Health Research Institute, National Institute of Advanced Industrial Science & Technology, Ikeda, Osaka, Japan.
Free Radic Res. 2012 Nov;46(11):1406-12. doi: 10.3109/10715762.2012.721542. Epub 2012 Sep 10.
Carotenoids act as physiological antioxidant by scavenging reactive-free radicals as well as quenching singlet oxygen. Fucoxanthin is one of the abundant carotenoids found in edible brown seaweeds. The assessment of radical scavenging capacity of carotenoids has been the subject of extensive studies, which, however, gave inconsistent results. In the present study, the capacity of fucoxanthin for scavenging peroxyl radicals, chain carrying species of lipid peroxidation, was assessed quantitatively by measuring the effect of α-tocopherol on the decay of fucoxanthin induced by peroxyl radicals. It was found that α-tocopherol was 7.1 times more reactive than fucoxanthin in heptane solution, but interestingly fucoxanthin exerted 1.6 times higher reactivity than α-tocopherol in methanol solution. In SDS micelles, the relative reactivity of fucoxanthin and α-tocopherol depended on the site of peroxyl radical formation. The efficacy of lipid peroxidation inhibition by fucoxanthin was much less than that of α-tocopherol.
类胡萝卜素可以通过清除活性自由基和淬灭单线态氧来作为生理抗氧化剂。岩藻黄质是在食用褐藻中发现的丰富类胡萝卜素之一。类胡萝卜素清除自由基能力的评估一直是广泛研究的课题，但结果并不一致。在本研究中，通过测量α-生育酚对岩藻黄质诱导的过氧自由基衰减的影响，定量评估了岩藻黄质清除过氧自由基的能力，过氧自由基是脂质过氧化的链载体。结果发现，α-生育酚在庚烷溶液中的反应性比岩藻黄质高 7.1 倍，但有趣的是，岩藻黄质在甲醇溶液中的反应性比 α-生育酚高 1.6 倍。在 SDS 胶束中，岩藻黄质和α-生育酚的相对反应性取决于过氧自由基形成的部位。岩藻黄质抑制脂质过氧化的效果远小于α-生育酚。
