Antiangiogenic effects of flavonoids and chalcones.

Angiogenesis, the development of new blood vessels from the existing vasculature, is essential in normal developmental processes. Uncontrolled angiogenesis is a major contributor to a number of disease states such as inflammatory disorders, obesity, asthma, diabetes, cirrhosis, multiple sclerosis, endometriosis, AIDS, bacterial infections and autoimmune disease. It is also considered a key step in tumour growth, invasion, and metastasis. Angiogenesis is required for proper nourishment and removal of metabolic wastes from tumour sites. Therefore, modulation of angiogenesis is considered as therapeutic strategies of great importance for human health. Numerous bioactive plant compounds are recently tested for their antiangiogenic potential. Among the most frequently studied are polyphenols present in fruits and vegetables. Plant polyphenols inhibit angiogenesis and metastasis through regulation of multiple signalling pathways. Specifically, flavonoids and chalcones regulate expression of VEGF, matrix metalloproteinases (MMPs), EGFR and inhibit NFkappaB, PI3-K/Akt, ERK1/2 signalling pathways, thereby causing strong antiangiogenic effects. This review focuses on the antiangiogenic properties of flavonoids and chalcones and examines underlying mechanisms.