Biochemistry Division, Chemistry Department, Faculty of Science, Mansoura University, Mansoura, Egypt.
Eur Rev Med Pharmacol Sci. 2010 Sep;14(9):731-8.
Many changes can occur in proteins, including amino acid modification, fragmentation, changes in absorption and fluorescence spectra and others. All these modifications can be used as markers of protein damage by free radicals.
The aim of the present study was to investigate the antioxidant activities of the aqueous extracts of dry green of pods Phaseolus vulgaris, leaves of Olea europaea, unripe fruits of Bitter melon and leaves of Morus nigra. The pro-oxidant activities of the aqueous extracts of the above plants towards protein and estimation of some markers of the protein oxidation were also investigated.
The antioxidant activities of the above plants extracts, such as superoxide dismutase (SOD)- like and scavenging of diphenyl picrylhydrazyl (DPPH) radicals were observed. A soluble protein (bovine serum albumin: BSA) was incubated with different concentrations of the aqueous extracts of the plants of the present study. An aliquot from this mixture was used for sodium dodecyl sulphate/polyacrylamide gel electrophoresis (SDS-PAGE). Oxidative protein damage was assessed as tryptophan oxidation, carbonyl, quenone and advanced oxidation protein products (AOPP) generation in BSA in separate aliquots of the mixture.
All the plant extracts of this study had an antioxidant activity, but the aqueous extracts of both Olea europaea and Morus nigra leaves showed the highest antioxidant activities. In addition only the extracts of the Olea europaea and Morus nigra leaves showed highly oxidative fragmentation on BSA, but not the other plant extracts, which was evaluated by sodium dodecyl sulphate/polyacrylamide gel electrophoresis (SDS-PAGE) technique. The increase in protein oxidation products was in concentration dependent manner. The carbonyl, quenone and AOPP contents were highly significantly elevated in Olea europaea and Morus nigra leaves-treated protein when compared to the control protein. The tryptophan fluorescence was also significantly decreased in Olea europaea and Morus nigra leaves-treated protein when compared to the control sample.
[corrected] These data demonstrate the antioxidant and pro-oxidant activities of the aqueous extracts of the plants examined, while the highly effective are Olea europaea and Morus nigra leaves. The pro-oxidant activity of these plant extracts may be attributed to the unstable state of their phenoxyl radicals.
蛋白质可能会发生多种变化，包括氨基酸修饰、片段化、吸收和荧光光谱变化等。所有这些修饰都可以作为自由基引起蛋白质损伤的标志物。
本研究旨在探讨干绿豆荚、油橄榄叶、未成熟苦瓜和黑桑树叶的水提物的抗氧化活性。还研究了上述植物水提取物对蛋白质的促氧化活性以及蛋白质氧化的一些标志物的估算。
观察了上述植物提取物的抗氧化活性，如超氧化物歧化酶（SOD）样活性和二苯代苦味肼（DPPH）自由基清除活性。将不同浓度的本研究植物的水提物与可溶性蛋白（牛血清白蛋白：BSA）孵育。从该混合物中取出一份用于十二烷基硫酸钠/聚丙烯酰胺凝胶电泳（SDS-PAGE）。在混合物的不同等分试样中评估 BSA 中色氨酸氧化、羰基、醌和高级氧化蛋白产物（AOPP）的生成，以评估氧化蛋白损伤。
本研究的所有植物提取物均具有抗氧化活性，但油橄榄叶和黑桑叶的水提取物表现出最高的抗氧化活性。此外，只有油橄榄叶和黑桑叶的提取物在 BSA 上显示出高度氧化性的片段化，而其他植物提取物则没有，这可以通过十二烷基硫酸钠/聚丙烯酰胺凝胶电泳（SDS-PAGE）技术来评估。蛋白质氧化产物的增加呈浓度依赖性。与对照蛋白相比，Olea europaea 和 Morus nigra 叶处理的蛋白质中的羰基、醌和 AOPP 含量显著升高。与对照样品相比，Olea europaea 和 Morus nigra 叶处理的蛋白质中的色氨酸荧光也显著降低。
这些数据表明，所检查的植物的水提取物具有抗氧化和促氧化活性，而效果较高的是油橄榄叶和黑桑叶。这些植物提取物的促氧化活性可能归因于其酚氧自由基的不稳定状态。
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