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Molecules 2018, 23(8), 1840;

Search of Neuroprotective Polyphenols Using the “Overlay” Isolation Method

Meikai University Research Institute of Odontology (M-RIO), 1-1 Keyakidai, Sakado, Saitama 350-0283, Japan
Department of Traditional Chinese Medicine, Shanghai Ninth People’s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 201900, China
Divisions of Biochemistry, Department of Oral Biology and Tissue Engineering, Meikai University School of Dentistry, Saitama 350-0283, Japan
Daiwa Biological Research Institute Co., Ltd., Kanagawa 213-0012, Japan
Authors to whom correspondence should be addressed.
Academic Editors: Hideyuki Ito, Tsutomu Hatano and Takashi Yoshida
Received: 30 June 2018 / Revised: 18 July 2018 / Accepted: 23 July 2018 / Published: 24 July 2018
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Previous studies of the neuroprotective activity of polyphenols have used ununiform culture systems, making it difficult to compare their neuroprotective potency. We have established a new and simple method for preparing differentiated PC12 cells by removing the toxic coating step. Cells were induced to differentiate with the nerve growth factor (NGF) in a serum-free medium, without a medium change, but with a one-time overlay supplementation of NGF. The optimal inoculation density of the cells was 6–12 × 103 cells/cm2, and the presence of serum inhibited the differentiation. Neuroprotective activity could be quantified by the specific index (SI) value, that is, the ratio of the 50% cytotoxic concentration to the 50% effective concentration. Alkaline extract from the leaves of Sasa senanensis Rehder (SE), having had hormetic growth stimulation, showed the highest SI value, followed by epigallocatechin gallate. The SI value of curcumin and resveratrol was much lower. This simple overly method, that can prepare massive differentiated neuronal cells, may be applicable for the study of the differentiation-associated changes in intracellular metabolites, and the interaction between neuronal cells and physiological factors. View Full-Text
Keywords: neuroprotection; PC12; NGF; differentiation; amyloid-β peptide; taxanes; hormesis; polyphenol; bamboo leaf extract; overlay method neuroprotection; PC12; NGF; differentiation; amyloid-β peptide; taxanes; hormesis; polyphenol; bamboo leaf extract; overlay method

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

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Sakagami, H.; Shi, H.; Bandow, K.; Tomomura, M.; Tomomura, A.; Horiuchi, M.; Fujisawa, T.; Oizumi, T. Search of Neuroprotective Polyphenols Using the “Overlay” Isolation Method. Molecules 2018, 23, 1840.

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