Fig 1: Effects of onion flavonoid extract (OFE) on tartrate-resistant acid phosphatase (TRAP) activity and mRNA expression of osteoclast markers. (A) Effects of OFE on RAW 264.7 cell viability. (B) TRAP activity in RAW 264.7 cells co-cultured with receptor activator of nuclear factor-kappa B ligand (RANKL) and different concentrations of OFE. (C) mRNA expression in RAW 264.7 cells co-cultured with RANKL and different concentrations of OFE. Data shown are the mean ± SD of three independent experiments. (n = 3) * p < 0.05, ** p < 0.01 compared with the control. Con: control group. Mmp9: matrix metalloproteinase 9, Ctsk: cathepsin K, Nfatc1: nuclear factor of activated T cells 1.