Promotion of direct angiogenesis in vitro and in vivo by Puerariae flos extract via activation of MEK/ERK-, PI3K/Akt/eNOS-, and Src/FAK-dependent pathways

Puerariae flos has been used for oriental herbal medicine; however, its angiogenic effect has not been elucidated. We found that the extract from Puerariae flos (PFE) increased in vitro angiogenic events, such as endothelial cell proliferation, migration, and tube formation, as well as in vivo neovascularization. These events were followed by the activation of multiple signal modulators, such as extracellular signal-regulated kinase (ERK), Akt, endothelial nitric oxide synthase (eNOS), nitric oxide production, p38, Src, and focal adhesion kinase (FAK), without increasing vascular endothelial growth factor (VEGF) expression. Inhibition of ERK, Akt, and eNOS suppressed PFE-induced angiogenic events, and inhibition of p38 and Src activities blocked PFE-induced endothelial cell migration. PFE did not affect the expression of intracellular adhesion molecule-1 and vascular cell adhesion molecule-1 and transendothelial permeability, which are involved in the adverse effects of the well-known angiogenic inducer VEGF. These results suggest that PFE directly stimulates angiogenesis through the activation of MEK/ERK-, phosphatidylinositol 3-kinase/Akt/eNOS-, and Src/FAK-dependent pathways, without altering VEGF expression, vascular inflammation, and permeability in vitro and in vivo and may be used as a therapeutic agent for ischemic disease and tissue regeneration.