Dufour Claire, Loonis Michèle
UMR A408 INRA/University of Avignon, Safety and Quality of Plant Products, INRA, Site Agroparc, 84914 Avignon Cedex 9, France.
Biochim Biophys Acta. 2007 Jun;1770(6):958-65. doi: 10.1016/j.bbagen.2007.02.005. Epub 2007 Feb 27.
Although LDL esterified polyunsaturated fatty acids (PUFA) contribute largely to the pool of oxidizable lipids in plasma, they coexist with a non-negligible content of free PUFA. In some pathological conditions, the free PUFA/albumin ratio becomes abnormally elevated. Modeling was performed in a system constituted of linoleic acid bound to human serum albumin (HSA) in which oxidation was initiated by hydrophilic AAPH. Inhibition of lipid peroxidation was evaluated for various flavonoids. The accumulations of hydroperoxyoctadecadienoic acids (HPODE), hydroxyoctadecadienoic acids (HODE) and ketooctadecadienoic acids (KODE) were similarly inhibited: isoquercitrin>quercetin>catechin=isorhamnetin>>kaempferol>quercetin-4'-beta-D-glucoside=quercetin-3,4'-di-beta-D-glucoside. Surprisingly, quercetin and isorhamnetin afforded a protection to linoleic acid long after their consumption. Elucidation by mass spectrometry and NMR of the quercetin oxidation products and assessment of their antioxidant capacity pointed out that 3,4-dihydroxybenzoic acid and 2-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxybenzofuran-3(2H)-one are major contributors to the apparent quercetin antioxidant capacity.
尽管低密度脂蛋白酯化多不饱和脂肪酸（PUFA）在很大程度上构成了血浆中可氧化脂质的总量，但它们与不可忽略的游离PUFA含量共存。在某些病理条件下，游离PUFA/白蛋白比值会异常升高。在由与人类血清白蛋白（HSA）结合的亚油酸组成的系统中进行建模，其中通过亲水性偶氮二异丁腈（AAPH）引发氧化反应。评估了各种黄酮类化合物对脂质过氧化的抑制作用。氢过氧化十八碳二烯酸（HPODE）、羟基十八碳二烯酸（HODE）和酮基十八碳二烯酸（KODE）的积累受到类似抑制：异槲皮苷>槲皮素>儿茶素=异鼠李素>>山奈酚>槲皮素-4'-β-D-葡萄糖苷=槲皮素-3,4'-二-β-D-葡萄糖苷。令人惊讶的是，槲皮素和异鼠李素在消耗后很长时间内都能为亚油酸提供保护。通过质谱和核磁共振对槲皮素氧化产物进行解析并评估其抗氧化能力，结果表明3,4-二羟基苯甲酸和2-(3,4-二羟基苯甲酰基)-2,4,6-三羟基苯并呋喃-3(2H)-酮是槲皮素表观抗氧化能力的主要贡献者。
