease, and cerebral ischemia. Additionally, gastrodin showcases immunomodulatory effects by mitigating inflammation and suppressing the expression of inflammatory cytokines. Its cytotoxic activity involves the inhibition of angiogenesis, suppression of tumor growth, and induction of apoptosis. This comprehensive review seeks to elucidate the myriad potential effects of Gastrodin, delving into the intricate molecular mechanisms underpinning its pharmacological properties. The findings underscore the therapeutic potential of gastrodin in addressing various conditions linked to neuroinflammation and cancer.

Gastrodin: a comprehensive pharmacological review

Tianma is the dried tuber of Gastrodia elata Blume (G. elata), which is frequently utilized in clinical practice as a traditional Chinese medicine. Gastrodin (GAS) is the main active ingredient of Tianma, which has good pharmacological activity. Therefore, for the first time, this review focused on the extraction, synthesis, pharmacological effects, and derivatives of GAS and to investigate additional development options for GAS. The use of microorganisms to create GAS is a promising method. GAS has good efficacy in the treatment of neurological diseases, cardiovascular diseases, endocrine diseases, and liver diseases. GAS has significant anti-inflammatory, antioxidant, neuroprotective, vascular protective, blood sugar lowering, lipid-regulating, analgesic, anticancer, and antiviral effects. The mechanism involves various signaling pathways such as Nrf2, NF-κB, PI3K/AKT, and AMPK. In addition, the derivatives of GAS and biomaterials synthesized by GAS and PU suggested a broader application of GAS. The research on GAS is thoroughly summarized in this paper, which has useful applications for tackling a variety of disorders and exhibits good development value.

The role of histamine H1 receptor in the anterior cingulate cortex on nociception level following acute restraint stress in male rats

Considering the importance of pain and stress, we decided to investigate the intra-anterior cingulate cortex (ACC) microinjection of histamine and mepyramine alone and concurrently on acute pain induced by hot plate following restraint stress in male rats. 24-gauge, 10 mm stainless steel guide cannula was implanted over the ACC in the incised scalp of 4 groups. Restraint stress in healthy rats produced a significant increase (p < .05) in the pain threshold. The simultaneous microinjection of 4 μg/side histamine and 8 μg/side mepyramine as a histaminergic system inverse agonist in healthy nonrestraint animals did not affect the pain threshold. Although Histamine decreased the threshold of pain meaningfully, mepyramine elevated it in a significant manner (p < .05). In the restrained animals, intra-ACC microinjection of histamine produced no significant impact on the pain threshold. However, intra-ACC microinjection of mepyramine before histamine, significantly (p < .01) altered the result and enhanced the threshold of pain. The results of our study demonstrated that histaminergic neurons have an important role in the processing of pain in the ACC following restraint stress.

Review on pharmacological effects of gastrodin

Gastrodia elata Blume is a well-known traditional Chinese medicine that is mainly used to treat diseases related to the nervous system, such as stroke, epilepsy, and headache. Gastrodin is the main bioactive component of Gastrodia elata Blume, and studies have shown that it has extensive pharmacological activity. This narrative review aims to systematically review relevant studies on the pharmacological effects of gastrodin to provide researchers with the latest and most useful information. Studies have shown that gastrodin has prominent neuroprotective effects and can treat or improve epilepsy, Tourette syndrome, Alzheimer's disease, Parkinson's disease, emotional disorders, cerebral ischemia-reperfusion injury, cognitive impairment, and neuropathic pain. Gastrodin can also improve myocardial hypertrophy, hypertension, and myocardial ischemia-reperfusion injury. In addition, gastrodin can mitigate liver, kidney, and bone tissue damage caused by oxidative stress and inflammation. In short, gastrodin is expected to treat many diseases, and it is worth investing more effort in research on this compound.

The effects of bioactive components from the rhizome of gastrodia elata blume (Tianma) on the characteristics of Parkinson's disease

Parkinson's disease (PD) is an age-related chronic neurodegenerative disease caused by the death and degeneration of dopaminergic neurons in the substantia nigra of the midbrain. The decrease of the neurotransmitter dopamine in the patient's brain leads to various motor symptoms. PD drugs mainly enhance dopamine levels but cannot prevent or slow down the loss of dopaminergic neurons. In addition, they exhibit significant side effects and addiction issues during long-term use. Therefore, it is particularly urgent to develop novel drugs that have fewer side effects, can improve PD symptoms, and prevent the death of dopaminergic neurons. The rhizome of Gastrodia elata Blume (Tianma) is a well-known medicinal herb and has long been used as a treatment of nervous system-related diseases in China. Several clinical studies showed that formula comprising Tianma could be used as an add-on therapy for PD patients. Pharmacological studies indicated that Tianma and its bioactive components can reduce the death of dopaminergic neurons, α-synuclein accumulation, and neuroinflammation in various PD models. In this review, we briefly summarize studies regarding the effects of Tianma and its bioactive components' effects on major PD features and explore the potential use of Tianma components for the treatment of PD.

Post treatment with Gastrodin suppresses oxidative stress and attenuates motor disorders following 6-OHDA induced Parkinson disease

BACKGROUND & OBJECTIVE

Researchers are currently trying to find new therapies with better symptomatic activity and fewer side effects to manage Parkinson's disease (PD). Although the protective effect of pre-treatment by Gastrodin (Gst) on a PD model has been evaluated, in the current experimental study, we investigated the symptomatic therapeutic effects of Gst microinjection in the same PD model but in the post-parkinsonism induction condition.

METHODS

Parkinsonism was induced by unilateral infusion of 6- hydroxydopamine (6-OHDA; 8 μg/ 2 μl/ rat) into the central region of the substantia nigra pars compacta (SNc). After the recovery period and confirmation of parkinsonism, daily Gst treatment in three doses (20, 40, 80 µg/ 2 µ/ rat, continued for ten days with motor monitoring by bar test and rotarod examinations. Moreover, lipid peroxidation and myeloperoxidase activity were evaluated.

RESULTS

In this model of 6-OHDA-induced parkinsonism, Gst treatment in all three doses showed a dose dependent symptomatic improvement in motor imbalance (P < 0.001) catalepsy (P < 0.001), decreased lipid peroxidation (P < 0.001) and SNc myeloperoxidase activity (P < 0.001) CONCLUSIONS: 6-OHDA induced parkinsonism symptomatically improved behaviorally with Gst post-induction treatment along with decreased markers of oxidative stress and microglial activation. We suggest that this agent is a candidate for symptomatic treatment of human PD.

Potential Molecular Mechanism of Guishao Pingchan Recipe in the Treatment of Parkinson’s Disease Based on Network Pharmacology and Molecular Docking

Objective: To investigate the potential mechanism of Guishao Pingchan Recipe (GPR) against Parkinson's disease (PD) based on network pharmacology and molecular docking. Methods: The main components of GPR were collected based on TCMSP database, Batman-TCM database, Chinese Pharmacopoeia, and Literatures. The potential therapeutic targets of PD were predicted by Drug Bank Database and Gene Cards database. Cytoscape 3.8.2 software was used to construct herb–component–target network. Then, String database was used to construct a PPI network, and DAVID database was used for gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotation of targets function. Core components of GPR and hub targets were imported into AutoDock Vina for molecular docking verification and results were visualized by Pymol. Results: 13 candidate components were selected and 288 corresponding targets of GPR for treating PD were obtained. The GO enrichment analysis mainly involved 135 cell components, 187 molecular functions, and 1753 biological processes. Moreover, KEGG pathway enrichment analysis mainly involved 200 signaling pathways. Molecular docking simulation indicated a good binding ability of components and targets. Conclusion: Based on network pharmacology and molecular docking, we found that sitosterol, 4-Cholesten-3-one and stigmasterol in GPR could combine with MAPK3, APP, VEGFA, and CXCR4 and involved in the cAMP, PI3K/Akt, Rap1 signaling pathways. It is suggested that GPR may have therapeutic effects on PD through multi-component, multi-target, and multi-pathway and predict the relevant mechanism of the anti-PD effect of GPR.

The pathogenesis and treatment mechanism of Parkinson's disease from the perspective of traditional Chinese medicine

BACKGROUND

Parkinson's disease (PD) is the second most common neurodegenerative disease with no treatment currently available to modify its progression. Traditional Chinese medicine (TCM) has gained attention for its unique theoretical basis and clinical effects. Many studies have reported on the clinical effects and pharmacological mechanisms of Chinese herbs in PD. However, few studies have focused on the treatment mechanisms of anti-PD TCM drugs from the perspective of TCM itself.

PURPOSE

To elaborate the treatment mechanisms of anti-PD TCM drugs in the perspective of TCM.

METHODS

We performed a literature survey using traditional books of Chinese medicine and online scientific databases including PubMed, Web of Science, Google Scholar, China National Knowledge Infrastructure (CNKI), and others up to July 2021.

RESULTS

TCM theory states that PD is caused by a dysfunction of the zang-fu organs (liver, spleen, kidney, and lung) and subsequent pathogenic factors (wind, fire, phlegm, and blood stasis). Based on the pathogenesis, removing pathogenic factors and restoring visceral function are two primary treatment principles for PD in TCM. The former includes dispelling wind, clearing heat, resolving phlegm, and promoting blood circulation, while the latter involves nourishing the liver and kidney and strengthening the spleen. The anti-PD mechanisms of the active ingredients of TCM compounds and herbs at different levels include anti-apoptosis, anti-inflammation, and anti-oxidative stress, as well as the restoration of mitochondrial function and the regulation of autophagy and neurotransmitters.

CONCLUSION

Chinese herbs and prescriptions can be used to treat PD by targeting multiple pharmacological mechanisms.

Focused Ultrasound Promotes the Delivery of Gastrodin and Enhances the Protective Effect on Dopaminergic Neurons in a Mouse Model of Parkinson’s Disease

Parkinson’s disease (PD) is the second most common chronic neurodegenerative disease globally; however, it lacks effective treatment at present. Focused ultrasound (FUS) combined with microbubbles could increase the efficacy of drug delivery to specific brain regions and is becoming a promising technology for the treatment of central nervous system diseases. In this study, we explored the therapeutic potential of FUS-mediated blood–brain barrier (BBB) opening of the left striatum to deliver gastrodin (GAS) in a subacute PD mouse model induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). The concentration of GAS in the left hemisphere was detected by ultra-high performance liquid chromatography electrospray Q-Orbitrap mass spectrometry (UHPLC/ESI Q-Orbitrap) and the distribution of tyrosine hydroxylase (TH) neurons was detected by immunohistochemical staining. The expression of TH, Dopamine transporter (DAT), cleaved-caspase-3, B-cell lymphoma 2 (Bcl-2), brain-derived neurotrophic factor (BDNF), postsynaptic density protein 95 (PSD-95), and synaptophysin (SYN) protein were detected by western blotting. Analysis showed that the concentration of GAS in the left hemisphere of PD mice increased by approximately 1.8-fold after the BBB was opened. FUS-mediated GAS delivery provided optimal neuroprotective effects and was superior to the GAS or FUS control group. In addition, FUS enhanced GAS delivery significantly increased the expression of Bcl-2, BDNF, PSD-95, and SYN protein in the left striatum (P &lt; 0.05) and reduced the levels of cleaved-caspase-3 remarkably (P = 0.001). In conclusion, the enhanced delivery by FUS effectively strengthened the protective effect of GAS on dopaminergic neurons which may be related to the reinforcement of the anti-apoptotic activity and the expression of synaptic-related proteins in the striatum. Data suggests that FUS-enhanced GAS delivery may represent a new strategy for PD treatment.

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.

Efficacy of Posidonia oceanica Extract against Inflammatory Pain: In Vivo Studies in Mice

Posidonia oceanica (L.) Delile is traditionally used for its beneficial properties. Recently, promising antioxidant and anti-inflammatory biological properties emerged through studying the in vitro activity of the ethanolic leaves extract (POE). The present study aims to investigate the anti-inflammatory and analgesic role of POE in mice. Inflammatory pain was modeled in CD-1 mice by the intraplantar injection of carrageenan, interleukin IL-1β and formalin. Pain threshold was measured by von Frey and paw pressure tests. Nociceptive pain was studied by the hot-plate test. POE (10–100 mg kg⁻¹) was administered per os. The paw soft tissue of carrageenan-treated animals was analyzed to measure anti-inflammatory and antioxidant effects. POE exerted a dose-dependent, acute anti-inflammatory effect able to counteract carrageenan-induced pain and paw oedema. Similar anti-hyperalgesic and anti-allodynic results were obtained when inflammation was induced by IL-1β. In the formalin test, the pre-treatment with POE significantly reduced the nocifensive behavior. Moreover, POE was able to evoke an analgesic effect in naïve animals. Ex vivo, POE reduced the myeloperoxidase activity as well as TNF-α and IL-1β levels; further antioxidant properties were highlighted as a reduction in NO concentration. POE is the candidate for a new valid strategy against inflammation and pain.

Neuronal degeneration and oxidative stress in the SNc of 6-OHDA intoxicated rats; improving role of silymarin long-term treatment

Progressive loss in dopaminergic neurons (DA) of substantia nigra pars compacta (SNc) leads to Parkinson's disease with a hypothesis of oxidative stress generation. The present study was conducted to determine the long-term efficacy of silymarin (SM) post-treatment on 6-OHDA-induced oxidative stress in the SNc of male rats. Male Wistar rats were received 6-OHDA (8 μg/rat) into SNc. After 3 weeks, as recovery period, the animals were treated with i.p. injection of SM at different doses of 100, 200, or 300 mg/kg for 15 days. At the end of the treatment, motor function, neuronal cell count, antioxidant enzymes, and lipid peroxidation and tyrosine hydroxylase (TH) activities were evaluated in the ventral midbrain tissue. The 6-OHDA significantly decreased (p ≤ 0.05) motor function, antioxidant enzyme activity, GSH level, and GSH/GSSG ratio and caused an augmentation in GSSG and lipid peroxidation level. The 6-OHDA also reduced the population of neurons and TH expression. The SM repaired the 6-OHDA-induced motor impairment, antioxidant enzyme suppression, and TH down-regulation. All three doses of SM could restore the MDA level to the normal range in the 6-OHDA-lesioned rats and could reversed the effect of 6-OHDA on GSH, GSSG level, and GSH/GSSG ratio. The SM treatment significantly and dose-dependently increased (p ≤ 0.001) the total number of surviving neurons in the SNc. Silymarin chronic treatment restored the brain's antioxidant capacity and salvaged neurons from oxidative stress-induced neurodegeneration. The SM could also improve motor function in parkinsonian animals by increasing TH expression. These results recommend that application of SM over initial clinical stages may depict a hopeful approach versus PD. However, more research is needed to confirm this issue.

Indomethacin loaded dextran stearate polymeric micelles improve adjuvant-induced arthritis in rats: design and in vivo evaluation

BACKGROUND

Indomethacin is a non-steroidal anti-inflammatory drug (NSAID) that can effectively control the pain and inflammation caused by rheumatoid arthritis (RA), but its usage is limited due to severe adverse effects. For this reason, making more specific formulations of this drug can be considered. The aim of the present study was designing a novel nano-sized indomethacin delivery system.

MATERIALS AND METHODS

Indomethacin-loaded dextran stearate polymeric micelles were prepared by dialysis method. Particle size and zeta potential of micelles were measured by a zeta sizer instrument. Drug release from micelles was investigated in phosphate buffer medium pH 7.4 and then the best formulation regarding physical properties and drug release was selected for animal studies. Arthritis was induced by complete Freund's adjuvant injection in rats. Then, the animals were randomly assigned into the model, the indomethacin solution and the polymeric micelles groups. The clinical effects of polymeric micelle formulation were assessed by measuring arthritis index, animal paw edema and measuring biochemical parameters including myeloperoxidase (MPO) activity, lipid peroxidation (LPO), glutathione (GSH), total antioxidant capacity (TAC), TNF-α, IL-17 and IL-1β.

RESULTS

Paw edema was attenuated following the administration of indomethacin-loaded polymeric micelles. Based on the findings of the present study, the use of indomethacin-loaded polymeric micelles could improve inflammatory symptoms, decrease arthritis index and decrease the diameter of the paw in arthritic rats in a significant manner (p ≤ 0.05). In addition, the use of polymeric micelles like indomethacin solution significantly reduced (p ≤ 0.05) the activity of MPO, LPO, TNF-α, IL-17 and IL-1β, and made a significant increase (p ≤ 0.05) in glutathione and TAC content and ameliorated structural changes in the paw tissue compared to the control group.

CONCLUSION

Our findings demonstrated that indomethacin-loaded dextran stearate polymeric micelles can provide more effective therapeutic effects in control of inflammation in arthritis in rat.

Behavioral Tests in Neurotoxin-Induced Animal Models of Parkinson's Disease

Currently, neurodegenerative diseases are a major cause of disability around the world. Parkinson's disease (PD) is the second-leading cause of neurodegenerative disorder after Alzheimer's disease. In PD, continuous loss of dopaminergic neurons in the substantia nigra causes dopamine depletion in the striatum, promotes the primary motor symptoms of resting tremor, bradykinesia, muscle rigidity, and postural instability. The risk factors of PD comprise environmental toxins, drugs, pesticides, brain microtrauma, focal cerebrovascular injury, aging, and hereditary defects. The pathologic features of PD include impaired protein homeostasis, mitochondrial dysfunction, nitric oxide, and neuroinflammation, but the interaction of these factors contributing to PD is not fully understood. In neurotoxin-induced PD models, neurotoxins, for instance, 6-hydroxydopamine (6-OHDA), 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), 1-Methyl-4-phenylpyridinium (MPP+), paraquat, rotenone, and permethrin mainly impair the mitochondrial respiratory chain, activate microglia, and generate reactive oxygen species to induce autooxidation and dopaminergic neuronal apoptosis. Since no current treatment can cure PD, using a suitable PD animal model to evaluate PD motor symptoms' treatment efficacy and identify therapeutic targets and drugs are still needed. Hence, the present review focuses on the latest scientific developments in different neurotoxin-induced PD animal models with their mechanisms of pathogenesis and evaluation methods of PD motor symptoms.

Oxidative Stress in Parkinson's Disease: Potential Benefits of Antioxidant Supplementation

Parkinson's disease (PD) occurs in approximately 1% of the population over 65 years of age and has become increasingly more common with advances in age. The number of individuals older than 60 years has been increasing in modern societies, as well as life expectancy in developing countries; therefore, PD may pose an impact on the economic, social, and health structures of these countries. Oxidative stress is highlighted as an important factor in the genesis of PD, involving several enzymes and signaling molecules in the underlying mechanisms of the disease. This review presents updated data on the involvement of oxidative stress in the disease, as well as the use of antioxidant supplements in its therapy.

Microglia mediated neuroinflammation - signaling regulation and therapeutic considerations with special reference to some natural compounds

Neuroinflammation plays a central role in multiple neurodegenerative diseases and neurological disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), cerebral ischemic injury etc. In this connection, microglia, the key players in the central nervous system, mediate the inflammatory response process. In brain injuries, activated microglia can clear the cellular debris and invading pathogens and release neurotrophic factors; however, prolonged microglia activation may cause neuronal death through excessive release of inflammatory mediators. Therefore, it is of paramount importance to understand the underlying molecular mechanisms of microglia activation to design an effective therapeutic strategy to alleviate neuronal injury. Recent studies have shown that some natural compounds and herbal extracts possess anti-inflammatory properties that may suppress microglial activation and ameliorate neuroinflammation and hence are neuroprotective. In this review, we will update some of the common signaling pathways that regulate microglia activation. Among the various signaling pathways, the Notch-1, mitogen-activated protein kinases (MAPKs), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) have been reported to exacerbate microglia mediated neuroinflammation that is implicated in different neuropathological diseases. The search for natural compounds or agents, specifically those derived from natural herbal extracts such as Gastrodin, scutellarin, RG1 etc. has been the focus of many of our recent studies because they have been found to regulate microglia activation. The pharmacological effects of these agents and their potential mechanisms for regulating microglia activation are systematically reviewed here for a fuller understanding of their biochemical action and therapeutic potential for treatment of microglia mediated neuropathological diseases.

Anti-inflammatory and anti-hyperalgesic effects of milnacipran in inflamed rats: involvement of myeloperoxidase activity, cytokines and oxidative/nitrosative stress

BACKGROUND

Many injuries cause pain and inflammation, which are one of the major challenges for physicians. In this study, the analgesic and the anti-inflammatory effects of milnacipran were investigated on carrageenan-induced nociception and inflammation in male rats.

METHODS

Pain and inflammation were induced by injection of λ-carrageenan (1% v/v) into the hind paw. Indomethacin (10 mg/kg: ip) or milnacipran (10, 20 and 40 mg/kg: ip) were administered 30 min before carrageenan. Analgesia and inflammation were measured by hot plate and plethysmometer. Finally, lipid peroxidation, tumor necrosis factor alpha (TNF-α), Interleukin 1 beta (IL-1β), Interleukin 6 (IL-6), myeloperoxidase (MPO) activity, nitric oxide (NO) and total antioxidant capacity (TAC) status evaluated in the hind paw tissue.

RESULTS

The results showed that carrageenan caused hyperalgesia and inflammation in the hind paw tissue. Milnacipran (20 and 40 mg/kg) significantly and dose-dependently attenuated (65 ± 3.2%; p ≤0.01 and 42 ± 6.2%; p ≤ 0.001, respectively) carrageenan-induced inflammation and significantly increased (p ≤ 0.001) nociception threshold. Also, milnacipran (20 and 40 mg/kg) significantly suppressed levels of malondialdehyde (MDA), NO (p ≤ 0.05), MPO activity, TNF-α, IL-1β and IL-6 (p ≤ 0.001) following carrageenan injection. Additionally, milnacipran (10, 20 and 40 mg/kg) significantly augmented (p ≤ 0.05) TAC status following carrageenan in the hind paw tissue.

CONCLUSION

In the present study, milnacipran showed anti-nociceptive and anti-inflammatory effects on carrageenan-induced hyperalgesia and inflammation in a dose-dependent manner. Milnacipran reduced inflammatory edema and increased the paw withdrawal threshold probably through suppression of MDA, NO, TNF-α, IL-1β, IL-6 and MPO activity, and increase of TAC status in the hind paw tissue. Therefore, milnacipran holds important potential as an anti-inflammatory and anti-nociceptive drug. Although, further clinical trials to confirm this issue, is required.

Shared cerebral metabolic pathology in non-transgenic animal models of Alzheimer's and Parkinson's disease

Parkinson's disease (PD) and Alzheimer's disease (AD) are the most common chronic neurodegenerative disorders, characterized by motoric dysfunction or cognitive decline in the early stage, respectively, but often by both symptoms in the advanced stage. Among underlying molecular pathologies that PD and AD patients have in common, more attention is recently paid to the central metabolic dysfunction presented as insulin resistant brain state (IRBS) and altered cerebral glucose metabolism, both also explored in animal models of these diseases. This review aims to compare IRBS and alterations in cerebral glucose metabolism in representative non-transgenic animal PD and AD models. The comparison is based on the selectivity of the neurotoxins which cause experimental PD and AD, towards the cellular membrane and intracellular molecular targets as well as towards the selective neurons/non-neuronal cells, and the particular brain regions. Mitochondrial damage and co-expression of insulin receptors, glucose transporter-2 and dopamine transporter on the membrane of particular neurons as well as astrocytes seem to be the key points which are further discussed in a context of alterations in insulin signalling in the brain and its interaction with dopaminergic transmission, particularly regarding the time frame of the experimental AD/PD pathology appearance and the correlation with cognitive and motor symptoms. Such a perspective provides evidence on IRBS being a common underlying metabolic pathology and a contributor to neurodegenerative processes in representative non-transgenic animal PD and AD models, instead of being a direct cause of a particular neurodegenerative disorder.

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.

Gastrodin protects dopaminergic neurons via insulin-like pathway in a Parkinson's disease model

BACKGROUND

Recently, the use of traditional Chinese medicine (TCM) has become more generally accepted, including by the Food and Drug Administration. To expand the use of TCM worldwide, it is important to study the molecular mechanisms by which TCM and its active ingredients produce effects. Gastrodin is an active ingredient from Gastrodia elata Blume. It is reported that gastrodin has neuroprotective function in Parkinson's disease. But its mechanisms of neuroprotection remain not clear in PD. Here, we build two C. elegans PD model using 6-OHDA and transgenic animal to observe the changes of PD worms treated with or without gastrodin to confirm the function of gastrodin, then utilize mutant worms to investigate DAF-2/DAF-16 signaling pathway, and finally verify the mechanism of gastrodin in PD.

RESULTS

Gastrodin attenuates the accumulation of α-synuclein and the injury of dopaminergic neurons, improves chemotaxis behavior in Parkinson's disease models, then recovers chemotaxis behavior by insulin-like pathway. DAF-2/DAF-16 is required for neuroprotective effect of dopamine neuron in PD.

CONCLUSIONS

Our study demonstrated that gastrodin rescued dopaminergic neurons and reduced accumulation of α-synuclein protein, and the activity of gastrodin against Parkinson's disease depended on the insulin-like DAF-2/DAF-16 signaling pathway. Our findings revealed that this insulin-like pathway mediates neuroprotection of gastrodin in a Parkinson's disease model.

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.