Department of Nutrition, University of Massachusetts, Amherst, MA 10003, USA.
Eur J Nutr. 2011 Mar;50(2):81-8. doi: 10.1007/s00394-010-0117-8. Epub 2010 Jun 23.
Naringenin, a flavonoid present in grapefruit, has recently been shown to exert hypolipidemic and hypocholesterolemic effects, which has a particular importance for protecting against chronic diseases. However, the lipid-lowering potential of naringenin at the concentrations in the dietary range and its underlying mechanisms have yet to be fully elucidated.
The aim of the present study was (1) to investigate the effects of dietary naringenin on plasma and hepatic triglyceride and cholesterol levels and on adipose deposition in rat and (2) to determine the contribution of hepatic peroxisome proliferators-activated receptor α (PPARα) expression to fatty acid oxidation.
Male Long-Evans hooded rats were fed a diet supplemented with naringenin (0.003, 0.006, and 0.012%) for 6 weeks. We analyzed plasma and hepatic lipid contents and determined the protein expression of PPARα, carnitine-palmitoyl transferase 1L (CPT-1), and uncoupling protein 2 (UCP2), all of which are critical genes for fatty acid oxidation.
Naringenin supplementation caused a significant reduction in the amount of total triglyceride and cholesterol in plasma and liver. In addition, naringenin supplementation lowered adiposity and triglyceride contents in parametrial adipose tissue. Naringenin-fed animals showed a significant increase in PPARα protein expression in the liver. Furthermore, expression of CPT-1 and UCP2, both of which are known to be regulated by PPARα, was markedly enhanced by naringenin treatment.
Our results indicate that the activation of PPARα transcription factor and upregulation of its fatty acid oxidation target genes by dietary naringenin may contribute to the hypolipidemic and anti-adiposity effects in vivo.
柚皮苷是葡萄柚中的一种类黄酮，最近的研究表明它具有降血脂和降胆固醇的作用，这对于预防慢性病具有特别重要的意义。然而，柚皮苷在饮食范围内的浓度的降脂潜力及其潜在机制尚未完全阐明。
本研究的目的是（1）研究饮食中柚皮苷对大鼠血浆和肝甘油三酯和胆固醇水平以及脂肪沉积的影响，（2）确定肝过氧化物酶体增殖物激活受体α（PPARα）表达对脂肪酸氧化的贡献。
雄性长耳大白鼠喂食添加柚皮苷（0.003、0.006 和 0.012%）的饮食 6 周。我们分析了血浆和肝脂质含量，并测定了 PPARα、肉碱棕榈酰转移酶 1L（CPT-1）和解偶联蛋白 2（UCP2）的蛋白表达，这些都是脂肪酸氧化的关键基因。
柚皮苷补充显著降低了血浆和肝脏中总甘油三酯和胆固醇的含量。此外，柚皮苷补充降低了前脂肪组织的肥胖和甘油三酯含量。柚皮苷喂养的动物肝脏中 PPARα 蛋白表达显著增加。此外，CPT-1 和 UCP2 的表达（已知受 PPARα 调节）也因柚皮苷处理而显著增强。
我们的结果表明，饮食中柚皮苷激活 PPARα 转录因子并上调其脂肪酸氧化靶基因，可能有助于体内的降血脂和抗肥胖作用。
