Thermodynamic versus Kinetic Control of Antioxidant Synergism between β-Carotene and (Iso)flavonoids and Their Glycosides in Liposomes
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- 作者：Ran Liang ; Chang-Hui Chen ; Rui-Min Han ; Jian-Ping Zhang ; Leif H. Skibsted
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2010
- 出版时间：August 25, 2010
- 年：2010
- 卷：58
- 期：16
- 页码：9221-9227
- 全文大小：858K
- 年卷期：v.58,no.16(August 25, 2010)
- ISSN：1520-5118
文摘
Antioxidant synergism (or antagonism) between plant (iso)flavonoids (daidzein, baicalein, and quercetin) or their glycosides (puerarin, baicalin, and rutin) and β-carotene in phosphatidylcholine liposomes (pH 7.4) with oxidation initiated thermally by the lipophilic free radical initiator 2,2′-azobis(2,4-dimethylvaleronitrile) (AMVN) and followed by the formation of conjugated dienes did not depend simply on the bond dissociation enthalpy (BDE) of the phenol O−H bond or the HOMO/LUMO energy gap based on density functional theory (DFT) calculations. Rate of regeneration of β-carotene from the β-carotene radical cation as the one-electron oxidation product of the lipid phase antioxidant by the monoanion form of the (iso)flavonoids in homogeneous (1:9 v/v methanol/chloroform) solution, as studied by laser flash photolysis and occurring on a microsecond time scale with biphasic kinetics, was in better agreement with the observed nonadditive antioxidative effects. However, correcting the observed (pseudo)-first-order rate constant for β-carotene regeneration for water/lipid distribution of the (iso)flavonoids provided an almost correct ordering of the (iso)flavonoids, according to the nonadditive effects with β-carotene on lipid oxidation.