In this study, we investigated whether Gelidium amansii extract (GAE) ameliorates obesity in diet-induced obese (DIO) mice.

The mice were maintained on a high-fat diet (HD) for 5 weeks to generate the DIO mouse model. And then mice fed HD plus 0.5% (GAE1), 1% (GAE2) or 2% (GAE3) for 8 weeks.

After the experimental period, GAE-supplemented groups were significantly lower than the HD group in body weight gain and liver weight. GAE supplemented groups were significantly lower than the HD group in both epididymal and mesenteric adipose tissue mass. The plasma leptin level was significantly higher in the HD group than in GAE-supplemented groups. The leptin level of HD+GAE3 group was significantly lower than that of the HD+conjugated linoleic acid (CLA) group. In contrast, plasma adiponectin level of the HD group was significantly lower than those of HD+GAE2 and HD+GAE3 groups. The expression levels of adipogenic proteins such as fatty acid synthase, sterol regulatory element-binding protein-1c, peroxisome proliferator-activated receptor γ, and CCAAT/enhancer binding protein α in the GAE supplemented groups were significantly decreased than those in HD group, respectively. In addition, the expression levels of HD+GAE2 and HD+GAE3 groups are significantly decreased compared to those of HD+CLA group. On the contrary, the expression levels of hormone-sensitive lipase and phospho-AMP-activated protein kinase, proteins associated with lipolysis, were significantly increased in the GAE supplemented groups compared to those in the HD group. HD+GAE3 group showed the highest level among the GAE supplemented groups.

These results suggested that GAE supplementation stimulated the expressions of lipid metabolic factors and reduced weight gain in HD-fed C57BL/6J obese mice.