Epigallocatechin gallate inhibits beta amyloid oligomerization in Caenorhabditis elegans and affects the daf-2/insulin-like signaling pathway

• Published in: Phytomedicine (Stuttgart) 2010-09, Vol.17 (11), p.902-909
• Main Authors: Abbas, S., Wink, M.
• Format: Article
• Language: English
• Subjects: Alzheimer's disease; Amyloid beta-Peptides - metabolism; Animals; Animals, Genetically Modified; Antioxidants - pharmacology; Beta amyloid; Biological Transport; Caenorhabditis elegans; Caenorhabditis elegans - genetics; Caenorhabditis elegans - metabolism; Caenorhabditis elegans Proteins - metabolism; Camellia sinensis - chemistry; Care and treatment; Catechin - analogs & derivatives; Catechin - pharmacology; Cell Nucleus; Cytoplasm; daf-16; EGCG; Gene expression; Genetic aspects; Health aspects; Heat-Shock Proteins - metabolism; Immunohistochemistry; Insulin - metabolism; Lipofuscin - biosynthesis; Naphthoquinones - pharmacology; Oxidative Stress - drug effects; Physiological aspects; Plant Extracts - pharmacology; Polymerization; Receptor, Insulin - metabolism; Resveratrol; sHSPs; Signal Transduction - drug effects; Somatomedins - metabolism; Transcription Factors - metabolism
• ISSN: 0944-7113; 1618-095X
• DOI: 10.1016/j.phymed.2010.03.008

Epidemiological studies have repeatedly demonstrated that green tea protects against oxidative stress involved in many diseases. Health benefits of green tea are attributed to its principal active constituent, epigallocatechin gallate (EGCG). EGCG was shown to increase the stress resistance and lifespan of Caenorhabditis elegans. The mechanism of this action has been investigated in this study. The expression of hsp-16.1 and hsp-16.2 in EGCG-treated worms (N2), as quantified by real-time PCR, was significantly lower under oxidative stress induced by juglone than in controls without EGCG. In the strain TJ356 (DAF-16::GFP) EGCG treatment induced translocation of DAF-16 from the cytoplasm into the nucleus, suggesting that EGCG may affect the daf-2/insulin-like signaling pathway. EGCG decreased the formation of lipofuscin, an aging related pigment. Also, EGCG reduced beta amyloid (Aβ) deposits and inhibited Aβ oligomerization in transgenic C. elegans (CL2006). Thus, the use of green tea and EGCG is apparently rational alternatives for protecting against ROS-mediated and age-related diseases.