Antiobesity effects of α-mangostin through glut4 and leptin expression together with pparγ activation in adipocytes

The increasing incidence of obesity has opened the gap to search for the adipogenic differentiation-inhibitory compounds from natural products. This has raised our concern to evaluate the effects of Garcinia species which is well-known for its phytochemical contents such as flavonoids, phenolic acids and xanthones. Despite its highest medical properties, there was no reported data for obesity prevention. In this study, we used α-mangostin, the major xanthone compounds in Garcinia malaccensis Hk.f (locally known as “manggis burung”). Firstly, we elucidated the inhibitory effect of the compounds on lipid accumulation of 3T3-L1 preadipocytes by using Oil red O staining. α-mangostin dose-dependently reduced the triglyceride accumulation on 3T3-L1 cells. All compounds showed high lipid inhibition activity at 50 μg/mL concentration (P 0.05) with MDI and metformin which were used as the positive control for the assay. In addition, analysis by using the adipolysis kit shows that α-mangostin increases the amount of free fatty acid (FFA) release from the cells into the medium. Further evaluation with the quantitative real time polymerase chain reaction (qRT-PCR) shows that α-mangostin reduced the expression of pparγ genes during adipocyte differentiation. At the same time, induction of glucose uptake and free fatty acid release by α-mangostin was accompanied by the increased mRNA expression of glut4 and leptin genes. As a result, we demonstrated that α-mangostin reduce lipid accumulation with decreased pparγ expression as well as stimulate the glucose uptake and free fatty acid release from the cells via glut4 and leptin expression. In conclusion, these results indicated that α-mangostin derived from Garcinia malaccencis may be a candidate for preventing metabolic disorders such as obesity.