Bioassay-guided isolation of active anti-adipogenic compound from royal jelly and the study of possible mechanisms

摘要

Royal jelly (RJ) has been used traditionally for dietary, cosmetic and health purposes for a long time in different parts of the world. Scientific studies have also shown its numerous health-promoting properties including hypoglycemic and anti-hypercholesterolemic action. In this study, we investigated the anti-adipogenic activity of RJ in 3?T3-L1 cells and isolated the major responsible root component for the activity. An active anti-adipogenic compound was isolated through bioassay-guided isolation process by successive treatment of RJ and its active fractions on 3?T3-L1 cell line. (E)-10-Hydroxy-2-decenoic Acid (10-HDA) was identified using NMR spectroscopy and ultra-performance liquid chromatography (UPLC). As 10-HDA showed significant anti-adipogenic activity with Oil Red O staining and TG content assay on 3?T3-L1 adipocytes, further study was carried out in molecular level for the expression of adipogenic transcription factors such as PPARγ, FABP4, C/EBPα, SREBP-1c, and Leptin. The effect of 10-HDA on preliminary molecules such as pAkt, pERK, C/EBPβ, and pCREB were studied in the early stage of adipogenesis. The effect of 10-HDA on reactive oxygen species (ROS) production in fully differentiating adipocytes was measured by nitro blue tetrazolium (NBT) assay. Results showed that triacylglycerol accumulation and ROS production was markedly suppressed by 10-HDA. Preliminary molecules such as pAkt, pERK, pCERB, and C/EBPβ were found to be down-regulated by 10-HDA, which led to down-regulation of key adipogenic transcription factors such as PPARγ, FABP4, CEBPα, SREBP-1c, and Leptin on 3?T3-L1 adipocytes. Our results suggest that anti-adipogenesis of 10-HDA on 3?T3-L1 adipocyte takes place via two mechanisms: inhibition of cAMP/PKA pathway and inhibition of p-Akt and MAPK dependent insulin signaling pathway. So it is considered that 10-HDA, a major component of RJ, can be a potential therapeutic medicine for obesity.