Aloe arborescens and American cranberry (Vaccinium macrocarpon) extracts inhibit tumor-induced cutaneous angiogenesis in mice

Abstract

Research in cancer control indicates the importance of adjuvant and complementary therapies. Medicinal plants are a rich source of substances that might be used for this purpose. Aloe vera (Aloe arborescens, Aloe barbadensis Mill) plants are succulents belonging to the Lillacea family. Aloe leaves contain many physiologically active substances with indirect and direct anti-tumor activity etc. Cranberries are a group of evergreen plants in the subgenus Oxycoccus of the genus Vaccinium. Anticancer properties of cranberries were also described, hypothetically connected to their potential antiangiogenic activity. The aim of the present study was to evaluate the in vivo effect of three commercially available preparations of the aforementioned plants on the neovascular reaction observed after intradermal injection of syngeneic sarcoma or xenogeneic (human) lung and kidney cancer cells. We have shown that, additionally to their immunostimulatory properties, Aloe and cranberry preparations behave as tumor angiogenesis inhibitors. We also present a tumor-induced cutaneous angiogenesis (TIA ) test as a valuable method for in vivo quantitative evaluation of activity of various anti-angiogenic compounds. As the extension of these studies it would be prudent to compare antiangiogenic potential of the assessed preparations with antiangiogenic compounds with clinically confirmed anticancer efficiency. It would facilitate reasoning about potential efficiency of these plant extracts, particularly in immunocompromised cancer patients, complementary to their standard therapies.