Suppressive effect of hot water extract of wasabi (Wasabia japonica Matsum.) leaves on the differentiation of 3T3-L1 preadipocytes.

Abstract This study investigated the effect of hot water extract of wasabi ( Wasabia japonica Matsum.) leaves (WLE), without its specific pungent constituents, such as allyl isothiocyanate, on the differentiation of 3T3-L1 preadipocytes. WLE suppressed the increase in glycerol-3-phosphate dehydrogenase (GPDH) activity and triglyceride (TG) accumulation, markers of adipogenesis, in a dose-dependent manner. Quantitative real time RT-PCR results showed that WLE significantly reduced the mRNA expression levels of peroxisome proliferator-activated receptor (PPAR) γ and CCAAT/enhancer-binding protein (C/EBP) α, both key adipogenic transcription factors, as subsequently were the mRNA expression levels of their target genes, such as adipocyte fatty acid binding protein 2 (aP2). Western blot analysis results showed that the protein expression levels of both PPARγ and C/EBPα were also inhibited by WLE. Thus, WLE suppressed the differentiation of 3T3-L1 preadipocytes, and the suppressive effect was mediated, in part, through the altered regulation of PPARγ, C/EBPα, and other specific genes, such as aP2. These results suggest that WLE may prevent obesity and insulin resistance by inhibiting the differentiation of preadipocytes.