The effects of bee products on VEGF-induced proliferation in HUVECs. HUVECs were incubated with the indicated concentrations of (A) royal jelly (RJ) and ruboxistaurin, (B) bee pollen, (C) Chinese red propolis, and (D) caffeic acid phenethyl ester (CAPE) in the presence or absence of VEGF (10 ng/ml) for 3 days at 37°C in 5% CO2 with humidity. Cell proliferation was estimated using a cell counting kit-8 (CCK-8). VEGF treatments increased cell viability two-fold (vs. Control). RJ (300 μg/ml), ruboxistaurin (1 μM), bee pollen (300 μg/ml), Chinese red propolis (3 μg/ml), and CAPE (3 to 10 μM) inhibited the proliferation. Data represent means ± SEM (n = 6). ##: P < 0.01 vs. Control, *: P < 0.05, **: P < 0.01 vs. VEGF alone.