Chen Chung-Yen, Milbury Paul E, Chung Shin-Kyo, Blumberg Jeffrey
Antioxidants Research Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111, USA.
J Nutr Biochem. 2007 Dec;18(12):785-94. doi: 10.1016/j.jnutbio.2006.12.015. Epub 2007 May 2.
Almond skin polyphenolics (ASP) and vitamin C (VC) or E (VE) inhibit the Cu(2+)-induced generation of conjugated dienes in human low-density lipoprotein (LDL) in a synergistic manner. However, the mechanism(s) by which this synergy occurs is unknown. As modification of apolipoprotein (apo) B-100 is an early, critical step in LDL oxidation, we examined the effects of combining ASP or quercetin and antioxidant vitamins on the oxidation of this moiety as well as on the alteration of LDL conformation and electronegativity (LDL-). In a dose-dependent manner, ASP (0.12-2.0 micromol/L gallic acid equivalents) decreased tryptophan (Trp) oxidation by 6.7-75.7%, increased the generalized polarity (Gp) of LDL by 21.0-81.5% at 90 min and reduced the ratio of LDL- to total LDL (tLDL) by 38.2-83.8% at 5 h. The actions of ASP on these parameters were generally additive to those of VC and VE. However, a 10-25% synergy of ASP plus VC in protecting apo B-100 Trp against oxidation may result from their synergistic interaction in prolonging the lag time to oxidation. ASP and VE acted in synergy to reduce LDL-/tLDL by 24-43%. Quercetin's actions were similar to ASP, though more effective at inhibiting Trp oxidation. Thus, ASP and quercetin reduce the oxidative modification of apo B-100 and stabilize LDL conformation in a dose-dependent manner, acting in an additive or synergistic fashion with VC and VE.
杏仁皮多酚（ASP）与维生素C（VC）或维生素E（VE）以协同方式抑制铜离子（Cu(2+)）诱导的人低密度脂蛋白（LDL）中共轭二烯的生成。然而，这种协同作用发生的机制尚不清楚。由于载脂蛋白（apo）B - 100的修饰是LDL氧化过程中早期的关键步骤，我们研究了将ASP或槲皮素与抗氧化维生素联合使用对该部分氧化以及LDL构象和负电性（LDL-）改变的影响。ASP（0.12 - 2.0微摩尔/升没食子酸当量）以剂量依赖方式使色氨酸（Trp）氧化减少6.7 - 75.7%，在90分钟时使LDL的广义极性（Gp）增加21.0 - 81.5%，并在5小时时使LDL-与总LDL（tLDL）的比率降低38.2 - 83.8%。ASP对这些参数的作用通常与VC和VE的作用相加。然而，ASP加VC在保护apo B - 100 Trp免受氧化方面可能有10 - 25%的协同作用，这可能源于它们在延长氧化延迟时间方面的协同相互作用。ASP和VE协同作用使LDL-/tLDL降低24 - 43%。槲皮素的作用与ASP相似，尽管在抑制Trp氧化方面更有效。因此，ASP和槲皮素以剂量依赖方式减少apo B - 100的氧化修饰并稳定LDL构象，与VC和VE以相加或协同方式起作用。
