研究课题：新鲜绿色咖啡豆及烘烤咖啡豆体内外抗羟基自由基效果
供稿：药物化学系，药学院，Pavia大学，意大利

    主要内容：分别测定了阿拉比卡豆和罗伯斯特豆的新鲜绿色咖啡豆及烘烤咖啡豆中的水溶成分抗羟基自由基作用，体外用脱氧核糖化学分析法，体内用生物学细胞系统（IMR32细胞）。所有测试的咖啡溶液都有明显的抗自由基效果。在体外的脱氧核糖分析过程中，所有测试的咖啡溶液对糖降解都具有类似的抑制活性（IA指从45.2到46.9%）。在体内细胞培养系统中，存活增加指数（SI）从197到394%不等。对咖啡溶液进行透析（3500道尔顿滤过膜）成分级分，无论新鲜绿色咖啡豆还是烘烤咖啡豆滤过液（分子量小于3500Da）对两种系统都具有抗自由基效果；而只有烘烤咖啡豆的保留液（分子量大于3500Da）才具有抗自由基活性。对烘烤豆的滤过液进行分子筛至备分离，获得对体内细胞培养系统有效的三个成分，均含有咖啡单宁酸衍生物。其中最有效的成分是含有5-氧-咖啡油酸的成分，其线性剂量相关性范围从0.02mM到0.10mM。
    结论：结果证明新鲜绿色咖啡豆及烘烤咖啡豆中都具有抗自由基作用，最强的活性成分是5-氧-咖啡油酸；另外烘烤咖啡的过程产生了高分子量抗自由基活性成分（后期梅拉德反应产物，如蛋白黑素）。这些结果可以解释流行病学最近调查发现的饮用咖啡可以保护神经系统的机制。

In vitro and ex vivo antihydroxyl radical activity of green and roasted coffee.
Daglia M, Racchi M, Papetti A, et al. J Agric Food Chem. 2004 Mar 24;52(6):1700-4.
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Pavia, Pavia, Italy.

    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.

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