Anti-obesity effect of Microalga, Melosira nummuloieds ethanolic extract in high-fat-diet-induced obesity C57BL/6J mice

Background: Melosira nummuloides is a microalga belonging to the Melosiracease diatom. The ability of the diatoms to mass-produce essential fatty acids and carotenoid pigments was reported, which has driven research and their industrial application. Melosira nummuloides mass-cultivated with Jeju Lava sea water contains fucoxanthin, which has excellent biological properties such as antioxidant, anti-inflammatory, anti-cancer, and anti-obesity activities. The effect of M. nummuloides ethanolic extract (MEE) on the reduction of fat accumulation was evaluated.Methods: C57BL/6J mice fed a high-fat diet (HFD) were treated over 8 weeks with Melosira ethanolic extract. Cholesterol in serum and triglyceride in liver after the 8-week were evaluated. The expression of SREBP-1c, FAS, PPAR-γ, SCD-1 and p-AMPK were measured by western blotting respectively.Results: The MEE-treated C57BL/6J showed significant body weight and visceral fat loss compared to HFD group. Cholesterol in serum and triglyceride levels in liver showed a significant decrease in MEE groups. Levels of SREBP-1c, FAS, PPAR-γ and SCD-1 were low in mice fed an HFD+MEE.Conclusion: These results show MEE reduces blood lipid levels by regulating the expression of factors related to lipid synthesis and adipocyte differentiation in adipose tissue and inhibiting new lipid synthesis in the liver. M. nummuloides ethanolic extract confirmed its suitability as an anti-obesity agent.Keywords: Melosira nummuloides; C57BL/6J mice; obesity: weight loss; fatty acid synthesis