title: Black Tea High-Molecular-Weight Polyphenol-Rich Fraction Promotes Hypertrophy during Functional Overload in Mice.
abstract: Mitochondria activation factor (MAF) is a high-molecular-weight polyphenol extracted from black tea that stimulates training-induced 5' adenosine monophosphate-activated protein kinase (AMPK) activation and improves endurance capacity. Originally, MAF was purified from black tea using butanol and acetone, making it unsuitable for food preparation. Hence, we extracted a MAF-rich sample "E80" from black tea, using ethanol and water only. Here, we examined the effects of E80 on resistance training. Eight-week old C57BL/6 mice were fed with a normal diet or a diet containing 0.5% E80 for 4, 7 and 14 days under conditions of functional overload. It was found that E80 administration promoted overload-induced hypertrophy and induced phosphorylation of the Akt/mammalian target of rapamycin (mTOR) pathway proteins, such as Akt, P70 ribosomal protein S6 kinase (p70S6K), and S6 in the plantaris muscle. Therefore, functional overload and E80 administration accelerated mTOR signaling and increased protein synthesis in the muscle, thereby inducing hypertrophy.
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan. yuki.aoki87@gmail.com.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Aoki
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan. tetsuoozawa@ybb.ne.jp.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Ozawa
authors.affiliation: Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8574, Japan. takemasa.tohru.gm@u.tsukuba.ac.jp.
authors.forename: Tohru
authors.initials: T
authors.lastname: Takemasa
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan. numata.osamu.gb@u.tsukuba.ac.jp.
authors.forename: Osamu
authors.initials: O
authors.lastname: Numata
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D000818:Animals; D028241:Camellia sinensis / Q000737:chemistry*; D006984:Hypertrophy / Q000139:chemically induced* / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018485:Muscle Fibers, Skeletal / Q000187:drug effects*; D010766:Phosphorylation; D010805:Physical Conditioning, Animal; D010936:Plant Extracts / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology; D059808:Polyphenols / Q000008:administration & dosage* / Q000302:isolation & purification / Q000494:pharmacology; D055070:Resistance Training / Q000379:methods*; D015398:Signal Transduction / Q000502:physiology; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism; D013662:Tea
chemical_list: D010936:Plant Extracts; D059808:Polyphenols; D013662:Tea; D058570:TOR Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases
keywords: Akt; black tea; hypertrophy; mTOR; overload; polyphenol