- 著者
- Kensuke Yasui Noriyuki Miyoshi Hiroki Tanabe Yoko Ishigami Ryuuta Fukutomi Shinjiro Imai Mamoru Isemura
- 出版者
- Biomedical Research Press
- 雑誌
- Biomedical Research (ISSN:03886107)
- 巻号頁・発行日
- vol.32, no.2, pp.119-125, 2011 (Released:2011-05-03)
- 参考文献数
- 15
- 被引用文献数
- 2 3
Many biological activities of green tea have been attributed to a major constituent, (-)-epigallocatechin gallate (EGCG). We previously reported that EGCG and a catechin-rich green tea beverage modulated the gene expression of gluconeogenic enzymes, glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK), in the mouse liver. However, it remains to be examined whether or not a constituent other than EGCG contributes to the change in gene expression of these enzymes. In this study, we separated the hot water infusion of green tea leaves (GT) into an ethanol-soluble fraction (GT-E) and an EGCG-free water-soluble fraction (GT-W), and examined their effects using rat hepatoma H4IIE cells. The inclusion of GT, GT-E, and GT-W in the culture medium reduced the gene expression of G6Pase and PEPCK. GT-W caused a decrease in expression of the transcription factor HNF4α. Reduced levels of PEPCK and HNF4α proteins were demonstrated in the cells treated with GT-W. GT-W showed an activity similar to insulin, but different from EGCG. Administration of GT-W to mice for 4 weeks reduced the hepatic expression of G6Pase, PEPCK, and HNF4α. These results suggest that green tea contains some component(s) with insulin-like activity distinguishable from EGCG and that drinking green tea may help to prevent diabetes.
- 著者
- Munehiro Nakagawa Takamasa Ohno Rumi Maruyama Munenori Okubo Akito Nagatsu Makoto Inoue Hiroki Tanabe Genzou Takemura Shinya Minatoguchi Hisayoshi Fujiwara
- 出版者
- The Pharmaceutical Society of Japan
- 雑誌
- Biological and Pharmaceutical Bulletin (ISSN:09186158)
- 巻号頁・発行日
- vol.30, no.9, pp.1754-1757, 2007-09-01 (Released:2007-09-01)
- 参考文献数
- 27
- 被引用文献数
- 5 12
Abnormal vascular smooth muscle cell (VSMC) proliferation and migration are involved in restenosis following percutaneous transluminal angioplasty (PTCA) as well as in the development and progression of atherosclerosis. We investigated the mechanisms underlying the inhibitory effect of the sesquiterpene 3-oxo-5αH,8βH-eudesma-1,4(15),7(11)-trien-8,12-olide (1) on rat VSMC proliferation and migration. VSMCs were isolated from rat aorta, and then the effect of 1 on cell proliferation and migration was examined using methylthiazolyldiphenyl-tetrazolium bromide (MTT) and chemotaxis assays, respectively. Compound 1 had a potent inhibitory effect on fetal calf serum-induced VSMC proliferation. This effect correlated with reduced expression of cyclin D1. In addition, 1 also inhibited platelet derived growth factor (PDGF)-induced migration of VSMCs. These results indicate that 1 is a promising candidate for additional biological evaluation to further define its potential as an inhibitory modulator of VSMC responses that contribute to restenosis following PTCA and to the development and progression of atherosclerosis.