The molecular mechanism underlying the reduction in abdominal fat accumulation by licorice flavonoid oil in high fat diet-induced obese rats.

Licorice (Glycyrrhiza glabra) has been widely used in traditional medicines, and its flavonoid oil (LFO) decreases abdominal adipose tissue weight in mammals. In the present study, we investigated the molecular mechanisms underlying the decrease in abdominal adipose tissue weight by LFO. LFO significantly decreased the mRNA levels of rate-limiting enzymes in the hepatic fatty acid synthetic pathway, whereas LFO significantly increased the mRNA levels of a rate-limiting enzyme in the hepatic fatty acid oxidative pathway. LFO significantly decreased the mRNA levels of sterol regulatory element-binding protein-1c (SREBP-1c) (a transcription factor that promotes hepatic fatty acid synthesis), whereas the mRNA levels of peroxisome proliferator-activated receptor-alpha (PPAR-alpha) (a transcription factor that promotes hepatic fatty acid oxidation) was significantly increased. All our findings suggest that the decrease in abdominal adipose tissue weight by LFO is mediated by the transcriptional regulation of SREBP-1c and PPAR-alpha in the liver. Thus, we infer that the natural ingredient LFO is a promising candidate for use as a feed additive to reduce abdominal fat accumulation in domestic animals.