Flavonoids and Related Compounds in Non-Alcoholic Fatty Liver Disease Therapy

Non-alcoholic fatty liver disease (NAFLD), the hepatic manifestation of metabolic syndrome, is one of the most common chronic liver diseases, which may progress to fibrosis, cirrhosis and hepatocellular carcinoma. NAFLD is characterized by the accumulation of lipids in the liver arising from multiple factors: increased fatty acid uptake, increased de novo lipogenesis, reduced fatty acid oxidation and very low density lipoproteins (VLDL) secretion. Most therapeutic approaches for this disease are often directed at reducing body mass index and improving insulin resistance through lifestyle modifications, bariatric surgery and pharmacological treatments. Nevertheless, there is increasing evidence that the use of natural compounds, as polyphenols, exert multiple benefits on the disorders associated with NAFLD. These molecules seem to be able to regulate the expression of genes mainly involved in de novo lipogenesis and fatty acid oxidation, which contributes to their lipid-lowering effect in the liver. Their antioxidant, anti-inflammatory, antifibrogenic and antilipogenic properties seem to confer on them a great potential as strategy for preventing NAFLD progression. In this review, we summarized the effects of these compounds, especially flavonoids, and their mechanisms of action, that have been reported in several studies carried out in in vitro and in vivo models of NAFLD.