Stagos Dimitrios, Umstead Todd M, Phelps David S, Skaltsounis Leandros, Haroutounian Serko, Floros Joanna, Kouretas Demetrios
Department of Biochemistry, University of Thessaly, Larissa, Greece.
Free Radic Res. 2007 Mar;41(3):357-66. doi: 10.1080/10715760601064714.
Surfactant protein-A (SP-A) is the best studied and most abundant of the protein components of lung surfactant and plays an important role in host defense of the lung. It has been shown that ozone-induced oxidation of SP-A protein changes its functional and biochemical properties. In the present study, eight plant polyphenols (three flavonoids, three hydroxycinnamic acids, and two hydroxybenzoic acids) known as strong antioxidants, were tested for their ability to inhibit ozone-induced SP-A oxidation as a mechanism for chemoprevention against lung damage. SP-A isolated from alveolar proteinosis patients was exposed to ozone (1 ppm) for 4 h. The flavonoids protected SP-A from oxidation in a dose dependent manner. ( - )-Epicatechin was the most potent flavonoid and exhibited inhibition of ozone-induced formation of carbonyls by 35% at a concentration as low as 5 microM. Hydroxybenzoic acids inhibited SP-A oxidation in a dose-dependent manner although they were less potent than flavonoids. On the other hand, hydroxycinnamic acids exhibited a different inhibitory pattern. Inhibition was observed only at medium concentrations. The results indicate that inhibition of SP-A oxidation by plant polyphenols may be a mechanism accounting for the protective activity of natural antioxidants against the effects of ozone exposure on lungs.
表面活性蛋白A（SP-A）是肺表面活性剂中研究最深入、含量最丰富的蛋白质成分，在肺部宿主防御中发挥重要作用。研究表明，臭氧诱导的SP-A蛋白氧化会改变其功能和生化特性。在本研究中，测试了八种已知为强抗氧化剂的植物多酚（三种黄酮类、三种羟基肉桂酸和两种羟基苯甲酸）抑制臭氧诱导的SP-A氧化的能力，作为预防肺部损伤的化学预防机制。从肺泡蛋白沉积症患者中分离出的SP-A暴露于臭氧（1 ppm）中4小时。黄酮类化合物以剂量依赖的方式保护SP-A不被氧化。（-）-表儿茶素是最有效的黄酮类化合物，在低至5 microM的浓度下，对臭氧诱导的羰基形成的抑制率为35%。羟基苯甲酸以剂量依赖的方式抑制SP-A氧化，尽管它们的效力不如黄酮类化合物。另一方面，羟基肉桂酸表现出不同的抑制模式。仅在中等浓度下观察到抑制作用。结果表明，植物多酚对SP-A氧化的抑制可能是天然抗氧化剂对臭氧暴露对肺部影响具有保护活性的一种机制。
