Mi Sun Ju

Mulberry fruit protects dopaminergic neurons in toxin-induced Parkinson's disease models

Parkinsons disease (PD), one of the most common neurodegenerative disorders, is characterised by the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) to the striatum (ST), and involves oxidative stress. Mulberry fruit from Morus alba L. (Moraceae) is commonly eaten, and has long been used in traditional oriental medicine. It contains well-known antioxidant agents such as anthocyanins. The present study examined the protective effects of 70 % ethanol extract of mulberry fruit (ME) against neurotoxicity in in vitro and in vivo PD models. In SH-SY5Y cells stressed with 6-hydroxydopamine (6-OHDA), ME significantly protected the cells from neurotoxicity in a dose-dependent manner. Other assays demonstrated that the protective effect of ME was mediated by its antioxidant and anti-apoptotic effects, regulating reactive oxygen species and NO generation, Bcl-2 and Bax proteins, mitochondrial membrane depolarisation and caspase-3 activation. In mesencephalic primary cells stressed with 6-OHDA or 1-methyl-4-phenylpyridinium (MPP+), pre-treatment with ME also protected dopamine neurons, showing a wide range of effective concentrations in MPP+-induced toxicity. In the sub-acute mouse PD model induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), ME showed a preventative effect against PD-like symptoms (bradykinesia) in the behavioural test and prevented MPTP-induced dopaminergic neuronal damage in an immunocytochemical analysis of the SNpc and ST. These results indicate that ME has neuroprotective effects in in vitro and in vivo PD models, and that it may be useful in preventing or treating PD.

6-Shogaol, a ginger product, modulates neuroinflammation: A new approach to neuroprotection

Inflammatory processes in the central nervous system play an important role in a number of neurodegenerative diseases mediated by microglial activation, which results in neuronal cell death. Microglia act in immune surveillance and host defense while resting. When activated, they can be deleterious to neurons, even resulting in neurodegeneration. Therefore, the inhibition of microglial activation is considered a useful strategy in searching for neuroprotective agents. In this study, we investigated the effects of 6-shogaol, a pungent agent from Zingiber officinale Roscoe, on microglia activation in BV-2 and primary microglial cell cultures. 6-Shogaol significantly inhibited the release of nitric oxide (NO) and the expression of inducible nitric oxide synthase (iNOS) induced by lipopolysaccharide (LPS). The effect was better than that of 6-gingerol, wogonin, or N-monomethyl-l-arginine, agents previously reported to inhibit nitric oxide. 6-Shogaol exerted its anti-inflammatory effects by inhibiting the production of prostaglandin E(2) (PGE(2)) and proinflammatory cytokines, such as interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), and by downregulating cyclooxygenase-2 (COX-2), p38 mitogen-activated protein kinase (MAPK), and nuclear factor kappa B (NF-κB) expression. In addition, 6-shogaol suppressed the microglial activation induced by LPS both in primary cortical neuron-glia culture and in an in vivo neuroinflammatory model. Moreover, 6-shogaol showed significant neuroprotective effects in vivo in transient global ischemia via the inhibition of microglia. These results suggest that 6-shogaol is an effective therapeutic agent for treating neurodegenerative diseases.

Cassiae semen, a seed of Cassia obtusifolia, has neuroprotective effects in Parkinson's disease models

Cassiae semen, a commonly consumed tea and medicinal food, has been shown to have multiple therapeutic actions related to the prevention of dementia and ischemia. In this study, we investigated the effects of extract of Cassiae semen (COE) against neurotoxicities in in vitro and in vivo Parkinsons disease (PD) models. In PC12 cells, COE attenuated the cell damage induced by 100 microM 6-hydroxydopamine (6-OHDA) stress in MTT assay, and it inhibited the overproduction of reactive oxygen species, glutathione depletion, mitochondrial membrane depolarization and caspase-3 activation at 0.1-10 microg/ml. In addition, COE showed radical scavenging activity in the DPPH and ABTS assays. In mesencephalic dopaminergic (DA) culture, COE protected DA cells against 10 microM 6-OHDA- and 10 microM 1-methyl-4-phenylpyridine-induced toxicities at 0.1-1 microg/ml. We also evaluated the effect of COE in a mouse PD model induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). In the pole test, COE (50mg/kg, 15 days)+MPTP (30 mg/kg, 5 days)-treated group had decreased T-turn and T-LA which were longer in MPTP group. Moreover, COE significantly protected DA neuronal degeneration induced by MPTP in the substantia nigra and striatum of these mice. These results demonstrate that COE can prevent DA neurons against the toxicities involved in PD.

Effects of the hook of Uncaria rhynchophylla on neurotoxicity in the 6-hydroxydopamine model of Parkinson's disease

ETHNOPHARMACOLOGICAL RELEVANCE While the hook of Uncaria rhynchophylla (URH) is a traditional herb used in northeast Asia for the treatment of Parkinsons disease (PD)-like symptoms such as tremor, it has not been experimentally evaluated in a PD model. AIM OF THE STUDY We investigated the effects of URH on 6-hydroxydapamine (6-OHDA)-induced neurotoxicity in in vitro and in vivo models of PD. MATERIALS AND METHODS The cell viability, anti-oxidative activity, and anti-apoptotic activity of a water extract of URH (URE) were assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide, reactive oxygen species (ROS), total glutathione (GSH), and caspase-3 assays in PC12 cells stressed by 6-OHDA. We also investigated the behavioral recovery and dopaminergic neuron protection of URE using an apomorphine-induced rotation test and tyrosine hydroxylase immunohistochemistry in the hemi-parkinsonian rat model of the unilateral 6-OHDA lesion of the medial forebrain bundle. RESULTS In PC12 cells, URE significantly reduced cell death and the generation of ROS, increased GSH levels, and inhibited caspase-3 activity induced by 6-OHDA. In 6-OHDA-lesioned rats, posttreatment with URE (5 mg/kg/day for 14 days) significantly reduced apomorphine-induced rotation, and it lowered dopaminergic neuronal loss in substantia nigra pars compacta. CONCLUSIONS URE possesses neuroprotective activity against 6-OHDA-induced toxicity through anti-oxidative and anti-apoptotic activities in PD models.

Protective effects of Chunghyuldan against ROS-mediated neuronal cell death in models of Parkinson's disease.

Previous reports have suggested that the herbal medicine Chunghyuldan (CHD, Qingxue-dan in Chinese and Daio-Orengedokuto in Japanese) has wide-ranging biological effects, including anti-hyperlipidaemic, anti-ischaemic, anti-inflammatory and antioxidant activities. Reactive oxygen species (ROS)-mediated mitochondrial dysfunction is thought to be one of the major pathological mechanisms responsible for Parkinsons disease (PD) and may underlie the selective loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) that is a hallmark of this disease. In this study, we examined the neuroprotective effects of CHD in PD models produced by treatment with neurotoxins that act via ROS-mediated mitochondrial dysfunction. In an in vitro PD model using 6-hydroxydopamine, CHD applied at concentrations of 10 and 100 μg/ml exhibited significant protective effects in PC12 cells by inhibiting intracellular ROS generation. CHD applied at 10 and 100 μg/ml also prevented 6-hydroxydopamine-induced mitochondrial depolarization and elevation of caspase-3 activity. At the same doses, CHD showed regulatory effects on the haem oxygenase-1 and gp91 phagocytic oxidase which have critical roles in generating ROS. In addition, CHD protected dopaminergic neurons in a primary mesencephalic culture against MPP+ neurotoxicity. In an in vivo PD model produced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine treatment (20 mg/kg, 4 times, i.p.), co-administration of CHD (50 mg/kg, 5 days, p.o.) ameliorated PD-like behavioural symptoms (bradykinesia) and reduced dopaminergic neuronal damage in the SNpc and striatum as measured by immunocytochemistry. These results demonstrate the neuroprotective effects of CHD in PD models that are mediated through inhibition of ROS generation and associated mitochondrial dysfunction.

Protective effects of standardized Thuja orientalis leaves against 6-hydroxydopamine-induced neurotoxicity in SH-SY5Y cells.

Although the etiology of Parkinsons disease (PD) remains unknown, recent studies have suggested that oxidative stress (OS) and apoptosis, as a result of mitochondrial defects, may play important roles in its pathogenesis. 6-Hydroxydopamine (6-OHDA), a neurotoxin commonly used in models of PD, induces selective catecholaminergic cell death, mediated by reactive oxygen species (ROS) and mitochondrial defects. This study investigated the protective effect of Thuja orientalis leaves (TOFE), a well-known oriental traditional medicine, on 6-OHDA-induced neurotoxicity in SH-SY5Y cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and Hoechst staining showed that TOFE attenuated the cell damage caused by 6-OHDA stress. TOFE showed strong radical scavenging effects in 2,2-diphenyl-2-picrylhydrazyl and 2,2-azinobis-(3-ethyl-benzthiazoline-6-sulphonic acid) assays, and it reduced the intracellular ROS and extracellular nitric oxide production induced by 6-OHDA. Additionally, TOFE blocked the reduction in the mitochondrial membrane potential, the release of cytochrome c, and the activation of caspase-3. Moreover, TOFE decreased the phosphorylation of extracellular signal-regulated kinase (pERK), which has pro-apoptotic functions. Taken together, TOFE might protect SH-SY5Y cells from 6-OHDA through the downregulation of OS and mitochondrial-mediated apoptosis, and regulation of pERK.

6-Shogaol, an active compound of ginger, protects dopaminergic neurons in Parkinson＇s disease models via anti-neuroinflammation

Aim:6-Shogaol [1-(4-hydroxy-methoxyphenyl)-4-decen-one], a pungent compound isolated from ginger, has shown various neurobiological and anti-inflammatory effects. The aim of this study was to examine the effects of 6-shogaol on neuroinflammatory-induced damage of dopaminergic (DA) neurons in Parkinsons disease (PD) models.Methods:Cultured rat mesencephalic cells were treated with 6-shogaol (0.001 and 0.01 μmol/L) for 1 h, then with MPP+(10 μmol/L) for another 23 h. The levels of TNF-α and NO in medium were analyzed spectrophotometrically. C57/BL mice were administered 6-shogaol (10 mg·kg−1·d−1, po) for 3 d, and then MPTP (30 mg/kg, ip) for 5 d. Seven days after the last MPTP injection, behavioral testings were performed. The levels of tyrosine hydroxylase (TH) and macrophage antigen (MAC)-1 were determined with immunohistochemistry. The expression of iNOS and COX-2 was measured using RT PCR.Results:In MPP+-treated rat mesencephalic cultures, 6-shogaol significantly increased the number of TH-IR neurons and suppressed TNF-α and NO levels. In C57/BL mice, treatment with 6-shogaol reversed MPTP-induced changes in motor coordination and bradykinesia. Furthermore, 6-shogaol reversed MPTP-induced reductions in TH-positive cell number in the substantia nigra pars compacta (SNpc) and TH-IR fiber intensity in stratum (ST). Moreover, 6-shogaol significantly inhibited the MPTP-induced microglial activation and increases in the levels of TNF-α, NO, iNOS, and COX-2 in both SNpc and ST.Conclusion:6-Shogaol exerts neuroprotective effects on DA neurons in in vitro and in vivo PD models.

Evaluation of Samjunghwan, a traditional medicine, for neuroprotection against damage by amyloid-beta in rat cortical neurons

AIM OF THE STUDY Samjunghwan (SJH) is a multi-herbal traditional medicine composed of Mori Fructus, Lycii Radicis Cortex, and Atractylodis Rhizoma Alba and it is clinically applied as an anti-aging agent in neurodegenerative disorders, to promote longevity. In the present study, we evaluated the neuroprotective effect of SJH in Alzheimers disease induced by amyloid-beta (Abeta) and examined the related pathways. MATERIALS AND METHODS To evaluate the protective effect of SJH, we conducted thiazolyl blue tetrazolium bromide, lactate dehydrogenase, and MAP-2 staining assays of primary cultured rat cortical neurons stressed by Abeta(25-35). To investigate the possible mechanism of action, we examined the Bcl-2/Bax expression ratio, mitochondrial membrane potential (Deltapsi(M)), cytochrome C release, and caspase-3 activation, focusing on the mitochondria-mediated apoptotic pathways. RESULTS SJH at concentrations of 10 and 100 microg/ml provided significant protection of rat cortical neurons from Abeta(25-35) neurotoxicity. At the maximum effective dose of 100 microg/ml, SJH significantly increased the anti-apoptotic protein (Bcl-2)/pro-apoptotic protein (Bax) ratio and inhibited Deltapsi(M) depolarization, cytosolic cytochrome C release, and caspase-3 activation. CONCLUSION SJH appears to provide neuroprotection against mitochondria-mediated apoptotic pathways in this Abeta(25-35)-induced Alzheimers disease model.

Clavulanic acid protects neurons in pharmacological models of neurodegenerative diseases

Clavulanic acid is a psychoactive compound with excellent blood‐brain barrier permeability and safety profiles. Previous studies showed that clavulanic acid suppresses anxiety in rodents and in a primate model. In addition, clavulanic acid is thought to enhance sexual function in animal models via central nervous system (CNS) mechanisms. To further examine its potential as a CNS‐modulating agent, we investigated the effects of clavulanic acid in neurotoxin‐induced animal models that emulate neurodegenerative disease symptoms. Clavulanic acid was administered to rodents that were exposed to kainic acid or 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP). Using histochemical staining of brain sections, we demonstrated that clavulanic acid protects hippocampal and dopaminergic neurons from toxin‐induced acute death. We also observed that clavulanic acid improves motor function in MPTP‐treated mice in a behavioral test. These data indicate that clavulanic acid may have neuroprotective effects and warrants further investigation of its therapeutic use in CNS disorders, such as Parkinsons and Alzheimers disease. Drug Dev Res 71:351–357, 2010.