Effects of Piceatannol and Resveratrol on Sirtuins and Hepatic Inflammation in High-Fat Diet-Fed Mice.

Piceatannol (PIC) is a natural hydroxylated analog of resveratrol (RSV) and considered as a potential metabolic regulator. The purpose of this study was to compare the effects of PIC and RSV on parameters affecting inflammation, oxidative stress, and sirtuins (Sirt). Male C57BL/6J mice, 20 weeks old, were assigned to the following groups; (1) lean control, (2) high-fat diet control (HF), (3) HF_PIC, and (4) HF_RSV. Oral administration of PIC and RSV (10 mg/kg/day) for 4 weeks improved glucose control as shown by decreasing levels of area under the curve (AUC) during the oral glucose tolerance test compared with HF group. PIC improved glycemic control by increasing hepatic levels of insulin receptor and AMP-activated protein kinase. PIC increased the levels of Sirt1, Sirt3, and Sirt6 and also increased two downstream targets of Sirt, peroxisome proliferator-activated receptor gamma coactivator 1-alpha and forkhead box O1, in the liver. The inflammatory markers, interleukin (IL)-1 and IL-6, in the liver were downregulated by RSV treatment. Exposure to PIC and RSV significantly lowered hepatic levels of tumor necrosis factor-alpha. However, PIC and RSV treatments showed minimal effects on hepatic markers of oxidative stress. The levels of antioxidant enzyme, NAD(P)H:quinone oxidoreductase 1 (NQO1), were only increased in livers of RSV-treated mice compared with HF control mice. In conclusion, PIC was superior to an equal concentration of RSV in the regulation of Sirt and its downstream targets as well as insulin signaling-related parameters, while RSV potentially suppressed levels of proinflammatory markers and increased NQO1 protein levels.