Long-term supplementation of honokiol and magnolol ameliorates body fat accumulation, insulin resistance, and adipose inflammation in high-fat fed mice

Scope: This study investigated the effect of honokiol (HON) and magnolol (MAG), phenolic compounds in Magnolia plants, on adiposity and adiposity-related metabolic disturbances in mice fed high-fat diet (HFD), and the potential underlying mechanisms focusing on the lipid metabolism and inflammatory response. Method and results: C57BL/6J mice were fed HFD (45 kcal% fat) with or without HON (0.02%, w/w) or MAG (0.02%, w/w) for 16 wk. Despite no changes in body weight, food intake, and hepatic fat accumulation, HON and MAG significantly lowered the weight of white adipose tissue (WAT) as well as adipocyte size and protected against insulin resistance induced by HFD. These effects were associated with increases in energy expenditure and adipose fatty acid oxidation and decreases in fatty acid synthase activity and expression of genes related to fatty acid synthesis, desaturation, and uptake, as well as adipocyte differentiation in WAT. Moreover, HON and MAG significantly lowered the expression of proinflammatory genes in WAT and elevated the plasma IL-10 level. Particularly, HON significantly decreased the plasma resistin level and increased the plasma adiponectin level compared to the control group. Conclusion: HON and MAG have potential as novel agents for amelioration of adiposity and associated insulin resistance and inflammation.