Heo Ho Jin, Lee Chang Yong
Department of Food Science and Technology, Cornell University, Geneva, NY 14456, USA.
J Agric Food Chem. 2004 Dec 15;52(25):7514-7. doi: 10.1021/jf049243r.
Clinical trials of several neurodegenerative diseases have increasingly targeted the evaluation of various antioxidants' effectiveness. The human diet contains several thousand phytochemicals, many of which have significant bioactivities. Vitamin C, a naturally occurring antioxidant, is known to reduce the risk of neurodegenerative disorders such as Alzheimer's disease. Quercetin, one of the major flavonoids in some fruits and vegetables, has much stronger antioxidative and anticarcinogenic activities than vitamin C. Therefore, we investigated the protective effects of quercetin on hydroxy peroxide-induced neurodegeneration. To determine the protective effects, PC12 cells were preincubated with quercetin and vitamin C before H(2)O(2) treatment for 2 h. Results showed that cell viability was clearly improved with quercetin, and quercetin showed a higher protective effect than vitamin C. Because oxidative stress is known to increase neuronal cell membrane breakdown, we further investigated lactate dehydrogenase and trypan blue exclusion assays. We observed that quercetin decreased oxidative stress-induced neuronal cell membrane damage more than vitamin C. These results suggest that quercetin, in addition to many other biological benefits, contributes significantly to the protective effects of neuronal cells from oxidative stress-induced neurotoxicity, such as Alzheimer disease.
几种神经退行性疾病的临床试验越来越多地以评估各种抗氧化剂的有效性为目标。人类饮食中含有数千种植物化学物质，其中许多具有显著的生物活性。维生素C是一种天然存在的抗氧化剂，已知可降低患神经退行性疾病如阿尔茨海默病的风险。槲皮素是一些水果和蔬菜中的主要类黄酮之一，其抗氧化和抗癌活性比维生素C强得多。因此，我们研究了槲皮素对过氧化氢诱导的神经退行性变的保护作用。为了确定保护作用，在H₂O₂处理前2小时，将PC12细胞与槲皮素和维生素C预孵育。结果表明，槲皮素能明显提高细胞活力，且槲皮素的保护作用高于维生素C。由于已知氧化应激会增加神经元细胞膜的破坏，我们进一步研究了乳酸脱氢酶和台盼蓝排斥试验。我们观察到，槲皮素比维生素C更能减少氧化应激诱导的神经元细胞膜损伤。这些结果表明，槲皮素除了具有许多其他生物学益处外，还对神经元细胞免受氧化应激诱导的神经毒性（如阿尔茨海默病）的保护作用有显著贡献。
