Black Rice (Oryza Sativa, Heukmi) Extracts Stimulate Osteogenesis but Inhibit Adipogenesis in Mesenchymal C3H10T1/2 Cells

We investigated the effects of BREs named Heukmi on osteogenic and adipogenic differentiation in C3H10T1/2 mesenchymal stem cells. BREs stimulate osteogenesis, enhancing the mRNA expression of runt-related transcription factor 2 and alkaline phosphatase (ALP), increasing ALP protein expression and cellular enzyme activity, thus elevating intracellular calcium deposition. BREs also suppressed adipogenesis by downregulating peroxisome proliferator-activated receptor-γ, C/EBPδ and C/EBPα, major regulators in adipogenesis. In cells stimulated with BREs, the rate of fatty acid synthesis was significantly decreased, while there was no effect on the rate of fatty acid oxidation, resulting in reduced intracellular lipid accumulation. This reciprocal regulation of osteogenesis and adipogenesis by BREs correlated with the regulation of Wnt signaling pathway. BREs enhanced the expression of genes in Wnt signaling pathway, including Wnt3a and β-catenin. Together, these results suggest that BREs may enhance osteogenic differentiation and suppress adipogenic differentiation via Wnt signaling. Practical Applications: Black rice (Oryza sativa, Heukmi) is a colored rice strain with several known biological effects including anti-obesogenic activity. Black rice extract regulates cell differentiation thus suppresses adipogenesis. In this study, we investigated the effects of black rice extract on the differentiation of MSCs. In MSCs, the suppression of adipogenesis could promote osteogenic differentiation program and facilitates bone formation. The present study attempts to shed some light on the questions whether black rice extract induces osteogenesis in MSCs with suppression of adipogenesis. The results of the study could be a basis for further research on this precious rice strain and also to promote its consumption on a large scale.