Laggner Hilde, Schreier Sabine, Hermann Marcela, Exner Markus, Mühl Adolf, Gmeiner Bernhard M K, Kapiotis Stylianos
Department of Medical Chemistry, Centre of Physiology and Pathophysiology, Medical University Vienna, Vienna, Austria.
Free Radic Res. 2007 Feb;41(2):234-41. doi: 10.1080/10715760600978831.
Hypericin and pseudohypericin are polycyclic-phenolic structurally related compounds found in Hypericum perforatum L. (St John's wort). As hypericin has been found to bind to LDL one may assume that it can act as antioxidant of LDL lipid oxidation, a property which is of prophylactic/therapeutic interest regarding atherogenesis as LDL oxidation may play a pivotal role in the onset of atherosclerosis. Therefore, in the present paper hypericin, pseudohypericin and hyperforin, an other structurally unrelated constituent in St John's wort were tested in their ability to inhibit LDL oxidation. LDL was isolated by ultracentrifugation and oxidation was initiated either by transition metal ions (copper), tyrosyl radical (myeloperoxidase/hydrogen peroxide/tyrosine) or by endothelial cells (HUVEC). LDL modification was monitored by conjugated diene and malondialdehyde formation. The data show that all compounds (hypericin, pseudohypericin and hyperforin) at doses as low as 2.5 micromol/l are potent antioxidants in the LDL oxidation systems used. The results indicate that the derivatives found in Hypericum perforatum have possible antiatherogenic potential.
金丝桃素和假金丝桃素是在贯叶连翘（圣约翰草）中发现的结构相关的多环酚类化合物。由于已发现金丝桃素能与低密度脂蛋白（LDL）结合，因此可以推测它能作为LDL脂质氧化的抗氧化剂，鉴于LDL氧化可能在动脉粥样硬化的发生中起关键作用，这一特性在动脉粥样硬化的预防/治疗方面具有重要意义。因此，在本论文中，对金丝桃素、假金丝桃素和贯叶连翘中另一种结构不相关的成分贯叶连翘素抑制LDL氧化的能力进行了测试。通过超速离心法分离LDL，并通过过渡金属离子（铜）、酪氨酰自由基（髓过氧化物酶/过氧化氢/酪氨酸）或内皮细胞（人脐静脉内皮细胞，HUVEC）引发氧化反应。通过共轭二烯和丙二醛的形成来监测LDL的修饰情况。数据表明，所有化合物（金丝桃素、假金丝桃素和贯叶连翘素）在低至2.5微摩尔/升的剂量下，在所使用的LDL氧化系统中都是有效的抗氧化剂。结果表明，贯叶连翘中发现的这些衍生物具有潜在的抗动脉粥样硬化作用。
