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Protective Effects of Ramie (Boehmeria nivea) against Oxidative Stress in C6 Glial Cells
Protective Effects of Ramie (Boehmeria nivea) against Oxidative Stress in C6 Glial Cells
Korean Journal of Plant Resources. 2015. Dec, 28(6): 675-681
Copyright © 2015, The Plant Resources Society of Korea
This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
  • Received : June 06, 2015
  • Accepted : September 09, 2015
  • Published : December 31, 2015
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About the Authors
Xiaoning Wang
Department of Food Science and Nutrition, Pusan National University, Busan 46241, Korea
Sunghun Cho
Department of Integrative Plant Science, Chung-Ang University, Anseong 17546, Korea
Ho Bang Kim
Life Sciences Research Institute, Biomedic Co. Ltd., Bucheon 14548, Korea
Yong-Su Jung
Yeong-Gwang Agricultural Technology Center, Yeonggwang 57031, Korea
Eun Ju Cho
Department of Food Science and Nutrition, Pusan National University, Busan 46241, Korea
Sanghyun Lee
Department of Integrative Plant Science, Chung-Ang University, Anseong 17546, Korea
slee@cau.ac.kr
Abstract
β amyloid protein (Aβ) plays a critical role in the pathogenesis of Alzheimer's disease (AD) and possibly in Aβ-induced mitochondrial dysfunction and oxidative stress. Aβ can directly cause reactive oxygen species (ROS) production. Overproduction of ROS is considered to be involved in the pathogenesis of neurodegeneration of AD. Here, we investigated 9 kinds of ramie ( Boehmeria nivea , (L.) Gaud., BN; hereafter denoted as BN) for their protective action against oxidative stress in a cellular system using C6 glial cells. We observed loss of cell viability and high levels of ROS generation after treatment with hydrogen peroxide (H 2 O 2 ) and Aβ 25-35 . However, treatments with BN extracts led to an increase in cell viability and decrease in ROS production induced by H2O2 and Aβ25-35. In particular, the extracts of BN-01 (seobang variety from Seocheon) and BN-09 (local variety from Yeonggwang) showed excellent anti-oxidative properties. This indicates that BN extracts could prevent neurodegeneration by reducing oxidative stress in cells.
Keywords
Introduction
Oxidative stress is a potential threat to most aerobic organisms and plays a crucial role in biocontrol systems. It leads to neuro-degeneration, also it has been closely implicated to neurodegenerative disorders ( Di Carlo , 2012 ; Han and Wang, 2010 ; Lee and Cho, 2007 ). Oxidative stress is one of the earliest events in Alzheimer’s disease (AD) ( Nunomura , 2001 ) and β amyloid protein (Aβ) is known to contribute to the oxidative damage leading to neuronal impairment ( Yatin , 1999 ). In addition, oxidative stress is associated with enhanced levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS) ( Castoria , 2003 ; Macarisin , 2010 ). At low levels, ROS act as signaling molecules to regulate cellular functions. However, at high levels, they cause oxidative stress ( Madeo , 1999 ; Tatone , 2010 ). In particular, the ROS containing O 2 , H 2 O 2 , 1 O 2 , HO 2 , •OH, ROOH, ROO•, and RO• radicals are highly reactive and toxic. They cause damage to proteins, lipids, carbohydrates, and DNA which ultimately results in cell death ( Gill and Tuteja, 2010 ). Neurons are most susceptible to direct oxidative injury by ROS and RNS ( Juvenet, 1889 ; Butterfield and Lauderback, 2002 ). Glial cells are very important for normal brain function and oxidative damage can cause rapid changes in almost all cells including glial cell ( Araujo and Cotman, 1992 ; Zhao 2013 ). Therefore, one of the most promising therapeutic strategies for the treatment of neurodegenerative diseases, including AD, is the reduction of oxidative damage in cells.
Ramie ( Boehmeria nivea (L.) Gaud., BN; hereafter referred to as BN) is a member of the nettle family (Urticaceae) and is mainly grown in temperate and tropical areas including China, Korea, Philippines, and India ( Angelini , 2000 ; Wang , 2006 ). Popularly known as “China grass”, it is a perennial herbaceous plant and has been used as a textile fiber for centuries because of its excellent fiber quality ( Wood and Angus, 1974 ; Liu , 2001 ). It is rich in nutrients such as vitamins, minerals, and various bioactive substances ( Gupta and Wagle, 1988 ). Phytochemicals are bioactive substances of plants that have been associated with the protection of human health against chronic degenerative diseases ( Fukumoto and Mazza, 2000 ). The major compounds of chemical constituents are chlorogenic acid, rutin, luteolin-7-glucoside, naringin, hesperidin, and tangeretin ( Park , 2010 ). It is known to contain behenic acid, ursolic acid, β-sitosterol, cholesterol, kiwiionoside, uracil, quercetin, α-amyrin, nonacosanol, emodin, emodin-8- O -β-glucoside, physcion, polydatin, catechin, epicatechin, and epicatechin gallate ( Nho , 2010 ; Shao , 2010 ). It has been used in foods such as cookies ( Yoon and Jang, 2006 ) and Jeolpyun (traditional Korean rice cakes) ( Tian , 2011 ). The edible parts of this plant - the leaves and roots - have been reported to have anti-inflammatory and anti-fungal effects ( Xu , 2011 ; Sung , 2013 ), in addition to anti-hepatitis B and anti-diabetic effects ( Huang , 2006 ; Kim , 2013 ). However, whether ramie has a neuroprotective effect has not been determined. In our previous study, we screened the biological activities of 90 kinds of Korean ramie ( Lee , 2014 ). Among them, 9 kinds cultivated in Seocheon, Goheung, Muan, Hampyeong, and Yeonggwang showed excellent biological anti-oxidative, anti-bacterial, anti-inflammatory, and anti-cancer properties ( Lee , 2014 ).
Therefore, in this study we evaluated the extracts from these 9 kinds for their potential in treating AD; for this, we measured their ability to reduce H 2 O 2 and Aβ 25-35 -induced oxidative stress in C6 glial cells.
Materials and Methods
- Plant materials and preparation of extracts
Nine kinds of ramie were collected by the staff at the Yeong-Gwang Agricultural Technology Center, Korea ( Table 1 ). Ten grams of dried BN were extracted with MeOH (200 ml × 3) under reflux conditions and the solvent was evaporated in vacuo . Each individual MeOH extract (0.1 mg) was dissolved in dimethyl sulfoxide (DMSO) (5 μl).
BN kinds and their collection sites
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BN kinds and their collection sites
- Instruments and reagents
MeOH was purchased from Sam Chun Pure Chemical Co. (Pyeongtaek, Korea). C6 glial cells were obtained from the Korea Cell Line Bank (KCLB, Korea). Dulbecco’s Modified Eagle Medium (DMEM), fetal bovine serum (FBS), trypsin EDTA, and penicillin-streptomycin (100 unit/ml) were obtained from Welgene (Daegu, Korea). Hydrogen peroxide (H 2 O 2 ) was purchased from Junsei Chemical Co. (Tokyo, Japan). The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) was purchased from Bio Basic Canada Inc. (New York, USA). DMSO and Aβ 25-35 were obtained from Sigma Chemical Co. (Louisiana, USA).
- Cell culture
C6 glial cells were cultured in DMEM medium (pH 7.2) containing 100 U/ml of penicillin streptomycin and 10% FBS at 37℃ in a 5% CO 2 incubator. Cells were sub-cultured 5 days with 0.05% trypsin-EDTA in phosphate buffered saline (PBS).
- Cell viability assay
Once the cells reached 80-90% confluence, they were plated into 96-well plates at 5 × 10 4 cells/ml and cells were incubated with medium for 2 h before treatment with H 2 O 2 /A β 25-35 and BN extracts. BN extracts (25 μ g/ml) and H 2 O 2 (250 μM) or Aβ 25-35 (25 μM) were added, and the plates were incubated for 24 hr. Thereafter, 100 μL of MTT (5 mg/ml) solution was added to each well. After the incubation for 4 h at 37℃, the medium was removed from the plate. The resultant formazan crystals in the C6 glial cells were solubilized by adding 100 μl of DMSO. The absorbance of each well was read at 540 nm using a microplate reader (Molecular Devices, Sunnyvale, USA) ( Mosmann, 1983 ).
- ROS measurement
Cells were plated into black 96-well plates at 5 × 10 4 cells/ml and cells were incubated with medium for 2 h before treatment with H 2 O 2 /Aβ 25-35 and BN extracts. BN extracts (25 μ g/ml) were added, and the plates were incubated for 24 hr. Cells were washed twice with PBS, and incubated with dichlorodihydro-fluorescein diacetate (DCFH-DA) (Sigma Chemical Co., Louisiana, USA) 20 μM for 30 min. Thereafter, H 2 O 2 (250 μM) or Aβ 25-35 (25 μM) was treated for 24 h, and the wells were read by FLUOstar OPTIMA (BMG Labtech., Ortenberg, Germany) at an excitation wavelength of 480 nm and an emission wavelength of 535 nm ( Byun , 2009 ).
- Statistical analysis
Significance was verified by performing Duncan’s multiple range tests using SAS software (version 6.0, SAS Institute, Cary, USA) to analyze the differences between the control and sample treated groups. Differences between groups were considered significant when the P -value was less than 0.05. The experimental results were expressed as means ± standard deviation (SD) (n = 6).
Results and Discussion
- Protective effects of BN extracts against H2O2-induced oxidative stress and ROS levels in C6 glial cells
ROS impairs the physiological functions of C6 glial cells and causes cell death. Free radicals, such as O 2 , •OH, and • 1 O 2 , as well as non-radical species, such as H 2 O 2 , cause cell damage by increasing oxidative stress ( Chen and Gibson, 2008 ). H 2 O 2 is known to be a strong inducer of ROS, and if present at high levels promotes cell death ( Woo , 2003 ; Miller , 2010 ). The cytotoxicity test using MTT assays is shown in Fig. 1 . The treatment of BN extracts showed 77.8% to 97.5% of cell viability. Most of the BN extracts showed little or no cytotoxic activity in C6 glial cells up to 25 μ g/ml, therefore we used the concentration of 25 μ g/ml. The protective effect of the BN extracts against H 2 O 2 -induced oxidative stress in C6 glial cells is shown in Fig. 2 . Cell viability was significantly lower (58.2%) in H 2 O 2 -treated cells than in untreated cells. Cell viability improved when the 9 kinds of BN extracts were added at concentration of 25 μg/ml. BN-04, BN-05 and BN-08 have a little cytotoxic activity in C6 glial cells, so it showed lower cell viability than control group. On the other hand, the BN-01 (64.4%), BN-02 (64.1%), BN-03 (63.5%), BN-06 (64.5%), BN-07 (78.6%), and BN-09 (70.1%) shown higher than cell viability of control group, which indicate the protective activity against oxidative stress induced by H 2 O 2 .
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Cytotoxicity of BN extracts at on viability of C6 glial cells.

Values are represented as the mean ± SD.

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Effect of BN extracts on viability of C6 glial cells treated with H2O2.

Values are represented as the mean ± SD.

The production of ROS was monitored using DCFH-DA, a standard compound used to detect and quantify intracellularly produced H 2 O 2 ( Myhre, 2003 ). The fluorescence was proportional to the amount of ROS produced by the cells ( Fig. 3 ). ROS generation in H 2 O 2 -treated cells was markedly higher, but in cells treated with the 9 kinds of BN extracts, there was a decrease in DCFH oxidation. In particular, BN-01 (69.3%), BN-04 (70.2%), and BN-09 (67.1%) showed strong protective effect against ROS levels. These results show that BN extracts can protect against H 2 O 2 -induced oxidative stress and decrease ROS productions in C6 glial cells.
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Effect of BN extracts on level of reactive oxygen species in C6 glial cell treated with H2O2 (A: Time course of change in intensity of fluorescence with the BN extracts, B: The production of ROS after treatment with BN extracts).

Values are represented as the mean ± SD.

- Protective effects of BN extracts against Aβ25-35-induced oxidative stress and ROS levels in C6 glial cells
Aβ, a byproduct formed during the processing of amyloid precursor protein, is a major constituent of senile plaques, suggesting that its deposition play a role in the pathogenesis of AD ( Pike , 1995 ; Xio , 2000 ). Elevation of oxidative stress and activation of the apoptotic pathway play key roles in mediating Aβ-induced toxicity and neural cell death ( Behl ll., 1994 ; Santos , 2005 ), which is observed in the brains of patients with AD ( Markesbery, 1997 ; Butterfield , 2001 ). In the present study, we used Aβ 25-35 that was dissolved in sterile distilled water and precipitated by incubation at 37℃ for 3 days. The protective effect of the BN extracts against Aβ 25-35 -induced oxidative stress in C6 glial cells is shown in Fig. 4 . Aβ 25-35 -treated cells (25 μM) showed lower viability (56.6%) than untreated cells. BN extracts were added at a concentration of 25 μ g/ml. Among the 9 kinds of BN extracts, the BN-01, BN-02, BN-04, BN-05, BN-06, BN-08, and BN-09 extracts improved cell viability. In particular, BN-01 (62.3%), BN-05 (62.5%), BN-08 (64.0%), and BN-09 (61.2%) showed significant high cell viability compared to control group. It suggests that BN-01, BN-05, BN-08 and BN-09 would play the protective role against Aβ 25-35 -induced oxidative stress.
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Effect of BN extracts on viability of C6 glial cells treated with Aβ25-35.

Values are represented as the mean ± SD.

ROS generation in Aβ 25-35 -treated cells was higher, but cells treated with the 9 kinds of BN extracts showed a decrease in DCFH oxidation. As shown in Fig. 5 , 9 kinds of BN extracts were able to prevent the increase of ROS production induced by Aβ 25-35 compared to non-treated control conditions. Therefore, BN extracts protect against Aβ 25-35 -induced oxidative stress and decrease ROS production in C6 glial cells. On the other hand, the protective activity from oxidative stress and ROS generation did not affect cell viability. It indicated that the other factors are related to cell survival or death. BN-04, BN-05 and BN-08 have also led to the decline of ROS generation. Combining with the cell viability and ROS generation, BN-04, BN-05 and BN-08 have cytotoxiciy at 25 μ g/ml.
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Lager Image
Effect of BN extracts on level of reactive oxygen species in C6 glial cell treated with Aβ25-35 (A: Time course of change in intensity of fluorescence with the BN extracts, B: The production of ROS after treatment with BN extracts).

Values are represented as the mean ± SD.

All of the results indicated that BN-01 and BN-09 showed excellent protective effects against oxidative stress. However, it is necessary to carry out further studies about BN’s chemical constituents to confirm the related protective mechanisms.
Acknowledgements
This research was supported by iPET (Korea Institute of Planning and Evaluation for Technology in Food, Agriculture, Forestry, and Fisheries), Ministry of Agriculture, Food, and Rural Affairs, Korea.
References
Angelini L.G. , Lazzeri A. , Levita G. , Fontanelli D. , Bozzi. C. 2000 Ramie (Boehmeria nivea (L.) Gaud.) and Spanish broom (Spartium junceum L.) fibres for composite materials: agronomical aspects, morphology and mechanical properties Ind. Crops Prod. 11 145 - 161
Araujo D.M. , Cotman C.W. 2000 Beta-amyloid stimulates glial cells in vitro to produce growth factors that accumulate in senile plaques in Alzheimer’s disease Brain Res. 569 141 - 145
Behl C. , Davis J.B. , Lesley R. , Schubert D. 1994 Hydrogen peroxide mediates amyloid beta protein toxicity Cell 77 817 - 827
Butterfield D.A. , Lauderback. C.M. 2002 Lipid peroxidation and protein oxidation in Alzheimer’s disease brain: potential causes and consequences involving amyloid beta-peptide-associated free radical oxidative stress Free Radic. Biol. Med. 32 1050 - 1060
Butterfield D.A. , Drake J. , Pocernich C. , Castegna A. 2001 Evidence of oxidative damage in Alzheimer’s disease brian: central role for amyliod beta-peptide Trends Mol. Med. 7 548 - 554
Byun Y.J. , Kim S.K. , Kim Y.M. , Chea G.T. , Jeong S.W. , Lee S.B. 2009 Hydrogen peroxide induces autophagic cell death in C6 glioma cells via BNIP3-mediated suppression of the mTOR pathway Neurosci. Lett. 461 131 - 135
Castoria, R. L. , Caputo C.F. De , De. C.V. 2003 Resistance of postharvest biocontrol yeasts to oxidative stress: a possible new mechanism of action Phytopathology 93 564 - 572
Chen Y. , Gibson S.B. 2008 Is mitochondrial generation of reactive oxygen species a trigger for autophagy Autophagy 4 246 - 248
Di Carlo M. , Giacomazza D. , Picone P. , Nuzzo D. , San Biaqio P.L. 2012 Are oxidative stress and mitochondrial dysfunction the key players in the neurodegenerative diseases? Free Radic. Res. 46 1327 - 1338
Fukumoto L.R. , Mazza G. 2000 Assessing antioxidant and prooxidant activities and phenolic compounds J. Agric. Food Chem. 48 3597 - 3604
Gill S.S. , Tuteja N. 2010 Reactive oxygen species and antioxidant machinery in abiotic stress tolerance in crop plants Plant Physiol. Biochem. 48 909 - 930
Gupta K. , Wagle D.S. 1988 Nutritional and antinutritional factors of green leafy vegetables J. Agric. Food Chem. 36 472 - 474
Han W. , Wang M.H. 2010 Phenylalanine ammonia – Lyase gene (NtPAL4) induced by abiotic stresses in tobacco (Nicotiana tabacum) Korean J. Plant Res. 23 535 - 540
Huang K.L. , Lai Y.K. , Lin C.C. , Chang J.M. 2006 Inhibition of hepatitis B virus production by Boehmeria nivea root extract in HepG2 2.2.15 cells World J. Gastroenterol. 12 5721 - 5725
Juvenet J. 1889 Ramie J. Franklin Inst. 128 371 - 376
Kim S.H. , Sung M.J. , Park J.H. , Yang H.J. , Hwang J.T. 2013 Boehmeria nivea stimulates glucose uptake by activating peroxisome proliferator-activated receptor gamma in C2C12 cells and improves glucose intolerance in mice fed a high-fat diet Evid. Based Complement. Alternat. Med. 2013 1 - 9
Lee A.Y. , Wang X. , Lee D.G. , Kim Y.M. , Jung Y.S. , Kim H.B. , Kim H.Y. , Cho E.J. , Lee S. 2014 Various biological activities of ramie (Boehmeria nivea) J. Appl. Biol. Chem. 57 279 - 286
Lee E. , Cho E.J. 2007 Effects of Coptidis Rhizoma on lowering lipid and oxidative stress Korean J. Plant Res. 20 544 - 547
Liu F. , Liang X. , Zhang N. , Huang Y. , Zhang S. 2001 Effect of growth regulators on yield and fiber quality in ramie (Boehmeria nivea (L.) Gaud.) China grass. Field Crops Res. 69 41 - 46
Macarisin D. , Droby S. , Bauchan G. , Wisniewski M. 2010 Superoxide anion and hydrogen peroxide in the yeast antagonist-fruit interaction: a new role for reactive oxygen species in postharvest biocontrol? Postharvest Biol. Technol. 58 194 - 202
Madeo F. , FÖhlich E. , Ligr M. , Grey M. , Sigrist S.J. , Wolf D.H. , FrÖhlich K.U. 1999 Oxygen stress: a regulator of apoptosis in yeast J. Cell Biol. 145 757 - 767
Markesbery W.R. 1997 Oxidative stress hypothesis in Alzheimer’s disease Free Radic. Biol. Med. 23 134 - 147
Miller E.W. , Dickinson B.C. , Chang C.J. 2010 Aquaporin-3 mediates hydrogen peroxide uptake to regulate downstream intracellular signaling Proc. Natl. Acad. Sci. USA 107 15681 - 15686
Mosmann T. 1983 Rapid colormetric assay for cellular growth and survival: application to proliferation and cytotoxicity assays J. Immunol. Methods 65 55 - 63
Myhre O. 1983 Evaluation of the probes 2’,7’-dichlorofluorescin diacetate, luminal, and lucigenin as indicators of reactive species formation Biochem. Pharmacol. 65 1575 - 1582
Nho J.W. , Hwang I.G. , Kim H.Y. , Lee Y.R. , Woo K.S. , Hwang B.Y. , Chang S.J. , Lee J.S. , Jeong H.S. 2010 Free radical scavenging, angiotensin I-converting enzyme (ACE) inhibitory, and in vitro anticancer activities of ramie (Boehmeria nivea) leaves extracts Food Sci. Biotechnol. 19 383 - 390
Nunomura A. , Perry G. , Aliev G. , Hirai K. , Takeda A. , Balraj E.K. , Jones P.K. , Ghanbari H. , Wataya T. , Shimohama S. , Chiba S. , Atwood C.S. , Petersen R.B. , Smith M.A. 2001 Oxidative damage is the earliest event in Alzheimer disease J. Neuropathol. Exp. Neurol. 60 759 - 767
Park J.E. , Bae H.J. , Joo N.M. , Lee S.J. , Jung H.A. , Ahn E.M. 2010 The quality characteristics of cookies with added Boehmeria nivea Korean J. Food Nutr. (in Korean) 23 446 - 452
Pike C.J. , Walencewicz-Wasserman A.J. , Kosmoski J. , Cribbs D.H. , Glabe C.G. , Cotman C.W. 1995 Structure-activity analyses of β-amyloid peptidesl; contribution of the β25-35 region to aggregation and neurotoxicity J. Neurochem. 64 253 - 265
Santos M.J. , Quintanilla R.A. , Toro A. , Grandy R. , Dinamarca M.C. , Godoy J.A. , Inestrosa N.C. 2005 Peroxisomal proliferation protects from beta-amyloid neurode-generation J. Biol. Chem. 280 41057 - 41068
Shao L.J. , Wang J.N. 2010 Studies on the chemical constituents of radix Boehmeriae J. Chin. Med. Mat. 33 1091 - 1093
Sung M.J. , Davaatseren M. , Kim S.H. , Kim M.J. , Hwang J.T. 2013 Boehmeria nivea attenuates LPS-induced inflammatory markers by inhibiting p38 and JNK phosphorylations in RAW264.7 macrophages Pharm. Biol. 51 1131 - 1136
Tatone C. , Emidio G.D. , Ventol M. , Ciriminna R. , Artini P.G. 2013 Cryopreservation and oxidative stress in reproductive cells Gynecol. Endocrinol. 26 563 - 567
Tian X.Y. , Xu M. , Deng B. , Leung K.S. , Cheng K.F. , Zhao Z.Z. , Zhang S.P. , Yang Z.J. , Deng P.X. , Xu D.Y. , X.P. Xu , Koo I. , Wong M. 2011 The effects of Boehmeria nivea (L.) Gaud. on embryonic development: in vivo and in vitro studies J. Ethnopharmacol. 134 393 - 398
Wang J.Y. , Wen L.L. , Huang Y.N. , Chen Y.T. , Ku M.C. 2006 Dual effects of antioxidants in neurodegeneration: direct neuroprotection against oxidative stress and indirect protection via suppression of glia-mediated inflammation Curr. Pharm. Des. 12 3521 - 3533
Woo H.A. , Chae H.Z. , Hwang S.C. , Yang K.S. , Kang S.W. , Kim K. , Rhee S.G. 2003 Reversing the inactivation of peroxiredoxins caused by cysteine sulfinic acid formation Science 300 653 - 656
Wood I.M. , Angus J.F. 1974 A review of prospective crops for the Ord irrigation area. II Fibre Crops. CSIRO Aust. Div. Land Use Res. Tech. Pap. 36 1 - 27
Xio X.Q. , Wang R. , Han Y.F. , Tang X.C. 1974 Protective effects of huperzine A on β-amyloid25-35 induced oxidative injury in rat pheochromocytoma cells Neurosci. Lett. 286 155 - 158
Xu Q.M. , Liu Y.L. , Li X.R. , Li X. , Yang S.L. 2011 Three new fatty acids from the roots of Boehmeria nivea (L.) Gaudich and their antifungal activities Nat. Prod. Res. 25 640 - 647
Yatin S.M. , Varadarajan S. , Link C.D. , Butterfield D.A. 1999 In vitro and in vivo oxidative stress associated with Alzheimer's amyloid beta-peptide (1-42) Neurobiol. Aging 20 325 - 330
Yoon S.J. , Jang M.S. 2006 Characteristics of quality in Jeolpyun with different amounts of ramie Korean J. Food Cookery Sci. (in Korean) 22 636 - 641
Zhao X. , Yuan L. , Yu H. , Xi Y. , Ma W. , Zhou X. , Ding J. , Xiao R. 2013 Genistein inhibited amyloid-β induced inflammatory damage in C6 glial cells Arch. Med. Res. 45 152 - 157