Inhibitory Effect of Water Soluble Fraction of Monascus-Fermented Rice on Lipid Accumulation in 3T3 L1 Adipocyte

Abstract

Excessive lipid accumulation in the body causes people to become overweight and obese, conditions that are associated with an amplified risk of serious diseases. The fungi of genus Monascus produce various secondary metabolites such as monacolins, citrinin and fungal pigments, which are water-insoluble and have inhibitory potency for the lipid accumulation in adipocytes. However, water-soluble adipogenesis inhibitors derived from Monascus-fermented products have not yet been reported. In this study, we investigated the inhibitory activity against intracellular lipid accumulation of water-soluble fractions of Monascus-fermented red mold rice (RMR) and red mold barley (RMB) on murine 3T3-L1 cells. Water soluble fractions of ten different Monascus strains were used and the inhibitory activity of their water-soluble fractions on lipid accumulation by differentiated 3T3-L1 cells was evaluated for 8 days using oil red staining. The water-soluble fraction from Monascus pilosus NBRC4507 fermented RMR cultivated at 30C for 14 days was selected since it showed comparatively the lowest relative lipid accumulation (62±1.2%), which indicated the highest inhibitory activity of lipid accumulation in adipocytes. To study the presence of monacolin and citrinin in the water soluble fractions, thin-layer chromatography was done and the results showed that the water-soluble fractions tested were free from both monacolin and citrinin. Therefore, the present study strongly suggested that the water-soluble components, except for monacolin and citrinin, in the water soluble fraction obtained from Monascus pilosus NBRC4507-fermented rice can be used as functional food material to control overweight and obesity.