【作者】 齐桂年； 田维熙； 姜波； 陈盛相； 李建华；

【Author】 QI Gui-nian;TIAN Wei-Xi;JIAN Bo;CHEN Sheng-xiang;LI Jian-hua;Department of Tea,Sichuan Agricultural University;Depatment of Biology,Graduate University of Chinese Academy of Siencese;The Quality Examination Center of Sichuan Border-sale Tea;

【机构】 四川农业大学园艺学院茶学系； 中国科学院研究生院生物系； 四川省边销茶质量检验中心；

【摘要】 脂肪酸合酶(Fatty Acid Synthase,FAS,E.C.2.3.1.85)是参与体内能量代谢的一种重要的酶。近几年研究报道,抑制FAS的活性可降低体重以及抑制癌细胞的生长,提出FAS是减肥和抑癌的双重潜在靶点。四川边茶(康砖)是我国最早的黑茶产品,也是我国西部少数民族的生活必需品,我国边疆少数民族地区有"宁可三日无食,不可一日无茶"的说法。本文利用酶动力学方法研究了四川边茶萃取物对FAS的抑制作用,结果表明,四川边茶萃取物对FAS有可逆和不可逆抑制双重作用,最佳萃取溶剂为50%左右的乙醇,在常温下2～3h即可达到最佳萃取效果。用开水泡茶的方法经两次浸取可提取出近60%的抑制FAS有效物,比绿茶的浸出效率约高1倍,但需较长的浸泡时间。四川边茶贮藏20年以上仍保持较强的对脂肪酸合酶的抑制能力,但贮藏30年以上抑制能力明显下降。四川边茶提取物与底物乙酰辅酶A和丙二酸单酰辅酶A的竞争性质都是竞争性与非竞争性的混合型;对FAS中的酮酰还原反应的抑制不明显,这说明酮酰还原酶结构域并不是其主要作用位点;进一步的实验表明四川边茶中的抑制剂不同于红茶和绿茶,是四川边茶中茶多酚氧化产物茶褐素起主要作用,其抑制能力高于绿茶中儿茶素而接近红茶中茶黄素。这些结果表明四川边茶在减肥、抑癌等方面具有良好的应用前景。更多还原

【Abstract】 Fatty acid synthase(E.C.2.1.3.85,FAS) is an important enzyme participating in energy metabolism in vivo.In recent years,it was reported that FAS inhibitors reduced body weight of test animals and inhibited the growth of tumour cell.And FAS has been proposed as a potential new therapeutic target for both cancer and obesity.Sichuan brick tea(Kang Zhuan) contains different tea polyphenols from green tea and black tea.The inhibition on FAS by the extract of brick tea is measured by inhibition kinetics.The results show that the inhibition included both reversible and irreversible process.The optimal solvent for the extraction of FAS inhibitors is about 50% ethanol.The extraction achieved during 2～3 hours in room temperature.The boiling water could extract about total 60% effective FAS inhibitors by two times extraction,which efficiency is two-folds of that for green tea.But longer time is needed for the extraction.The inhibitors in brick tea showed very stable for over 20 years.The brick tea extracts inhibited the overall reaction of FAS in a mixed manner of competitive and noncompetetive with acetyl-CoA and malonyl-CoA,But it inhibited the ketoacyl reduction of FAS weakly,which indicated that the ketoacyl reductase domain is not the reacted site that brick tea extracts attracted.These results shows that inhibitor in brick tea is different with that in green tea and black tea.It is proposed that the effective in brick tea should be theabrownine(TB),which inhibitory ability is higher than catechins and is closed with theaflavins.The results exhibited applicable foreground of brick tea for fat-reducing and anti-cancer.更多还原