ABSTRACT
Blood vessel plays a crucial role in solid tumor development. It has been suggested that blocking of angiogenesis and the action of the cytokine VEGF could be possible in cancer therapy. In a screen for naturally occurring angiogenic inhibitors, we have identified an extract from the roots of Glycyrrhiza glabra, which has potent antiangiogenic and antitumor activity. The aqueous extract inhibits the in vivo and in vitro proliferation of Ehrlich ascites tumor cells. The angioinhibitory activity of G. glabra was confirmed by its inhibition of angiogenesis in in vivo assays, peritoneal and chorioallantoic membrane assay. Reduction in the levels of the cytokine VEGF and microvessel density count in the peritoneum of mice treated with G. glabra indicated that the plant extract decreased VEGF production and the cytokine induced neovascularization. Our results suggest that the extract from the roots of G. glabra may be a potential supplemental source for cancer therapy.