【作者】 周杰；

【导师】 宛晓春； 张梁；

【作者基本信息】 安徽农业大学 ， 食品科学， 2014， 硕士

【摘要】 按照加工方法分类,茯砖茶属于黑茶的一种,属于后发酵茶,它的历史可以追溯到公元1500年的明朝。在我国新疆、西藏、内蒙古等地区.茯砖茶是我国西部少数民族的“生命之茶”。这些地区的膳食富含饱和脂肪酸的牛羊肉制品,茯砖茶常常与酥油一起作为西北少数民族的日常饮品。泾渭茯茶是以陕西南部(汉中和安康)山区的优质晒青毛茶为原料(主要为夏秋荼),经汽蒸、渥堆、压制、发花、干燥等工序加工而制成。独特的发花工艺造就了茯砖茶独特的品质和滋味以及植物化学成分。据此,本文以泾渭茯茶为原料,以GB15193.3-2003为规程,评价了泾渭茯茶的急性毒性。并参照2003版《保健食品检验与评价技术规范》中有关减肥降脂性功能产品的评价方法,采用预防型肥胖模型法,将造模和茶叶干预同时进行,采用不同剂量的茶汤对其进行为期4周的持续灌胃,测定体重、腹脂重量,血清、肝脏、粪便的脂质水平。我们利用GC-MS的脂质组学对肝组织脂肪成分进行系统分析,并结合RT-PCR相分析了肝脏脂肪酸合成和代谢相关基因的相对表达量,为阐明泾渭茯茶在调节脂质代谢方面的功效,提供一种新颖的研究模式。本研究的主要结果如下：1.泾渭茯茶急性毒性14天毒性试验结果显示泾渭茯茶对雄性昆明种小鼠的急性经口LD50为15.163g/kg.bw,95%可信限为13.575-17.036 g/kg.bw;对雌性昆明种小鼠的急性经口LD50为16.944 g/kg.bw,95%可信限为15.141-19.072 g/kg.bw。大于国标规定的无毒物质的半致死剂量,泾渭茯茶属无毒物质。2.泾渭茯茶对肥胖大鼠减肥降脂作用(1)泾渭茯茶抑制体重增长,并减少腹部脂肪重量。与高脂模型组相比,中、高剂量预防肥胖效果显著(p<0.05,p<0.01),且呈剂量依赖性,体重增长率分别降低了14.2%和19.4%,腹部脂肪堆积率分别降低了31.1%和42.0%。(2)泾渭茯茶具有一定的降血脂功能,由于泾渭茯茶干预时间较短,仅高剂量(2.0g/kg,p<0.05)降血脂(TG、TC、LDL-C)效果显著。(3)与高脂模型组动物相比,低、中、高剂量泾渭茯茶能够明显地降低肝脏总胆固醇(TC)水平(p<0.05,p<0.05,p<0.001),分别降低了15.93%,17.24%和29.56%,同时在中、高剂量能显著降低肝脏总甘油三酯(TG)水平(p<0.05,p<0.05),分别降低了42.34%,55.49%,表明泾渭茯茶对预防由于脂质在肝脏中过度沉积所导致的非酒精性脂肪肝具有很大的潜力。(4)与高脂模型组相比,低、中、高剂量的茯砖茶均能够促进大鼠粪便中脂质的排泄,尤其以促进总胆固醇(TC)的排泄最为明显(p<0.05,p<0.01),胆固醇排泄增加量分别为55.7%、65.6%、67.0%。3. GC-MS对泾渭茯茶干预后大鼠肝脏脂肪酸代谢差异性分析泾渭茯茶能够调节大鼠肝脏脂肪酸的代谢,促使肝脏脂肪酸比例发生改变。C16:1n-7/C16:0、C18:1n-9/C18:0的比例一般用来表征SCD1酶活性,高剂量泾渭茯茶可以显著降低这两组脂肪酸比例：且GC-MS脂质代谢组学分析显示高脂组动物肝脏脂质水平与正常动物差异显著,而灌胃低、中、高剂量泾渭茯茶后的大鼠肝脏脂质代谢趋近于正常动物,表明泾渭茯茶对于高脂动物肝脏脂肪酸代谢的正常化具有恢复作用。4.荧光定量PCR对泾渭茯茶干预后大鼠肝脏脂质代谢相关基因差异表达的研究(1)与正常对照组相比,高脂模型组脂肪酸从头合成基因FAS、ACC、SCD1的相对表达量均显著下调,而参与β-氧化的CPT-1则被显著上调。表明动物在高脂的干预下自身存在“自适性反应”：增加外源性脂肪的分解(β-氧化),减少内源性脂肪的从头合成。(2)灌胃泾渭茯茶4周后,大鼠肝脏FAS、ACC、SCD1基因表现出更为显著的下调表达,CPT-1基因出现更显著的上调表达。表明高脂组动物在泾渭茯茶的干预下机体“自适性反应”增强,以维持机体脂质代谢平衡。更多还原

【Abstract】 "Fu" tea is a kind of the Chinese dark teas according to the classification of processing method, and belongs to post-fermented tea, the history of which should be dated back to the Ming Dynasty at 1500 A.D. It is indispensible for the highland minority who consume high levels of dietary saturated animal products rather than vegetables and fruits in Western China, such as Sinkiang, Tibet, Inner Mongolia. But their chances of developing metabolic disease is not high, this may be related to their daily drinking lots of Fu brick tea, Fu brick tea may be able to help digest fats, promote the metabolism of lipid. JWFT is produced from the mature leaves of Camellia sinensis, undergoes a special process of fermentation with the fungus Eurotuim cristotium in the areas of Yellow river basin. The detailed manufacture process of the tea has been described as panning, rapid pile fermentation, rolling, drying, softening with steam, piling, tea brick pressing, fungal fermentation, and drying. The "fungal fermentation" phase is critical for forming the typical fungal aroma and taste, and unique phytochemical profile.In this study, we based on GB15193.3-2003 procedures to assessing the acute toxicity of Jing-wei fu tea. And referred to the 2003 Edition of the health food testing and evaluation technical norms regarding function product evaluation method of reducing weight and lipid-lowering, adopt the obesity prevention model, high-fat diet and tea aqueous extract were given at the same time, administration different doses of tea for 4 weeks to analysis the influence of JWFT on serum total cholesterol, triglyceride, LDL-C, hepatic total cholesterol and triglyceride, fecal total cholesterol and triglyceride were determined. Hepatic fatty acid composition and relative expression of lipids metabolism gene in liver were investigated by the GC-MS based lipidomics and RT-PCR analysis. The aim of this paper is to discover the marker fatty acids of high-fat diet fed rats treated with JWFT, elucidate JWFT’s function in regulating lipid metabolism and provide a novel understanding of JWFT’s efficacy on lipid-related disease, especially lipid-lowering and anti-obesity. Research results are as follows:1. Acute toxicity of Jing-wei fu tea14 days acute toxicity test of Jing-wei fu tea, showed Jing-wei fu tea on acute oral LD50 in male mice was 15.163 g/kg,95% trusted limit 13.575～17.036 g/kg.bw; acute oral LD50 in female mice 16.944 g/kg,95% credible limit 15.141～19.072 g/kg.bw. According to the PRC national standard, it is greater than the half lethal dose of non-toxic substances, so Jing-wei fu tea is a non-toxic substance.2. The effect of anti-obesity and lipid-lowering of Jing-wei fu tea.The control group of hyperlipidemic rats gained significantly more weight during the study than those fed a normal chow diet (p<0.05). Within the groups fed the hyperlipidemic diet, the group treated with daily administration of the medium and high dose (1.0,2.0g/kg) of JWFT extract exhibited a remarkably decreasing on body weight and abdominal fat over the course of the study compared with the control-treated hyperlipidemic group (p< 0.05,0.01), and the body weight again were reduced 14.2% and 19.4%, abdominal fat accumulation rate decreased 31.1% and 42.0% respectively。But treatment with low dose of JWFT extract did not exert significant effect on the weight increase in hyperlipidemic rats.Serum levels of total cholesterol (TC) and triglycerides (TG) consistently were much higher in rats fed the hyperlipidemic diet compared with the basal diet group after 28days (p< 0.01). After four weeks treatment of high dose of JWFT extract(2.0g/Kg), levels of TC, TG and LDL-C were significantly lower than the high fat control group (p <0.05)The high fat-diet caused the elevation of hepatic total TG and TC levels. Consumption of JWFT suppressed the increase in hepatic total TG and TC concentrations. TC levels dose-dependently decreased by 15.93%,17.24%,29.56% when treat with 0.5,1.0 and 2.0 g/kg, respectively, of JWFT extract. JWFT also significantly inhabited the increase of hepatic total TG levels in moderate and high doses, and had 42.34%,55.49% reduction respectively compared with HFC. Although, the low dose did not reduce TG level evidently than other two doses, it also had 27.57% reduction.The above results demonstrate that moderate and high dose of JWFT both have potent effect on lowering hepatic total TG and TC levels in hyperlipidemic.3. The relative proportional fatty acid composition of liverJing-wei fu tea can regulate fatty acid metabolism of rat liver, and promote liver fatty acid ratio changed. Hepatic stearoyl-CoA desaturase 1 (SCD1) activity can estimate from the C16:1/C16:0 or C18:1n-9/C18:0 ratios, high dose Jing-wei fu tea can significantly reduce this two group fatty acids proportion. The principal components analysis (PCA) of GC-MS data of fatty acids of liver showed that the fatty acids composition of rat liver of HFC is highly different from NC. After the treatment of JWFT, the profiles of fatty acids of liver were reversed and similar to the normal diet feed rats. It indicate that jing-wei fu tea can normalize the liver fatty acids metabolism of high fat fed rats4. Relative mRNA expression of hepatic lipid metabolism geneCompared with normal control group, hyperlipidemia model group of fatty acids de novo genes relative expression of SCD1, FAS and ACC mRNA were significantly down-regulated, while the CPT-1 gene involved in theβ-oxidation was up-regulated. It shows that animals had the ability to regulate lipid metabolism by "self-adaptive response":increase of exogenous fat breakdown (β-oxidation), reduce endogenous lipid de novo synthesis under high-fat diet condition.After four weeks’Jing-wei fu tea administration, relative expression of rat hepatic SCD1, FAS and ACC mRNA were more significantly down-regulated, and the CPT-1 gene appeared more markedly up-regulated. It indicates that Jing-wei fu tea can enhance the effect of "self-adaptive response" to balace the lipid metabolism.更多还原