Protective effects of mangosteen extract on H2O2-induced cytotoxicity in SK-N-SH cells and scopolamine-induced memory impairment in mice.
ABSTRACT: Mangosteen extracts (ME) contain high levels of polyphenolic compounds and antioxidant activity. Protective effects of ME against ?-amyloid peptide (A?), induced cytotoxicity have been reported. Here, we further studied the protective effects of ME against oxidative stress induced by hydrogen peroxide (H2O2) and polychlorinated biphenyls (PCBs), and demonstrated the protection against memory impairment in mice. The cytoprotective effects of ME were measured as cell viability and the reduction in ROS activity. In SK-N-SH cell cultures, 200 ?g/ml ME could partially antagonize the effects of 150 or 300 µM H2O2 on cell viability, ROS level and caspase-3 activity. At 200, 400 or 800 µg/ml, ME reduced AChE activity of SK-N-SH cells to about 60% of the control. In vivo study, Morris water maze and passive avoidance tests were used to assess the memory of the animals. ME, especially at 100 mg/kg body weight, could improve the animal's memory and also antagonize the effect of scopolamine on memory. The increase in ROS level and caspase-3 activity in the brain of scopolamine-treated mice were antagonized by the ME treatment. The study demonstrated cytoprotective effects of ME against H2O2 and PCB-52 toxicity and having AChE inhibitory effect in cell culture. ME treatment in mice could attenuate scopolamine-induced memory deficit and oxidative stress in brain.
Project description:Terminalia chebula Retz. (Combretaceae) is a traditional herbal medicine that is widely used in the treatment of diabetes, immunodeficiency diseases, and stomach ulcer in Asia. However, the anti-amnesic effect of T. chebula has not yet been investigated. The present study was designed to determine whether T. chebula extract (TCE) alleviates amnesia induced by scopolamine in mice. We also investigated possible mechanisms associated with cholinergic system and anti-oxidant effects.TCE (100 or 200 mg/kg) was orally administered to mice for fourteen days (days 1-14), and scopolamine was intraperitoneally injected to induce memory impairment for seven days (days 8-14). Learning and memory status were evaluated using the Morris water maze. Hippocampal levels of acetylcholine (ACh), acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) were measured ex vivo. Levels of reactive oxygen species (ROS), nitric oxide (NO), and malondialdehyde (MDA) in the hippocampus were also examined.In the Morris water maze task, TCE treatment reversed scopolamine-induced learning and memory deficits in acquisition and retention. TCE reduced hippocampal AChE activities and increased ChAT and ACh levels in the scopolamine-induced model. Moreover, TCE treatment suppressed scopolamine-induced oxidative damage by ameliorating the increased levels of ROS, NO, and MDA.These findings suggest that TCE exerts potent anti-amnesic effects via cholinergic modulation and anti-oxidant activity, thus providing evidence for its potential as a cognitive enhancer for amnesia.
Project description:Acetylcholinesterase (AChE) inhibitors represent a major class of drugs which provide symptomatic relief and improvement in cognitive function in Alzheimer's disease (AD). In this study, cubebin, a dibenzylbutyrolactone lignan, was isolated from Piper cubeba and investigated for its AChE inhibitory activity in an attempt to explore its potential for memory-enhancing activities in mice.Molecular docking of cubebin was carried out followed by in vitro AChE activity. Mice were treated with cubebin (25 & 50 mg/kg; i.p.), for three days and memory impairment was induced by scopolamine (3 mg/kg; i.p.). Memory function was evaluated by Morris water maze (MWM) test. Biochemical parameters of oxidative stress and cholinergic function were estimated in brain.Molecular docking study revealed that cubebin was well bound within the binding site of the AChE enzyme showing interactions such as π-π stacking and hydrogen bonding with residues present therein. Cubebin inhibited AChE enzyme in an in vitro assay with IC50value of 992 μM. Scopolamine administration caused a significant impairment of learning and memory in mice, as indicated by a marked decrease in MWM performance. Scopolamine administration also produced a significant enhancement of brain AChE activity and oxidative stress in mice brain. Pre-treatment of cubebin (25 and 50 mg/kg; i.p.) significantly prevented scopolamine-induced learning and memory deficits along with attenuation of scopolamine-induced rise in brain AChE activity and oxidative stress level.Cubebin showed promising protective activity in scopolamine-induced spatial memory impairment in mice. This could be attributed to its brain AChE inhibition and antioxidant activity.
Project description:Neuronal cell death, in neurodegenerative disorders, is mediated through a spectrum of biological processes. Excessive amounts of free radicals, such as reactive oxygen species (ROS), has detrimental effects on neurons leading to cell damage via peroxidation of unsaturated fatty acids in the cell membrane. Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) has been used for neurological recovery in several countries, including Japan and China, and it has been suggested that Edaravone may have cytoprotective effects in neurodegeneration. Edaravone protects nerve cells in the brain by reducing ROS and inhibiting apoptosis. To gain further insight into the cytoprotective effects of Edaravone against oxidative stress condition we have performed comparative two-dimensional gel electrophoresis (2DE)-based proteomic analyses on SH-SY5Y neuroblastoma cells exposed to oxidative stress and in combination with Edaravone. We showed that Edaravone can reverse the cytotoxic effects of H2O2 through its specific mechanism. We observed that oxidative stress changes metabolic pathways and cytoskeletal integrity. Edaravone seems to reverse the H2O2-mediated effects at both the cellular and protein level via induction of Peroxiredoxin-2.
Project description:Among a series of xanthones identified from mangosteen, the fruit of Garcinia mangostana L. (Guttifereae), ?- and ?-mangostins are known to be major constituents exhibiting diverse biological activities. However, the effects of ?-mangostin on oxidative neurotoxicity and impaired memory are yet to be elucidated. In the present study, the protective effect of ?-mangostin on oxidative stress-induced neuronal cell death and its underlying action mechanism(s) were investigated and compared to that of ?-mangostin using primary cultured rat cortical cells. In addition, the effect of orally administered ?-mangostin on scopolamine-induced memory impairment was evaluated in mice. We found that ?-mangostin exhibited prominent protection against H2O2- or xanthine/xanthine oxidase-induced oxidative neuronal death and inhibited reactive oxygen species (ROS) generation triggered by these oxidative insults. In contrast, ?-mangostin had no effects on the oxidative neuronal damage or associated ROS production. We also found that ?-mangostin, not ?-mangostin, significantly inhibited H2O2-induced DNA fragmentation and activation of caspases 3 and 9, demonstrating its antiapoptotic action. In addition, only ?-mangostin was found to effectively inhibit lipid peroxidation and DPPH radical formation, while both mangostins inhibited ?-secretase activity. Furthermore, we observed that the oral administration of ?-mangostin at dosages of 10 and 30?mg/kg markedly improved scopolamine-induced memory impairment in mice. Collectively, these results provide both in vitro and in vivo evidences for the neuroprotective and memory enhancing effects of ?-mangostin. Multiple mechanisms underlying this neuroprotective action were suggested in this study. Based on our findings, ?-mangostin could serve as a potentially preferable candidate over ?-mangostin in combatting oxidative stress-associated neurodegenerative diseases including Alzheimer's disease.
Project description:Deficits in cognitive functioning have been reported in humans exposed to dioxins and dioxin-like compounds. Evidence suggests that dioxins induce cholinergic dysfunction mediated by hypothyroidism. However, little is known about direct effects of dioxins on the cholinergic system.We investigated the action of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on acetylcholinesterase (AChE), a key enzyme in cholinergic neurotransmission.We used SK-N-SH human-derived neuronal cells to evaluate the effect of dioxin exposure on AChE.We consistently found a significant decrease in enzymatic activity of AChE in cultured neurons treated with TCDD. We also found that, unlike organophosphate pesticides that directly act on the catalytic center of AChE, the suppressive effect of dioxin was through transcriptional regulation. The addition of CH223191, an inhibitor of the aryl hydrocarbon receptor (AhR)-dependent pathway, counteracted the TCDD-induced suppression of AChE, suggesting involvement of the AhR-dependent pathway. The existence of putative dioxin-responsive element (DRE) consensus sequences in the human ACHE promoter region further supported this hypothesis. Consistent with the absence of DRE elements in mouse or rat ACHE promoter regions, suppression of AChE by TCDD did not occur in rat neuronal cells, indicating a potential species-specific effect.In SK-N-SH cells, dioxin suppressed the activity of neuronal AChE via AhR-mediated transcriptional down-regulation. This is the first study to report direct interference by dioxin with the cholinergic neurotransmission system.
Project description:BACKGROUND:E. coccinae (SIMS) G. (Asteraceae) is an annual plant commonly found throughout the plain of the Central Africa and widely used in Cameroonian folk medicine for the treatment of fever and convulsions in children. We previously reported that the methanolic extract of this plant improved spatial memory. However no underlying mechanism was explored. The present study was undertaken to investigate the effects of the hydroalcoholic extract of Emilia coccinae on memory in scopolamine treated rats and to propose possible mechanisms of action. METHODS:Novel object recognition and Y-maze paradigm were used to test memory while oxidative profile, AChE and ACh level of the whole brain were assessed to outline the mechanism of nootropic activity of the extract. 200 and 400 mg/kg of the extract were chronically administrated during 14 consecutive days in separate groups of scopolamine intraperitoneal treated rats (1.5 mg/kg). RESULTS:The hydroalcoholic extract of Emilia coccinae (HEEC) at the dose of 200 mg/kg significantly improved the memory of rats and reversed the amnesia induced by scopolamine. In addition, we showed that this extract is decreasing the acetyl cholinesterase activity while also increasing the acetylcholine levels in the brain. HEEC (200 and 400 mg/kg) significantly increased antioxidant enzyme activities (SOD, GSH and CAT) and reduced lipid peroxidation (MDA level) in the rat whole brain homogenates. CONCLUSIONS:Taken together, our results suggested that the hydroalcoholic extract of Emilia coccinae ameliorated the cognitive dysfunction in scopolamine treated rats through the blockage of the oxidative effect of scopolamine and inhibition of AChE activity.
Project description:Over recent years, utilization of green synthesized nanomaterials has been widely growing on human body because of its special properties. With the increasing acceptance of nanoparticle approach for various clinical treatments, the biosafety and toxicological effects on the vital organs such as central nervous system, have received more concern. Main focus of this study was to evaluate acute exposure of n-butanol fraction of Prosopis cineraria (L.) Druce hydroethanolic extract (BuPC) and green synthesized zinc oxide nanoparticles of BuPC (ZnOPC) on spatial cognition behavior, and to assess underlying mechanism by estimation of enzymatic antioxidative status along with acetylcholinesterase (AChE) activity in mice brain. Strongest in vitro antioxidant and AChE inhibitory activity exhibiting fraction, BuPC, was examined for inhibition kinetic study by Lineweaver-Burk and Dixon plots. BuPC was further used for fabrication ZnOPC and characterized by UV-visible spectroscopy, Fourier Transform Infrared (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X ray (EDX), and Dynamic Light Scattering (DLS) analysis. Old male swiss albino mice were randomly divided into seven groups and treated for 21 days. Subsequently spatial memory was determined by two behavioral models [Elevated plus maze (EPM) and Hebbs William maze (HWM)] and supernatant of brain homogenate was analyzed for enzymatic antioxidant level and AChE inhibitory activity. Zinc content of blood plasma and brain was estimated. Results showed prolonged transfer latency (TL) and time taken to reach reward chamber (TRC) by scopolamine was not ameliorated by the ZnOPC group, whereas BuPC group showed significant reduction in scopolamine induced increase in TL and TRC compared to control and scopolamine treated groups. ZnOPC alleviated enzymatic antioxidant activity and AChE as compared to donepezil and BuPC treated groups. Study concludes that ZnOPC attenuated spatial learning and memory by increase in oxidative stress and decrease in AChE activity at both dose levels. Our results suggest that BuPC exhibited a strong neuroprotective effect on cognitive deficit mice and it may be employed as a strong substance for the treatment of dementia whereas the green synthesized ZnOPC was not proficient to reverse the memory impairment induced by scopolamine.
Project description:Rosmarinus officinalis L. is a traditional herb with various therapeutic applications such as antibacterial, antioxidant, anti-inflammatory, antidepressant, and anticholinesterase activities, and can be used for the prevention or treatment of dementia. In the present study, we tested whether Rosmarinus officinalis L. could counteract scopolamine-induced anxiety, dementia, and brain oxidative stress in the zebrafish model and tried to find the underlying mechanism. Rosmarinus officinalis L. essential oil (REO: 25, 150, and 300 µL/L) was administered by immersion to zebrafish (Danio rerio) once daily for eight days while scopolamine (100 µM) treatment was delivered 30 min before behavioral tests. The antidepressant and cognitive-enhancing actions of the essential oil in the scopolamine zebrafish model was measured in the novel tank diving test (NTT) and Y-maze test. The chemical composition was identified by Gas chromatograph-Mass spectrometry (GC-MS) analysis. The brain oxidative status and acetylcholinesterase (AChE) activity was also determined. REO reversed scopolamine-induced anxiety, memory impairment, and brain oxidative stress. In addition, a reduced brain AChE activity following the administration of REO in scopolamine-treated fish was observed. In conclusion, REO exerted antidepressant-like effect and cognitive-enhancing action and was able to abolish AChE alteration and brain oxidative stress induced by scopolamine.
Project description:Schisandra, Ginseng, Notoginseng, and Lycium barbarum are traditional Chinese medicinal plants sharing cognitive-enhancing properties. To design a functional food to improve memory, we prepared a compound Schisandra-Ginseng-Notoginseng-Lycium (CSGNL) extract and investigated its effect on scopolamine-induced learning and memory loss in mice. To optimize the dose ratios of the four herbal extracts in CSGNL, orthogonal experiments were performed. Mice were administered CSGNL by gavage once a day for 30 days and then mouse learning and memory were evaluated by Morris water maze and step-through tests. The mechanisms of CSGNL improving learning and memory were investigated by assaying acetylcholine (ACh) levels and choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) activities in the brain tissues of treated mice. The results showed that CSGNL significantly ameliorated scopolamine-induced learning and memory impairment, at least in part, by modulating ACh levels and ChAT and AChE activities in the mouse brain. Our data support the use of CSGNL as a functional food for learning and memory enhancement.
Project description:Homocysteine-inducible, endoplasmic reticulum (ER) stress-inducible, ubiquitin-like domain member 1 (HERPUD1), an ER resident protein, is upregulated in response to ER stress and Ca(2+) homeostasis deregulation. HERPUD1 exerts cytoprotective effects in various models, but its role during oxidative insult remains unknown. The aim of this study was to investigate whether HERPUD1 contributes to cytoprotection in response to redox stress and participates in mediating stress-dependent signaling pathways. Our data showed that HERPUD1 protein levels increased in HeLa cells treated for 30 min with H2O2 or angiotensin II and in aortic tissue isolated from mice treated with angiotensin II for 3 weeks. Cell death was higher in HERPUD1 knockdown (sh-HERPUD1) HeLa cells treated with H2O2 in comparison with control (sh-Luc) HeLa cells. This effect was abolished by the intracellular Ca(2+) chelating agent BAPTA-AM or the inositol 1,4,5-trisphosphate receptor (ITPR) antagonist xestospongin B, suggesting that the response to H2O2 was dependent on intracellular Ca(2+) stores and the ITPR. Ca(2+) kinetics showed that sh-HERPUD1 HeLa cells exhibited greater and more sustained cytosolic and mitochondrial Ca(2+) increases than sh-Luc HeLa cells. This higher sensitivity of sh-HERPUD1 HeLa cells to H2O2 was prevented with the mitochondrial permeability transition pore inhibitor cyclosporine A. We concluded that the HERPUD1-mediated cytoprotective effect against oxidative stress depends on the ITPR and Ca(2+) transfer from the ER to mitochondria.