The Phenolic Components of Gastrodia elata improve Prognosis in Rats after Cerebral Ischemia/Reperfusion by Enhancing the Endogenous Antioxidant Mechanisms

Astrocyte modulation in cerebral ischemia-reperfusion injury: A promising therapeutic strategy

Cerebral ischemia-reperfusion injury (CIRI) poses significant challenges for drug development due to its complex pathogenesis. Astrocyte involvement in CIRI pathogenesis has led to the development of novel astrocyte-targeting drug strategies. To comprehensively review the current literature, we conducted a thorough analysis from January 2012 to December 2023, identifying 82 drugs aimed at preventing and treating CIRI. These drugs target astrocytes to exert potential benefits in CIRI, and their primary actions include modulation of relevant signaling pathways to inhibit neuroinflammation and oxidative stress, reduce cerebral edema, restore blood-brain barrier integrity, suppress excitotoxicity, and regulate autophagy. Notably, active components from traditional Chinese medicines (TCM) such as Salvia miltiorrhiza, Ginkgo, and Ginseng exhibit these important pharmacological properties and show promise in the treatment of CIRI. This review highlights the potential of astrocyte-targeted drugs to ameliorate CIRI and categorizes them based on their mechanisms of action, underscoring their therapeutic potential in targeting astrocytes.

20(R)-ginsenoside Rg3 attenuates cerebral ischemia-reperfusion injury by mitigating mitochondrial oxidative stress via the Nrf2/HO-1 signaling pathway

Reducing mitochondrial oxidative stress has become an important strategy to prevent neuronal death in ischemic stroke. Previous studies have shown that 20(R)-ginsenoside Rg3 can significantly improve behavioral abnormalities, reduce infarct size, and decrease the number of apoptotic neurons in cerebral ischemia/reperfusion injury rats. However, it remains unclear whether 20(R)-ginsenoside Rg3 can inhibit mitochondrial oxidative stress in ischemic stroke and the potential molecular mechanism. In this study, we found that 20(R)-ginsenoside Rg3 notably inhibited mitochondrial oxidative stress in middle cerebral artery occlusion/reperfusion (MCAO/R) rats and maintained the stability of mitochondrial structure and function. Treatment with 20(R)-ginsenoside Rg3 also decreased the levels of mitochondrial fission proteins (Drp1 and Fis1) and increased the levels of fusion proteins (Opa1, Mfn1, and Mfn2) in MCAO/R rats. Furthermore, we found that 20(R)-ginsenoside Rg3 promoted nuclear aggregation of nuclear factor erythroid2-related factor 2 (Nrf2) but did not affect Kelch-like ECH-associated protein-1 (Keap1), resulting in the downstream expression of antioxidants. In in vitro oxygen-glucose deprivation/reperfusion stroke models, the results of PC12 cells treated with 20(R)-ginsenoside Rg3 were consistent with animal experiments. After transfection with Nrf2 short interfering RNA (siRNA), the protective effect of 20(R)-ginsenoside Rg3 on PC12 cells was reversed. In conclusion, the inhibition of mitochondrial oxidative stress plays a vital position in the anti-cerebral ischemia-reperfusion injury of 20(R)-ginsenoside Rg3, and its neuroprotective mechanism is related to the activation of the nuclear factor erythroid2-related factor 2/heme oxygenase 1 signaling pathway.

P-hydroxy benzaldehyde facilitates reprogramming of reactive astrocytes into neurons via endogenous transcriptional regulation

BACKGROUND

Cerebral ischemia leads to linguistic and motor dysfunction, as the death of neurons in ischemic core is permanent and non-renewable. An innovative avenue is to induce and/or facilitate reprogramming of adjacent astrocytes into neurons to replace the lost neurons and re-establish brain homeostasis.

PURPOSE

This study aimed to investigate whether the p-hydroxy benzaldehyde (p-HBA), a phenolic compound isolated from Gastrodia elata Blume, could facilitate the reprogramming of oxygen-glucose deprivation/reperfusion (OGD/R)-damaged astrocytes into neurons.

STUDY DESIGN/METHODS

The primary parenchymal astrocytes of rat were exposure to OGD and reperfusion with define culture medium. Cells were then incubated with different concentration of p-HBA (1, 10, 100, 400 μM) and collected at desired time point for reprogramming process analysis.

RESULTS

OGD/R could elicit endogenous neurogenic program in primary parenchymal astrocytes of rat under define culture condition, and these so-called reactive astrocytes could be reprogrammed into neurons. However, the neonatal neurons produced by this endogenous procedure could not develop into mature neurons, and the conversion rate was only 1.9%. Treatment of these reactive astrocytes with p-HBA could successfully promote the conversion rate to 6.1%, and the neonatal neurons could develop into mature neurons within 14 days. Further analysis showed that p-HBA down-regulated the Notch signal component genes Dll1, Hes1 and SOX2, while the transcription factor NeuroD1 was up-regulated.

CONCLUSION

The results of this study demonstrated that p-HBA facilitated the astrocyte-to-neuron conversion. This chemical reprogramming was mediated by inhibition of Notch1 signaling pathway and transcriptional activation of NeuroD1.

Bioactivity Profiling and Quantification of Gastrodin in Gastrodia elata Cultivated in the Field versus Facility via Hyphenated High-Performance Thin-Layer Chromatography

Gastrodia elata (Orchidaceae) is native to mountainous areas of Asia and is a plant species used in traditional medicine for more than two thousand years. The species was reported to have many biological activities, such as neuroprotective, antioxidant, and anti-inflammatory activity. After many years of extensive exploitation from the wild, the plant was added to lists of endangered species. Since its desired cultivation is considered difficult, innovative cultivation methods that can reduce the costs of using new soil in each cycle and at the same time avoid contamination with pathogens and chemicals are urgently needed on large scale. In this work, five G. elata samples cultivated in a facility utilizing electron beam-treated soil were compared to two samples grown in the field concerning their chemical composition and bioactivity. Using hyphenated high-performance thin-layer chromatography (HPTLC) and multi-imaging (UV/Vis/FLD, also after derivatization), the chemical marker compound gastrodin was quantified in the seven G. elata rhizome/tuber samples, which showed differences in their contents between facility and field samples and between samples collected during different seasons. Parishin E was also found to be present. Combining HPTLC with on-surface (bio)assays, the antioxidant activity and inhibition of acetylcholinesterase as well as the absence of cytotoxicity against human cells were demonstrated and compared between samples.

The processing methods, phytochemistry and pharmacology of Gastrodia elata Bl.: A comprehensive review

ETHNOPHARMACOLOGICAL RELEVANCE

Gastrodia elata Bl. (GE) is one of the rare Chinese medicinal materials with a long history of medicine and cooking. It consists of a variety of chemical components, including aromatic compounds, organic acids and esters, steroids, saccharides and their glycosides, etc., which has medicinal and edible value, and is widely used in various diseases, such as infantile convulsions, epilepsy, tetanus, headache, dizziness, limb numbness, rheumatism and arthralgia. It is also commonly used in health care products and cosmetics. Thus, its chemical composition and pharmacological activity have attracted more and more attention from the scientific community.

AIM

In this review, the processing methods, phytochemistry and pharmacological activities of GE were comprehensively and systematically summarized, which provides a valuable reference for researchers the rational of GE.

MATERIALS AND METHODS

A comprehensive search of published literature and classic books from 1958 to 2023 was conducted using online bibliographic databases PubMed, Google Scholar, ACS, Science Direct Database, CNKI and others to identify original research related to GE, its processing methods, active ingredients and pharmacological activities.

RESULTS

GE is traditionally used to treat infantile convulsion, epilepsy, tetanus, headache, dizziness, limb numbness, rheumatism and arthralgia. To date, more than 435 chemical constituents were identified from GE including 276 chemical constituents, 72 volatile components and 87 synthetic compounds, which are the primary bioactive compounds. In addition, there are other biological components, such as organic acids and esters, steroids and adenosines. These extracts have nervous system and cardiovascular and cerebrovascular system activities such as sedative-hypnotic, anticonvulsant, antiepileptic, neuron protection and regeneration, analgesia, antidepressant, antihypertensive, antidiabetic, antiplatelet aggregation, anti-inflammatory, etc. CONCLUSION: This review summarizes the processing methods, chemical composition, pharmacological activities, and molecular mechanism of GE over the last 66 years, which provides a valuable reference for researchers to understand its research status and applications.

Neuroprotective effect of a Keap1-Nrf2 Protein-Protein Inter-action inhibitor on cerebral Ischemia/Reperfusion injury

Oxidative stress has been confirmed to be closely related to the occurrence and development of cerebral ischemic/reperfusion (I/R). The Keap1-Nrf2 pathway is widely recognized as a defensive system to maintain cellular redox homeostasis. Targeting Keap1-Nrf2 interaction by small molecules to release Nrf2 should be a promising strategy to treat cerebral I/R injury. The piperazinyl-naphthalenesulfonamide 6 K was reported to be a Keap1-Nrf2 protein-protein interaction inhibitor, showing promising antioxidative effect. Herein, this study is to investigate whether 6 K could prevent brain from I/R injury. The related mechanism of oxidative stress was also elucidated using in vivo mice middle cerebral artery occlusion (MCAO) model and in vitro SH-SY5Y oxygen-glucose deprivation/reperfusion (OGD/R) model. The results indicated that treatment of 6 K markedly decreased infarct volume, apoptotic neurons and oxidative damage and promoted neurologic recovery in vivo. The cell model revealed that the reactive oxygen species (ROS) was decreased, and cell viability was increased. Western blots and immunofluorescence staining demonstrated that compound treatment promoted Nrf2 release and nuclear translocation. The downstream protective enzymes were significantly enhanced at both in vivo and in vitro levels. Collectively, 6 K is a promising protective agent against cerebral I/R injury through activation of Nrf2 to suppress oxidative stress.

The Role of Nrf2 in Relieving Cerebral Ischemia-Reperfusion Injury

Ischemic stroke includes two related pathological damage processes: brain injury caused by primary ischemia and secondary ischemia reperfusion (I/R) injury. I/R injury has become a worldwide health problem. Unfortunately, there is still a lack of satisfactory drugs for ameliorating cerebral I/R damage. Nrf2 is a vital endogenous antioxidant protein, which combines with Keap1 to maintain a dormant state under physiological conditions. When pathological changes such as I/R occurs, Nrf2 dissociates from Keap1 and activates the expression of downstream antioxidant proteins to exert a protective effect. Recent research have shown that the activated Nrf2 not only effectively inhibits oxidative stress, but also performs the ability to repair the function of compromised mitochondria, alleviate endoplasmic reticulum stress, eliminate inflammatory response, reduce blood-brain barrier permeability, inhibit neuronal apoptosis, enhance the neural network remolding, thereby exerting significant protective effects in alleviating the injuries caused by cell oxygen-glucose deprivation, or animal cerebral I/R. However, no definite clinical application report demonstrated the efficacy of Nrf2 activators in the treatment of cerebral I/R. Therefore, further efforts are needed to elaborate the role of Nrf2 activators in the treatment of cerebral I/R. Here, we reviewed the possible mechanisms underlying its potential pharmacological benefits in alleviating cerebral I/R injury, so as to provide a theoretical basis for studying its mechanism and developing Nrf2 activators.

Para-Hydroxybenzyl Alcohol Delays the Progression of Neurodegenerative Diseases in Models of Caenorhabditis elegans through Activating Multiple Cellular Protective Pathways

The traditional Chinese medicine Gastrodia elata (commonly called “Tianma” in Chinese) has been widely used in the treatment of rheumatism, epilepsy, paralysis, headache, and dizziness. Phenolic compounds, such as gastrodin, para-hydroxybenzyl alcohol (HBA), p-hydroxybenzaldehyde, and vanillin are the main bioactive components isolated from Gastrodia elata. These compounds not only are structurally related but also share similar pharmacological activities, such as antioxidative and anti-inflammatory activities, and effects on the treatment of aging-related diseases. Here, we investigated the effect of para-hydroxybenzyl alcohol (HBA) on neurodegenerative diseases and aging in models of Caenorhabditis elegans (C. elegans). Our results showed that HBA effectively delayed the progression of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and Huntington's disease in models of C. elegans. In addition, HBA could increase the average lifespan of N2 worms by more than 25% and significantly improve the age-related physiological functions of worms. Moreover, HBA improved the survival rate of worms under stresses of oxidation, heat, and pathogenic bacteria. Further mechanistic investigation revealed that HBA could activate FOXO/DAF-16 and SKN-1 to regulate antioxidative and xenobiotic metabolism pathway. HBA could also activate HSF-1 to regulate proteostasis maintenance pathway, mitochondrial unfolded stress response, endoplasmic stress response and autophagy pathways. The above results suggest that HBA activated multiple cellular protective pathways to increase stress resistance and protect against aging and aging-related diseases. Overall, our study indicates that HBA is a potential candidate for future development of antiaging pharmaceutical application.

Recent Advances in Chinese Herbal Medicine for Cerebral Ischemic Reperfusion Injury

Cerebral ischemic reperfusion injury (CI/RI) is a critical factor that leads to a poor prognosis in patients with ischemic stroke. It is an extremely complicated pathological process that is clinically characterized by high rates of disability and mortality. Current available treatments for CI/RI, including mechanical and drug therapies, are often accompanied by significant side effects. Therefore, it is necessary to discovery new strategies for treating CI/RI. Many studies confirm that Chinese herbal medicine (CHM) was used as a potential drug for treatment of CI/RI with the advantages of abundant resources, good efficacy, and few side effects. In this paper, we investigate the latest drug discoveries and advancements on CI/RI, make an overview of relevant CHM, and systematically summarize the pathophysiology of CI/RI. In addition, the protective effect and mechanism of related CHM, which includes extraction of single CHM and CHM formulation and preparation, are discussed. Moreover, an outline of the limitations of CHM and the challenges we faced are also presented. This review will be helpful for researchers further propelling the advancement of drugs and supplying more knowledge to support the application of previous discoveries in clinical drug applications against CI/RI.

Research Trends, Hot Spots, and Prospects for Traditional Chinese Medicine in the Field of Ischemia-Reperfusion Injury

Ischemia-reperfusion (I/R) injury is one of the most common phenomena in ischemic disease or processes that causes progressive disability or even death. It has a major impact on global public health. Traditional Chinese medicine (TCM) has a long history of application in ischemic diseases and has significant clinical effect. Numerous studies have shown that the formulas or single herbs in TCM have specific roles in regulating oxidative stress, anti-inflammatory, inhibiting cell apoptosis, etc., in I/R injury. We used bibliometrics to quantitatively analyze the global output of publications on TCM in the field of I/R injury published in the period 2001–2021 to identify research hotspots and prospects. We included 446 related documents published in the Web of Science during 2001–2021. Visualization analysis revealed that the number of publications related to TCM in the field of I/R injury has increased year by year, reaching a peak in 2020. China is the country with the largest number of publications. Keywords and literature analyses demonstrated that neuroregeneration is likely one of the research hotspots and future directions of research in the field. Taken together, our findings suggest that although the inherent limitations of bibliometrics may affect the accuracy of the literature-based prediction of research hotspots, the results obtained from the included publications can provide a reference for the study of TCM in the field of I/R injury.

RTA-408 protects against propofol-induced cognitive impairment in neonatal mice via the activation of Nrf2 and the inhibition of NF-κB p65 nuclear translocation

OBJECTIVE

To explore the effect of RTA-408 on the propofol-induced cognitive impairment of neonatal mice via regulating Nrf2 and NF-κB p65 nuclear translocation.

METHODS

C57BL/6 neonatal mice were randomized into intralipid, propofol, vehicle + propofol, and RTA-408 + propofol groups. The learning and memory ability was inspected by Morries water maze (MWM) test. TUNEL staining was performed to examine the apoptosis of neurons in hippocampus. The gene and protein expressions in hippocampus were detected by immunohistochemistry, qRT-PCR, or Western blotting. The activities of glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) were tested by the corresponding kits.

RESULTS

Propofol prolonged escape latency of mice, decreased the times of crossing the platform, and shortened the time of staying in the target quadrant, while RTA-408 treatment improved the above-mentioned situation. Besides, Nrf2 protein in hippocampus of mice induced by propofol was decreased with the increased NF-κB p65 nuclear translocation, which was reversed by RTA-408. Meanwhile, RTA-408 decreased the apoptosis of neurons accompanying with the down-regulation of Caspase-3 and the up-regulations of neuronal-specific nuclear protein (NeuN), microtubule-associated protein 2 (Map2), Ca₂⁺ /Calmodulin-dependent Protein Kinase II (CaMKII), and parvalbumin (PV) immunostaining in hippocampus. Besides, propofol-induced high levels of proinflammatory cytokines and antioxidase activities in hippocampus were reduced by RTA-408.

CONCLUSION

RTA-408 improved propofol-induced cognitive impairment in neonatal mice via enhancing survival of neurons, reducing the apoptosis of hippocampal neurons, mitigating the inflammation and oxidative stress, which may be correlated with the activation of Nrf2 and the inhibition of NF-κB p65 nuclear translocation.

Activation of Nrf2 by Natural Bioactive Compounds: A Promising Approach for Stroke?

Stroke represents one of the main causes of disability and death worldwide. The pathological subtypes of stroke are ischemic stroke, the most frequent, and hemorrhagic stroke. Nrf2 is a transcription factor that regulates redox homeostasis. In stress conditions, Nrf2 translocates inside the nucleus and induces the transcription of enzymes involved in counteracting oxidative stress, endobiotic and xenobiotic metabolism, regulators of inflammation, and others. Different natural compounds, including food and plant-derived components, were shown to be able to activate Nrf2, mediating an antioxidant response. Some of these compounds were tested in stroke experimental models showing several beneficial actions. In this review, we focused on the studies that evidenced the positive effects of natural bioactive compounds in stroke experimental models through the activation of Nrf2 pathway. Interestingly, different natural compounds can activate Nrf2 through multiple pathways, inducing a strong antioxidant response associated with the beneficial effects against stroke. According to several studies, the combination of different bioactive compounds can lead to a better neuroprotection. In conclusion, natural bioactive compounds may represent new therapeutic strategies against stroke.

Protection of the Geum japonicum Thunb. var. chinense extracts against oxygen-glucose deprivation and re-oxygenation induced astrocytes injury via BDNF/PI3K/Akt/CREB pathway

Geum japonicum Tunb. var. chinense (GJ) is a traditional Chinese medicine usually used for the alleviation of dizziness and headache. Previous studies have reported that the GJ extracts could alleviate cerebral I/R injury by reducing apoptosis in vivo. To further elucidate the positive role and underlying mechanism of the GJ extracts in cerebral I/R injury, the current study investigated the effects of the GJ extracts on oxygen-glucose deprivation and re-oxygenation (OGD/R)-induced astrocytes injury in light of BDNF/PI3K/Akt/CREB signaling pathway with seropharmacological method. In the present study, the LC-MS profiling of the GJ extracts, obtain by reflux extraction, led to the identification of three possible active components were 5-desgalloylstachyurin, tellimagrandin II (TG II) and 3,4,5-Trihydroxybenzaldehyde (THBA). Drug-containing serum was collected from rats given different doses of the GJ extracts (0, 1.75 g/kg, 7 g/kg). Data indicated that the GJ extracts could increase the cell viability and decrease apoptosis and the expression of glial fibrillary acidic protein (GFAP) in OGD/R-induced astrocytes. In addition, the detection of apoptosis-related factors showed that the GJ extracts could obviously increase the expression of Bcl-2 and reduce the expression of Bax, Caspase-3 and cleaved-Caspase-3. Furthermore, the GJ extracts markedly increased the expression of BDNF, TrkB, PI3K, p-Akt and p-CREB. All these effects of the GJ extracts could be significantly reversed by LY294002, an inhibitor of PI3K. These data indicated that the GJ extracts could protect astrocytes against OGD/R-induced injury by inhibiting astrocytes reactivity and apoptosis, owing to the activation of the BDNF/PI3K/Akt/CREB pathway. The results support the application of the GJ extracts in the treatment of ischemic stroke and other ischemic encephalopathy.

Exploring the effects of Gastrodia elata Blume on the treatment of cerebral ischemia-reperfusion injury using UPLC-Q/TOF-MS-based plasma metabolomics

Gastrodia elata Blume (Orchidaceae, GEB) is a medicinal plant that has been widely used in the treatment of cerebrovascular disease. This study explored the protective effects of GEB against cerebral ischemia-reperfusion using Information-Dependent Acquisition (IDA)-mediated UPLC-Q/TOF-MS-based plasma metabolomics. Cerebral ischemia-reperfusion (IR) injury was induced in male Wistar rats using the Zea Longa method. Biochemical and histological assays were performed to evaluate the therapeutic effects of GEB on IR rats. We found that the neurobehavioral scores and infarction areas of GEB and nimodipine treated groups were dramatically lower than those of the IR groups. Hematoxylin and Eosin (HE) staining and TdT-mediated dUTP Nick-End Labeling (TUNEL) showed that GEB significantly improved neuronal injury and prevented neuronal apoptosis. Biochemical analysis revealed that GEB prevented cerebral ischemia-reperfusion injury by regulating inflammation and oxidative injury. Through ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry-metabolomics-based approaches, 43 plasma metabolites related to GEB treatment were detected, 6 of which significantly differed (p < 0.05) between the model and GEB groups. The levels of l-histidine, sphinganine, thymine, spermidine and deoxycytidine in the IR group were significantly higher than those in the sham group, but decreased following GEB treatment. Arachidonic acid levels were lower in the IR group, but dramatically increased in response to GEB. Pharmacodynamics and metabolomics confirmed that the mechanism of GEB in the treatment of cerebral ischemia was not only related to the reduction of inflammation, oxidation, neurotoxicity, and apoptosis, but also mediated through arachidonic acid metabolism, histidine metabolism, pyrimidine metabolism, arginine and proline metabolism, sphingolipid metabolism, and glycerophospholipid metabolism in vivo.

Gastrodia elata Blume Polysaccharides: A Review of Their Acquisition, Analysis, Modification, and Pharmacological Activities

Gastrodia elata Blume (G. elata) is a valuable Traditional Chinese Medicine (TCM) with a wide range of clinical applications. G. elata polysaccharides, as one of the main active ingredients of G. elata, have interesting extraction, purification, qualitative analysis, quantitative analysis, derivatization, and pharmacological activity aspects, yet a review of G. elata polysaccharides has not yet been published. Based on this, this article summarizes the progress of G. elata polysaccharides in terms of the above aspects to provide a basis for their further research and development.

Neuroprotective Effect of Swertiamain on Cerebral Ischemia/Reperfusion Injury by Inducing the Nrf2 Protective Pathway

Oxidative stress plays a vital role in the development of cerebral ischemic/reperfusion (I/R). Targeting oxidative stress is proposed to be an effective strategy to treat cerebral I/R injury. Gentiana macrophylla Pall is reported to have a potential protective effect against stroke. Swertiamarin (Swe), an active secoiridoid glycoside compound isolated from Gentiana macrophylla Pall, has been reported to possess antioxidative potential. This study is to explore whether Swe could prevent brain from I/R injury, and the related mechanisms of oxidative stress are also elucidated using mice middle cerebral artery occlusion (MCAO) model and primary hippocampal neurons oxygen-glucose deprivation/reperfusion (OGD/R) model. Swe (25, 100, or 400 mg/kg) was pretreated intraperitoneally for 7 days until establishment of the MCAO model, while hippocampal neurons were maintained in Swe (0.1, 1, or 10 μM) in the entire process of reoxygenation. The results indicated that Swe pretreatment markedly decreased infarct volume, apoptotic neurons, and oxidative damage and promoted neurologic recovery in vivo. It also decreased reactive oxygen species (ROS) and increased cell viability in vitro. Western blot analyses and immunofluorescence staining demonstrated that Swe pretreatment promoted Nrf2 nuclear translocation from Keap1-Nrf2 complex and enhanced the expressions of NAD(P)H: quinone oxidoreductase-1 (NQO1) and heme oxygenase-1 (HO-1) both in vivo and in vitro, while the expressions could be reversed by a Nrf2 inhibitor. The binding mode of Keap1 with Swe was also proposed by covalent molecular docking. Collectively, Swe could be considered as a promising protective agent against cerebral I/R injury through suppressing oxidative stress by activation of the Nrf2 protective pathway.

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.

Uric Acid Protects against Focal Cerebral Ischemia/Reperfusion-Induced Oxidative Stress via Activating Nrf2 and Regulating Neurotrophic Factor Expression

The aim of this study was to investigate whether uric acid (UA) might exert neuroprotection via activating the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway and regulating neurotrophic factors in the cerebral cortices after transient focal cerebral ischemia/reperfusion (FCI/R) in rats. UA was intravenously injected through the tail vein (16 mg/kg) 30 min after the onset of reperfusion in rats subjected to middle cerebral artery occlusion for 2 h. Neurological deficit score was performed to analyze neurological function at 24 h after reperfusion. Terminal deoxynucleotidyl transferase-mediated dNTP nick end labeling (TUNEL) staining and hematoxylin and eosin (HE) staining were used to detect histological injury of the cerebral cortex. Malondialdehyde (MDA), the carbonyl groups, and 8-hydroxyl-2′-deoxyguanosine (8-OHdG) levels were employed to evaluate oxidative stress. Nrf2 and its downstream antioxidant protein, heme oxygenase- (HO-) 1,were detected by western blot. Nrf2 DNA-binding activity was observed using an ELISA-based measurement. Expressions of BDNF and NGF were analyzed by immunohistochemistry. Our results showed that UA treatment significantly suppressed FCI/R-induced oxidative stress, accompanied by attenuating neuronal damage, which subsequently decreased the infarct volume and neurological deficit. Further, the treatment of UA activated Nrf2 signaling pathway and upregulated BDNF and NGF expression levels. Interestingly, the aforementioned effects of UA were markedly inhibited by administration of brusatol, an inhibitor of Nrf2. Taken together, the antioxidant and neuroprotective effects afforded by UA treatment involved the modulation of Nrf2-mediated oxidative stress and regulation of BDNF and NGF expression levels. Thus, UA treatment could be of interest to prevent FCI/R injury.