Water extracts of red mold rice suppress lipid accumulation in 3T3-L1 adipocytes by downregulating PPARγ and C/EBPα transcription factors

Red mold rice (RMR), produced by the fermentation of rice with Monascus species, is known to yield a wide array of secondary metabolites. Recently, increasing attention has been directed towards the water-soluble components of RMR as potential alternative therapies for obesity and overweight. This study investigates the effects of water-soluble, adipogenesis inhibitory compounds from the water extract of red mold rice produced by Monascus pilosus NBRC4507 on key adipogenic transcription factors, peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα). Lovastatin- and citrinin-free red mold rice water extract was evaluated for its potential to inhibit lipid accumulation in 3T3-L1 adipocytes. Treatment with the extract resulted in a marked reduction in intracellular triglyceride content and glycerol-3-phosphate dehydrogenase activity. A strong negative correlation between triglyceride content and glycerol release indicated enhanced lipolytic activity. Furthermore, expression levels of PPARγ and C/EBPα were downregulated in a concentration-dependent manner. These findings suggest that the water-soluble constituents of red mold rice exert an antilipogenic effect by suppressing lipogenesis and enhancing lipolysis, likely through the synergistic action of bioactive secondary metabolites.