(−)-Epigallocatechin gallate but not chlorogenic acid suppresses EGF-stimulated migration of osteoblasts via attenuation of p38 MAPK activity

Phenolic compounds provide health benefits in humans. A previous study by our group has indicated that the epidermal growth factor (EGF)-induced migration of osteoblast-like MC3T3-E1 cells is mediated by the phosphorylation of p44/p42 mitogen-activated protein (MAPK), p38 MAPK, stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK) and Akt, and that resveratrol, a major polyphenol in grape skin, suppresses the EGF-induced migration by attenuating Akt and SAPK/JNK activation. In the present study, the effects of chlorogenic acid, a major phenolic acid in coffee, and (−)-epigallocatechin gallate (EGCG), a major flavonoid in green tea, on the EGF-induced migration of MC3T3-E1 cells were investigated. EGCG significantly reduced the EGF-induced migration as evaluated by a Transwell migration assay and by a wound healing assay. However, chlorogenic acid failed to affect the EGF-induced migration. The phosphorylation of p38 MAPK induced by EGF was significantly suppressed by EGCG; however, the EGF-induced phosphorylation of p44/p42 MAP kinase, SAPK/JNK or Akt was not affected by EGCG. These results suggest that EGCG, but not chlorogenic acid, suppresses EGF-induced osteoblast migration through inhibiting p38 MAPK activation.