Slide-A-Lyzer MINI Dialysis Unit (Thermo Scientific,Hitchin, UK) with a molecular weight cut off of 3500 Da was used for dialysis assay. VEGF (900 ng/mL) was incubated with or without the polyphenol (36 M) in 20 mM ammonium bicarbonate buffer pH 7.0 for 30 min at room temperature.