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Zhang S, Duangjan C, Tencomnao T, Liu J, Lin J, Wink M. Neuroprotective effects of oolong tea extracts against glutamate-induced toxicity in cultured neuronal cells and β-amyloid-induced toxicity in Caenorhabditis elegans. Food Funct 2021; 11:8179-8192. [PMID: 32966472 DOI: 10.1039/d0fo01072c] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Oolong tea, a traditional Chinese tea, is especially popular in south China and has a variety of health benefits. However, studies about its neuroprotective and neuroregenerative properties are still limited. This study explored the neuroprotective and neurite outgrowth-promoting properties of oolong tea in cultured neuronal cells (Neuro-2a and HT22) and Caenorhabditis elegans models. Ultra performance liquid chromatography was applied to identify the main natural bioactive compounds in oolong tea. Using Neuro-2a and HT22 cells, we found that oolong tea extracts had a protective effect against glutamate-induced cell death. The extracts reduced intracellular reactive oxygen species accumulation and induced gene expression of cellular antioxidant enzymes such as GPx, GSTs and SODs. These extracts also increased the average neurite length, and GAP-43 and Ten-4 mRNA expression in Neuro-2a cells. Moreover, they had protective effects against Aβ-induced paralysis, chemotaxis deficiency and α-synuclein aggregation in C. elegans. This is the first study showing the neuroregenerative and neuroprotective potential of the oolong tea extracts against glutamate/Aβ/α-synuclein-induced toxicity in vitro and in vivo. Our study may support oolong tea extracts as potential candidates for the prevention of neurodegenerative diseases.
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Affiliation(s)
- Shaoxiong Zhang
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China and Age-Related Inflammation and Degeneration Research Unit, Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, 10330, Thailand and Institute of Pharmacy and Molecular Biotechnology, Im Neuenheimer Feld 329, Heidelberg University, Heidelberg, 69120, Germany.
| | - Chatrawee Duangjan
- Age-Related Inflammation and Degeneration Research Unit, Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, 10330, Thailand and Institute of Pharmacy and Molecular Biotechnology, Im Neuenheimer Feld 329, Heidelberg University, Heidelberg, 69120, Germany. and Leonard Davis School of Gerontology, University of Southern California, Los Angeles, 90089, USA
| | - Tewin Tencomnao
- Age-Related Inflammation and Degeneration Research Unit, Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Jianghong Liu
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Jinke Lin
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China and Anxi College of Tea Science, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
| | - Michael Wink
- Institute of Pharmacy and Molecular Biotechnology, Im Neuenheimer Feld 329, Heidelberg University, Heidelberg, 69120, Germany.
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Zhu WL, Shi HS, Wei YM, Wang SJ, Sun CY, Ding ZB, Lu L. Green tea polyphenols produce antidepressant-like effects in adult mice. Pharmacol Res 2012; 65:74-80. [DOI: 10.1016/j.phrs.2011.09.007] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 09/15/2011] [Accepted: 09/18/2011] [Indexed: 01/13/2023]
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Gundimeda U, McNeill TH, Schiffman JE, Hinton DR, Gopalakrishna R. Green tea polyphenols potentiate the action of nerve growth factor to induce neuritogenesis: possible role of reactive oxygen species. J Neurosci Res 2010; 88:3644-55. [PMID: 20936703 DOI: 10.1002/jnr.22519] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Revised: 08/11/2010] [Accepted: 08/20/2010] [Indexed: 12/21/2022]
Abstract
Exogenously administered nerve growth factor (NGF) repairs injured axons, but it does not cross the blood-brain barrier. Thus, agents that could potentiate the neuritogenic ability of endogenous NGF would be of great utility in treating neurological injuries. Using the PC12 cell model, we show here that unfractionated green tea polyphenols (GTPP) at low concentrations (0.1 μg/ml) potentiate the ability of low concentrations of NGF (2 ng/ml) to induce neuritogenesis at a level comparable to that induced by optimally high concentrations of NGF (50 ng/ml) alone. In our experiments, GTPP by itself did not induce neuritogenesis or increase immunofluorescent staining for β-tubulin III; however, it increased expression of mRNA and proteins for the neuronal markers neurofilament-L and GAP-43. Among the polyphenols present in GTPP, epigallocatechin-3-gallate (EGCG) alone appreciably potentiated NGF-induced neurite outgrowth. Although other polyphenols present in GTPP, particularly epigallocatechin and epicatechin, lack this activity, they synergistically promoted this action of EGCG. GTPP also induced an activation of extracellular signal-regulated kinases (ERKs). PD98059, an inhibitor of the ERK pathway, blocked the expression of GAP-43. K252a, an inhibitor of TrkA-associated tyrosine kinase, partially blocked the expression of these genes and ERK activation. Antioxidants, catalase (cell-permeable form), and N-acetylcysteine (both L and D-forms) inhibited these events and abolished the GTPP potentiation of NGF-induced neuritogenesis. Taken together, these results show for the first time that GTPP potentiates NGF-induced neuritogenesis, likely through the involvement of sublethal levels of reactive oxygen species, and suggest that unfractionated GTPP is more effective in this respect than its fractionated polyphenols.
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Affiliation(s)
- Usha Gundimeda
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089-9112, USA
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