Bone-strengthening activity of pinocembrin and the exploration of the mechanism by proteomics analysis

Pinocembrin, an ingredient of foods such as fruits, vegetables, and propolis was found as osteoclastogenesis inhibitor in our previous study. This study conducted an in vivo test on osteoporosis model mice and identified the target proteins using pull-down and cellular thermal shift assays (CETSA) with liquid chromatography–mass spectrometry (LC-MS) proteomics. Pinocembrin significantly improved indicators of bone density in mice, such as trabecular separation, trabecular number, and bone mineral density. A pulldown assay and LC-MS analysis revealed 53 proteins were significantly bound to pinocembrin beads. CETSA identified 20 target proteins, including integrins. Pinocembrin inhibited the adhesion of RAW264 cells to collagen in a concentration-dependent manner. The scratch assay showed that cell migration was inhibited. These results suggest that pinocembrin interacts with integrin to suppress osteoclastogenesis and the interaction between osteoclasts and bone.