Lipogenesis inhibition by water-soluble components from Monascus-fermented rice on 3T3-L1 cells

Abstract

Obesity is a risk factor for several diseases, and overcoming this problem has become a big challenge in the world. Red mold rice (RMR)/Monascus-fermented rice has been traditionally used in East Asian region, and reportedly it contains valuable secondary metabolites that could decrease the risk of several diseases including obesity. Recently, it has been drawn attention that water-insoluble azaphilone pigments produced by Monascus fungi can also suppress lipid accumulation. However^ there are no information about water-soluble components from RMR to control adipogenesis process in adipocytes. This study therefore focused on lipid accumulation inhibitory activity during differentiation of 3T3-L1 preadipocytes by the water-extracts from RMR. Monascus pilosus NBRC4507 was selected as the best strain to induce lipid accumulation inhibitory activity. It produced high inhibitory activity in the water-extracts prepared from RMR cultured at 30°C for 14 days. Thin-layer chromatography (TLC) analyses showed no lovastatin citrinin presence in the water-extracts. Intracellular triglyceride content and glycerol-3-phosphate dehydrogenase activity in 3T3-L1 adipocytes were decreased concentration-dependently by treatment of the water-extracts. In contrast, free glycerol content in the cell culture medium increased in a concentration-dependent manner. These findings suggest that the water-extracts from RMR using M. pilosus NBRC4507 effectively inhibit lipid accumulation through lipogenesis inhibition and lipolysis promotion during differentiation of 3T3-L1 cells. Finally, it can be concluded that the water-soluble components of RMR can be used in food industry for health promotion including prevention of obesity.