Molecular structure, biological functions, and metabolic regulation of flavonoids

Abstract

Flavonoids, constituting about 5-10% of the known secondary metabolites, are important for plant growth and development and thus can have a large impact on agricultural productivity. Plants are specialized in synthesizing and accumulating specific combinations of about 5000 flavonoids. The richness of flavonoids in plant sources cannot be underestimated and they are found closely associated with human daily dietary intake; hence, it is significant to understand the biochemistry of flavonoids. The flavonoid biosynthetic pathway is under tight developmental control, and multiple environmental factors like temperature lights stress and fertilizers affect the expression of flavonoid biosynthetic genes. Flavonoids exhibit a wide range of biological effects such as antibacterial, antiviral, antifungal, antiosteoporotic, antitumor, antithrombogenic, anti-inflammation, antiatherosclerotic, and antihepatotoxic activities. They also have a regulatory role on different hormones like estrogens, androgens, and thyroid hormones. Due to their diverse pharmacological activities, functional artificial polymeric flavonoids, flavonoid polymers, and amine-containing polymer-flavonoid conjugates have also been developed. As research advances in natural products, further achievements will certainly lead to a new age of flavonoids as either food supplements or pharmaceuticals.