Figure 1. Dose-dependent effects of several vegetable polyphenols on the secretion of vascular endothelial growth factor from retinal pigment epithelial cells. (A) epigallocatechin-3-gallate, (B) luteolin, (C) apigenin, (D) myricetin, (E) quercetin, and (F) cyanidin. The effects were determined in the absence (control) and presence of platelet-derived growth factor (PDGF; 10 ng/ml) and CoCl₂ (150 µM), respectively, for 6 h. The level of VEGF-A₁₆₅ in the cultured media was determined with enzyme-linked immunosorbent assay. The concentrations of the test substances (in µM) are given in the bars. The vehicle controls were made with acetone (Ac; 0.1%), dimethyl sulfoxide (DMSO; 0.1%), and methanol (MeOH; 0.2%), respectively. Data are means±standard error of the mean (SEM) of three to six independent experiments performed in triplicate using cells from different donors, and are expressed in percent of untreated control (100%). Significant difference vs. untreated control: *p<0.05. Significant difference vs. PDGF and CoCl₂ control, respectively: ●p<0.05.