Evaluation of anti-angiogenetic property of green tea and its combination with other herbs against vasular endothelial growth factor (VEGF)-induced angiogenesis

Aqueous extracts of green tea (GT), Ocimum gratissimum (OG), Cymbopogon citratus (CC), Cymbopogon flexuosus (CF), and Hibiscus rosa-sinensis (HR) along with their binary infusions, were tested for antioxidant and anti-angiogenic activities. The average number of blood vessels in the chick embryo chorioallantoic membrane (CAM) model parameter was mainly employed to assess anti-angiogenic effectiveness against vascular endothelial growth factor (VEGF)-induced angiogenesis. All aqueous infusions, including GT, OG, CC, CF, HR, GT+OG, GT+CC, GT+CF, and GT+HR, showed inhibition against VEGF-induced angiogenesis in the CAM model. The infusions at a concentration of 5 μg/ml exhibited reduction in blood vessel development in different treatment groups compared to positive control. All infusion groups showed a reduction in total blood vessel length, except for OG, HR, and GT+CC, which had a similar effect (p ≥ 0.05) as that of the control group. GT and GT+OG infusions demonstrated a significantly increased but equivalent (p ≥ 0.05) anti-angiogenic impact as that of other infusions. The in-vivo CAM model demonstrated that all infusions reduced new blood production, with the GT and GT+OG combinations having the greatest effect.