Hegele Jörg, Münch Gerald, Pischetsrieder Monika
Department of Chemistry and Pharmacy, Food Chemistry, Friedrich-Alexander University Erlangen, Germany.
Mol Nutr Food Res. 2009 Jun;53(6):760-9. doi: 10.1002/mnfr.200800221.
The cytotoxic activity of Maillard reaction products and coffee was studied using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay and the neutral red uptake (NRU) assay. Equimolar mixtures of sugars and lysine were heated at 120 degrees C and used to stimulate bovine aorta endothelial cells for 24 h. The cytotoxic activity increased with increase in educt concentration and heating time. Mixtures containing ribose were most active, followed by lactose and glucose. Hydrogen peroxide, which was present in the Maillard mixtures in concentrations between 7 and 87 microM, was identified as one of their major cytotoxic components. H2O2-concentrations increased further up to 130 microM under cell culture conditions. Filter coffee, espresso, and green coffee extract reduced cell viability significantly to 10, 19, and 83% of PBS-treated control. The effect was largely attenuated by the addition of catalase. Nil, 33, and 41 microM H2O2 was measured in green coffee extract, filter coffee, and espresso, respectively, increasing to 13, 369, and 333 microM during cell culture conditions. No additional H2O2 formation was detected when coffee was incubated for up to 5 h without further treatment. In conclusion, hydrogen peroxide is a major product in Maillard mixtures and coffee inducing cell death in vitro.
使用3-(4,5-二甲基噻唑-2-基)-2,5-二苯基溴化四氮唑(MTT)法和中性红摄取(NRU)法研究了美拉德反应产物和咖啡的细胞毒性活性。将糖和赖氨酸的等摩尔混合物在120℃下加热，并用于刺激牛主动脉内皮细胞24小时。细胞毒性活性随着反应物浓度和加热时间的增加而增加。含有核糖的混合物活性最高，其次是乳糖和葡萄糖。美拉德混合物中浓度在7至87微摩尔之间的过氧化氢被确定为其主要细胞毒性成分之一。在细胞培养条件下，H2O2浓度进一步增加至130微摩尔。过滤咖啡、浓缩咖啡和生咖啡提取物显著降低细胞活力，分别降至经PBS处理的对照的10%、19%和83%。添加过氧化氢酶后，这种影响在很大程度上减弱。在生咖啡提取物、过滤咖啡和浓缩咖啡中分别测得0、33和41微摩尔H2O2，在细胞培养条件下增加到13、369和333微摩尔。未经进一步处理的咖啡孵育长达5小时时，未检测到额外的H2O2形成。总之，过氧化氢是美拉德混合物和咖啡在体外诱导细胞死亡的主要产物。
