Therapeutic Effects of Decursin and Angelica gigas Nakai Root Extract in Gerbil Brain after Transient Ischemia via Protecting BBB Leakage and Astrocyte Endfeet Damage

Angelica gigas Nakai (Korean Dang-gui) Root Alcoholic Extracts in Health Promotion and Disease Therapy - active Phytochemicals and In Vivo Molecular Targets

Angelica gigas Nakai (AGN) root is a medicinal herbal widely used in traditional medicine in Korea. AGN root ethanolic extracts have been marketed as dietary supplements in the United States for memory health and pain management. We have recently reviewed the pharmacokinetics (PK) and first-pass hepatic metabolism of ingested AGN supplements in humans for the signature pyranocoumarins decursin (D, Cmax 1x), decursinol angelate (DA, Cmax ~ 10x) and their common botanical precursor and hepatic metabolite decursinol (DOH, Cmax ~ 1000x). Here we update in vivo medicinal activities of AGN and/or its pyranocoumarins and furanocoumarin nodakenin in cancer, pain, memory loss, cerebral ischemia reperfusion stroke, metabolic syndrome and vascular endothelial dysfunctions, anxiety, sleep disorder, epilepsy, inflammatory bowel disease, osteoporosis and osteoarthritis. Given their polypharmacology nature, the pertinent mechanisms of action are likely misrepresented by many cell culture studies that did not consider the drug metabolism knowledge. We report here Rho-associated protein kinases (ROCK1/2) as novel targets for DA and DOH. Combining with published inhibitory activity of DOH on acetylcholinesterase, agonist activity of DOH and antagonist/degrader activity of DA/D on androgen and estrogen receptors, D/DA promoting activity for glutamic acid decarboxylase (GAD)- gamma-aminobutyric acid (GABA) inhibitory axis and inhibition of glutamate dehydrogenase (GDH), monoamine oxidase-A (MAO-A) and transient receptor potential vanilloid 1 (TRPV1), we postulate their contributions to neuro-cognitive, metabolic, oncologic, vascular and other beneficial bioactivities of AGN extracts. A clinical trial is being planned for an AGN extract to manage side effects of androgen deprivation therapy in prostate cancer patients.

Exploring the Therapeutic Potential of BBB-Penetrating Phytochemicals With p38 MAPK Modulatory Activity in Addressing Oxidative Stress-Induced Neurodegenerative Disorders, With a Focus on Alzheimer's Disease

Oxidative stress plays an important role in the occurrence of neurodegenerative diseases. Previous studies indicate a strong connection between oxidative stress, inappropriate activation of the p38 MAPK signaling pathway, and the pathogenesis of neurodegenerative diseases. Although antioxidant therapy is a valid strategy to alleviate these problems, the most important limitation of this approach is the ineffectiveness of drug administration due to the limited permeability of the BBB. Therefore, BBB-penetrating p38 MAPK modulators with proper antioxidant capacity could be useful in preventing/reducing the complications of neurodegenerative disorders. The current manuscript aims to review the therapeutic capabilities of some recently reviewed naturally occurring p38 MAPK inhibitors in the management of neurodegenerative problems such as Alzheimer's disease. In data collection, we tried to use more recent studies published in high-quality journals indexed in databases Scopus, Web of Science, PubMed, and so on, but no specific time frame was considered due to the nature of the study. Our evaluations indicate that natural compounds tanshinones, protoberberines, pinocembrin, osthole, rhynchophylline, oxymatrine, schisandrin, piperine, paeonol, ferulic acid, 6-gingerol, obovatol, and trolox have significant potential for use as supplements/adjuvants in the reduction of neurodegenerative-related problems. Our findings emphasize the usefulness of BBB-penetrating phytochemicals with p38 MAPK modulatory activity as potential therapeutic options against neurodegenerative disorders. Of course, the proper use of these compounds depends on considering their toxicity/safety profile and pharmacokinetic characteristics as well as the clinical conditions of users.

Protective effect of Tat fused HPCA protein on neuronal cell death caused by ischemic injury

Background

Bain ischemia is a disease that occurs for various reasons, induces reactive oxygen species (ROS), and causes fatal damage to the nervous system. Protective effect of HPCA on ischemic injury has not been extensively studied despite its significance in regulating calcium homeostasis and promoting neuronal survival in CA1 region of the brain.

Objective

We investigate the role of HPCA in ischemic injury using a cell-permeable Tat peptide fused HPCA protein (Tat-HPCA).

Methods

Western blot analysis determined the penetration of Tat-HPCA into HT-22 cells and apoptotic signaling pathways. 5-CFDA, AM, DCF-DA, and TUNEL staining confirmed intracellular ROS production and DNA damage. The intracellular Ca2+ was measured in primary cultured neurons treated with H2O2. Protective effects were examined using immunohistochemistry and cognitive function tests by passive avoidance test and 8-arm radial maze test.

Results

Tat-HPCA effectively penetrated into HT-22 cells and inhibited H2O2-induced apoptosis, oxidative stress, and DNA fragmentation. It also effectively inhibited phosphorylation of JNK and regulated the activation of Caspase, Bax, Bcl-2, and PARP, leading to inhibition of apoptosis. Moreover, Ca2+ concentration decreased in cells treated with Tat-HPCA in primary cultured neurons. In an animal model of ischemia, Tat-HPCA effectively penetrated the hippocampus, inhibited cell death, and regulated activities of astrocytes and microglia. Additionally, Cognitive function tests show that Tat-HPCA improves neurobehavioral outcomes after cerebral ischemic injury.

Conclusion

These results suggest that Tat-HPCA might have potential as a therapeutic agent for treating oxidative stress-related diseases induced by ischemic injury, including ischemia.

Angelica gigas extract inhibits acetylation of eNOS via IRE1α sulfonation/RIDD-SIRT1-mediated posttranslational modification in vascular dysfunction

Angelica gigas NAKAI (AG) is a popular traditional medicinal herb widely used to treat dyslipidemia owing to its antioxidant activity. Vascular disease is intimately linked to obesity-induced metabolic syndrome, and AG extract (AGE) shows beneficial effects on obesity-associated vascular dysfunction. However, the effectiveness of AGE against obesity and its underlying mechanisms have not yet been extensively investigated. In this study, 40 high fat diet (HFD) rats were supplemented with 100-300 mg/kg/day of AGE to determine its efficacy in regulating vascular dysfunction. The vascular relaxation responses to acetylcholine were impaired in HFD rats, while the administration of AGE restored the diminished relaxation pattern. Endothelial dysfunction, including increased plaque area, accumulated reactive oxygen species, and decreased nitric oxide (NO) and endothelial nitric oxide synthase (eNOS) Ser1177 phosphorylation, were observed in HFD rats, whereas AGE reversed endothelial dysfunction and its associated biochemical signaling. Furthermore, AGE regulated endoplasmic reticulum (ER) stress and IRE1α sulfonation and its subsequent sirt1 RNA decay through controlling regulated IRE1α-dependent decay (RIDD) signaling, ultimately promoting NO bioavailability via the SIRT1-eNOS axis in aorta and endothelial cells. Independently, AGE enhanced AMPK phosphorylation, additionally stimulating SIRT1 and eNOS deacetylation and its associated NO bioavailability. Decursin, a prominent constituent of AGE, exhibited a similar effect in alleviating endothelial dysfunctions. These data suggest that AGE regulates dyslipidemia-associated vascular dysfunction by controlling ROS-associated ER stress responses, especially IRE1α-RIDD/sirt1 decay and the AMPK-SIRT1 axis.

Pharmacokinetics of Extended-release Buprenorphine in Mongolian Gerbils (Meriones unguiculatus)

Both the Guide for the Care and Use of Laboratory Animals and the Animal Welfare Act and Regulations require animals in research to receive adequate analgesia unless an exception can be scientifically justified and IACUC approved. Extended- release buprenorphine (BUP-XR) is a pharmaceutical-grade formulation that is FDA-indexed for use in mice and rats. However, this new formulation has not been evaluated in adult Mongolian gerbils (Meriones unguiculatus). Our goal was to determine whether the extrapolated dose (1 mg/kg SC) would achieve plasma buprenorphine concentrations above the murine therapeutic threshold (> 1.0 ng/mL) in male and female gerbils. We hypothesized that BUP-XR administered at 1 mg/kg would achieve the murine therapeutic threshold in both male and female gerbils until at least 48 h after injection. Gerbils received one injection of BUP-XR (1 mg/kg SC) and underwent 4 serial blood collections (0.5, 1, 2, and 4, or 0.5, 24, 48, and 72 h after injection). The average plasma buprenorphine concentrations were above 1 ng/mL within 30 min of administration for both males and females. Plasma buprenorphine concentrations remained above 1.0 ng/mL for 48 h after administration. In males, plasma buprenorphine concentrations were significantly higher at 1 h after injection as compared with females; no other significant differences were observed between sexes. Mild to moderate injection-site granulomas were observed in five of nine gerbils, presumably due to the lipid matrix of the BUP-XR formulation. Our findings demonstrate that a single BUP-XR dose (1 mg/kg SC) achieves plasma buprenorphine levels that remain above the murine therapeutic threshold of 1.0 ng/mL for up to 48 h in both sexes.

Neuroprotective Potential of Pyranocoumarins from Angelica gigas Nakai on Glutamate-Induced Hippocampal Cell Death

Chronic neurodegenerative diseases are typically associated with oxidative stress conditions leading to neuronal cell death. We aimed to investigate the neuroprotective effect of three pyranocoumarins (decursin, decursinol angelate, and decursinol) targeting oxidative stress factors. Decursin (also known as dehydro-8-prenylnaringenin) is a prenylated coumarin compound consisting of a coumarin ring system with a prenyl group attached to one of the carbons in the ring. As a secondary metabolite of plants, pyranocoumarin decursin from Angelica gigas Nakai presented protective effects against glutamate-induced oxidative stress in HT22, a murine hippocampal neuronal cell line. Decursinol (DOH) is a metabolite of decursin, sharing same coumarin ring system but a slightly different chemical structure with the prenyl group replaced by a hydroxyl group (-OH). In our findings, DOH was ineffective while decursin was, suggesting that this prenyl structure may be important for compound absorption and neuroprotection. By diminishing the accumulation of intracellular reactive oxygen species as well as stimulating the expression of HO-1, decursin triggers the self-protection system in neuronal cells. Additionally, decursin also revealed an anti-apoptotic effect by inhibiting chromatin condensation and reducing the forming of annexin-V-positive cells.

Aucubin Exerts Neuroprotection against Forebrain Ischemia and Reperfusion Injury in Gerbils through Antioxidative and Neurotrophic Effects

Aucubin is an iridoid glycoside that displays various pharmacological actions including antioxidant activity. However, there are few reports available on the neuroprotective effects of aucubin against ischemic brain injury. Thus, the aim of this study was to investigate whether aucubin protected against damage to hippocampal function induced by forebrain ischemia-reperfusion injury (fIRI) in gerbils, and to examine whether aucubin produced neuroprotection in the hippocampus against fIRI and to explore its mechanisms by histopathology, immunohistochemistry, and Western analysis. Gerbils were given intraperitoneal injections of aucubin at doses of 1, 5, and 10 mg/kg, respectively, once a day for seven days before fIRI. As assessed by the passive avoidance test, short-term memory function following fIRI significantly declined, whereas the decline in short-term memory function due to fIRI was ameliorated by pretreatment with 10 mg/kg, but not 1 or 5 mg/kg, of aucubin. Most of the pyramidal cells (principal cells) of the hippocampus died in the Cornu Ammonis 1 (CA1) area four days after fIRI. Treatment with 10 mg/kg, but not 1 or 5 mg/kg, of aucubin protected the pyramidal cells from IRI. The treatment with 10 mg/kg of aucubin significantly reduced IRI-induced superoxide anion production, oxidative DNA damage, and lipid peroxidation in the CA1 pyramidal cells. In addition, the aucubin treatment significantly increased the expressions of superoxide dismutases (SOD1 and SOD2) in the pyramidal cells before and after fIRI. Furthermore, the aucubin treatment significantly enhanced the protein expression levels of neurotrophic factors, such as brain-derived neurotrophic factor and insulin-like growth factor-I, in the hippocampal CA1 area before and after IRI. Collectively, in this experiment, pretreatment with aucubin protected CA1 pyramidal cells from forebrain IRI by attenuating oxidative stress and increasing neurotrophic factors. Thus, pretreatment with aucubin can be a promising candidate for preventing brain IRI.

Decursin alleviates LPS-induced lung epithelial cell injury by inhibiting NF-κB pathway activation

OBJECTIVE

To reveal the possible effects of decursin on viability, oxidative stress, and inflammatory response in lipopolysaccharide (LPS)-treated human bronchial epithelial cells-2B (BEAS-2B) and human pulmonary artery endothelial cells (HPAEC) cells, and revealed the potential mechanisms.

METHODS

LPS was used to induce acute lung injury (ALI) in normal human lung epithelial cells, including BEAS-2B and HPAEC cells. Cell viability and apoptosis in response to LPS and decursin in BEAS-2B and HPAEC cells were, respectively, evaluated by MTT colorimetric and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays. The oxidative stress and inflammatory response in LPS-treated BEAS-2B and HPAEC cells were detected by enzyme-linked-immunosorbent serologic assay. In addition, the role of decursin in nuclear -factor-kappa B (NF-κB) activation was analyzed by immunoblot and immunofluorescence assays.

RESULTS

Our data revealed that decursin could alleviate the viability of LPS-induced BEAS-2B and HPAEC cells. Decursin could also reduce LPS-induced oxidative stress in BEAS-2B and HPAEC cells. In addition, it could reduce LPS-induced inflammation in BEAS-2B and HPAEC cells. Mechanically, decursin suppressed the activation of NF-κB pathway.

CONCLUSION

Decursin suppressed NF-κB pathway, and therefore alleviated ALI.

Hematopoietic Effects of Angelica gigas Nakai Extract on Cyclophosphamide-Induced Myelosuppression

Myelosuppression is a major adverse effect of chemotherapy. With the increasing number of cancer patients worldwide, there is a growing interest in therapeutic approaches that reduce the adverse effects of chemotherapy. Angelica gigas Nakai (AGN) roots have been widely used in oriental medicine to treat blood-related diseases, including cancer. However, the effects of AGN on myelosuppression have not been studied. Here, we investigated the effects of AGN ethanol extract (AGNEX) on cyclophosphamide-induced myelosuppression. AGNEX treatment significantly decreased white blood cell levels while increasing red blood cell and platelet levels in the peripheral blood. It inhibited thymus and spleen atrophy. It also enhanced serum levels of interleukin (IL)-6 and tumor necrosis factor (TNF)-α. qRT-PCR results showed that AGNEX decreased the expression of IL-1b and stem cell factor (SCF) in the bone marrow (BM) while increasing the mRNA expression of IL-3 and IL-6 in the spleen. Although AGNEX did not significantly decrease apoptosis and cell cycle arrest in the BM and splenocytes, AGNEX plays a positive role in cyclophosphamide-induced myelosuppression. AGNEX administration increased BM cells in the femur while decreasing apoptotic BM cells. These findings suggest that AGNEX could be used to treat myelosuppression and as a combination therapy in cancer patients.

Angelica gigas: Signature Compounds, In Vivo Anticancer, Analgesic, Neuroprotective and Other Activities, and the Clinical Translation Challenges

Angelica gigas Nakai (AGN) root is a medicinal herbal widely used in traditional medicine in Korea. AGN root ethanolic extract dietary supplements are marketed in the United States for memory health and pain management. We comprehensively reviewed the anticancer, analgesic, pro-memory and other bio-activities of AGN extract and its signature phytochemicals decursin, decursinol angelate, and decursinol a decade ago in 2012 and updated their anticancer activities in 2015. In the last decade, significant progress has been made for understanding the pharmacokinetics (PK) and metabolism of these compounds in animal models and single dose human PK studies have been published by us and others. In addition to increased knowledge of the known bioactivities, new bioactivities with potential novel health benefits have been reported in animal models of cerebral ischemia/stroke, anxiety, sleep disorder, epilepsy, inflammatory bowel disease, sepsis, metabolic disorders, osteoporosis, osteoarthritis, and even male infertility. Herein, we will update PK and metabolism of pyranocoumarins, review in vivo bioactivities from animal models and human studies, and critically appraise the relevant active compounds, the cellular and molecular pharmacodynamic targets, and pertinent mechanisms of action. Knowledge gaps include whether human pyranocoumarin PK metrics are AGN dose dependent and subjected to metabolic ceiling, or metabolic adaptation after repeated use. Critical clinical translation challenges include sourcing of AGN extracts, product consistency and quality control, and AGN dose optimization for different health conditions and disease indications. Future research directions are articulated to fill knowledge gaps and address these challenges.

Relationship between Neuronal Damage/Death and Astrogliosis in the Cerebral Motor Cortex of Gerbil Models of Mild and Severe Ischemia and Reperfusion Injury

Neuronal loss (death) occurs selectively in vulnerable brain regions after ischemic insults. Astrogliosis is accompanied by neuronal death. It can change the molecular expression and morphology of astrocytes following ischemic insults. However, little is known about cerebral ischemia and reperfusion injury that can variously lead to damage of astrocytes according to the degree of ischemic injury, which is related to neuronal damage/death. Thus, the purpose of this study was to examine the relationship between damage to cortical neurons and astrocytes using gerbil models of mild and severe transient forebrain ischemia induced by blocking the blood supply to the forebrain for five or 15 min. Significant ischemia tFI-induced neuronal death occurred in the deep layers (layers V and VI) of the motor cortex: neuronal death occurred earlier and more severely in gerbils with severe ischemia than in gerbils with mild ischemia. Distinct astrogliosis was detected in layers V and VI. It gradually increased with time after both ischemiae. The astrogliosis was significantly higher in severe ischemia than in mild ischemia. The ischemia-induced increase of glial fibrillary acidic protein (GFAP; a maker of astrocyte) expression in severe ischemia was significantly higher than that in mild ischemia. However, GFAP-immunoreactive astrocytes were apparently damaged two days after both ischemiae. At five days after ischemiae, astrocyte endfeet around capillary endothelial cells were severely ruptured. They were more severely ruptured by severe ischemia than by mild ischemia. However, the number of astrocytes stained with S100 was significantly higher in severe ischemia than in mild ischemia. These results indicate that the degree of astrogliosis, including the disruption (loss) of astrocyte endfeet following ischemia and reperfusion in the forebrain, might depend on the severity of ischemia and that the degree of ischemia-induced neuronal damage may be associated with the degree of astrogliosis.

Therapeutic effects of stiripentol against ischemia-reperfusion injury in gerbils focusing on cognitive deficit, neuronal death, astrocyte damage and blood brain barrier leakage in the hippocampus

Stiripentol is an anti-epileptic drug for the treating of refractory status epilepticus. It has been reported that stiripentol can attenuate seizure severity and reduce seizure-induced neuronal damage in animal models of epilepsy. The objective of the present study was to investigate effects of post-treatment with stiripentol on cognitive deficit and neuronal damage in the cornu ammonis 1 (CA1) region of the hippocampus proper following transient ischemia in the forebrain of gerbils. To evaluate ischemia-induced cognitive impairments, passive avoidance test and 8-arm radial maze test were performed. It was found that post-treatment with stiripentol at 20 mg/kg, but not 10 or 15 mg/kg, reduced ischemia-induced memory impairment. Transient ischemia-induced neuronal death in the CA1 region was also significantly attenuated only by 20 mg/kg stiripentol treatment after transient ischemia. In addition, 20 mg/kg stiripentol treatment significantly decreased ischemia-induced astrocyte damage and immunoglobulin G leakage. In brief, stiripentol treatment after transient ischemia ameliorated transient ischemia-induced cognitive impairment in gerbils, showing that pyramidal neurons were protected and astrocyte damage and blood brain barrier leakage were significantly attenuated in the hippocampus. Results of this study suggest stiripentol can be developed as a candidate of therapeutic drug for ischemic stroke.

Ischemia-Induced Cognitive Impairment Is Improved via Remyelination and Restoration of Synaptic Density in the Hippocampus after Treatment with COG-Up® in a Gerbil Model of Ischemic Stroke

Cerebrovascular disease such as ischemic stroke develops cognitive impairment due to brain tissue damage including neural loss, demyelination and decrease in synaptic density. In the present study, we developed transient ischemia in the forebrain of the gerbil and found cognitive impairment using the Barnes maze test and passive avoidance test for spatial memory and learning memory, respectively. In addition, neuronal loss/death was detected in the Cornu Ammonis 1 (CA1) region of the gerbil hippocampus after the ischemia by cresyl violet histochemistry, immunohistochemistry for neuronal nuclei and histofluorescence with Fluoro-Jade B. Furthermore, in the CA1 region following ischemia, myelin and vesicular synaptic density were significantly decreased using immunohistochemistry for myelin basic protein and vesicular glutamate transporter 1. In the gerbils, treatment with COG-up^® (a combined extract of Erigeron annuus (L.) Pers. and Brassica oleracea Var.), which was rich in scutellarin and sinapic acid, after the ischemia, significantly improved ischemia-induced decline in memory function when compared with that shown in gerbils treated with vehicle after the ischemia. In the CA1 region of these gerbils, COG-up^® treatment significantly promoted the remyelination visualized using immunohistochemistry myelin basic protein, increased oligodendrocytes visualized using a receptor-interacting protein, and restored the density of glutamatergic synapses visualized using double immunofluorescence for vesicular glutamate transporter 1 and microtubule-associated protein, although COG-up^® treatment did not protect pyramidal cells (principal neurons) located in the CA1 region form the ischemic insult. Considering the current findings, a gerbil model of ischemic stroke apparently showed cognitive impairment accompanied by ischemic injury in the hippocampus; also, COG-up^® can be employed for improving cognitive decline following ischemia-reperfusion injury in brains.

Populus tomentiglandulosa Extract Is Rich in Polyphenols and Protects Neurons, Astrocytes, and the Blood-Brain Barrier in Gerbil Striatum Following Ischemia-Reperfusion Injury

Transient ischemia in brains causes neuronal damage, gliosis, and blood-brain barrier (BBB) breakdown, which is related to ischemia-induced brain dysfunction. Populus species have various pharmacological properties including antioxidant and anti-inflammatory activities. In this study, we found that phenolic compounds were rich in Populus tomentiglandulosa extract and examined the effects of Populus tomentiglandulosa extract on neuronal damage/death, astrogliosis, and BBB breakdown in the striatum, which is related to motor behavior, following 15-min transient ischemia in the forebrain in gerbils. The gerbils were pre-treated with 50, 100, and 200 mg/kg of the extract. The latter showed significant effects against ischemia-reperfusion injury. Ischemia-induced hyperactivity using spontaneous motor activity test was significantly attenuated by the treatment. Striatal cells (neurons) were dead at five days after the ischemia; however, pre-treatment with the extract protected the striatal cells from ischemia/reperfusion injury. Ischemia-induced reactive astrogliosis was significantly alleviated, in particular, astrocyte end feet, which are a component of BBB, were significantly preserved. Immunoglobulin G, which is not found in intact brain parenchyma, was apparently shown (an indicator of extravasation) in striatal parenchyma at five days after the ischemia, but IgG leakage was dramatically attenuated in the parenchyma by the pre-treatment. Based on these findings, we suggest that Populus tomentiglandulosa extract rich in phenolic compounds can be employed as a pharmaceutical composition to develop a preventive material against brain ischemic injury.