Hyperoside protects cortical neurons from oxygen–glucose deprivation–reperfusion induced injury via nitric oxide signal pathway

Temperature-dependent neuroprotective effects of acorn flour extract in SH-SY5Y cells against gliotoxin

Gliotoxin (GTX) is a potent mycotoxin that has been shown to induce neurotoxicity through the generation of oxidative stress and disruption of cellular signaling, leading to neuronal cell damage. The neurotoxic effects of GTX have been implicated in various neurodegenerative conditions, making the search for protective agents crucial. This study investigates the chemoprotective effects of acorn flour extract (ACFE) at different temperatures (20 °C, 60 °C, 80 °C, and 100 °C) on SH-SY5Y cells exposed to GTX using both pretreatment and simultaneous treatment strategies (direct treatment, pretreatment and simultaneous treatment). Cell viability was assessed using the MTT assay after 24 and 48 h of exposure. ACFE exhibited varying cytoprotective effects depending on the temperature and exposure conditions. Pre- treatment with 100 °C significantly increased cell viability by up to 51.6% at low GTX concentrations after 48 h; however, ACFE at 60 °C and 80 °C also demonstrated notable protective effects in pretreatment, suggesting a broader range of effective temperatures. Similarly, simultaneous treatment with ACFE (20 °C and 60 °C) enhanced cell viability by up to 124.7% at specific GTX concentrations. In general, higher extraction temperatures (80 °C and 100 °C) were associated with greater chemoprotective potential. These findings support the potential therapeutic application of ACFE in protecting against oxidative stress and neuronal damage, emphasizing the influence of extraction temperature and treatment timing on its efficacy. Further investigations are needed to explore the underlying molecular mechanisms involved in ACFE's protective effects.

Hypericum perforatum: a comprehensive review on pharmacognosy, preclinical studies, putative molecular mechanism, and clinical studies in neurodegenerative diseases

The herb Hypericum perforatum, also referred to as St. John's wort, has drawn a lot of interest because of its potential therapeutic benefits in treating neurodegenerative illnesses. Due to the absence of effective therapies, illnesses like Alzheimer's and Parkinson's disease pose an increasing worldwide health concern. Because of its wide variety of phytochemicals, especially hyperforin, and hypericin, Hypericum perforatum is well known for its neuroprotective properties. These substances have proven to be able to affect different cellular processes linked to neurodegeneration. They can act as anti-inflammatory, antioxidant, and neurotransmitter system regulators, which may help halt neurodegenerative illnesses' progression. The use of Hypericum perforatum extracts and its contents has shown encouraging results in research on animal models of neurodegenerative disorders. These advantages include higher nerve cell survival, lowered oxidative stress, and higher cognitive performance. Underscoring its versatile potential to combat neurodegeneration, Hypericum perforatum has neuroprotective mechanisms that modulate neuroinflammation and prevent apoptotic pathways. In conclusion, Hypericum perforatum shows tremendous promise as a potential treatment for neurological illnesses due to its wide variety of phytochemicals. To completely comprehend its specific mechanisms of action and turn these discoveries into efficient clinical therapies, additional research is needed. Investigating Hypericum perforatum's function in neurodegenerative disorders may present new opportunities for the advancement of ground-breaking therapeutic strategies.

Potential Implications of Hyperoside on Oxidative Stress-Induced Human Diseases: A Comprehensive Review

Hyperoside is a flavonol glycoside mainly found in plants of the genera Hypericum and Crataegus, and also detected in many plant species such as Abelmoschus manihot, Ribes nigrum, Rosa rugosa, Agrostis stolonifera, Apocynum venetum and Nelumbo nucifera. This compound exhibits a multitude of biological functions including anti-inflammatory, antidepressant, antioxidative, vascular protective effects and neuroprotective effects, etc. This review summarizes the quantification, original plant, chemical structure and property, structure-activity relationship, pharmacologic effect, pharmacokinetics, toxicity and clinical application of hyperoside, which will be significant for the exploitation for new drug and full utilization of this compound.

Synergistic effects of flavonoids and paclitaxel in cancer treatment: a systematic review

Paclitaxel is a natural anticancer compound with minimal toxicity, the capacity to stabilize microtubules, and high efficiency that has remained the standard of treatment alongside platinum-based therapy as a remedy for a variety of different malignancies. In contrast, polyphenols such as flavonoids are also efficient antioxidant and anti-inflammatory and have now been shown to possess potent anticancer properties. Therefore, the synergistic effects of paclitaxel and flavonoids against cancer will be of interest. In this review, we use a Boolean query to comprehensively search the well-known Scopus database for literature research taking the advantage of paclitaxel and flavonoids simultaneously while treating various types of cancer. After retrieving and reviewing the intended investigations based on the input keywords, the anticancer mechanisms of flavonoids and paclitaxel and their synergistic effects on different targets raging from cell lines to animal models are discussed in terms of the corresponding involved signaling transduction. Most studies demonstrated that these signaling pathways will induce apoptotic / pro-apoptotic proteins, which in turn may activate several caspases leading to apoptosis. Finally, it can be concluded that the results of this review may be beneficial in serving as a theoretical foundation and reference for future studies of paclitaxel synthesis, anticancer processes, and clinical applications involving different clinical trials.

Development of Novel Herbal Compound Formulations Targeting Neuroinflammation: Network Pharmacology, Molecular Docking, and Experimental Verification

Neuroinflammation plays an important role in the onset and progression of neurodegenerative diseases. The multicomponent and multitarget approach may provide a practical strategy to address the complex pathological mechanisms of neuroinflammation. This study aimed to develop synergistic herbal compound formulas to attenuate neuroinflammation using integrated network pharmacology, molecular docking, and experimental bioassays. Eight phytochemicals with anti-neuroinflammatory potential were selected in the present study. A compound-gene target-signaling pathway network was constructed to illustrate the mechanisms of action of each phytochemical and the interactions among them at the molecular level. Molecular docking was performed to verify the binding affinity of each phytochemical and its key gene targets. An experimental study was conducted to identify synergistic interactions among the eight phytochemicals, and the associated molecular mechanisms were examined by immunoblotting based on the findings from the network pharmacology analysis. Two paired combinations, andrographolide and 6-shogaol (AN-SG) (IC50 = 2.85 μg/mL), and baicalein-6-shogaol (BA-SG) (IC50 = 3.28 μg/mL), were found to synergistically (combination index <1) inhibit the lipopolysaccharides (LPS)-induced nitric oxide production in microglia N11 cells. Network pharmacology analysis suggested that MAPK14, MAPK8, and NOS3 were the top three relevant gene targets for the three phytochemicals, and molecular docking demonstrated strong binding affinities of the phytochemicals to their coded proteins. Immunoblotting suggested that the AN-SG and BA-SG both showed prominent effects in inhibiting inducible nitric oxide synthase (iNOS) (p < 0.01 and p < 0.05, respectively) and MAPKp-p38 (both p < 0.05) compared with those induced by the LPS stimulation only. The AN-SG combination exhibited greater inhibitions of the protein expressions of iNOS (p < 0.05 vs. individual components), which may partly explain the mechanisms of the synergy observed. This study established a practical approach to developing novel herbal-compound formulations using integrated network pharmacology analysis, molecular docking, and experimental bioassays. The study provides a scientific basis and new insight into the two synergistic combinations against neuroinflammation.

Antigenotoxic effect of hyperoside against Mitomycin C and hydrogen peroxide-induced genotoxic damage on human lymphocytes

Hyperoside is a flavonol glycoside isolated from various plant genera such as Hypericum and Crataegus. It has an important place in the human diet and is used medically to relieve pain and ameliorate cardiovascular functions. However, a comprehensive profile of the genotoxic and antigenotoxic effects of hyperoside is not known. The current study aimed to investigate the genotoxic and antigenotoxic effects of hyperoside against genetic damages induced by two genotoxins (MMC and H₂O₂) in human lymphocytes using chromosomal aberrations (CAs), sister chromatid exchanges (SCEs), and micronucleus (MN) assays in human peripheral blood lymphocytes in vitro. Blood lymphocytes were incubated with 7.8-62.5 μg/mL concentrations of hyperoside alone and simultaneously with 0.20 μg/mL Mitomycin C (MMC) or 100 μM Hydrogen peroxide (H₂O₂). Hyperoside did not exhibit genotoxic potential in the CA, SCE, and MN assays. Moreover, it did not cause a decrease in mitotic index (MI) which is an indicator of cytotoxicity. On the other hand, hyperoside significantly decreased CA, SCE, and MN (except for MMC treatment) frequencies induced by MMC and H₂O₂. Hyperoside, increased mitotic index against both mutagenic agents at 24-h treatment when compared to positive control. Our results demonstrate that hyperoside exhibited antigenotoxic effects rather than genotoxic in vitro human lymphocytes. Therefore, hyperoside may be a potential preventive agent in inhibiting chromosomal and oxidative damage induced by genotoxic chemicals.

Neuroprotective effect of hyperoside in MPP+/MPTP -induced dopaminergic neurodegeneration

Parkinson's disease (PD) is a neurodegenerative disease characterized by the pathological loss of nigrostriatal dopaminergic neurons, which causes an insufficient release of dopamine (DA) and then induces motor and nonmotor symptoms. Hyperoside (HYP) is a lignan component with anti-inflammatory, antioxidant, and neuroprotective effects. In this study, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its active neurotoxic metabolite 1-methyl-4-phenylpyridinium ion (MPP⁺) were used to induce dopaminergic neurodegeneration. The results showed that HYP (100 µg/mL) reduced MPTP-mediated cytotoxicity of SH-SY5Y cells in vitro, and HYP [25 mg/(kg d)] alleviated MPTP-induced motor symptoms in vivo. HYP treatment reduced the contents of nitric oxide (NO), H₂O₂, and malondialdehyde (MDA), as well as the mitochondrial damage of dopaminergic neurons, both in vitro and in vivo. Meanwhile, HYP treatment elevated the levels of neurotrophic factors such as glial cell line-derived neurotrophic factor, brain-derived neurotrophic factor, and recombinant cerebral dopamine neurotrophic factor in vivo, but not in vitro. Finally, Akt signaling was activated after the administration of HYP in MPP⁺/MPTP-induced dopaminergic neurodegeneration. However, the blockage of the Akt pathway with Akt inhibitor did not abolish the neuroprotective effect of HYP on DA neurons. These results showed that HYP protected the dopaminergic neurons from the MPP⁺- and MPTP-induced injuries, which did not rely on the Akt pathway.

Screening and identification of anti-acetylcholinesterase ingredients from Tianzhi granule based on ultrafiltration combined with ultra-performance liquid chromatography-mass spectrometry and in silico analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Tianzhi granule (TZG) is a traditional Chinese formula that is widely used for the treatment of vascular dementia (VaD).

AIM OF THE STUDY

To discover the herbs in TZG possessing acetylcholinesterase (AChE) inhibitory activity and to screen the anti-acetylcholinesterase ingredients from active herbs.

MATERIALS AND METHODS

In vitro AChE inhibitory activity assay of eleven herbal extracts was conducted. An ultrafiltration combined with ultra-performance liquid chromatography-mass spectrometry method was established to screen and identify the anti-acetylcholinesterase ingredients from active extracts. In addition, in vitro AChE inhibitory activity assay and molecular docking were adopted for further investigation. Moreover, ultra-performance liquid chromatography-mass spectrometry was performed for the content determination of active compounds in TZG.

RESULTS

Three herbs in TZG showed significant AChE inhibitory activity. A total of thirteen active ingredients were screened out and identified, and all of these compounds were present in TZG. Five available commercial standards presented moderate AChE inhibitory activity, and all of which have a relatively high content in TZG.

CONCLUSION

A number of herbs and compounds with acetylcholinesterase inhibitory activity were found in TZG, which provided a scientific basis for the material basis and quality control research of TZG.

Therapeutic potential of dietary flavonoid hyperoside against non-communicable diseases: targeting underlying properties of diseases

Non-communicable diseases (NCDs) are a global epidemic with diverse pathogenesis. Among them, oxidative stress and inflammation are the most fundamental co-morbid features. Therefore, multi-targets and multi-pathways therapies with significant anti-oxidant and anti-inflammatory activities are potential effective measures for preventing and treating NCDs. The flavonol glycoside compound hyperoside (Hyp) is widely found in a variety of fruits, vegetables, beverages, and medicinal plants and has various health benefits, especially excellent anti-oxidant and anti-inflammatory properties targeting nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear factor-κB (NF-κB) signaling pathways. In this review, we summarize the pathogenesis associated with oxidative stress and inflammation in NCDs and the biological activity and therapeutic potential of Hyp. Our findings reveal that the anti-oxidant and anti-inflammatory activities regulated by Hyp are associated with numerous biological mechanisms, including positive regulation of mitochondrial function, apoptosis, autophagy, and higher-level biological damage activities. Hyp is thought to be beneficial against organ injuries, cancer, depression, diabetes, and osteoporosis, and is a potent anti-NCDs agent. Additionally, the sources, bioavailability, pharmacy, and safety of Hyp have been established, highlighting the potential to develop Hyp into dietary supplements and nutraceuticals.

Therapeutic Potential of Quercetin and its Derivatives in Epilepsy: Evidence from Preclinical Studies

Quercetin is a polyphenolic bioactive compound highly enriched in dietary fruits, vegetables, nuts, and berries. Quercetin and its derivatives like rutin and hyperoside are known for their beneficial effects in various neurological conditions including epilepsy. The clinical studies of quercetin and its derivatives in relation to epilepsy are limited. This review provides the evidence of most recent knowledge of anticonvulsant properties of quercetin and its derivatives on preclinical studies. Additionally, the studies demonstrating antiseizure potential of various plants extracts enriched with quercetin and its derivatives has been included in this review. Herein, we have also discussed neuroprotective effect of these bioactive compound and presented underlying mechanisms responsible for anticonvulsant properties in brief. Finally, limitations of quercetin and its derivatives as antiseizure compounds as well as possible strategies to enhance efficacy have also been discussed.

Hyperoside: A review on its sources, biological activities, and molecular mechanisms

Hyperoside is a natural flavonol glycoside in various plants, such as Crataegus pinnatifida Bge, Forsythia suspensa, and Cuscuta chinensis Lam. Medical research has found that hyperoside possesses a broad spectrum of biological activities, including anticancer, anti-inflammatory, antibacterial, antiviral, antidepressant, and organ protective effects. These pharmacological properties lay the foundation for its use in treating multiple diseases, such as sepsis, arthritis, colitis, diabetic nephropathy, myocardial ischemia-reperfusion, pulmonary fibrosis, and cancers. Hyperoside is obtained from the plants and chemical synthesis. This study aims to provide a comprehensive overview of hyperoside on its sources and biological activities to provide insights into its therapeutic potential, and to provide a basis for high-quality studies to determine the clinical efficacy of this compound.

Interaction mechanisms and structure-affinity relationships between hyperoside and soybean β-conglycinin and glycinin

Hyperoside (HYP) is an important natural product that is widely distributed in fruits and whole grasses of various plants. It is also used by consumers as a healthy ingredient. This work explored the interaction mechanisms between HYP and two main soy proteins, namely, β-conglycinin (7S) and glycinin (11S), using computational simulation and multi-spectroscopic technology. In this study, the docking and dynamic simulation showed that HYP was stable in the hydrophobic pockets of the proteins. The conformation and microenvironment of 7S/11S also changed after binding to HYP. The binding of HYP to 7S/11S was a state quenching with a good affinity at 4 °C. This result was determined from the binding constant values of (1.995 ± 0.170) × 107 M-1 and (2.951 ± 0.109) × 107 M-1, respectively. The 7S/11S-HYP complex delineated here will provide a novel idea to construct an embedding and delivery system in improving the benefits of HYP for the development of high value-added food products.

Transcriptomic and Metabolomic Profiling Reveals the Protective Effect of Acanthopanax senticosus (Rupr. & Maxim.) Harms Combined With Gastrodia elata Blume on Cerebral Ischemia-Reperfusion Injury

The effects of current treatment strategies used in ischemic stroke are weakened by cerebral ischemia-reperfusion (CIR) injury. Suitable treatment regimens targeting CIR injury are still lacking. Two herbs, namely, Acanthopanax senticosus (Rupr. & Maxim.) Harms (ASE) and Gastrodia elata Blume (GEB), have been used as traditional Chinese medicine and are indicated in the treatment of stroke and cerebrovascular diseases. However, there are no studies that report the effects of ASE combined with GEB in the treatment of CIR injury. In this study, we used the Zea Longa method to induce CIR injury in male Wistar rats. Results of the pharmacodynamic studies revealed that co-administration of ASE and GEB may improve neuronal injury and prevent neuronal apoptosis by reducing oxidative stress and inflammation, and also help prevent CIR injury. On the basis of our hypothesis, we combined the results from transcriptomic and metabonomic analyses and found that ASE and GEB could prevent CIR injury by targeting phenylalanine, pyrimidine, methionine, and sphingolipid metabolism. Therefore, our study provides the basis for the compatibility and efficacy of ASE and GEB.

UPLC-MS/MS Method for the Determination of Hyperoside and Application to Pharmacokinetics Study in Rat After Different Administration Routes

A rapid and sensitive UPLC-MS/MS method was developed and fully validated for the quantification of hyperoside in rat plasma after intragastric, intraperitoneal and intravenous administration. Geniposide was used as an internal standard, and simple liquid–liquid extraction by ethyl acetate was utilized for to extracting the analytes from the rat plasma samples. Chromatographic separation was carried out on an InfinityLab Poroshell 120EC-C18column (2.1 mm × 50 mm, 1.9-Micro, Agilent technologies, USA). The mobile phase consisted of methanol (A) and water (B) (containing 0.1% acetic acid) at a flow rate of 0.4 mL/min. A run time of 3 min for each sample made it possible to analyze more than 300 plasma samples per day. The validated linear ranges of hyperoside were 2–1000 ng/mL in rat plasma. The intra-day and inter-day precision were within 2.6–9.3%, and accuracy were ± 8.6%. And the results of recovery and matrix interference studies were well within the accepted variability limits. Finally, this method was fully validated and successfully applied to the pharmacokinetic studies of hyperoside via different administration routes in rats.

Hyperoside alleviates epilepsy-induced neuronal damage by enhancing antioxidant levels and reducing autophagy

ETHNOPHARMACOLOGICAL RELEVANCE

Hypericum perforatum L. (genus Hypericum, family Hypericaceae), a plant commonly used in traditional Chinese medicine, is believed to confer a wide range of benefits, including fever reduction, detoxification, calming, and pain relief via decoctions of its stems and leaves. Hyperoside (HYP), a natural compound extracted from Hypericum perforatum L., has been shown to demonstrate a wide array of bioactivities including antioxidative, anti-inflammatory, and anti-apoptotic effects. In this study, we investigated the effects of HYP on epilepsy-induced neuronal damage in mice and the associated regulatory factors.

AIM OF THE STUDY

This study examined the potential therapeutic use of HYP for the treatment of neuronal damage in a mouse model of epilepsy and explored the relationships of the potential neuroprotective effects of HYP pretreatment with antioxidant levels and autophagy.

MATERIALS AND METHODS

ICR mice were randomly divided into six groups: sham group, sham-HYP group, KA group, KA-HYP group, KA-HYP-DDC group and KA-CQ group. Immunohistochemical staining was used to assess changes in NeuN, IBA-1, and GFAP expression in the CA3 region of the hippocampus. Immunofluorescence staining was used to assess the effects of HYP on the number of autophagosomes that accumulated in neurons in the hippocampal CA3 region. The levels of SOD1, SOD2, LC3I/II, Beclin1, and PI3K/AKT and MAPK signaling-related proteins were detected by Western blot.

RESULTS

Pretreatment with 50 mg/kg HYP protected against epilepsy-induced neuronal damage in the hippocampal CA3 region. Additionally, HYP enhanced antioxidant levels and reduced the levels of autophagy-related proteins via the PI3K/AKT and MAPK pathways.

CONCLUSION

HYP protected the hippocampal CA3 region against epilepsy-induced neuronal damage via enhancing antioxidant levels and reducing autophagy. The mechanism of action may be related to the maintenance of antioxidant levels and the suppression of autophagy via the PI3K/Akt and MAPK pathways.

Quercetin mitigates monosodium glutamate-induced excitotoxicity of the spinal cord motoneurons in aged rats via p38 MAPK inhibition

Various studies reported the possibility of deterioration of blood-brain barrier (BBB) integrity owing to the aging process. The current work was performed to investigate the ability of Monosodium glutamate (MSG) to cross BBB in aged rats, the damage affecting the anterior horn cells of the spinal cord due to excitotoxicity, and the mechanisms by which quercetin (Que) administration might suppress such damage. Forty male rats aged 18 months were assigned equally to 4 groups: control group, Que group (received Que, 20 mg/kg/d intraperitonealy for 10 days), MSG group (received MSG, 4.0 g/kg/d subcutaneously for 10 days), MSG + Que group (received both Que and MSG as done in the Que and MSG groups respectively). Cervical spinal cord specimens were obtained and prepared for routine histological study, immunohistochemical staining by caspase-3 and glial fibrillary acidic protein (GFAP), assessment of oxidative stress, measurement of cytokines, assessment of caspase-3 activity and GFAP levels as well as for western blotting of phosphorylated activating transcription factor 2 (ATF2^pp) as an indicator for the activity of p38 mitogen-activated protein kinase (MAPK). The MSG group revealed variable degenerative and apoptotic changes in the motoneurons and neuroglia, a marked rise in the cytoplasmic caspase-3 expression in motoneurons and a significant reduction (p < 0.001) in the astrocyte surface area percentage. In addition, the spinal cord tissue exhibited a significant elevation (p < 0.001) in the levels of malondialdehyde (MDA), IL-1, IL-6, TNFα, INFɣ, caspase-3 activity and ATF2 ^pp expression as well as a significant reduction (p < 0.001) in SOD, IL-10 and GFAP levels compared with the control group. On combining Que with MSG, most of the degenerative changes were reversed and all the impaired parameters were nearly normalized except for IL-6 and GFAP levels which were still significantly (p < 0.05) different from those of the control group. Our study suggests that MSG can break through the BBB of the aged rats and induce excitotoxicity dependent changes in spinal cord motoneurons. Most of these changes were reversed by Que probably via targeting the p38 MAPK-ATF2 pathway, antagonizing oxidative stress, anti-inflammatory effect, and promoting GFAP expression.

Nose to brain drug delivery - A promising strategy for active components from herbal medicine for treating cerebral ischemia reperfusion

Cerebral ischemia reperfusion injury (CIRI), one of the major causes of death from stroke in the world, not only causes tremendous damage to human health, but also brings heavy economic burden to society. Current available treatments for CIRI, including mechanical therapies and drug therapies, are often accompanied by significant side-effects. Therefore, it is necessary to discovery new strategies for treating CIRI. Many studies have confirmed that the herbal medicine has the advantages of abundant resources, good curative effect and little side effects, which can be used as potential drug for treatment of CIRI through multiple targets. It's known that oral administration commonly has low bioavailability, and injection administration is inconvenient and unsafe. Many drugs can't delivery to brain through routine pathways due to the blood-brain-barrier (BBB). Interestingly, increasing evidences have suggested the nasal administration is a potential direct route to transport drug into brain avoiding the BBB and has the characteristics of high bioavailability for treating brain diseases. Therefore, intranasal administration can be treated as an alternative way to treat brain diseases. In the present review, effective methods to treat CIRI by using active ingredients derived from herbal medicine through nose to brain drug delivery (NBDD) are updated and discussed, and some related pharmacological mechanisms have also been emphasized. Our present study would be beneficial for the further drug development of natural agents from herbal medicines via NBDD.

Hyperoside suppresses hypoxia-induced A549 survival and proliferation through ferrous accumulation via AMPK/HO-1 axis

BACKGROUND

Hypoxia is commonly existed in tumors and lead to cancer cell chemo/radio-resistance. It is well-recognized that tumor hypoxia is a major challenge for the treatment of various solid tumors. Hyperoside (quercetin-3-O-galactoside, Hy) possesses antioxidant effects and has been reported to protect against hypoxia/reoxygenation induced injury in cardiomyocytes. Therefore, Hy may be attractive compound applicable to hypoxia-related diseases.

PURPOSE

This study was designed to determine the role of Hy in hypoxia-induced proliferation of non-small cell lung cancer cells and the underlying mechanism.

STUDY DESIGN AND METHODS

A549, a human non-small cell lung cancer (NSCLC) cell line, was used in the present study. 1% O₂ was used to mimic the in vivo hypoxic condition of NSCLC. The potential mechanisms of Hy on hypoxia-induced A549 survival and proliferation, as well as the involvement of AMPK/HO-1 pathway were studied via CCK-8 assay, EdU staining, flow cytometry, qRT-PCR and western blot.

RESULTS

We showed that pretreatment with Hy suppressed hypoxia-induced A549 survival and proliferation in dose-dependent manner. In terms of mechanism, hypoxia-treated A549 showed the lower AMPK phosphorylation and the reduced HO-1 expression, which were reversed by Hy pretreatment. Both AMPK inhibitor (Compound C) and HO-1 activity inhibitor (Zinc protoporphyrin IX) abolished Hy-evoked A549 cell death under hypoxia stimuli. Of note, Ferrous iron contributed to Hy-induced A549 cell death under hypoxia, while Hy had no effect on lipid peroxidation under hypoxia.

CONCLUSION

Taken together, our results highlighted the beneficial role of Hy against hypoxia-induced A549 survival and proliferation through ferrous accumulation via AMPK/HO-1 axis.

Phycocyanobilin reduces brain injury after endothelin-1- induced focal cerebral ischaemia

Pharmacological therapies for interrupting biochemical events of the ischaemic cascade and protecting against stroke in humans are as yet unavailable. Up to now, the neuroprotective activity in cerebral ischaemia of phycocyanobilin (PCB), a tetrapyrrolic natural antioxidant, has not been fully examined. Here, we evaluated if PCB protects PC12 neuronal cells against oxygen and glucose deprivation plus reperfusion, and its protective effects in a rat model of endothelin-1-induced focal brain ischaemia. PCB was purified from the cyanobacteria Spirulina platensis and characterized by spectrophotometric, liquid and gas chromatography and mass spectrometry techniques. In Wistar rats, PCB at 50, 100 and 200 μg/kg or phosphate-buffered saline (vehicle) was administered intraperitoneally at equal subdoses in a therapeutic schedule (30 minutes, 1, 3 and 6 hours after the surgery). Brain expression of myelin basic protein (MBP) and the enzyme CNPase was determined by immunoelectron microscopy. PCB was obtained with high purity (>95%) and the absence of solvent contaminants and was able to ameliorate PC12 cell ischaemic injury. PCB treatment significantly decreased brain infarct volume, limited the exploratory behaviour impairment and preserved viable cortical neurons in ischaemic rats in a dose-dependent manner, compared to the vehicle group. Furthermore, PCB at high doses restored the MBP and CNPase expression levels in ischaemic rats. An improved PCB purification method from its natural source is reported, obtaining PCB that is suitable for pharmacological trials showing neuroprotective effects against experimental ischaemic stroke. Therefore, PCB could be a therapeutic pharmacological alternative for ischaemic stroke patients.

Suppression of 6-Hydroxydopamine-Induced Oxidative Stress by Hyperoside Via Activation of Nrf2/HO-1 Signaling in Dopaminergic Neurons

In our ongoing research to discover natural products with neuroprotective effects, hyperoside (quercetin 3-O-galactoside) was isolated from Acer tegmentosum, which has been used in Korean traditional medicine to treat liver-related disorders. Here, we demonstrated that hyperoside protects cultured dopaminergic neurons from death via reactive oxygen species (ROS)-dependent mechanisms, although other relevant mechanisms of hyperoside activity remain largely uncharacterized. For the first time, we investigated the neuroprotective effects of hyperoside on 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in neurons, and the possible underlying mechanisms. Hyperoside significantly ameliorated the loss of neuronal cell viability, lactate dehydrogenase release, excessive ROS accumulation and mitochondrial membrane potential dysfunction associated with 6-OHDA-induced neurotoxicity. Furthermore, hyperoside treatment activated the nuclear erythroid 2-related factor 2 (Nrf2), an upstream molecule of heme oxygenase-1 (HO-1). Hyperoside also induced the expression of HO-1, an antioxidant response gene. Remarkably, we found that the neuroprotective effects of hyperoside were weakened by an Nrf2 small interfering RNA, which blocked the ability of hyperoside to inhibit neuronal death, indicating the vital role of HO-1. Overall, we show that hyperoside, via the induction of Nrf2-dependent HO-1 activation, suppresses neuronal death caused by 6-OHDA-induced oxidative stress. Moreover, Nrf2-dependent HO-1 signaling activation represents a potential preventive and therapeutic target in Parkinson's disease management.

Hyperoside Attenuates Hepatic Ischemia-Reperfusion Injury by Suppressing Oxidative Stress and Inhibiting Apoptosis in Rats

PURPOSE

Hepatic ischemia-reperfusion (IR) injury is a serious complication of many clinical conditions, which may lead to liver or multiple organ failure. Hyperoside, a flavonoid compound, has been reported to protect against myocardial and cerebral injury induced by IR. This study aimed to investigate the protective effects of hyperoside on hepatic IR injury in rats.

METHODS

Using the 70% hepatic IR injury model, we divided 32 male Wistar rats into 4 groups (n = 8): sham-operated, IR+saline (saline/p.o.), IR+vehicle (carboxy methyl cellulose/p.o.), and IR+hyperoside (50 mg/kg/d/p.o.). At 24 hours after reperfusion, blood and liver tissue were collected. The effects of hyperoside on hepatic IR injury were assessed through tests of serum transaminase, hepatic histopathology, and measurement of markers of oxidative stress and apoptosis.

RESULTS

Pretreatment with hyperoside protected the liver from IR injury by a reduction in serum aspartate aminotransferase/alanine aminotransferase levels and a decrease in the severity of histologic changes. Hyperoside treatment also decreased the activity of malondialdehyde, increased the activities of superoxide dismutase and glutathione peroxidase, up-regulated the expression of heme oxygenase 1 and NAD(P)H:quinone oxidoreductase 1, and reduced the apoptotic index after IR injury. A decrease in the expression of caspase-3 and an increase in the ratio of B cell lymphoma 2 to B cell lymphoma 2-associated X also were observed.

CONCLUSION

Hyperoside has a protective effect on hepatic IR injury in rats, which may be due to its antioxidant and antiapoptotic properties.

Plant morphology, physiological characteristics, accumulation of secondary metabolites and antioxidant activities of Prunella vulgaris L. under UV solar exclusion

Background

Prunella vulgaris L. has been an important medicinal plant for the treatment of thyroid gland malfunction and mastitis in China for over 2000 years. There is an urgent need to select effective wavelengths for greenhouse cultivation of P. vulgaris as light is a very important factor in P. vulgaris growth. Here, we described the effects of natural light (control) and UV solar exclusion on the morphological and physiological traits, secondary metabolites contents and antioxidant activities of P. vulgaris.

Results

The results showed that UV solar exclusion resulted in remarkable alterations to morphological and biomass traits; significantly reduced the chlorophyll a, chlorophyll b and total chlorophyll contents; significantly enhanced the ratio of chlorophyll a to b; and significantly increased the carotenoid and anthocyanin contents in P. vulgaris. UV solar exclusion significantly increased the catalase (CAT) and peroxidase (POD) activities, increased superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities and slightly decreased the glutathione (GSH) content. UV solar exclusion significantly increased the soluble sugar and H₂O₂ contents and increased the soluble protein content but significantly decreased the proline content and slightly decreased the MDA content. The secondary metabolite contents (total phenolics, rosmarinic acid, caffeic acid, hyperoside, ursolic acid and oleanolic acid) and in vitro antioxidative properties (DPPH· and ABTS·⁺scavenging activities) were significantly increased in P. vulgaris spicas under UV solar exclusion. Additionally, the total polysaccharide and total flavonoids contents were slightly increased by UV solar exclusion. The salviaflaside content was significantly reduced by UV solar exclusion.

Conclusion

Our study demonstrated that P. vulgaris activates several antioxidant defence systems against oxidative damage caused by UV solar exclusion.

Pretreated Oenanthe Javanica extract increases anti-inflammatory cytokines, attenuates gliosis, and protects hippocampal neurons following transient global cerebral ischemia in gerbils

Recently, we have reported that Oenanthe javanica extract (OJE) displays strong neuroprotective effect against ischemic damage after transient global cerebral ischemia. However, neuroprotective mechanisms of OJE have not been fully identified. Thus, this study investigated the neuroprotection of OJE in the hippocampal CA1 area and its anti-inflammatory activity in gerbils subjected to 5 minutes of transient global cerebral ischemia. We treated the animals by intragastrical injection of OJE (100 and 200 mg/kg) once daily for 1 week prior to transient global cerebral ischemia. Neuroprotection of OJE was observed by immunohistochemistry for neuronal nuclear antigen and histofluorescence staining for Fluoro-Jade B. Immunohistochemistry of glial fibrillary acidic protein and ionized calcium-binding adapter molecule 1 was done for astrocytosis and microgliosis, respectively. To investigate the neuroprotective mechanisms of OJE, we performed immunohistochemistry of tumor necrosis factor-alpha and interleukin-2 for pro-inflammatory function and interleukin-4 and interleukin-13 for anti-inflammatory function. When we treated the animals by intragastrical administration of 200 mg/kg of OJE, hippocampal CA1 pyramidal neurons were protected from transient global cerebral ischemia and cerebral ischemia-induced gliosis was inhibited in the ischemic hippocampal CA1 area. We also found that interleukin-4 and -13 immunoreactivities were significantly increased in pyramidal neurons of the ischemic CA1 area after OJE pretreatment, and the increased immunoreactivities were sustained in the CA1 pyramidal neurons after transient global cerebral ischemia. However, OJE pretreatment did not increase interleukin-2 and tumor necrosis factor-alpha immunoreactivities in the CA1 pyramidal neurons. Our findings suggest that pretreatment with OJE can protect neurons and attenuate gliosis from transient global cerebral ischemia via increasing expressions of interleukin-4 and -13. The experimental plan of this study was reviewed and approved by the Institutional Animal Care and Use Committee (IACUC) in Kangwon National University (approval No. KW-160802-1) on August 10, 2016.

Naringenin prevents ischaemic stroke damage via anti-apoptotic and anti-oxidant effects

Apoptosis and oxidative stress are considered to be the major factors associated with the development and progression of many ischaemic cerebrovascular diseases. Naringenin (NAR) is an abundant flavanone in citrus plants and has been found to exhibit anti-oxidant, anti-carcinogenic and anti-apoptotic effects. This study aimed to investigate the anti-apoptotic and anti-oxidant effects of naringenin on ischaemic stroke. In vitro, cortical neuron cells isolated from the brains of neonatal Sprague-Dawley rats were randomly divided into control, oxygen and glucose deprivation/reperfusion (OGD/Rep), NAR-L, NAR-M and NAR-H groups. MTT and RT-PCR were used for cell proliferation and apoptosis-related proteins analyses. The effects of NAR on the Nrf2 signalling pathway were investigated using transfection approaches. Differences in mitochondrial dysfunction were analyzed by flow cytometry. In vivo, middle cerebral artery occlusion (MCAO) model was prepared and neurological defects and the brain wet/dry (W/D) ratio were assessed and recorded; apoptosis was measured based on the TUNEL assay. Additionally, biochemical indices were detected both in vitro and in vivo. NAR promoted cortical neuron cell proliferation, inhibited apoptosis and oxidative stress, and regulated the localization of Nrf2 protein (P<.05). Furthermore, silencing and overexpression of Nrf2 affected cortical neuron cell proliferation and apoptosis (P<.05). In vivo, NAR could alleviate cerebral oedema, improve neurological defects, and reduce apoptosis and oxidative stress (P<.05). These findings demonstrated that NAR could reduce apoptosis and oxidative stress and that Nrf2 signalling pathway is involved in this regulatory process. NAR has health-promoting properties because of its anti-apoptotic and anti-oxidant effects in cases of ischaemic stroke.

Vitexin protects against hypoxic-ischemic injury via inhibiting Ca2+/Calmodulin-dependent protein kinase II and apoptosis signaling in the neonatal mouse brain

Neonatal hypoxic-ischemic is a major cause of death and disability in neonates. In this study, we suggest for the first time that pretreatment with vitexin may suppress a pro-apoptotic signaling pathway in hypoxic-ischemic neuronal injury in neonates by inhibition of the phosphorylation of Ca²⁺/Calmodulin-dependent protein kinase II. Here we found that vitexin pretreatment reduced brain infarct volume in a dose-dependent manner. In addition, vitexin decreased the number of TUNEL-positive cells and brain atrophy. Furthermore, vitexin improved neurobehavioral outcomes. Vitexin also reduced oxygen glucose deprivation-induced neuronal injury and calcium entry. Vitexin pretreatment increased the Bcl-2/Bax protein ratio and decreased phosphorylation of Ca²⁺/Calmodulin-dependent protein kinase II and NF-κB, cleaved caspase-3 protein expression 24 hours after injury. Our data indicate that pretreatment with vitexin protects against neonatal hypoxic-ischemic brain injury and thus has potential as a treatment for hypoxic-ischemic brain injury.

Neuroprotective effects of quercetin 4'-O-β-d-diglucoside on human striatal precursor cells in nutrient deprivation condition

Several investigations have demonstrated neuroprotective effects of quercetin, a polyphenol widely present in nature, against neurotoxic chemicals, as well as in neuronal injury/neurodegenerative disease models. Most of these studies have been performed with quercetin aglycone and its metabolites, while scanty data are available on its glycosides. This study is aimed at investigating the neuroprotective effects of quercetin 3,4'-O-β-d-diglucoside (Q3,4'dG), isolated from the bulbs of the white cultivar (Allium cepa L.), using an in vitro model of human striatal precursor cells (HSPs), a primary culture isolated from the striatal primordium and previously characterized. To study the effect of Q3,4'dG on cell survival, HSPs were exposed to nutrient deprivation created by replacing culture medium with phosphate buffer saline (PBS). Our findings showed that Q3,4'dG treatment significantly promoted cell survival and strongly decreased apoptosis induced by nutrient deprivation, as evaluated by cell proliferation/death analyses. In addition, since the adhesive capacities of cells are essential for cell survival, the expression of some adhesion molecules, such as pancadherin and focal adhesion kinase, was evaluated. Interestingly, PBS exposure significantly decreased the expression of both molecules, while in the presence of Q3,4'dG this effect was prevented. This study provides evidence of a neuroprotective role exerted by Q3,4'dG and suggests its possible implication in sustaining neuronal survival for prevention and treatment of neurodegenerative disorders.

Hyperoside protects against hypoxia/reoxygenation induced injury in cardiomyocytes by suppressing the Bnip3 expression

AIMS

Role of hyperoside in protecting cardiomyocytes from ischemia/reperfusion induced injury has been proved. However, possible protecting mechanisms remain unclear. To fix the problem, an essential pro-apoptotic protein Bnip3 was studied in our experiments.

METHODS AND RESULTS

Neonatal rat cardiomyocytes were used and submitted to hypoxia for 8h followed by reoxygenation for 2h to simulate the ischemia/reperfusion injury. Hypoxia/reoxygenation(H/R) induced damage to cardiomyocytes and the protective effect of hyperoside were examined by means of MTT assay. H/R-induced apoptosis was assessed by Terminal-deoxynucleoitidyl Transferase Mediated Nick End Labeling(TUNEL) and DNA Ladder assay. mRNA expression of Bnip3 was determined by use of quantitative real-time reverse transcription polymerase chain reaction assay. Protein levels of Bnip3, Bax, Bcl-2 and cleaved caspase-3 were examined using western-blot assay. Our results showed that H/R caused great damage to cardiomyocytes, upregulated the protein expressions of Bnip3, Bax, cleaved caspase3, and decreased the expression of the anti-apoptotic protein of Bcl-2. Whereas, compared with the H/R group, a decrease in activities of Bnip3, Bax, cleaved caspase3, and a promoting expression of Bcl-2 were detected in the H/R goup pretreated with hyperoside.

CONCLUSION

It was concluded in our study that H/R-induced apoptotic effect in cardiomyocytes could be attenuated by hyperoside, and the protective role of hyperoside, if not completely, could be partly through the suppression of the pro-apoptotic gene Bnip3.

Hyperoside pre-treatment prevents glomerular basement membrane damage in diabetic nephropathy by inhibiting podocyte heparanase expression

Glomerular basement membrane (GBM) damage plays a pivotal role in pathogenesis of albuminuria in diabetic nephropathy (DN). Heparan sulfate (HS) degradation induced by podocyte heparanase is the major cause of GBM thickening and abnormal perm-selectivity. In the present study, we aimed to examine the prophylactic effect of hyperoside on proteinuria development and GBM damage in DN mouse model and the cultured mouse podocytes. Pre-treatment with hyperoside (30 mg/kg/d) for four weeks could significantly decrease albuminuria, prevent GBM damage and oxidative stress in diabetes mellitus (DM) mice. Immunofluorescence staining, Real time PCR and Western blot analysis showed that decreased HS contents and increased heparanase expression in DN mice were also significantly improved by hyperoside pre-treatment. Meanwhile, transmission electron microscope imaging showed that hyperoside significantly alleviated GBM thickening in DN mice. In addition, hyperoside pre-treatment inhibited the increased heparanase gene (HPR1) promoter activity and heparanase expression induced by high glucose or reactive oxidative species (ROS) in cultured podocytes. Our data suggested that hyperoside has a prophylactic effect on proteinuria development and GBM damage in DM mice by decreasing podocyte heparanase expression.

Hyperoside protects against chronic mild stress-induced learning and memory deficits

Hyperoside (quercetin-3-O-b-d-galactosidepyranose) is a plant-derived flavonoid mainly found in fruits, fruit juices (most notably flavanols, flavanones, and anthocyanins) and Chinese traditional medicines. It has been applied to relieve pain and improve cardiovascular functions in clinic. However, the effects of hyperoside on cognitive impairment induced by chronic stress and the underlying molecular mechanisms remain unclear. In the current study, we used chronic mild stress (CMS) rats to investigate the effects of hyperoside on learning and memory and further explore the possible mechanisms. Our results demonstrated that hyperoside reduced the escape latency and the swimming distance of CMS rats in Morris water maze test and reversed depressive symptoms in forced swim test (FST) and sucrose preference test. In addition, hyperoside increased the expression of brain-derived neurotrophic factor (BDNF) in hippocampus of CMS rats without influencing the corticosterone (CORT) level in blood plasma. Furthermore, K252a, an inhibitor of the BDNF receptor TrkB, prevented the protective effects of hyperoside on learning and memory in CMS rats. Taken together, these results indicate that hyperoside reverses the cognitive impairment induced by CMS, which is associated with the regulation of BDNF signaling pathway.

N-stearoyltyrosine protects primary cortical neurons against oxygen-glucose deprivation-induced apoptosis through inhibiting anandamide inactivation system

N-stearoylthrosine (NST), a synthesized anandamide (AEA) analogue, plays a neuroprotective role in neurodegenerative diseases and cerebrovascular diseases. Several studies have demonstrated that the endocannabinoids systems (ECS) are involved in the neuroprotective effects against cerebral ischemic injury. Oxygen-glucose deprivation (OGD)-induced neuronal injury elevated the levels of endocannabinoids and activated ECS. This research was conducted to investigate the neuroprotective effect of NST against OGD-induced neuronal injury in cultured primary cortical neurons and the potential mechanism involved. Cortical neurons were treated with NST at indicate concentrations for 30min prior to injury and OGD injured neurons were incubated with normal conditions for 0-24h. The best neuroprotective effect of NST against OGD-induced injury occurred at 10μM. All data indicated that the neuroprotective effect of NST against OGD-induced injury resulted from blocking anandamide membrane transporter (AMT) (IC₅₀=11.74nM) and inhibiting fatty acid amide hydrolase activity (FAAH) (IC₅₀=16.54nM). Our findings demonstrated that NST has an important role in cerebral ischemic injury pathological progression through activating cannabinoid receptors by inhibiting AEA inactivation system. These data suggested a potential role for NST in the therapeutic consideration of cerebral ischemic injury. However, inhibition of AEA inactivation system may provide a neuroprotective effect during cerebral ischemic injury.

Hyperoside inhibits the effects induced by oxidized low-density lipoprotein in vascular smooth muscle cells via oxLDL-LOX-1-ERK pathway

Hyperoside is a major active constituent in many medicinal plants traditionally used in Chinese medicines for their anti-inflammatory, antioxidative, and vascular protective effects. Recent studies have focused on the protective effects of hyperoside on hyperlipidemia. However, the molecular mechanisms underlying these effects are unknown. In this study, vascular smooth muscle cells (VSMCs) were treated in vitro with oxidized low-density lipoprotein (oxLDL) in the presence or absence of hyperoside. Western blotting, quantitative PCR, and tetrazolium assay were used to detect lectin-like oxLDL receptor-1 (LOX-1) expression and extracellular signal-regulated kinases (ERK) activation, and to determine VSMCs viability. The results demonstrated that oxLDL promoted LOX-1 expression, ERK activation, and proliferation in VSMCs. Hyperoside significantly inhibited the oxLDL-stimulated effects after long time exposure. However, it promoted ERK activation directly following a short incubation duration (25 min). In conclusion, hyperoside inhibits oxLDL-induced LOX-1 expression, ERK activation, and cell proliferation through the oxLDL-LOX-1-ERK pathway in VSMCs. Our findings suggest a novel role of hyperoside in treating and preventing atherosclerosis.

Isoquercetin activates the ERK1/2-Nrf2 pathway and protects against cerebral ischemia-reperfusion injury in vivo and in vitro

Isoquercetin has exhibited a wide range of therapeutic properties, including antioxidant, anti-inflammatory and anti-allergic activities. The aim of the present study was to investigate the effect of isoquercetin on rats with 2 h middle cerebral artery occlusion (MCAO) and evaluate the neuroprotective effect of isoquercetin on a primary culture of rat hippocampal neuronal cells subjected to oxygen-glucose deprivation followed by reoxygenation (OGD/R). In vivo, the rats treated with isoquercetin exhibited a lower degree of neurological dysfunction and smaller infarct volume than the vehicle-treated rats. In vitro, it was found that isoquercetin prevented the OGD/R-induced increase in apoptosis, lactate dehydrogenase release and reduction in cell viability. Additionally, isoquercetin induced the upregulation of nuclear factor erythroid 2-related factor 2 gene and protein expression, and increased extracellular signal-regulated kinase 1 and 2 (ERK1/2) phosphorylation. This indicates that the ERK1/2 pathway may contribute to the neuroprotective effect of isoquercetin against OGD/R-induced oxidative damage in rat hippocampal neurons. These findings suggest the potential importance of isoquercetin in the treatment of ischemia/reperfusion-related brain injury and associated diseases.

Therapeutic Potential of Polyphenols from Epilobium Angustifolium (Fireweed)

Epilobium angustifolium is a medicinal plant used around the world in traditional medicine for the treatment of many disorders and ailments. Experimental studies have demonstrated that Epilobium extracts possess a broad range of pharmacological and therapeutic effects, including antioxidant, anti-proliferative, anti-inflammatory, antibacterial, and anti-aging properties. Flavonoids and ellagitannins, such as oenothein B, are among the compounds considered to be the primary biologically active components in Epilobium extracts. In this review, we focus on the biological properties and the potential clinical usefulness of oenothein B, flavonoids, and other polyphenols derived from E. angustifolium. Understanding the biochemical properties and therapeutic effects of polyphenols present in E. angustifolium extracts will benefit further development of therapeutic treatments from this plant. Copyright © 2016 John Wiley & Sons, Ltd.

Hyperbaric oxygen preconditioning ameliorates hypoxia-ischemia brain damage by activating Nrf2 expression in vivo and in vitro

The present study aimed to investigate whether hyperbaric oxygen preconditioning (HBO-PC) could ameliorate hypoxia-ischemia brain damage (HIBD) by an increase of Nrf2 expression. P7 Sprague-Dawley rats (aged 7 d, n = 195) were used in two in vivo experiments, including BO-PC exposure experiments in non-HIBD models and treatment experiments in HIBD models. 2,3,5-triphenyltetrazolium chloride (TTC) staining, Nissl Staining, and TUNEL staining were performed. And expressions of Nrf2, HO-1, and GSTs were measured. For in vitro studies, oxygen-glucose deprivation cells were established. Morphological and apoptotic staining and gene silencing of Nrf2 by siRNA transfection were investigated. For exposure experiments, HBO-PC for longer time increased the expression of Nrf2 significantly. And for treatment experiments, HBO-PC treatment significantly decreased infarction area, lessened neuronal injury, reduced apoptosis, and increased both the expression of Nrf2 and activities of its downstream proteins. Cytology tests confirmed effects of HBO-PC treatments. Besides, Nrf2 siRNA significantly reduced protective effects of HBO-PC. These observations demonstrated that an up-regulation of Nrf2 by HBO-PC might play an important role in the generation of tolerance against HIBD.

Neuroprotective Activity of Hypericum perforatum and Its Major Components

Hypericum perforatum is a perennial plant, with worldwide distribution, commonly known as St. John's wort. It has been used for centuries in traditional medicine for the treatment of several disorders, such as minor burns, anxiety, and mild to moderate depression. In the past years, its antidepressant properties have been extensively studied. Despite that, other H. perforatum biological activities, as its neuroprotective properties have also been evaluated. The present review aims to provide a comprehensive summary of the main biologically active compounds of H. perforatum, as for its chemistry, pharmacological activities, drug interactions and adverse reactions and gather scattered information about its neuroprotective abilities. As for this, it has been demonstrated that H. perforatum extracts and several of its major molecular components have the ability to protect against toxic insults, either directly, through neuroprotective mechanisms, or indirectly, through is antioxidant properties. H. perforatum has therefore the potential to become an effective neuroprotective therapeutic agent, despite further studies that need to be carried out.

Pretreatment with baicalin attenuates hypoxia and glucose deprivation-induced injury in SH-SY5Y cells

OBJECTIVE

To explore the neuroprotective effects of baicalin against hypoxia and glucose deprivation-reperfusion (OGD/RO)-induced injury in SH-SY5Y cells.

METHODS

SH-SY5Y cells were divided into a control group, a OGD/RO group, which was subject to OGD/RO induction; and 3 baicalin groups subject to baicalin (1, 5, 25 μmol/L) for 2 h before induction of OGD/RO (low-, medium-, and high-dose baicalin groups). Cell viability was detected by thiazolyl blue tetrazolium bromide (MTT) assay and flow cytometric analysis was used to detect cell apoptosis. Real-time polymerase chain reaction was performed to determine the mRNA expression of caspase-3 gene. Western blot analysis was conducted to determine the expression of nuclear factor (NF)-κB and N-methyl-daspartic acid receptor-1 (NMDAR1).

RESULTS

Baicalin could significantly attenuate OGD/RO mediated apoptotic cell death in SH-SY5Y cells; the apoptosis rates in the low-, medium- and high-dose groups were 12.1%, 7.9%, and 5.4%, respectively. Western blot and real-time PCR analysis revealed that significant decrease in caspase-3 expression in the baicalin group compared with the OGD/RO group (P<0.01). Additionally, down-regulation of NF-κB and NMDAR1 was observed in the baicalin group compared with those obtained from the OGD/RO group. Compared with the low-dose baicalin group, remarkable decrease was noted in the medium- and high-dose groups (P<0.01).

CONCLUSION

Baicalin pre-treatment attenuates brain ischemia reperfusion injury by suppressing cellular apoptosis.

Synergistic neuroprotection by epicatechin and quercetin: Activation of convergent mitochondrial signaling pathways

In view of evidence that increased consumption of epicatechin (E) and quercetin (Q) may reduce the risk of stroke, we have measured the effects of combining E and Q on mitochondrial function and neuronal survival following oxygen-glucose deprivation (OGD). Relative to mouse cortical neuron cultures pretreated (24h) with either E or Q (0.1-10μM), E+Q synergistically attenuated OGD-induced neuronal cell death. E, Q and E+Q (0.3μM) increased spare respiratory capacity but only E+Q (0.3μM) preserved this crucial parameter of neuronal mitochondrial function after OGD. These improvements were accompanied by corresponding increases in cyclic AMP response element binding protein (CREB) phosphorylation and the expression of CREB-target genes that promote neuronal survival (Bcl-2) and mitochondrial biogenesis (PGC-1α). Consistent with these findings, E+Q (0.1 and 1.0μM) elevated mitochondrial gene expression (MT-ND2 and MT-ATP6) to a greater extent than E or Q after OGD. Q (0.3-3.0μM), but not E (3.0μM), elevated cytosolic calcium (Ca(2+)) spikes and the mitochondrial membrane potential. Conversely, E and E+Q (0.1 and 0.3μM), but not Q (0.1 and 0.3μM), activated protein kinase B (Akt). Nitric oxide synthase (NOS) inhibition with L-N(G)-nitroarginine methyl ester (1.0μM) blocked neuroprotection by E (0.3μM) or Q (1.0μM). Oral administration of E+Q (75mg/kg; once daily for 5days) reduced hypoxic-ischemic brain injury. These findings suggest E and Q activate Akt- and Ca(2+)-mediated signaling pathways that converge on NOS and CREB resulting in synergistic improvements in neuronal mitochondrial performance which confer profound protection against ischemic injury.

Receptor interacting protein 3-induced RGC-5 cell necroptosis following oxygen glucose deprivation

BACKGROUND

Necroptosis is a type of regulated form of cell death that has been implicated in the pathogenesis of various diseases. Receptor-interacting protein 3 (RIP3), a member of the RIP family of proteins, has been reported as an important necroptotic pathway mediator in regulating a variety of human diseases, such as myocardial ischemia, inflammatory bowel disease, and ischemic brain injury. Our previous study showed that RIP3 was expressed in rat retinal ganglion cells (RGCs), where it was significantly upregulated during the early stage of acute high intraocular pressure. Furthermore, RIP3 expression was co-localized with propidium iodide (PI)-positive staining (necrotic cells). These results suggested that RIP3 up-regulation might be involved in the necrosis of injured RGCs. In this study, we aimed to reveal the possible involvement of RIP3 in oxygen glucose deprivation (OGD)-induced retinal ganglion cell-5 (RGC-5) necroptosis.

METHODS

RGC-5 cells were cultured in Dulbecco's-modified essential medium and necroptosis was induced by 8 h OGD. PI staining and flow cytometry were performed to detect RGC-5 necrosis. RIP3 expression was detected by western blot and flow cytometry was used to detect the effect of RIP3 on RGC-5 necroptosis following OGD in rip3 knockdown cells. Malondialdehyde (MDA) lipid peroxidation assay was performed to determine the degree of oxidative stress.

RESULTS

PI staining showed that necrosis was present in the early stage of OGD-induced RGC-5 cell death. The presence of RGC-5 necroptosis after OGD was detected by flow cytometry using necrostatin-1, a necroptosis inhibitor. Western blot demonstrated that RIP3 up-regulation may be involved in RGC-5 necroptosis. Flow cytometry revealed that the number of OGD-induced necrotic RGC-5 cells was reduced after rip3 knockdown. Furthermore, MDA levels in the normal RGC-5 cells were much higher than in the rip3-knockdown cells after OGD.

CONCLUSIONS

Our findings suggest that RGC-5 cell necroptosis following OGD is mediated by a RIP3-induced increase in oxidative stress.

Complex effects of aqueous extract of Melampyrum pratense and of its flavonoids on activity of primary cultured hippocampal neurons

ETHNOPHARMACOLOGICAL RELEVANCE

The aqueous extract of the plant Malmpyrum pratense (Mp), is widely used in traditional medicine as a sedative, yet the biological basis of its action is not known.

AIM OF THE STUDY

The effects of Mp on network activity and intrinsic and synaptic properties were studied in cultured hippocampal neurons in an attempt to analyze its mode of action.

MATERIALS AND METHODS

Dissociated cultures of rat hippocampal neurons were used. Spontaneous network activity was assessed by variations in intracellular [Ca(2+)] concentrations, reflecting action potential discharges. Individual neuronal synaptic activity was measured by patch clamp recordings from similar neurons. The effect of exposure to different concentrations of Mp and some of its main ingredients was measured.

RESULTS

Mp produced complex, dose dependent, reversible effects on network activity, increasing it with low concentrations, and decreasing it at high concentrations. Individual flavonoids contained in Mp mimicked the effects of the extract, both for the facilitating and suppressing effects of the extract. Electrophysiologically, Mp caused a reduction in spontaneous activity, but did not affect membrane properties of individual patch clamped neurons, nor did it affect mEPSCs recorded from these neurons. However, a transient increase in reactivity to pulse application of GABA was evident.

CONCLUSIONS

These results suggest that a main sedative effect of Mp is on GABAergic neurotransmission in cultured hippocampal neurons.

Ischemia/reperfusion-induced upregulation of TIGAR in brain is mediated by SP1 and modulated by ROS and hormones involved in glucose metabolism

We previously found that TIGAR (TP53-induced glycolysis and apoptosis regulator) was upregulated in response to ischemia/reperfusion insult in a TP53-independent manner. The present study sought to investigate the regulatory mechanisms of TIGAR upregulation in animal and cellular models of stroke. The animal and cellular models of ischemia/reperfusion were produced by transient middle cerebral artery occlusion and reperfusion (tMCAO/R) and oxygen-glucose deprivation/reoxygenation (OGD/R), respectively. The expression of TIGAR protein in cortical tissues and hippocampal neuronal cell line HT22 cells or primary neurons was determined. Glucose, hormones and hydrogen peroxide (H2O2) were administered to mice via injection into the tail vein or lateral ventricle or directly added into cell culture medium. In mice subjected to tMCAO/R, the blood glucose level rapidly increased, peaking at 0.5 h and then declined. TIGAR protein was also significantly increased and then declined with a delayed time-course. The increase in TIGAR protein was blunted when blood glucose levels were controlled with insulin. However, administering glucose solution to mice or adding glucose to cell culture medium had no effect on TIGAR protein levels. In contrast adrenaline, hydrocortisone, glucagon and H2O2 significantly increased TIGAR protein expression, whereas insulin inhibited TIGAR expression. The transcription factor SP1 was induced by ischemia/reperfusion ahead of TIGAR upregulation. Inhibiting SP1 with mithramycin A or silencing SP1 with siRNA blocked the ischemia-induced TIGAR upregulation. These results suggest that ROS and hormones regulating blood glucose metabolism play a role in ischemia/reperfusion-induced TIGAR upregulation.

GM1 ganglioside activates ERK1/2 and Akt downstream of Trk tyrosine kinase and protects PC12 cells against hydrogen peroxide toxicity

Ganglioside GM1 at micro- and nanomolar concentrations was shown to increase the viability of pheochromocytoma PC12 cells exposed to hydrogen peroxide and diminish the accumulation of reactive oxygen species and oxidative inactivation of Na(+),K(+)-ATPase, the effects of micromolar GM1 being more pronounced than those of nanomolar GM1. These effects of GM1 were abolished by Trk receptor tyrosine kinase inhibitor and diminished by MEK1/2, phosphoinositide 3-kinase and protein kinase C inhibitors. Hydrogen peroxide activates Trk tyrosine kinase; Akt and ERK1/2 are activated downstream of this protein kinase. GM1 was found to activate Trk receptor tyrosine kinase in PC12 cells. GM1 (100 nM and 10 µM) increased the basal activity of Akt, but did not change Akt activity in cells exposed to hydrogen peroxide. Basal ERK1/2 activity in PC12 cells was increased by GM1 at a concentration of 10 µM, but not at nanomolar concentrations. Activation of ERK1/2 by hydrogen peroxide was enhanced by GM1 at a concentration of 10 µM and to a lesser extent at a concentration of 100 nM. Thus, the protective and metabolic effects of GM1 ganglioside on PC12 cells exposed to hydrogen peroxide appear to depend on the activation of Trk receptor tyrosine kinase and downstream activation of Akt and ERK1/2.

Pretreatment with 2-(4-methoxyphenyl)ethyl-2-acetamido-2-deoxy-β-D-pyranoside attenuates cerebral ischemia/reperfusion-induced injury in vitro and in vivo

Salidroside, extracted from the root of Rhodiola rosea L, is known for its pharmacological properties, in particular its neuroprotective effects. 2-(4-Methoxyphenyl) ethyl-2-acetamido-2-deoxy-β-D-pyranoside (GlcNAc-Sal), an analog of salidroside, was recently synthesized and shown to possess neuroprotective properties. The purpose of the current study was to investigate the neuroprotective effects of GlcNAc-Sal against oxygen-glucose deprivation-reperfusion (OGD-R)-induced neurotoxicity in vitro and global cerebral ischemia-reperfusion (GCI-R) injury in vivo. Cell viability tests and Hoechst 33342 staining confirmed that GlcNAc-Sal pretreatment markedly attenuated OGD-R induced apoptotic cell death in immortalized mouse hippocampal HT22 cells. Western blot, immunofluorescence and PCR analyses revealed that GlcNAc-Sal pretreatment restored the balance of pro- and anti-apoptotic proteins and inhibited the activation of caspase-3 and PARP induced by OGD-R treatment. Further analyses showed that GlcNAc-Sal pretreatment antagonized reactive oxygen species (ROS) generation, iNOS-derived NO production and NO-related apoptotic cell death during OGD-R stimulation. GCI-R was induced by bilateral common carotid artery occlusion (BCCAO) and reperfusion in mice in vivo. Western blot analysis showed that GlcNAc-Sal pretreatment decreased the expression of caspase-3 and increased the expression of Bcl-2 (B-cell lymphoma 2)/Bax (Bcl-2-associated X protein) induced by GCI-R treatment. Our findings suggest that GlcNAc-Sal pretreatment prevents brain ischemia reperfusion injury by the direct or indirect suppression of cell apoptosis and GlcNAc-Sal could be developed as a broad-spectrum agent for the prevention and/or treatment of cerebral ischemic injury.

Adaptive cellular stress pathways as therapeutic targets of dietary phytochemicals: focus on the nervous system

During the past 5 decades, it has been widely promulgated that the chemicals in plants that are good for health act as direct scavengers of free radicals. Here we review evidence that favors a different hypothesis for the health benefits of plant consumption, namely, that some phytochemicals exert disease-preventive and therapeutic actions by engaging one or more adaptive cellular response pathways in cells. The evolutionary basis for the latter mechanism is grounded in the fact that plants produce natural antifeedant/noxious chemicals that discourage insects and other organisms from eating them. However, in the amounts typically consumed by humans, the phytochemicals activate one or more conserved adaptive cellular stress response pathways and thereby enhance the ability of cells to resist injury and disease. Examplesof such pathways include those involving the transcription factors nuclear factor erythroid 2-related factor 2, nuclear factor-κB, hypoxia-inducible factor 1α, peroxisome proliferator-activated receptor γ, and forkhead box subgroup O, as well as the production and action of trophic factors and hormones. Translational research to develop interventions that target these pathways may lead to new classes of therapeutic agents that act by stimulating adaptive stress response pathways to bolster endogenous defenses against tissue injury and disease. Because neurons are particularly sensitive to potentially noxious phytochemicals, we focus on the nervous system but also include findings from other cell types in which actions of phytochemicals on specific signal transduction pathways have been more thoroughly studied.

Ginsenoside Rd attenuates tau protein phosphorylation via the PI3K/AKT/GSK-3β pathway after transient forebrain ischemia

Phosphorylated tau was found to be regulated after cerebral ischemia and linked to high risk for the development of post-stroke dementia. Our previous study showed that ginsenoside Rd (Rd), one of the main active ingredients in Panax ginseng, decreased tau phosphorylation in Alzheimer model. As an extending study, here we investigated whether Rd could reduce tau phosphorylation and sequential cognition impairment after ischemic stroke. Sprague-Dawley rats were subjected to focal cerebral ischemia. The tau phosphorylation of rat brains were analyzed following ischemia by Western blot and animal cognitive functions were examined by Morris water maze and Novel object recognition task. Ischemic insults increased the levels of phosphorylated tau protein at Ser199/202 and PHF-1 sites and caused animal memory deficits. Rd treatment attenuated ischemia-induced enhancement of tau phosphorylation and ameliorated behavior impairment. Furthermore, we revealed that Rd inhibited the activity of Glycogen synthase kinase-3β (GSK-3β), the most important kinase involving tau phosphorylation, but enhanced the activity of protein kinase B (PKB/AKT), a key kinase suppressing GSK-3β activity. Moreover, we found that LY294002, an antagonist for phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway, abolished the inhibitory effect of Rd on GSK-3β activity and tau phosphorylation. Taken together, our findings provide the first evidence that Rd may reduce cerebral ischemia-induced tau phosphorylation via the PI3K/AKT/GSK-3β pathway.