Bone-strengthening activity of pinocembrin in vitro and in vivo.

Pinocembrin, an ingredient of foods such as fruits, vegetables, and propolis was found as osteoclastogenesis inhibitor in previous study. However, the in vivo effects and its mechanisms have not been elucidated yet. This study conducted in vivo experiment with osteoporosis model mice and identified the target proteins using pull-down with synthesised pinocembrin prove and cellular thermal shift assays (CETSA) with liquid chromatography-mass spectrometry (LC-MS) proteomics. (±)-Pinocembrin significantly inhibited osteoclast differentiation and improved bone parameters such as bone mineral density, trabecular number, and trabecular separation in osteoporotic SAMP6 mice without toxicity. LC-MS with CETSA identified some potential target proteins, including osteoporosis-related proteins. (±)-Pinocembrin inhibited RAW264 cell adhesion and migration, suggesting effects on osteoclast motility via integrins, but not actin polymerisation. Pinocembrin strengthened bone by interacting with cell adhesion and cell motility factors, and inhibiting osteoclastogenesis.