Eichler Olaf, Sies Helmut, Stahl Wilhelm
Institut für Physiologische Chemie I and Biologisch-Medizinisches Forschunggzentrum, Heinrich-Heine-Universität Düsseldorf, Germany.
Photochem Photobiol. 2002 May;75(5):503-6. doi: 10.1562/0031-8655(2002)075<0503:dololc>2.0.co;2.
Exposure of living organisms to UV light leads to photooxidative reactions. Peroxyl radicals are involved in the propagation of lipid peroxidation. Carotenoids are dietary antioxidants and show photoprotective effects in human skin, efficiently scavenging peroxyl radicals and inhibiting lipid peroxidation. Cultured human skin fibroblasts were used to examine the protective effects of the carotenoids, lycopene, beta-carotene and lutein on UVB-induced lipid peroxidation. The carotenoids were delivered to the cells using liposomes as the vehicle. The cells were exposed to UVB light for 20 min. Lycopene, beta-carotene and lutein were capable of decreasing UV-induced formation of thiobarbituric acid-reactive substances at 1 h to levels 40-50% of controls free of carotenoids. The amounts of carotenoid needed for optimal protection were divergent at 0.05, 0.40 and 0.30 nmol/mg protein for lycopene, beta-carotene and lutein, respectively. Beyond the optimum levels, further increases of carotenoid levels in cells led to prooxidant effects.
生物体暴露于紫外线下会引发光氧化反应。过氧自由基参与脂质过氧化的传播过程。类胡萝卜素是膳食抗氧化剂，对人体皮肤具有光保护作用，能有效清除过氧自由基并抑制脂质过氧化。使用培养的人皮肤成纤维细胞来研究类胡萝卜素、番茄红素、β-胡萝卜素和叶黄素对紫外线B诱导的脂质过氧化的保护作用。以脂质体为载体将类胡萝卜素递送至细胞。细胞暴露于紫外线B下20分钟。番茄红素、β-胡萝卜素和叶黄素能够在1小时时将紫外线诱导的硫代巴比妥酸反应性物质的形成量降低至不含类胡萝卜素对照组的40%-50%。番茄红素、β-胡萝卜素和叶黄素实现最佳保护所需的类胡萝卜素量分别为0.05、0.40和0.30 nmol/mg蛋白质，各不相同。超过最佳水平后，细胞内类胡萝卜素水平的进一步增加会导致促氧化作用。
