Natural flavonoids: classification, potential role, and application of flavonoid analogues

Nowadays, it is assumed that natural flavonoids occurring in fruits and plant derived-foods are relevant, not only for organoleptic properties or technological reasons, but also because of their potential health-promoting effects, as suggested by the available experimental and epidemiological studies. This large group of phenolic plant constituents can be divided into several classes: flavanols, flavanones, flavonols, isoflavones, flavones and anthocyanins depending on the differences in their structures.The beneficial biological effects are also attributed to flavonoid analogues and their metal complexes. These compounds are characterized by antioxidant, pharmacological, anti-inflammatory, anti-allergic, antiviral, anticarcinogenic, as well as therapeutic and cytotoxic properties. Furthermore, they possess a wide range of applications including various fields of industry