绿茶、乌龙茶、红茶中的主要组分和酚类化合物抑制脂肪氧合酶活性和抗油脂自动氧化特性的研究

绿茶、乌龙茶和红茶中含有多种抑制脂肪氧合酶及抗油脂自动氧化的有效成分。实验结果表明,其中以表没食子儿茶素没食子酸酯(EGCG)的抗氧化活性最强,延缓猪油自动氧化诱导期为55.5小时,比无添加抗氧化成分的延长11倍,抑制脂肪氧合酶活性的IC_(50)值为10.0μmol/L。茶黄素单酯-2B(TFM-2B)和茶黄素双酯(TFD)比EGCG抑制脂肪氧合酶活性的效果更强,其IC_(60)值分别为0.57和0.23μmol/L。在三种茶叶的四种溶剂萃取物中,以乙酸乙酯萃取物的抗氧化活性最强。本文还研究了茶叶中主要生物活性物质的分离与纯化方法,以及抗氧化活性与结构的关系。

ANTIOXIDANT PROPERTIES OF FRACTIONS AND POLYPHENOL CONSTITUENTS FROM GREEN,OOLONG AND BLACK TEAS

Green,oollong and black teas were extracted with water,and the water extracts were extracted separately with three types of solvent:chloroform,ethylacetate and butanol to obtain twelve fractions.Major flavanol was extracted by EtOAc,while most of the alkaloid was in the chloroform fraction.Thearubigin was greatest in the butanol fraction,and most of the amino acid remained in the water fraction.All fractions were systematecally analyzed by UV speetrophotometer and reverse phase HPLC for those important components existing in green tea,Oolong tea,black tea.The pure compounds of EC,ECG,EGC,EGCG,free theaflavin,theaflavin monogallate-A,theaflavin monogallate-B,and theaflavin digallate were separated by sephadex LH-20 chromtography and reverse phase HPLC.All fractions and pure compounds were assayed for antioxidant activity and lipoxygenase inhibition activity.Flavanol showed very strong antioxidant activity and lipoxygenase inhibition.