Chinese red yeast rice (Monascus purpureus-fermented rice) promotes bone formation

BACKGROUND Statin can induce the gene expression of bone morphogenetic protein-2. Red yeast rice (RYR, Hongqu), i.e. rice fermented with Monascus purpureus, contains a natural form of statin. This study demonstrates the effects of RYR extract on bone formation. METHODS Bone defects were created in the parietal bones of two New Zealand white rabbits. In the test animal, two defects were grafted with collagen matrix mixed with RYR extract. In the control animal, two defects were grafted with collagen matrix alone. UMR 106 cell line was used to test RYR extract in vitro. In the control group, cells were cultured for three durations (24 hours, 48 hours and 72 hours) without any intervention. In the RYR group, cells were cultured for the same durations with various concentrations of RYR extract (0.001 g/ml, 0.005 g/ml and 0.01 g/ml). Bicinchoninic acid (BCA) assay, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and alkaline phosphatase (ALP) assay were performed to measure total protein, mitochondrial activity and bone cell formation respectively. RESULTS The test animal showed more formation of new bone in the defects than the control animal. RYR significantly increased the optical density in the MTT assay and ALP activity in vitro. CONCLUSION RYR extract stimulated new bone formation in bone defects in vivo and increased bone cell formation in vitro.