Chen Zhen-Yu, Wong Ivan Yuen Fan, Leung Magnolia Wing Shan, He Zhen-Dan, Huang Yu
Food and Nutritional Science Programme, Department of Biochemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, People's Republic of China.
J Agric Food Chem. 2002 Dec 18;50(26):7530-5. doi: 10.1021/jf0206421.
The present study examined the antioxidants present in bitter tea (Ligustrum pedunculare). It was found that the crude glycoside fraction strongly protected human low-density lipoprotein (LDL) from oxidation. Further column chromatography led to purification of eight phenylethanoid or monoterpene glycosides: lipedoside A-I, lipedoside A-II, lipedoside B-I, lipedoside B-III, lipedoside B-V, lipedoside B-VI, osmanthuside B, and anatolioside. It was found that lipedoside A-I, lipedoside A-II, lipedoside B-V, and lipedoside B-VI were protective, whereas the other four compounds did not protect human LDL from Cu(2+)-medicated oxidation. Lipedoside A-I, lipedoside A-II, lipedoside B-V, and lipedoside B-VI also had a scavenging effect on 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH), comparable to that of alpha-tocopherol. The inhibitory effect of these four phenylethanoid or monoterpene glycosides on oxidation of human LDL and alpha-tocopherol was dose-dependent at concentrations of 5-40 microM. The present results demonstrate that bitter tea as a beverage contains effective antioxidants that may have benefits similar to those of green tea in terms of antioxidant activity.
本研究检测了苦茶（毛梗女贞）中的抗氧化剂。结果发现，粗糖苷部分能强烈保护人低密度脂蛋白（LDL）不被氧化。进一步的柱色谱法纯化出了8种苯乙醇苷或单萜苷：女贞苷A-I、女贞苷A-II、女贞苷B-I、女贞苷B-III、女贞苷B-V、女贞苷B-VI、桂花苷B和安纳托利苷。结果发现，女贞苷A-I、女贞苷A-II、女贞苷B-V和女贞苷B-VI具有保护作用，而其他4种化合物不能保护人LDL免受铜（2+）介导的氧化。女贞苷A-I、女贞苷A-II、女贞苷B-V和女贞苷B-VI对2,2-二苯基-1-苦基肼自由基（DPPH）也有清除作用，与α-生育酚相当。这4种苯乙醇苷或单萜苷对人LDL氧化和α-生育酚的抑制作用在5-40微摩尔浓度范围内呈剂量依赖性。目前的结果表明，作为一种饮品，苦茶含有有效的抗氧化剂，在抗氧化活性方面可能具有与绿茶类似的益处。
