Goya Luis, Delgado-Andrade Cristina, Rufián-Henares José A, Bravo Laura, Morales Francisco J
Consejo Superior de Investigaciones Científicas, Instituto del Frío, José Antonio Novais 10, Madrid, Spain.
Mol Nutr Food Res. 2007 May;51(5):536-45. doi: 10.1002/mnfr.200600228.
Soluble high-molecular weight fraction (named melanoidin) from coffee brew was isolated by ultrafiltration, subsequently digested by simulating a gastric plus pancreatic digestive condition and partly characterized by CZE, gel-filtration and browning. The objective of the present study was to investigate the potential protective effect of the coffee melanoidin submitted to gastrointestinal digestion on cell viability (lactate dehydrogenase leakage) and redox status of cultured human hepatoma HepG2 cells submitted to oxidative stress induced by tert-butylhydroperoxide (t-BOOH). Concentration of reduced glutathione (GSH) and malondialdehyde (MDA), generation of reactive oxygen species (ROS) and activity of antioxidant enzymes glutathione peroxidase (GPx) and reductase (GR) were used as markers of cellular oxidative status. Pretreatment of cultured HepG2 cells with 0.5-10 microg/mL digested coffee melanoidin (DCM) for 2 or 20 h completely prevented the increase in cell damage and GR and partly prevented the decrease of GSH and the increase of MDA and GPx evoked by t-BOOH in HepG2 cells. In contrast, increased ROS generation induced by t-BOOH was not prevented when cells were pretreated with DCM. The results show that treatment of HepG2 cells with concentrations of DCM within the expected physiological range confers the cells a significant protection against an oxidative insult.
通过超滤从咖啡冲泡液中分离出可溶性高分子量组分（称为类黑素），随后通过模拟胃加胰腺消化条件进行消化，并通过毛细管区带电泳、凝胶过滤和褐变进行部分表征。本研究的目的是探讨经胃肠道消化的咖啡类黑素对叔丁基过氧化氢（t-BOOH）诱导的氧化应激下培养的人肝癌HepG2细胞的细胞活力（乳酸脱氢酶泄漏）和氧化还原状态的潜在保护作用。还原型谷胱甘肽（GSH）和丙二醛（MDA）的浓度、活性氧（ROS）的产生以及抗氧化酶谷胱甘肽过氧化物酶（GPx）和还原酶（GR）的活性被用作细胞氧化状态的标志物。用0.5-10μg/mL消化的咖啡类黑素（DCM）预处理培养的HepG2细胞2或20小时，可完全防止t-BOOH诱导的HepG2细胞损伤增加和GR增加，并部分防止GSH减少以及MDA和GPx增加。相比之下，用DCM预处理细胞时，t-BOOH诱导的ROS产生增加并未得到阻止。结果表明，用预期生理范围内浓度的DCM处理HepG2细胞可使细胞对氧化损伤具有显著的保护作用。
