Daglia Maria, Racchi Marco, Papetti Adele, Lanni Cristina, Govoni Stefano, Gazzani Gabriella
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Pavia, via Taramelli 12, 27100 Pavia, Italy.
J Agric Food Chem. 2004 Mar 24;52(6):1700-4. doi: 10.1021/jf030298n.
The specific antiradical activity against the hydroxyl radical of the water soluble components in green and dark roasted Coffea arabica and Coffea robusta coffee samples, both in vitro by the chemical deoxiribose assay and ex vivo in a biological cellular system (IMR32 cells), were determined. All the tested coffee solutions showed remarkable antiradical activity. In the deoxiribose assay, all the tested solutions showed similar inhibitory activity (IA%) against the sugar degradation (IA values ranged from 45.2 to 46.9%). In the cell cultures, the survival increase (SI%) ranged from 197.0 to 394.0% with C. robusta roasted coffee being significantly more active than the other samples. The coffee solutions underwent dialysis (3500 Da cutoff membrane) to fraction their components. In both systems, the dialysates (MW < 3500 Da) either from green or roasted coffee, showed antiradical activity, while the only retentates (MW > 3500 Da) from the roasted coffee samples were active. The preparative gel-filtration chromatography of roasted coffee C. robusta dialysate gave three fractions active in the biological system, all containing chlorogenic acid derivatives. The most active fraction was found to be that containing the 5-O-caffeoilquinic acid, which shows a linear relation dose-response ranging from 0.02 to 0.10 mM. The results show that both green and roasted coffee possess antiradical activity, that their more active component is 5-O-caffeoyl-quinic acid, and moreover that roasting process induces high MW components (later Maillard reaction products, i.e., melanoidins), also possessing antiradical activity in coffee. These results could explain the neuroprotective effects found for coffee consumption in recent epidemiological studies.
测定了生咖啡豆和深度烘焙的阿拉伯咖啡豆及罗布斯塔咖啡豆样品中水溶性成分对羟基自由基的特定抗自由基活性，包括通过化学脱氧核糖测定法进行的体外实验以及在生物细胞系统（IMR32细胞）中进行的体内实验。所有测试的咖啡溶液均显示出显著的抗自由基活性。在脱氧核糖测定中，所有测试溶液对糖降解均表现出相似的抑制活性（IA%）（IA值范围为45.2%至46.9%）。在细胞培养中，罗布斯塔烘焙咖啡的存活率增加（SI%）范围为197.0%至394.0%，其活性显著高于其他样品。对咖啡溶液进行透析（截留分子量为3500 Da的膜）以分离其成分。在这两个系统中，生咖啡或烘焙咖啡的透析液（分子量<3500 Da）均显示出抗自由基活性，而烘焙咖啡样品中唯一的保留物（分子量>3500 Da）具有活性。对罗布斯塔烘焙咖啡透析液进行制备性凝胶过滤色谱分析得到了在生物系统中具有活性的三个组分，所有组分均含有绿原酸衍生物。发现活性最高的组分是含有5-O-咖啡酰奎尼酸的组分，其在0.02至0.10 mM范围内呈现剂量反应线性关系。结果表明，生咖啡和烘焙咖啡均具有抗自由基活性，其活性较高的成分是5-O-咖啡酰奎尼酸，此外烘焙过程会诱导高分子量成分（后期美拉德反应产物，即类黑素）产生，这些成分在咖啡中也具有抗自由基活性。这些结果可以解释近期流行病学研究中发现的咖啡消费对神经的保护作用。
