Diet, Genomics, and Immunology Laboratory, BHNRC, ARS, USDA, Bldg. 307C, Rm. 131, Beltsville, MD 20705, USA.
Food Funct. 2013 Nov;4(11):1632-8. doi: 10.1039/c3fo60138b.
Coffee is a most consumed drink worldwide, with potential health effects on several chronic diseases including neuronal degenerative diseases. Chlorogenic acids (CHAs) are phenolic compounds found in coffee and they are reported to have strong antioxidant and anti-inflammatory activities. However, the amounts of CHAs often vary in coffee drinks and their potential effects on ROS-induced neuronal cell death still require more investigation. Therefore, in this paper, major CHAs were isolated from three major instant coffee brands, confirmed and quantified using HPLC and NMR spectroscopic methods. Then, their antioxidant activities and protective effects on H2O2-induced apoptosis in PC-12 cells were investigated using radical scavenging, mitochondrial membrane potential and caspase assays. In the coffee samples, three major CHAs (3-O-caffeoylquinic acid, 4-O-caffeoylquinic acid, 5-O-caffeoylquinic acid) and some minor CHAs (3-O-feruloylquinic acid, 4-O-feruloylquinic acid, 5-O-feruloylquinic acid, 3,5-O-dicaffeoylquinic acid, 3,4-O-dicaffeoylquinic acid, and 4,5-O-dicaffeoylquinic acid) were detected. The three major CHAs were further isolated and their chemical structures were confirmed using NMR spectroscopic techniques. Also, the amounts of the three major CHAs were individually quantified using a HPLC method. At the concentration of 10 μM, all three major CHAs quenched DPPH and/or xanthine oxidase-generated radical species by 21-51% (P < 0.014). They also inhibited H2O2-induced mitochondrial membrane depolarization and caspase-9 activation by 27% (P < 0.034) and 50% (P < 0.05), respectively. This study suggests that the major CHAs found in coffee are likely to be potent antioxidant compounds able to quench radical species as well as inhibit H2O2-induced apoptosis via suppressing mitochondrial membrane depolarization and caspase-9 activation in the cells.
咖啡是全球范围内最受欢迎的饮品之一，其对多种慢性疾病（包括神经退行性疾病）可能具有健康影响。绿原酸（CHAs）是咖啡中含有的酚类化合物，据报道具有很强的抗氧化和抗炎活性。然而，咖啡饮料中的 CHA 含量差异较大，其对 ROS 诱导的神经元细胞死亡的潜在影响仍需要更多的研究。因此，在本文中，我们从三个主要的速溶咖啡品牌中分离出主要的 CHA，使用 HPLC 和 NMR 光谱方法进行鉴定和定量。然后，通过自由基清除、线粒体膜电位和 caspase 测定研究它们的抗氧化活性以及对 H2O2 诱导的 PC-12 细胞凋亡的保护作用。在咖啡样品中，检测到三种主要的 CHA（3-O-咖啡酰奎宁酸、4-O-咖啡酰奎宁酸、5-O-咖啡酰奎宁酸）和一些次要的 CHA（3-O-阿魏酰奎宁酸、4-O-阿魏酰奎宁酸、5-O-阿魏酰奎宁酸、3,5-O-二咖啡酰奎宁酸、3,4-O-二咖啡酰奎宁酸和 4,5-O-二咖啡酰奎宁酸）。进一步分离出这三种主要的 CHA，并使用 NMR 光谱技术确定其化学结构。此外，还使用 HPLC 方法分别定量了这三种主要 CHA 的含量。在 10 μM 浓度下，三种主要的 CHA 均能通过 21%-51%（P < 0.014）淬灭 DPPH 和/或黄嘌呤氧化酶产生的自由基。它们还分别抑制了 27%（P < 0.034）和 50%（P < 0.05）的 H2O2 诱导的线粒体膜去极化和 caspase-9 活化。本研究表明，咖啡中发现的主要 CHA 可能是有效的抗氧化化合物，能够通过淬灭自由基以及抑制线粒体膜去极化和 caspase-9 活化来抑制细胞中的 H2O2 诱导的细胞凋亡。
