Ketsawatsakul U, Whiteman M, Halliwell B
International Antioxidant Research Centre, GKT School of Biomedical Sciences, Third Floor Hodgkin Building, St. Thomas Street, London, SE1 9RT, United Kingdom.
Biochem Biophys Res Commun. 2000 Dec 20;279(2):692-9. doi: 10.1006/bbrc.2000.4014.
Peroxynitrite is implicated in many diseases. Hence, there is considerable interest in potential therapeutic peroxynitrite scavengers. Diet-derived phenolics have been claimed to be powerful peroxynitrite scavengers. However, the reactivity of peroxynitrite can be significantly modified by bicarbonate and this has not been considered in evaluations of the scavenging activity of phenols. Bicarbonate (25 mM) significantly decreased the ability of several phenolic compounds (caffeic acid, o- and p-coumaric acid, gallic acid, ferulic acid) but not others (catechin and epicatechin) to inhibit peroxynitrite-mediated tyrosine nitration. Bicarbonate (25 mM) also decreased the ability of catechin, epicatechin, quercetin and ferulic acid but not chlorogenic acid, gallic acid, caffeic acid and o-coumaric acid to inhibit peroxynitrite-mediated alpha(1)-antiproteinase inactivation. These results show that physiological concentrations of bicarbonate substantially modify the ability of dietary phenolics to prevent peroxynitrite-mediated reactions. When assessing compounds for peroxynitrite scavenging, experiments should be conducted in the presence of bicarbonate to avoid misleading results.
过氧亚硝酸根与多种疾病有关。因此，人们对潜在的治疗性过氧亚硝酸根清除剂有着浓厚的兴趣。饮食中的酚类物质据称是强大的过氧亚硝酸根清除剂。然而，碳酸氢根可显著改变过氧亚硝酸根的反应活性，而在评估酚类物质的清除活性时并未考虑这一点。碳酸氢根（25 mM）显著降低了几种酚类化合物（咖啡酸、邻香豆酸和对香豆酸、没食子酸、阿魏酸）但不是其他化合物（儿茶素和表儿茶素）抑制过氧亚硝酸根介导的酪氨酸硝化的能力。碳酸氢根（25 mM）还降低了儿茶素、表儿茶素、槲皮素和阿魏酸但不是绿原酸、没食子酸、咖啡酸和邻香豆酸抑制过氧亚硝酸根介导的α1抗蛋白酶失活的能力。这些结果表明，生理浓度的碳酸氢根会显著改变饮食中酚类物质预防过氧亚硝酸根介导反应的能力。在评估用于过氧亚硝酸根清除的化合物时，应在有碳酸氢根存在的情况下进行实验，以避免产生误导性结果。
