Li Yuk Man, Chan Ho Yin Edwin, Huang Yu, Chen Zhen Yu
Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, China.
Mol Nutr Food Res. 2007 May;51(5):546-54. doi: 10.1002/mnfr.200600238.
Chinese Longjing green tea is an excellent source of polyphenol antioxidants. HPLC analysis revealed that Longjing green tea catechin extract (GTC) contained 62% epigallocatechin gallate (EGCG), 19% epigallocatechin (EGC), 9% epicatechin gallate (ECG), and 7% epicatechin (EC). Investigating the effect of GTC on the lifespan of Drosophila melanogaster, we observed that a 10 mg GTC/mL diet could prolong its 50% survival time by 36% and mean lifespan by 16%. This was consistent with 17% reduction in total body lipid hydroperoxide (LPO) level in GTC-treated flies compared to the control group. Supplementation of 10 mg GTC/mL diet increased the survival time only in wild type Oregon-R-C (OR) but not in two mutant fly lines, SOD(n108)/TM3 (gene for superoxide dismutase (SOD) was knocked out) and Cat(n1)/TM3 (gene for catalase was knocked out), when the flies were challenged with paraquat or hydrogen peroxide. Accordingly, SOD and catalase activities in OR wild type increased by 40 and 19%, respectively. RT-PCR analysis indicated that the genes for copper-zinc containing SOD (CuZnSOD), manganese containing SOD (MnSOD), and catalase were upregulated. It was concluded that prolonging lifespan by GTC in D. melanogaster was influenced, among others, by upregulation of endogenous antioxidant enzymes.
中国龙井绿茶是多酚类抗氧化剂的优质来源。高效液相色谱分析表明，龙井绿茶儿茶素提取物（GTC）含有62%的表没食子儿茶素没食子酸酯（EGCG）、19%的表没食子儿茶素（EGC）、9%的表儿茶素没食子酸酯（ECG）和7%的表儿茶素（EC）。在研究GTC对黑腹果蝇寿命的影响时，我们观察到，含10 mg GTC/mL的食物能使其50%存活时间延长36%，平均寿命延长16%。这与GTC处理组果蝇体内脂质氢过氧化物（LPO）总水平相比对照组降低17%是一致的。当用百草枯或过氧化氢对果蝇进行攻击时，在含10 mg GTC/mL的食物中添加营养成分仅在野生型俄勒冈-R-C（OR）果蝇中延长了存活时间，而在两个突变果蝇品系（SOD(n108)/TM3，超氧化物歧化酶（SOD）基因被敲除；Cat(nl)/TM3，过氧化氢酶基因被敲除）中则没有延长存活时间。相应地，OR野生型果蝇中SOD和过氧化氢酶的活性分别提高了40%和19%。逆转录-聚合酶链反应分析表明，含铜锌超氧化物歧化酶（CuZnSOD）、含锰超氧化物歧化酶（MnSOD）和过氧化氢酶的基因上调。得出的结论是，GTC延长黑腹果蝇寿命受到内源性抗氧化酶上调等因素的影响。
