Effect of KoreanMagnolia obovataExtract on Platelet-Derived Growth Factor-Induced Vascular Smooth Muscle Cells

Objective To investigate the effects of KoreanMagnolia obovatacrude extract (KME) on plateletderived growth factor (PDGF)-BB-induced proliferation and migration of vascular smooth muscle cells (VSMCs). Methods KME composition was analyzed by high-performance liquid chromatography (HPLC). VSMCs were isolated from the aorta of a Sprague-Dawley rat, incubated in serum free-Dulbecco's modified Eagle's medium in the presence or absence of KME (10, 30, 100, and 300 mu g/mL), then further treated with PDGF-BB (10 ng/mL). VSMC proliferation was detected using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and VSMC migration was determined using the Boyden chamber and scratch wound healing assays. Western blot analysis was used to detect phosphorylation of extracellular signal-regulated protein kinases 1 and 2 (p-ERK1/2), protein kinase B (p-Akt), and stress-activated protein kinase/c-Jun NH2-terminal kinase (p-SAPK/JNK). The antimigration and proliferation effects of KME were tested using aortic sprout outgrowth. Results The HPLC analysis identified honokiol (0.45 mg/g) and magnolol (0.34 mg/g) as the major components of KME. KME (30, 100, and 300 mu g/mL) significantly decreased the proliferation and migration of PDGF-BB-stimulated (10 ng/mL) VSMCs and the PDGF-BB-induced phosphorylation of EKR1/2, Akt, and SAPK/JNK (P<0.05). Furthermore, PDGF-BBinduced VSMCs treated with 300 mu g/mL of KME showed reduction in aortic sprout outgrowth. Conclusion KME could inhibit abnormal proliferation and migration of VSMCs by down-regulating the phosphorylation of EKR1/2 and Akt. Thus, KME might be a functional food for preventing vascular disorders.