Enhancement of antioxidative ability of rat plasma by oral administration of (-)-epicatechin.
Enhancement of antioxidative ability of rat plasma by oral administration of (-)-epicatechin.
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口服(-)-表儿茶素增强大鼠血浆抗氧化能力。
DOI：
10.1016/s0891-5849(97)00438-3
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发表时间：
1998
影响因子：
7.4
通讯作者：
J. Terao
中科院分区：
文献类型：
--
作者：
E. Silva;M. Piskuła;J. Terao
为了检查摄入（-）-表儿茶素（EC）是否影响血浆中的抗氧化防御，我们研究了Wistar大鼠灌胃给予10或50 mg/只EC后血浆的氧化能力。用硫酸铜或2，2 ′-偶氮二（2-脒基丙烷）二盐酸盐（AAPH）氧化从对照或EC给药大鼠获得的血浆池。EC给药后1 h血浆中的EC代谢物含有游离和O-甲基化形式的葡糖苷酸和葡糖苷酸-硫酸盐结合物。6小时后，总EC代谢物的血浆浓度降低，剩余的缀合物主要以O-甲基化形式存在。与对照组相比，EC给药后1和6小时从大鼠获得的血浆对硫酸铜诱导的氧化的基础上，胆固醇酯氢过氧化物（CE-OOH）积累更有抵抗力。此外，在EC处理大鼠的血浆中，氧化过程中α-生育酚的消耗受到抑制。EC给药动物血浆中CE-OOH的含量和α-生育酚的消耗量远低于血浆中存在的未代谢EC量的预期值。从AAPH诱导的大鼠血浆氧化EC给药后，获得了类似的结果，除了CE-OOH积累的事实，在血浆中抑制较少6小时后给药。当EC给药大鼠血浆在37°自动氧化时，发现O-甲基化形式比游离形式更稳定。这些结果表明，EC代谢产物，特别是游离形式的缀合物，在血浆中具有有效的抗氧化活性。
To check whether ingestion of (−)-epicatechin (EC) affects the antioxidative defense in blood plasma, we studied the oxidizability of plasma from Wistar rats after intragastrical EC administration at 10 or 50 mg/rat. The plasma pool obtained from control or EC-administered rats was oxidized with copper sulfate or 2,2′-azobis(2-amidinopropane)dihydrochloride (AAPH). EC metabolites in plasma 1 h after EC administration contained glucuronide and glucuronide-sulfate conjugates in both the free and O-methylated form. After 6 h, the plasma concentration of total EC metabolites decreased and the remaining conjugates were mostly present as the O-methylated form. Compared to the control group, the plasma obtained from rats 1 and 6 h after EC administration was more resistant against copper sulfate-induced oxidation on the basis of cholesteryl ester hydroperoxide (CE-OOH) accumulation. Also, the consumption of α-tocopherol during oxidation was suppressed in the plasma obtained from EC-treated rats. The content of CE-OOH and consumption of α-tocopherol in the plasma from EC-administered animals was much lower than those expected from the amount of nonmetabolized EC present in the plasma. Similar results were obtained from AAPH-induced oxidation of rat plasma after EC administration, except for the fact that CE-OOH accumulation was less suppressed in the plasma 6 h following administration. The O-methylated form was found to be more stable than the free form when EC-administered rat plasma was auto-oxidized at 37°. These results suggest that EC metabolites, particularly conjugates in the free form, possess an effective antioxidative activity in blood plasma.