BACKGROUND Non-alcoholic fatty liver disease (NAFLD) is characterized by hepatic accretion of triacylglycerides in the absence of alcohol intake that may progress to steatohepatitis, fibrosis and cirrhosis, becoming the main cause of chronic liver disease. This article discusses recent data concerning the use of dietary polyphenols in the prevention and treatment of NAFLD in vitro, in vivo, and in clinical trials. METHODS Study searches were performed using the PubMed database from the National Library of Medicine-National Institutes of Health. RESULTS Polyphenols exert beneficial effects in NAFLD, with positive outcomes being related to body weight gain, insulin resistance, liver fat accumulation, oxidative stress, proinflammatory status, mitochondrial dysfunction and ER stress. Data reported for hydroxytyrosol suggest that the activation of the hepatic PPAR-α-FGF21-AMPK-PGC-1α signaling cascade is associated with fatty acid oxidation enhancement, de novo lipogenesis diminution and recovery of mitochondrial function, a contention that is supported by the actions of several polyphenols on specific components of this signaling pathway. Besides, polyphenols downregulate NF-κB, suppressing the pro-inflammatory state developed in NAFLD and upregulate liver Nrf2, increasing the cellular antioxidant potential. The latter feature of polyphenols is contributed by chelation of pro-oxidant trace elements, reduction of free radicals to stable forms and inhibition of free radical generating systems. CONCLUSION Polyphenols are relevant bioactive compounds in terms of prevention and treatment of NAFLD, which exhibit low bioavailability and instability in biological systems that could limit their health effects. These drawbacks reinforce the necessity of further studies to improve the efficacy of polyphenol formulations for human interventions.

中文翻译：

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膳食多酚在预防和治疗 NAFLD 中的有益作用：影响健康的细胞信号通路。

背景技术非酒精性脂肪性肝病(NAFLD)的特征是在没有饮酒的情况下肝脏中甘油三酯的增生，可能发展为脂肪性肝炎、纤维化和肝硬化，成为慢性肝病的主要原因。本文讨论了有关在体外、体内和临床试验中使用膳食多酚预防和治疗 NAFLD 的最新数据。方法 研究检索是使用来自美国国家医学图书馆-美国国立卫生研究院的 PubMed 数据库进行的。结果 多酚在 NAFLD 中发挥有益作用，其积极结果与体重增加、胰岛素抵抗、肝脏脂肪积累、氧化应激、促炎状态、线粒体功能障碍和 ER 应激有关。报道的羟基酪醇数据表明，肝脏 PPAR-α-FGF21-AMPK-PGC-1α 信号级联的激活与脂肪酸氧化增强、从头脂肪生成减少和线粒体功能恢复有关，这一观点得到了行动的支持几种多酚对该信号通路的特定成分的影响。此外，多酚可下调 NF-κB，抑制 NAFLD 中的促炎状态，上调肝脏 Nrf2，增加细胞抗氧化能力。多酚的后一个特征是通过螯合促氧化剂微量元素、将自由基还原为稳定形式和抑制自由基生成系统。结论 多酚是防治 NAFLD 的相关生物活性化合物，它们在生物系统中表现出低生物利用度和不稳定性，可能会限制其对健康的影响。这些缺点加强了进一步研究以提高多酚制剂对人类干预的功效的必要性。