Oral Administration of Gintonin Attenuates Cholinergic Impairments by Scopolamine, Amyloid-β Protein, and Mouse Model of Alzheimer's Disease

Emerging evidence that ginseng components improve cognition in subjective memory impairment, mild cognitive impairment, and early Alzheimer's disease dementia

Ginseng is a traditional herbal medicine used for prevention and treatment of various diseases as a tonic. Recent scientific cohort studies on life prolongation with ginseng consumption support this record, as those who consumed ginseng for more than 5 years had reduced mortality and cognitive decline compared to those who did not. Clinical studies have also shown that acute or long-term intake of ginseng total extract improves acute working memory performance or cognitive function in healthy individuals and those with subjective memory impairment (SMI), mild cognitive impairment (MCI), or early Alzheimer's disease (AD) dementia who are taking AD medication(s). Ginseng contains various components ranging from classical ginsenosides and polysaccharides to more recently described gintonin. However, it is unclear which ginseng component(s) might be the main candidate that contribute to memory or cognitive improvements or prevent cognitive decline in older individuals. This review describes recent clinical contributors to ginseng components in clinical tests and introduces emerging evidence that ginseng components could be novel candidates for cognitive improvement in older individuals, as ginseng components improve SMI cognition and exhibits add-on effects when co-administered with early AD dementia drugs. The mechanism behind the beneficial effects of ginseng components and how it improves cognition are presented. Additionally, this review shows how ginseng components can contribute to SMI, MCI, or early AD dementia when used as a supplementary food and/or medicine, and proposes a novel combination therapy of current AD medicines with ginseng component(s).

Atypical formations of gintonin lysophosphatidic acids as new materials and their beneficial effects on degenerative diseases

Fresh ginseng is prone to spoilage due to its high moisture content. For long-term storage, most fresh ginsengs are dried to white ginseng (WG) or steamed for hours at high temperature/pressure and dried to form Korean Red ginseng (KRG). They are further processed for ginseng products when subjected to hot water extraction/concentration under pressure. These WG or KRG preparation processes affect ginsenoside compositions and also other ginseng components, probably during treatments like steaming and drying, to form diverse bioactive phospholipids. It is known that ginseng contains high amounts of gintonin lysophosphatidic acids (LPAs). LPAs are simple lipid-derived growth factors in animals and humans and act as exogenous ligands of six GTP-binding-protein coupled LPA receptor subtypes. LPAs play diverse roles ranging from brain development to hair growth in animals and humans. LPA-mediated signaling pathways involve various GTP-binding proteins to regulate downstream pathways like [Ca2+]i transient induction. Recent studies have shown that gintonin exhibits anti-Alzheimer's disease and anti-arthritis effects in vitro and in vivo mediated by gintonin LPAs, the active ingredients of gintonin, a ginseng-derived neurotrophin. However, little is known about how gintonin LPAs are formed in high amounts in ginseng compared to other herbs. This review introduces atypical or non-enzymatic pathways under the conversion of ginseng phospholipids into gintonin LPAs during steaming and extraction/concentration processes, which exert beneficial effects against degenerative diseases, including Alzheimer's disease and arthritis in animals and humans via LPA receptors.

Active Compounds of Panax ginseng in the Improvement of Alzheimer's Disease and Application of Spatial Metabolomics

Panax ginseng C.A. Meyer (P. ginseng) is one of the more common traditional Chinese medicines (TCMs). It contains numerous chemical components and exhibits a range of pharmacological effects. An enormous burden is placed on people's health and life by Alzheimer's disease (AD), a neurodegenerative condition. Recent research has shown that P. ginseng's chemical constituents, particularly ginsenosides, have a significant beneficial impact on the prevention and management of neurological disorders. To understand the current status of research on P. ginseng to improve AD, this paper discusses the composition of P. ginseng, its mechanism of action, and its clinical application. The pathogenesis of AD includes amyloid beta protein (Aβ) generation and aggregation, tau protein hyperphosphorylation, oxidant stress, neuroinflammation, mitochondrial damage, and neurotransmitter and gut microbiota disorders. This review presents the key molecular mechanisms and signaling pathways of the active ingredients in P. ginseng involved in improving AD from the perspective of AD pathogenesis. A P. ginseng-related signaling pathway network was constructed to provide effective targets for the treatment of AD. In addition, the application of spatial metabolomics techniques in studying P. ginseng and AD is discussed. In summary, this paper discusses research perspectives for the study of P. ginseng in the treatment of AD, including a systematic and in-depth review of the mechanisms of action of the active substances in P. ginseng, and evaluates the feasibility of applying spatial metabolomics in the study of AD pathogenesis and pharmacological treatment.

Cognitive function improvement effects of gintonin-enriched fraction in subjective memory impairment: An assessor- and participant-blinded placebo-controlled study

Background

Gintonin is a new material of ginseng that acts through the ginseng-derived lysophosphatidic acid (LPA) receptor ligand. The gintonin-enriched fraction (GEF) inhibits amyloid plaque accumulation in the cortex and hippocampus, improves cognitive dysfunction by increasing acetylcholine levels, and promoted hippocampal neurogenesis in an animal model of Alzheimer's disease. We evaluated the effect of the GEF on the cognitive performance of subjects with subjective memory impairment (SMI).

Methods

In this eight-week, randomized, assessor- and participant-blinded, placebo-controlled study, participants with SMI were assigned to three groups receiving placebo, GEF 300 mg/day or GEF 600 mg/day. The Korean versions of the Alzheimer's Disease Assessment Scale (K-ADAS), Mini-Mental State Examination (K-MMSE), and Stroop color-word test (K-SCWT) were also evaluated along with the safety profiles.

Results

One hundred thirty-six participants completed the study. After eight weeks, we analyzed intergroup differences in primary or secondary outcome score changes. When we compared the GEF group with the placebo group, we observed significant improvements in the K-ADAS and K-SCWT scores. The GEF group did not show a significant improvement in K-MMSE and BDI scores compared to the placebo group. No adverse events were observed in the gintonin and placebo groups for eight weeks.

Conclusion

The GEF is safe and effective in improving subjective cognitive impairment related to both the K-ADAS and K-SCWT in this study. However, further large-scale and randomized controlled studies are warranted to secure other cognitive function tests besides the K-ADAS and K-SCWT, and to confirm the findings of the current study.

Neurohormetic phytochemicals in the pathogenesis of neurodegenerative diseases

The world population is progressively ageing, assuming an enormous social and health challenge. As the world ages, neurodegenerative diseases are on the rise. Regarding the progressive nature of these diseases, none of the neurodegenerative diseases are curable at date, and the existing treatments can only help relieve the symptoms or slow the progression. Recently, hormesis has increased attention in the treatment of age-related neurodegenerative diseases. The concept of hormesis refers to a biphasic dose-response phenomenon, where low levels of the drug or stress exert protective of beneficial effects and high doses deleterious or toxic effects. Neurohormesis, as the adaptive aspect of hormetic dose responses in neurons, has been shown to slow the onset of neurodegenerative diseases and reduce the damages caused by aging, stroke, and traumatic brain injury. Hormesis was also observed to modulate anxiety, stress, pain, and the severity of seizure. Thus, neurohormesis can be considered as a potentially innovative approach in the treatment of neurodegenerative and other neurologic disorders. Herbal medicinal products and supplements are often considered health resources with many applications. The hormesis phenomenon in medicinal plants is valuable and several studies have shown that hormetic mechanisms of bioactive compounds can prevent or ameliorate the neurodegenerative pathogenesis in animal models of Alzheimer’s and Parkinson’s diseases. Moreover, the hormesis activity of phytochemicals has been evaluated in other neurological disorders such as Autism and Huntington’s disease. In this review, the neurohormetic dose–response concept and the possible underlying neuroprotection mechanisms are discussed. Different neurohormetic phytochemicals used for the better management of neurodegenerative diseases, the rationale for using them, and the key findings of their studies are also reviewed.

Pharmacological sequestration of mitochondrial calcium uptake protects against dementia and β-amyloid neurotoxicity

All forms of dementia including Alzheimer's disease are currently incurable. Mitochondrial dysfunction and calcium alterations are shown to be involved in the mechanism of neurodegeneration in Alzheimer's disease. Previously we have described the ability of compound Tg-2112x to protect neurons via sequestration of mitochondrial calcium uptake and we suggest that it can also be protective against neurodegeneration and development of dementia. Using primary co-culture neurons and astrocytes we studied the effect of Tg-2112x and its derivative Tg-2113x on β-amyloid-induced changes in calcium signal, mitochondrial membrane potential, mitochondrial calcium, and cell death. We have found that both compounds had no effect on β-amyloid or acetylcholine-induced calcium changes in the cytosol although Tg2113x, but not Tg2112x reduced glutamate-induced calcium signal. Both compounds were able to reduce mitochondrial calcium uptake and protected cells against β-amyloid-induced mitochondrial depolarization and cell death. Behavioral effects of Tg-2113x on learning and memory in fear conditioning were also studied in 3 mouse models of neurodegeneration: aged (16-month-old) C57Bl/6j mice, scopolamine-induced amnesia (3-month-old mice), and 9-month-old 5xFAD mice. It was found that Tg-2113x prevented age-, scopolamine- and cerebral amyloidosis-induced decrease in fear conditioning. In addition, Tg-2113x restored fear extinction of aged mice. Thus, reduction of the mitochondrial calcium uptake protects neurons and astrocytes against β-amyloid-induced cell death and contributes to protection against dementia of different ethology. These compounds could be used as background for the developing of a novel generation of disease-modifying neuroprotective agents.

Protective Effect of Ginsenosides from Stems and Leaves of Panax ginseng against Scopolamine-Induced Memory Damage via Multiple Molecular Mechanisms

Although growing evidence has shown that ginsenosides from stems and leaves of Panax ginseng (GSLS) exercise a protective impact on the central nervous system, in the model of memory damage induced by scopolamine, it is still rarely reported. Thus, the mechanism of action needs to be further explored. This study was to investigate the effect of GSLS on scopolamine (SCOP)-induced memory damage and the underlying mechanism. Male ICR mice were treated with SCOP (3 mg/kg) for 7 days, with or without GSLS (75 and 150 mg/kg) treatment for 14 days. After GSLS treatment, the memory damage induced by SCOP was significantly ameliorated as shown by the improvement of cholinergic function (AChE and ChAT), brain tissue hippocampus morphology (H&E staining), and oxidative stress (MDA, GSH, and NO). Meanwhile, immunohistochemical assay suggested that GSLS increased the expression of brain-derived neurotrophic factor (BDNF) and Tyrosine Kinase receptor B (TrkB). Further mechanism research indicated that GSLS inhibited the Tau hyperphosphorylation and cell apoptosis by regulating the PI3K/AKT pathway and inhibited neuroinflammation by regulating the NF-κB pathway, thereby exerting a cognitive impairment improvement effect. This work suggested that GSLS could protect against SCOP-induced memory defects possibly through inhibiting oxidative stress, inhibiting neuroinflammation and cell apoptosis.

Effects of Gintonin-enriched fraction on the gene expression of six lysophosphatidic receptor subtypes

Background

Gintonin, isolated from ginseng, acts as a ginseng-derived lysophosphatidic acid (LPA) receptor ligand and elicits the [Ca²⁺]_i transient through six LPA receptor subtypes (LPARSs). However, the long-term effects of gintonin-enriched fraction (GEF) on the gene expression of six LPARSs remain unknown. We examined changes in the gene expression of six LPA receptors in the mouse whole brain, heart, lungs, liver, kidneys, spleen, small intestine, colon, and testis after long-term oral GEF administration.

Methods

C57BL/6 mice were divided into two groups: control vehicle and GEF (100 mg/kg, p.o.). After 21-day saline or GEF treatment, total RNA was extracted from nine mouse organs. Quantitative-real-time PCR (qRT-PCR) and western blot were performed to quantify changes in the gene and protein expression of the six LPARSs, respectively.

Results

qRT-PCR analysis before GEF treatment revealed that the LPA6 RS was predominant in all organs except the small intestine. The LPA2 RS was most abundant in the small intestine. Long-term GEF administration differentially regulated the six LPARSs. Upon GEF treatment, the LPA6 RS significantly increased in the liver, small intestine, colon, and testis but decreased in the whole brain, heart, lungs, and kidneys. Western blot analysis of the LPA6 RS confirmed the differential effects of GEF on LPA6 receptor protein levels in the whole brain, liver, small intestine, and testis.

Conclusion

The LPA6 receptor was predominantly expressed in all nine organs examined; long-term oral GEF administration differentially regulated LPA3, LPA4, and LPA6 receptors in the whole brain, heart, lungs, liver, kidneys, small intestine, and testis.

Amelioration of muscle wasting by gintonin in cancer cachexia

Cancer cachexia is characterized by systemic inflammation, protein degradation, and loss of skeletal muscle. Despite extensive efforts to develop therapeutics, only few effective treatments are available to protect against cancer cachexia. Here, we found that gintonin (GT), a ginseng-derived lysophosphatidic acid receptor (LPAR) ligand, protected C2C12 myotubes from tumor necrosis factor α (TNFα)/interferon γ (IFNγ)- induced muscle wasting condition. The activity of GT was found to be dependent on LPAR/Gαi2, as the LPAR antagonist Ki16425 and Gαi2 siRNA abolished the anti-atrophic effects of GT on myotubes. GT suppressed TNFα-induced oxidative stress by reducing reactive oxygen species and suppressing inflammation-related genes, such as interleukin 6 (IL-6) and NADPH oxidase 2 (NOX-2). In addition, GT exhibited anti-atrophy effects in primary normal human skeletal myoblasts. Further, GT protected against Lewis lung carcinoma cell line (LLC1)-induced cancer cachexia in a mouse model. Specifically, GT rescued the lower levels of grip strength, hanging, and cross-sectional area caused by LLC1. Collectively, our findings suggest that GT may be a good therapeutic candidate for protecting against cancer cachexia.

Effect of the Gintonin-Enriched Fraction on Glucagon-Like-Protein-1 Release

Ginseng-derived gintonin reportedly contains functional lysophosphatidic acids (LPAs) as LPA receptor ligands. The effect of the gintonin-enriched fraction (GEF) on in vitro and in vivo glucagon-like protein-1 (GLP-1) secretion, which is known to stimulate insulin secretion, via LPA receptor(s) remains unclear. Accordingly, we examined the effects of GEF on GLP-1 secretion using human enteroendocrine NCI-H716 cells. The expression of several of LPA receptor subtypes in NCI-H716 cells using qPCR and Western blotting was examined. LPA receptor subtype expression was in the following order: LPA6 > LPA2 > LPA4 > LPA5 > LPA1 (qPCR), and LPA6 > LPA4 > LPA2 > LPA1 > LPA3 > LPA5 (Western blotting). GEF-stimulated GLP-1 secretion occurred in a dose- and time-dependent manner, which was suppressed by cAMP-Rp, a cAMP antagonist, but not by U73122, a phospholipase C inhibitor. Furthermore, silencing the human LPA6 receptor attenuated GEF-mediated GLP-1 secretion. In mice, low-dose GEF (50 mg/kg, peroral) increased serum GLP-1 levels; this effect was not blocked by Ki16425 co-treatment. Our findings indicate that GEF-induced GLP-1 secretion could be achieved via LPA6 receptor activation through the cAMP pathway. Hence, GEF-induced GLP secretion via LPA6 receptor regulation might be responsible for its beneficial effects on human endocrine physiology.

Safety and efficacy of dietary supplement (gintonin-enriched fraction from ginseng) in subjective memory impairment: A randomized placebo-controlled trial

Background

Gintonin inhibits β-amyloid production, increases acetylcholine level in the brain, and promotes neurogenesis. We evaluated the efficacy of gintonin-enriched fraction (GEF) in improving the cognitive performance in subjective memory impairment.

Methods

In this 8-week, randomized, assessor and participant blinded, placebo–controlled study, participants with subjective memory impairment but preserved cognitive function (Korean Mini-Mental State Examination [K-MMSE] score ≥23) were assigned to GEF 300mg/day or placebo. K-MMSE, Korean versions of the Alzheimer's disease assessment scale, color-word stroop test (K-CWST), clinical dementia rating, and Beck depression inventory-II were evaluated along with the safety profiles. The primary outcome was set as the change in the K-MMSE.

Results

Seventy-six participants complete the study protocol. After 8 weeks, there was no inter-group difference in the primary or secondary outcome score changes. However, GEF group showed an improvement in the K-MMSE scores (P= 0.026), and in the number of correct answers in both word reading (P= 0.008) and color reading (P= 0.005) of K-CWST, although only the improvement in the K-CWST scores were higher than the minimum clinically important difference. The frequency of adverse events was comparable between the groups and all were of mild severity.

Conclusion

GEF is safe but might not be effective in treating subjective memory impairment within the current study setting. However, GEF showed a trend of improving the global cognition and the frontal executive function. Further large-sized studies with longer follow-up period are warranted.

Clinical trial registration

This clinical trial was registered at Clinical Research Information Service of Korea Centers for Disease Control and Prevention: KCT0004636.

Neuroprotective Potentials of Panax Ginseng Against Alzheimer's Disease: A Review of Preclinical and Clinical Evidences

Alzheimer's disease (AD), a neurodegenerative disorder, is a major health concern in the increasingly aged population worldwide. Currently, no clinically effective drug can halt the progression of AD. Panax ginseng C.A. Mey. is a well-known medicinal plant that contains ginsenosides, gintonin, and other components and has neuroprotective effects against a series of pathological cascades in AD, including beta-amyloid formation, neuroinflammation, oxidative stress, and mitochondrial dysfunction. In this review, we summarize the effects and mechanisms of these major components and formulas containing P. ginseng in neuronal cells and animal models. Moreover, clinical findings regarding the prevention and treatment of AD with P. ginseng or its formulas are discussed. This review can provide new insights into the possible use of ginseng in the prevention and treatment of AD.

Oral Administration of Gintonin Protects the Brains of Mice against Aβ-Induced Alzheimer Disease Pathology: Antioxidant and Anti-Inflammatory Effects

The study was aimed at analyzing the protective effects of gintonin in an amyloid beta- (Aβ-) induced Alzheimer's disease (AD) mouse model. For the development of the Aβ-induced AD mouse model, the amyloid-β (Aβ 1-42) peptide was stereotaxically injected into the brains of mice. Subsequently, gintonin was administered at a dose of 100 mg/kg/day/per oral (p.o) for four weeks daily, and its effects were evaluated by using western blotting, fluorescence analysis of brain sections, biochemical tests, and memory-related behavioral evaluations. To elucidate the effects of gintonin at the mechanistic level, the activation of endogenous antioxidant mechanisms, as well as the activation of astrocytes, microglia, and proinflammatory mediators such as nuclear factor erythroid 2-related factor 2 (NRF-2) and heme oxygenase-1 (HO-1), was evaluated. In addition, microglial cells (BV-2 cells) were used to analyze the effects of gintonin on microglial activation and signaling mechanisms. Collectively, the results suggested that gintonin reduced elevated oxidative stress by improving the expression of NRF-2 and HO-1 and thereby reducing the generation of reactive oxygen species (ROS) and lipid peroxidation (LPO). Moreover, gintonin significantly suppressed activated microglial cells and inflammatory mediators in the brains of Aβ-injected mice. Our findings also indicated improved synaptic and memory functions in the brains of Aβ-injected mice after treatment with gintonin. These results suggest that gintonin may be effective for relieving AD symptoms by regulating oxidative stress and inflammatory processes in a mouse model of AD. Collectively, the findings of this preclinical study highlight and endorse the potential, multitargeted protective effects of gintonin against AD-associated oxidative damage, neuroinflammation, cognitive impairment, and neurodegeneration.

Cognitive improvement effect of gintonin might be associated with blood-brain barrier permeability enhancement: dynamic contrast-enhanced MRI pilot study

Along with the multiple neuroprotective effect, recent studies suggest that gintonin might increase the blood brain barrier permeability. We evaluated the effect of gintonin on the vascular permeability changes in different brain segments, using dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI). In this 8-week, randomized, open label pilot study, ten participants with subjective memory impairment but preserved cognitive function assigned to gintonin-enriched fraction (GEF) 300 mg/day or placebo groups. Korean versions of the Alzheimer's disease assessment scale (ADAS-K) and DCE-MRI parameters including Ktrans and Vp in different brain segments were evaluated at baseline and at 8 weeks after treatment. Nine participants completed the study protocol. No adverse events occurred during the observation period for 8 weeks in both groups. Following gintonin administration, increment trends of the brain permeability that did not reach a statistical significance were observed in the left hippocampus (Ktrans and Vp, both, p = 0.062), left thalamus and in left putamen (Ktrans, p = 0.062), and left insula and right amygdala (Vp, p = 0.062), but not in the control placebo group. The increment of the Ktrans value in the left thalamus from the baseline was highly correlated with the change of the ADAS scores (r = -0.900, p = 0.037). Gintonin might enhance the blood-brain barrier (BBB) permeability in the brain structures involved in cognitive functions. Further efficacy exploration for the synergistic effect of gintonin's BBB permeability enhancement to its other cognitive enhancing mechanisms are warranted.

TRIAL REGISTRATION

Clinical Research Information Service Identifier: KCT0003418.

Ginseng gintonin attenuates the disruptions of brain microvascular permeability and microvascular endothelium junctional proteins in an APPswe/PSEN-1 double-transgenic mouse model of Αlzheimer's disease

It has been previously indicated that gintonin, which is a novel exogenous ginseng-derived lysophosphatidic acid (LPA) receptor ligand, restores memory dysfunctions in an APPswe/PSEN-1 double-transgenic mouse model of Alzheimer's disease (AD Tg mice) by attenuating β-amyloid plaque deposition, recovering cholinergic dysfunctions and upregulating hippocampal neurogenesis in the cortex and hippocampus. Although β-amyloid plaque depositions in AD is accompanied with disruptions of brain microvessels, including the brain-blood barrier (BBB), it is unknown whether gintonin exerts protective effects on brain microvascular dysfunctions in AD Tg mice. In the present study, the effects of gintonin-enriched fraction (GEF) on the changes in β-amyloid plaque depositions, brain permeability of Evans blue, and microvascular junctional proteins were investigated in AD Tg mice. Long-term oral administration of GEF reduced β-amyloid plaque depositions in the cortex and hippocampus of AD Tg mice. GEF treatment also reduced the permeability of Evans blue through BBB and decreased immunoreactivity of platelet endothelial cell adhesion molecule-1 (a marker of BBB disruption) in the cortex and hippocampus of AD Tg mice in a dose-dependent manner. However, GEF elevated the protein expression of occludin, claudin-5 and zonula occludens-1, which are tight-junction proteins. The present results demonstrated that long-term oral GEF treatment not only attenuates β-amyloid plaque depositions in the brain but also exhibits protective effects against microvascular disruptions in AD Tg mice. Finally, GEF exhibits anti-AD effects through attenuation of β-amyloid plaque depositions and protection against brain microvascular damage in an AD animal model.

An adenoviral vector encoded with the GPx-1 gene attenuates memory impairments induced by β-amyloid (1-42) in GPx-1 KO mice via activation of M1 mAChR-mediated signalling

In the present study, we examined whether glutathione peroxidase-1 (GPx-1), a major H₂O₂ scavenger in the brain, affects memory deficits induced by Aβ (1-42) in mice. Treatment with 400 pmol/5 μl Aβ (1-42) (i.c.v.) resulted in a reduction of GPx-1 expression in wild-type (WT) mice. An Aβ (1-42)-induced reduction in acetylcholine (ACh) level was observed in the hippocampus. Treatment with Aβ (1-42) consistently resulted in reduced expression and activity of choline acetyltransferase (ChAT) and in an increase in expression and activity of acetylcholinesterase (AChE). Upon examining each of the muscarinic acetylcholine receptors (mAChRs) and nicotinic AChRs, we noted that Aβ (1-42) treatment selectively reduced the levels of M1 mAChR. In addition, Aβ (1-42) induced a significant reduction in phospho-cAMP response element-binding protein (p-CREB) and brain-derived neurotrophic factor (BDNF) expression. The cholinergic impairments induced by Aβ (1-42) were more pronounced in GPx-1 knockout mice than in WT mice. Importantly, an adenoviral vector encoded with the GPx-1 gene (Ad-GPx-1) significantly rescued Aβ (1-42)-induced cholinergic impairments in GPx-1 knockout mice. In addition, M1 mAChR antagonist dicyclomine significantly counteracted Ad-GPx-1-mediated increases in p-CREB and BDNF expression, as well as memory-enhancing effects in GPx-1 knockout mice, thus indicating that M1 mAChR might be a critical mediator for the rescue effects of Ad-GPx-1. Combined, our results suggest that GPx-1 gene protected against Aβ (1-42)-induced memory impairments via activation of M1 mAChR-dependent CREB/BDNF signalling.

Inhibitory activity of gintonin on inflammation in human IL-1β-stimulated fibroblast-like synoviocytes and collagen-induced arthritis in mice

Background

Gintonin is a newly derived glycolipoprotein from the roots of ginseng. The purpose of this study is to investigate the anti-arthritic efficacy of Gintonin on various proteases and inflammatory mediators that have an important role in arthritis.

Methods

Fibroblast-like synoviocytes (FLS) were treated with Gintonin and stimulated with interleukin (IL)-1β 1 hour later. The antioxidant effect of Gintonin was measured using MitoSOX and H₂DCFDA experiments. The anti-arthritic efficacy of Gintonin was examined by analyzing the expression levels of inflammatory mediators using RT-PCR, western blot, and ELISA. The phosphorylation of mitogen-activated protein kinase (MAPK) pathways and translocation of nuclear factor kappa B (NF-κB)/p65 into the nucleus were also analyzed using western blot, ELISA, and immunocytochemistry. Collagen-induced arthritis (CIA) mice model was used. Mice were orally administered with Gintonin (25, 50, and 100 mg/kg) every 2 days for 45 days. The body weight, arthritis score, squeaking score, and paw volume were measured as the behavioral parameters. After sacrifice, H&E and safranin-O staining were performed for histological analysis.

Results

Gintonin significantly inhibited the expression of inflammatory intermediates. Gintonin prevented NF-κB/p65 from moving into the nucleus through the JNK and ERK MAPK phosphorylation in FLS cells. Moreover, Gintonin suppressed the symptoms of arthritis in the CIA mice model.

Conclusion

As a result, the antioxidant and anti-inflammatory effects of Gintonin were demonstrated, and ultimately the anti-arthritic effect was proved. Collectively, Gintonin has a great potential as a therapeutic agent for arthritis treatment.

Glutathione Peroxidase-1 Knockout Facilitates Memory Impairment Induced by β-Amyloid (1-42) in Mice via Inhibition of PKC βII-Mediated ERK Signaling; Application with Glutathione Peroxidase-1 Gene-Encoded Adenovirus Vector

A growing body evidence suggests that selenium (Se) deficiency is associated with an increased risk of developing Alzheimer's disease (AD). Se-dependent glutathione peroxidase-1 (GPx-1) of a major antioxidant enzyme, and the most abundant isoform of GPx in the brain. In the present study, we investigated whether GPx-1 is protective against memory impairments induced by beta-amyloid (Aβ) (1-42) in mice. As the alteration of protein kinase C (PKC)-mediated ERK activation was recognized in the early stage of AD, we examined whether the GPx-1 gene modulates Aβ (1-42)-induced changes in PKC and ERK levels. We observed that Aβ (1-42) treatment (400 pmol, i.c.v.) significantly decreased PKC βII expression in the hippocampus of mice. Aβ (1-42)-induced neurotoxic changes [i.e., oxidative stress (i.e., reactive oxygen species, 4-hydroxy-2-noneal, and protein carbonyl), reduced PKC βII and phospho-ERK expressions, and memory impairment under Y-maze and passive avoidance test] were more pronounced in GPx-1 knockout than in wild type mice. Importantly, exposure to a GPx-1 gene-encoded adenovirus vector (Adv-GPx-1) significantly increased GPx-1 mRNA and GPx activity in the hippocampus of GPx-1 knockout mice. Adv-GPx-1 exposure also significantly blocked the neurotoxic changes induced by Aβ (1-42) in GPx-1 knockout mice. Treatment with ERK inhibitor U0126 did not significantly change Adv-GPx-1-mediated attenuation in PKC βII expression. In contrast, treatment with PKC inhibitor chelerythrine (CHE) reversed Adv-GPx-1-mediated attenuation in ERK phosphorylation, suggesting that PKC βII-mediated ERK signaling is important for Adv-GPx-1-mediated potentials against Aβ (1-42) insult. Our results suggest that treatment with the antioxidant gene GPx-1 rescues Aβ (1-42)-induced memory impairment via activating PKC βII-mediated ERK signaling.

Biological evidence of gintonin efficacy in memory disorders

Gintonin is a novel glycolipoprotein, which has been abundantly found in the root of Korean ginseng. It holds lysophosphatidic acids (LPAs), primarily identified LPA C18:2, and is an exogenous agonist of LPA receptors (LPARs). Gintonin maintains blood-brain barrier integrity, and it has recently been studied in several models of neurodegenerative diseases (NDDs) such as Alzheimer's disease (AD), Parkinson's disease, Huntington's disease and amyotrophic lateral sclerosis. Gintonin demonstrated neuroprotective activity by providing action against neuroinflammation-, apoptosis- and oxidative stress-mediated neurodegeneration. Gintonin showed an emerging role as a modulator of synaptic transmission and neurogenesis and also potentially regulated autophagy in primary cortical astrocytes. It also ameliorated the toxic agent-induced and genetic models of cognitive deficits in experimental NDDs. As a novel agonist of LPARs, gintonin regulated several G protein-coupled receptors (GPCRs) including GPR40 and GPR55. However, further study needs to be investigated to understand the underlying mechanism of action of gintonin in memory disorders.

The Gintonin-Enriched Fraction of Ginseng Regulates Lipid Metabolism and Browning via the cAMP-Protein Kinase a Signaling Pathway in Mice White Adipocytes

Obesity is a major health concern and is becoming an increasingly serious societal problem worldwide. The browning of white adipocytes has received considerable attention because of its potential protective effect against obesity-related metabolic disease. The gintonin-enriched fraction (GEF) is a non-saponin, glycolipoprotein component of ginseng that is known to have neuroprotective and anti-inflammatory effects. However, the anti-obesity and browning effects of GEF have not been explored to date. Therefore, we aimed to determine whether GEF has a preventive effect against obesity. We differentiated 3T3-L1 cells and mouse primary subcutaneous adipocytes for 8 days in the presence or absence of GEF, and then measured the expression of intermediates in signaling pathways that regulate triglyceride (TG) synthesis and browning by Western blotting and immunofluorescence analysis. We found that GEF reduced lipid accumulation by reducing the expression of pro-adipogenic and lipogenic factors, and increased lipolysis and thermogenesis, which may be mediated by an increase in the phosphorylation of protein kinase A. These findings suggest that GEF may induce fat metabolism and energy expenditure in white adipocytes and therefore may represent a potential treatment for obesity.

Effects of gintonin-enriched fraction on hippocampal gene expressions

Background

Recently, gintonin and gintonin-enriched fraction (GEF) have been isolated from ginseng, a herbal medicine. Gintonin induces [Ca²⁺]_i transition in cultured hippocampal neurons and stimulates acetylcholine release through LPA receptor activation. Oral administration of GEF is linked to hippocampus-dependent cognitive enhancement and other neuroprotective effects; however, effects of its long-term administration on hippocampal gene expression remains unknown. Here, we used next-generation sequence (NGS) analysis to examine changes in hippocampal gene expressions after long-term oral administration of GEF.

Methods

C57BL/6 mice were divided into three groups: control group, GEF50 (GEF 50 mg/kg, p.o.), and GEF100 (GEF 100 mg/kg, p.o.). After 22 days, total RNA was extracted from mouse hippocampal tissues. NGS was used for gene expression profiling; quantitative-real-time PCR and western blot were performed to quantify the changes in specific genes and to confirm the protein expression levels in treatment groups.

Results

NGS analysis screened a total of 23,282 genes, analyzing 11-related categories. We focused on the neurogenesis category, which includes four genes for candidate markers: choline acetyltransferase (ChAT) gene, β₃-adrenergic receptor (Adrb3) gene, and corticotrophin-releasing hormone (Crh) gene, and tryptophan 2,3-dioxygenase (Tdo2) gene. Real-time PCR showed a marked overexpression of ChAT, Adrb3, and Crh genes, while reduced expression of Tdo2. Western blot analysis also confirmed increased ChAT and decreased Tdo2 protein levels.

Conclusion

We found that GEF affects mouse hippocampal gene expressions, associated with memory, cognitive, anti-stress and anti-anxiety functions, and neurodegeneration at differential degree, that might explain the genetic bases of GEF-mediated neuroprotective effects.

Ongoing Research on the Role of Gintonin in the Management of Neurodegenerative Disorders

Neurodegenerative disorders, namely Parkinson’s disease (PD), Huntington’s disease (HD), Alzheimer’s disease (AD), and multiple sclerosis (MS), are increasingly major health concerns due to the increasingly aged population worldwide. These conditions often share the same underlying pathological mechanisms, including elevated oxidative stress, neuroinflammation, and the aggregation of proteins. Several studies have highlighted the potential to diminish the clinical outcomes of these disorders via the administration of herbal compounds, among which gintonin, a derivative of ginseng, has shown promising results. Gintonin is a noncarbohydrate/saponin that has been characterized as a lysophosphatidic acid receptor (LPA Receptor) ligand. Gintonin may cause a significant elevation in calcium levels [Ca2+]i intracellularly, which promotes calcium-mediated cellular effects via the modulation of ion channels and cell surface receptors, regulating the inflammatory effects. Years of research have suggested that gintonin has antioxidant and anti-inflammatory effects against different models of neurodegeneration, and these effects may be employed to tackle the neurological changes. Therefore, we collected the main scientific findings and comprehensively presented them, covering preparation, absorption, and receptor-mediated functions, including effects against Alzheimer’s disease models, Parkinson’s disease models, anxiety and depression-like models, and other neurological disorders, aiming to provide some insights for the possible usage of gintonin in the management of neurodegenerative conditions.

Ginseng gintonin, aging societies, and geriatric brain diseases

Background

A dramatic increase in aging populations and low birth rates rapidly drive aging societies and increase aging-associated neurodegenerative diseases. However, functional food or medicinal formulations to prevent geriatric brain disorders are not readily available. Panax ginseng is a candidate, since ginseng has long-been consumed as a rejuvenating agent. However, the underlying molecular mechanisms and the components of ginseng that are responsible for brain rejuvenation and human longevity are unknown. Accumulating evidence shows that gintonin is a candidate for the anti-aging ingredient of ginseng, especially in brain senescence.

Methods

Gintonin, a glycolipoprotein complex, contains three lipid-derived G protein-coupled receptor ligands: lysophosphatidic acids (LPAs), lysophosphatidylinositols (LPIs), and linoleic acid (LA). LPA, LPI, and LA act on six LPA receptor subtypes, GPR55, and GPR40, respectively. These G protein-coupled receptors are distributed within the nervous and non-nervous systems of the human body.

Results

Gintonin-enriched fraction (GEF) exhibits anti-brain senescence and effects against disorders such as Alzheimer's disease (AD), Huntington's disease (HD), and Parkinson's disease (PD). Oral administration of gintonin in animal models of d-galactose-induced brain aging, AD, HD, and PD restored cognitive and motor functions. The underlying molecular mechanisms of gintonin-mediated anti-brain aging and anti-neurodegenerative diseases include neurogenesis, autophagy stimulation, anti-apoptosis, anti-oxidative stress, and anti-inflammatory activities. This review describes the characteristics of gintonin and GEF, and how gintonin exerts its effects on brain aging and brain associated-neurodegenerative diseases.

Conclusion

Finally, we describe how GEF can be applied to improve the quality of life of senior citizens in aging societies.

Hormesis and Ginseng: Ginseng Mixtures and Individual Constituents Commonly Display Hormesis Dose Responses, Especially for Neuroprotective Effects

This paper demonstrates that ginseng mixtures and individual ginseng chemical constituents commonly induce hormetic dose responses in numerous biological models for endpoints of biomedical and clinical relevance, typically providing a mechanistic framework. The principal focus of ginseng hormesis-related research has been directed toward enhancing neuroprotection against conditions such as Alzheimer's and Parkinson's Diseases, stroke damage, as well as enhancing spinal cord and peripheral neuronal damage repair and reducing pain. Ginseng was also shown to reduce symptoms of diabetes, prevent cardiovascular system damage, protect the kidney from toxicities due to immune suppressant drugs, and prevent corneal damage, amongst other examples. These findings complement similar hormetic-based chemoprotective reports for other widely used dietary-type supplements such as curcumin, ginkgo biloba, and green tea. These findings, which provide further support for the generality of the hormetic dose response in the biomedical literature, have potentially important public health and clinical implications.

Neuroprotective Effects of Apocynin and Galantamine During the Chronic Administration of Scopolamine in an Alzheimer's Disease Model

Alzheimer's disease (AD) is one of the most complicated neurodegenerative diseases, and several hypotheses have been associated with its development and progression, such as those involving glucose hypometabolism, the cholinergic system, calcium imbalance, inflammation, oxidative imbalance, microtubule instability, and the amyloid cascade, several of which are related to oxidative stress (free radical generation), which contributes to neuronal death. Therefore, several efforts have been made to establish a sporadic AD model that takes into account these hypotheses. One model that replicates the increase in amyloid beta (Aβ) and oxidative stress in vivo is the scopolamine model. In the present work, the chronic administration (6 weeks) of scopolamine was used to analyze the neuroprotective effects of apocynin and galantamine. The results showed that scopolamine induced cognitive impairment, which was evaluated 24 h after the final dose was administered. In addition, after scopolamine administration, the Aβ and superoxide anion levels were increased, and NADPH oxidase 2 (NOX2), nuclear factor erythroid 2-related factor 2 (Nrf2), and nuclear factor kappa B (NFkB) genes were overexpressed. These effects were not observed when either apocynin or galantamine was administered during the last 3 weeks of scopolamine treatment, and although the results from both molecules were related to lower Aβ production and, consequently, lower superoxide anion production, they were likely realized through different pathways. That is, both apocynin and galantamine diminished NADPH oxidase expression, but their effects on transcription factor expression differed. Moreover, experiments in silico showed that galantamine did not interact with the active site of beta secretase, whereas diapocynin, an apocynin metabolite, interacted with the beta-site APP-cleaving enzyme (BACE1) at the catalytic site.

Gintonin Mitigates MPTP-Induced Loss of Nigrostriatal Dopaminergic Neurons and Accumulation of α-Synuclein via the Nrf2/HO-1 Pathway

Gintonin, a ginseng-derived glycolipoprotein isolated from ginseng, has been shown to be neuroprotective in several neurological disorders such as Alzheimer's disease models and depressive-like behaviors. In this study, we sought to investigate the potential protective mechanisms of gintonin in an in vivo MPTP and in vitro MPP+-mediated Parkinson's disease (PD) model. We hypothesized that activation of nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1, potential therapeutic targets for neurodegeneration) with gintonin could abrogate PD-associated neurotoxicity by modulating the accumulation of α-synuclein, neuroinflammation, and apoptotic cell death in an MPTP/MPP+ models of PD. Our in vivo and in vitro findings suggest that the neuroprotective effects of gintonin were associated with the regulation of the Nrf2/HO-1 pathway, which regulated the expression of proinflammatory cytokines and nitric oxide synthase and apoptotic markers in the substantia nigra and striatum of the mice. Moreover, the neuroprotective effects of gintonin were also associated with a reduction in α-synuclein accumulation in the mouse substantia nigra and striatum. The neuroprotective effects of gintonin were further validated by analyzing the effects of gintonin on MPP+-treated SH-SY5Y cells, which confirmed the protective effects of gintonin. It remains for future basic and clinical research to determine the potential use of gintonin in Parkinson's disease. However, to the best of our knowledge, marked alterations in biochemical and morphological setup of midbrain dopaminergic pathways by gintonin in MPTP mice model have not been previously reported. We believe that gintonin might be explored as an important therapeutic agent in the treatment of PD.

Panax ginseng as an adjuvant treatment for Alzheimer's disease

Longevity in medicine can be defined as a long life without mental or physical deficits. This can be prevented by Alzheimer's disease (AD). Current conventional AD treatments only alleviate the symptoms without reversing AD progression. Recent studies demonstrated that Panax ginseng extract improves AD symptoms in patients with AD, and the two main components of ginseng might contribute to AD amelioration. Ginsenosides show various AD-related neuroprotective effects. Gintonin is a newly identified ginseng constituent that contains lysophosphatidic acids and attenuates AD-related brain neuropathies. Ginsenosides decrease amyloid β-protein (Aβ) formation by inhibiting β- and γ-secretase activity or by activating the nonamyloidogenic pathway, inhibit acetylcholinesterase activity and Aβ-induced neurotoxicity, and decrease Aβ-induced production of reactive oxygen species and neuroinflammatory reactions. Oral administration of ginsenosides increases the expression levels of enzymes involved in acetylcholine synthesis in the brain and alleviates Aβ-induced cholinergic deficits in AD models. Similarly, gintonin inhibits Aβ-induced neurotoxicity and activates the nonamyloidogenic pathway to reduce Aβ formation and to increase acetylcholine and choline acetyltransferase expression in the brain through lysophosphatidic acid receptors. Oral administration of gintonin attenuates brain amyloid plaque deposits, boosting hippocampal cholinergic systems and neurogenesis, thereby ameliorating learning and memory impairments. It also improves cognitive functions in patients with AD. Ginsenosides and gintonin attenuate AD-related neuropathology through multiple routes. This review focuses research demonstrating that ginseng constituents could be a candidate as an adjuvant for AD treatment. However, clinical investigations including efficacy and tolerability analyses may be necessary for the clinical acceptance of ginseng components in combination with conventional AD drugs.

Active ginseng components in cognitive impairment: Therapeutic potential and prospects for delivery and clinical study

Cognitive impairment is a state that affects thinking, communication, understanding, and memory, and is very common in various neurological disorders. Among many factors, age-related cognitive decline is an important area in mental health research. Research to find therapeutic medications or supplements to treat cognitive deficits and maintain cognitive health has been ongoing. Ginseng and its active components may have played a role in treating chronic disorders. Numerous preclinical studies have confirmed that ginseng and its active components such as ginsenosides, gintonin, and compound K are pharmacologically efficacious in different models of and are linked to cognitive impairment. Among their several roles, they act as an anti-neuroinflammatory and help fight against oxidative stress and modulate the cholinergic signal. These roles may be involved in enhancing cognition and attenuating impairment. There have been some clinical studies on the activity of ginseng in cognitive impairment, but many ginseng species and active compounds remain to be investigated. In addition, new formulations of active ginseng components such as nanoparticles and liposomes could be used for preclinical and clinical models of cognitive impairment. Here, we discuss the therapeutic potential of active ginseng components in cognitive impairment and their chemistry and pharmacokinetics and consider prospects for their delivery and clinical study with respect to cognitive impairment.

Gintonin stimulates autophagic flux in primary cortical astrocytes

Background

Gintonin (GT), a novel ginseng-derived exogenous ligand of lysophosphatidic acid (LPA) receptors, has been shown to induce cell proliferation and migration in the hippocampus, regulate calcium-dependent ion channels in the astrocytes, and reduce β-amyloid plaque in the brain. However, whether GT influences autophagy in cortical astrocytes is not yet investigated.

Methods

We examined the effect of GT on autophagy in primary cortical astrocytes using immunoblot and immunocytochemistry assays. Suppression of specific proteins was performed via siRNA. LC3 puncta was determined using confocal microscopy.

Results

GT strongly upregulated autophagy marker LC3 by a concentration- as well as time-dependent manner via G protein–coupled LPA receptors. GT-induced autophagy was further confirmed by the formation of LC3 puncta. Interestingly, on pretreatment with an mammalian target of rapamycin (mTOR) inhibitor, rapamycin, GT further enhanced LC3-II and LC3 puncta expression. However, GT-induced autophagy was significantly attenuated by inhibition of autophagy by 3-methyladenine and knockdown Beclin-1, Atg5, and Atg7 gene expression. Importantly, when pretreated with a lysosomotropic agent, E-64d/peps A or bafilomycin A1, GT significantly increased the levels of LC3-II along with the formation of LC3 puncta. In addition, GT treatment enhanced autophagic flux, which led to an increase in lysosome-associated membrane protein 1 and degradation of ubiquitinated p62/SQSTM1.

Conclusion

GT induces autophagy via mTOR-mediated pathway and elevates autophagic flux. This study demonstrates that GT can be used as an autophagy-inducing agent in cortical astrocytes.

Stress, Depression, Resilience and Ageing: A Role for the LPA-LPA1 Pathway

BACKGROUND

Chronic stress affects health and the quality of life, with its effects being particularly relevant in ageing due to the psychobiological characteristics of this population. However, while some people develop psychiatric disorders, especially depression, others seem very capable of dealing with adversity. There is no doubt that along with the identification of neurobiological mechanisms involved in developing depression, discovering which factors are involved in positive adaptation under circumstances of extreme difficulty will be crucial for promoting resilience.

METHODS

Here, we review recent work in our laboratory, using an animal model lacking the LPA1 receptor, together with pharmacological studies and clinical evidence for the possible participation of the LPA1 receptor in mood and resilience to stress.

RESULTS

Substantial evidence has shown that the LPA1 receptor is involved in emotional regulation and in coping responses to chronic stress, which, if dysfunctional, may induce vulnerability to stress and predisposition to the development of depression. Given that there is commonality of mechanisms between those involved in negative consequences of stress and in ageing, this is not surprising, considering that the LPA1 receptor may be involved in coping with adversity during ageing.

CONCLUSION

Alterations in this receptor may be a susceptibility factor for the presence of depression and cognitive deficits in the elderly population. However, because this is only a promising hypothesis based on previous data, future studies should focus on the involvement of the LPA-LPA1 pathway in coping with stress and resilience in ageing.

Systemic blockade of LPA1/3 lysophosphatidic acid receptors by ki16425 modulates the effects of ethanol on the brain and behavior

The systemic administration of lysophosphatidic acid (LPA) LPA_1/3 receptor antagonists is a promising clinical tool for cancer, sclerosis and fibrosis-related diseases. Since LPA₁ receptor-null mice engage in increased ethanol consumption, we evaluated the effects of systemic administration of an LPA_1/3 receptor antagonist (intraperitoneal ki16425, 20 mg/kg) on ethanol-related behaviors as well as on brain and plasma correlates. Acute administration of ki16425 reduced motivation for ethanol but not for saccharine in ethanol self-administering Wistar rats. Mouse experiments were conducted in two different strains. In Swiss mice, ki16425 treatment reduced both ethanol-induced sedation (loss of righting reflex, LORR) and ethanol reward (escalation in ethanol consumption and ethanol-induced conditioned place preference, CPP). Furthermore, in the CPP-trained Swiss mice, ki16425 prevented the effects of ethanol on basal c-Fos expression in the medial prefrontal cortex and on adult neurogenesis in the hippocampus. In the c57BL6/J mouse strain, however, no effects of ki16425 on LORR or voluntary drinking were observed. The c57BL6/J mouse strain was then evaluated for ethanol withdrawal symptoms, which were attenuated when ethanol was preceded by ki16425 administration. In these animals, ki16425 modulated the expression of glutamate-related genes in brain limbic regions after ethanol exposure; and peripheral LPA signaling was dysregulated by either ki16425 or ethanol. Overall, these results suggest that LPA_1/3 receptor antagonists might be a potential new class of drugs that are suitable for treating or preventing alcohol use disorders. A pharmacokinetic study revealed that systemic ki16425 showed poor brain penetration, suggesting the involvement of peripheral events to explain its effects.

Bioactive lipids in gintonin-enriched fraction from ginseng

Background

Ginseng is a traditional herbal medicine for human health. Ginseng contains a bioactive ligand named gintonin. The active ingredient of gintonin is lysophosphatidic acid C18:2 (LPA C18:2). We previously developed a method for gintonin-enriched fraction (GEF) preparation to mass-produce gintonin from ginseng. However, previous studies did not show the presence of other bioactive lipids besides LPAs. The aim of this study was to quantify the fatty acids, lysophospholipids (LPLs), and phospholipids (PLs) besides LPAs in GEF.

Methods

We prepared GEF from white ginseng. We used gas chromatography-mass spectrometry for fatty acid analysis and liquid chromatography-tandem mass spectrometry for PL analysis, and quantified the fatty acids, LPLs, and PLs in GEF using respective standards. We examined the effect of GEF on insulin secretion in INS-1 cells.

Results

GEF contains about 7.5% linoleic (C18:2), 2.8% palmitic (C16:0), and 1.5% oleic acids (C18:1). GEF contains about 0.2% LPA C18:2, 0.06% LPA C16:0, and 0.02% LPA C18:1. GEF contains 0.08% lysophosphatidylcholine, 0.03% lysophosphatidylethanolamine, and 0.13% lysophosphatidylinositols. GEF also contains about 1% phosphatidic acid (PA) 16:0-18:2, 0.5% PA 18:2-18:2, and 0.2% PA 16:0-18:1. GEF-mediated insulin secretion was not blocked by LPA receptor antagonist.

Conclusion

We determined four characteristics of GEF through lipid analysis and insulin secretion. First, GEF contains a large amount of linoleic acid (C18:2), PA 16:0-18:2, and LPA C18:2 compared with other lipids. Second, the main fatty acid component of LPLs and PLs is linoleic acid (C18:2). Third, GEF stimulates insulin secretion not through LPA receptors. Finally, GEF contains bioactive lipids besides LPAs.

DL0410 Ameliorates Memory and Cognitive Impairments Induced by Scopolamine via Increasing Cholinergic Neurotransmission in Mice

Deficiency of the cholinergic system is thought to play a vital role in cognitive impairment of dementia. DL0410 was discovered as a dual inhibitor of acetylcholinesterase (AChE) and butyrylcholinestease (BuChE), with potent efficiency in in-vitro experiments, but its in vivo effect on the cholinergic model has not been evaluated, and its action mechanism has also not been illustrated. In the present study, the capability of DL0410 in ameliorating the amnesia induced by scopolamine was investigated, and its effect on the cholinergic system in the hippocampus and its binding mode in the active site of AChE was also explored. Mice were administrated DL0410 (3 mg/kg, 10 mg/kg, and 30 mg/kg), and mice treated with donepezil were used as a positive control. The Morris water maze, escape learning task, and passive avoidance task were used as behavioral tests. The test results indicated that DL0410 could significantly improve the learning and memory impairments induced by scopolamine, with 10 mg/kg performing best. Further, DL0410 inhibited the AChE activity and increased acetylcholine (ACh) levels in a dose-dependent manner, and interacted with the active site of AChE in a similar manner as donepezil. However, no difference in the activity of BuChE was found in this study. All of the evidence indicated that its AChE inhibition is an important mechanism in the anti-amnesia effect. In conclusion, DL0410 could be an effective therapeutic drug for the treatment of dementia, especially Alzheimer’s disease.

Gintonin absorption in intestinal model systems

Background

Recently, we identified a novel ginseng-derived lysophosphatidic acid receptor ligand, called gintonin. We showed that gintonin induces [Ca²⁺]i transient-mediated morphological changes, proliferation, and migration in cells expressing lysophosphatidic acid receptors and that oral administration of gintonin exhibits anti-Alzheimer disease effects in model mice. However, little is known about the intestinal absorption of gintonin. The aim of this study was to investigate gintonin absorption using two model systems.

Methods

Gintonin membrane permeation was examined using a parallel artificial membrane permeation assay, and gintonin absorption was evaluated in a mouse everted intestinal sac model.

Results

The parallel artificial membrane permeation assay showed that gintonin could permeate an artificial membrane in a dose-dependent manner. In the everted sac model, gintonin absorption increased with incubation time (from 0 min to 60 min), followed by a decrease in absorption. Gintonin absorption into everted sacs was also dose dependent, with a nonlinear correlation between gintonin absorption and concentration at 0.1–3 mg/mL and saturation at 3–5 mg/mL. Gintonin absorption was inhibited by the Rho kinase inhibitor Y-27632 and the sodium–glucose transporter inhibitor phloridzin. Moreover, lipid extraction with methanol also attenuated gintonin absorption, suggesting the importance of the lipid portion of gintonin in absorption. This result shows that gintonin might be absorbed through passive diffusion, paracellular, and active transport pathways.

Conclusion

The present study shows that gintonin could be absorbed in the intestine through transcellular and paracellular diffusion, and active transport. In addition, the lipid component of gintonin might play a key role in its intestinal absorption.

Plant Lysophosphatidic Acids: A Rich Source for Bioactive Lysophosphatidic Acids and Their Pharmacological Applications

Lysophosphatidic acid (1-acyl-2-lyso-sn-glycero-3-phosphatidic acid; LPA) is a simple and minor phospholipid in plants. Plant LPAs are merely metabolic intermediates in de novo lipid synthesis in plant cell membranes or for glycerophospholipid storage. The production and metabolisms of LPAs in animals are also well characterized and LPAs have diverse cellular effects in animal systems; i.e., from brain development to wound healing through the activation of G protein-coupled LPA receptors. Recent studies show that various foodstuffs such as soybean, cabbage and seeds such as sesame and sunflower contain bioactive LPAs. Some LPAs are produced from phosphatidic acid during the digestion of foodstuff. In addition, herbal medicines such as corydalis tuber, and especially ginseng, contain large amounts of LPAs compared to foodstuffs. Herbal LPAs bind to cell surface LPA receptors in animal cells and exert their biological effects. Herbal LPAs elicit [Ca(2+)]i transient and are coupled to various Ca(2+)-dependent ion channels and receptor regulations via the activation of LPA receptors. They also showed beneficial effects of in vitro wound healing, in vivo anti-gastric ulcer, anti-Alzheimer's disease, autotaxin inhibition and anti-metastasis activity. Thus, herbal LPAs can be useful agents for human health. Humans can utilize exogenous plant-derived LPAs for preventive or therapeutic purposes if plant-derived LPAs are developed as functional foods or natural medicine targeting LPA receptors. This brief review article introduces the known rich sources of herbal LPAs and herbal LPA binding protein, describes their biological effects, and further addresses possible clinical applications.

Effects of gintonin-enriched fraction on hippocampal cell proliferation in wild-type mice and an APPswe/PSEN-1 double Tg mouse model of Alzheimer's disease

We previously showed that gintonin, an exogenous lysophosphatidic acid (LPA) receptor ligand, attenuated β-amyloid plaque formation in the cortex and hippocampus, and restored β-amyloid-induced memory dysfunction. Both endogenous LPA and LPA receptors play a key role in embryonic brain development. However, little is known about whether gintonin can induce hippocampal cell proliferation in adult wild-type mice and an APPswe/PSEN-1 double Tg mouse model of Alzheimer's disease (AD). In the present study, we examined the effects of gintonin on the proliferation of hippocampal neural progenitor cells (NPCs) in vitro and its effects on the hippocampal cell proliferation in wild-type mice and a transgenic AD mouse model. Gintonin treatment increased 5-bromo-2'-deoxyuridine (BrdU) incorporation in hippocampal NPCs in a dose- and time-dependent manner. Gintonin (0.3 μg/ml) increased the immunostaining of glial fibrillary acidic protein, NeuN, and LPA1 receptor in hippocampal NPCs. However, the gintonin-induced increase in BrdU incorporation and immunostaining of biomarkers was blocked by an LPA1/3 receptor antagonist and Ca²⁺ chelator. Oral administration of the gintonin-enriched fraction (50 and 100 mg/kg) increased hippocampal BrdU incorporation and LPA1/3 receptor expression in adult wild-type and transgenic AD mice. The present study showed that gintonin could increase the number of hippocampal neurons in adult wild-type mice and a transgenic AD mouse model. Our results indicate that gintonin-mediated hippocampal cell proliferation contributes to the gintonin-mediated restorative effect against β-amyloid-induced hippocampal dysfunction. These results support the use of gintonin for the prevention or treatment of neurodegenerative diseases such as AD via promotion of hippocampal neurogenesis.

Ginseng pharmacology: a new paradigm based on gintonin-lysophosphatidic acid receptor interactions

Ginseng, the root of Panax ginseng, is used as a traditional medicine. Despite the long history of the use of ginseng, there is no specific scientific or clinical rationale for ginseng pharmacology besides its application as a general tonic. The ambiguous description of ginseng pharmacology might be due to the absence of a predominant active ingredient that represents ginseng pharmacology. Recent studies show that ginseng abundantly contains lysophosphatidic acids (LPAs), which are phospholipid-derived growth factor with diverse biological functions including those claimed to be exhibited by ginseng. LPAs in ginseng form a complex with ginseng proteins, which can bind and deliver LPA to its cognate receptors with a high affinity. As a first messenger, gintonin produces second messenger Ca²⁺ via G protein-coupled LPA receptors. Ca²⁺ is an intracellular mediator of gintonin and initiates a cascade of amplifications for further intercellular communications by activation of Ca²⁺-dependent kinases, receptors, gliotransmitter, and neurotransmitter release. Ginsenosides, which have been regarded as primary ingredients of ginseng, cannot elicit intracellular [Ca²⁺]_i transients, since they lack specific cell surface receptor. However, ginsenosides exhibit non-specific ion channel and receptor regulations. This is the key characteristic that distinguishes gintonin from ginsenosides. Although the current discourse on ginseng pharmacology is focused on ginsenosides, gintonin can definitely provide a mode of action for ginseng pharmacology that ginsenosides cannot. This review article introduces a novel concept of ginseng ligand-LPA receptor interaction and proposes to establish a paradigm that shifts the focus from ginsenosides to gintonin as a major ingredient representing ginseng pharmacology.