Abstract:

Bitter melon (Momordica charantia) has been shown to ameliorate high-fat diet-induced obesity, but theunderlying molecular mechanisms are still unknown. The objective of this study was to elucidate the effect of bitter melonextracts on adipogenesis in 3T3-L1 adipocytes. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assaywas used to measure cell viability; Oil red O staining and spectrometric determination were carried out to investigate theeffect of bitter melon extracts on adipocyte differentiation.The mRNA expression levels of adipogenic genes were measuredby real time-polymerase chain reaction (RT-PCR). The results revealed that bitter melon extracts markedly inhibited lipidaccumulation. The n-butanol fraction blocked the expression of adipogenic transcription factors, including peroxisomeproliferator-activated receptor-gamma (PPARγ), ccaat-enhancer-binding protein-alpha (C/EBPα) and sterol regulatoryelement-binding protein-1c (SREBP-1c) at the mRNA level. Moreover, the mRNA levels of 5 key lipogenic enzymesincluding glucose transporter-4 (GLUT4), acetyl-CoA carboxylase (ACC1) fatty acid synthase (Fasn), adipocyte protein 2(AP2) and lipoprotein lipase (LPL) were down-regulated. These results indicate that the n-butanol fraction of bitter melonsuppresses adipocyte differentiation and lipid accumulation through inhibiting the transcription of adipogenic genes and mayhave applications for the treatment of obesity.

Key words: bitter melon, adipogenesis, 3T3-L1 adipocytes