The effect of Astragalus Membranaceus on Pathological Angiogenesis

Abstract

Abnormality of angiogenesis can contribute to several pathologic processes including atherosclerosis and cancer. Different bioactive components of astragalus membranaceus (huangqi), a commonly used herb in traditional Chinese medicine, exert different effects on the angiogenesis of human cancer cells and endothelial cells. Therefore, the effect of astragalus membranaceus and its active components on angiogenesis under different pathological conditions were investigated. Human umbilical endothelial cells (HUVECs) and human colon cancer cell HCT 116 were used for in vitro studies. The effect of astragalus membranaceus on proliferation were examined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The results indicated that the viabilities of HUVECs treated with astragalus saponin (0.1 to 25 µg/ml), astragaloside IV (0.01 to 100 µM) and calycosin (1 to 200 µM) for 24-72 hours were not significantly different from the control group (without any treatment). Astragalus saponin and astragaloside IV, at the same concentrations as used in HUVECs, also did not affect the viability of HCT 116 cells, while the highest concentration of calycosin (200 µM) inhibited the growth of HCT 116 cells. The angiogenic potential of these components of astragalus membranaceus are examined in both HUVECs [under the stimulation of phorbol myristate acetate (PMA), a protein kinase C activator] and HCT 116 cells by wound healing migration assay and tube formation assay, in order to identify the influence of astragalus membranaceus and its components on pathological angiogenesis.