Polyphenol-rich functional foods have shown promise in ameliorating NAFLD but the relative effectiveness and mechanisms of different polyphenols are largely unknown. In a model of steatosis using HepG2 hepatocytes exposed to palmitic acid, we investigated the effect of selected polyphenols (resveratrol, quercetin, catechin, cyanidin, kuromanin) and berberine. Exposure to palmitic acid produced steatosis and intracellular ROS production, which were prevented by all of the polyphenols and berberine, at 10 µM. Palmitic acid produced a 245% increase in mRNA for inducible nitric oxide synthase (iNOS) that was almost completely prevented by all of the polyphenols (but not by berberine). Most of the polyphenols also partially inhibited palmitic acid-induced increases in markers of endoplasmic reticulum stress, and decreases in mitochondrial content and mitochondrial membrane potential. In conclusion, the polyphenols all similarly prevented steatosis, ROS generation and iNOS induction, and protected against ER stress and mitochondrial impairment.

富含多酚的功能性食品在改善NAFLD方面已显示出希望，但各种多酚的相对功效和机理尚不清楚。在使用暴露于棕榈酸的HepG2肝细胞进行脂肪变性的模型中，我们研究了选定的多酚（白藜芦醇，槲皮素，儿茶素，花青素，kuromanin）和小碱的作用。暴露于棕榈酸会导致脂肪变性和细胞内ROS的产生，而所有多酚和小ber碱均以10 µM的浓度阻止了脂肪变性和细胞内ROS的产生。棕榈酸使可诱导型一氧化氮合酶（iNOS）的mRNA增加了245％）几乎完全被所有多酚（但不是黄连素）所阻止。大多数多酚还部分抑制棕榈酸诱导的内质网应激标志物增加，并降低线粒体含量和线粒体膜电位。总之，所有的多酚都可以类似地预防脂肪变性，ROS的产生和iNOS的诱导，并能抵抗ER应激和线粒体损伤。