An updated review on flavonoids

Abstract

Flavonoids, a group of natural substances with variable phenolic structures, are found in fruits, vegetables, grains, bark, roots, stems, flowers, tea and wine. Flavonoids are now considered as an indispensable component in a variety of nutraceutical, pharmaceutical, medicinal and cosmetic applications. This is attributed to their anti-oxidative, anti-inflammatory, anti-mutagenic and anti-carcinogenic properties coupled with their capacity to modulate key cellular enzyme function. Flavonoid constitute one of the largest class of naturally occurring plant products mostly phenols either in the Free State or as their respective glycosides. The main constituent of flavonoid drugs are 2-phenyl-γ-benzopyrones. The family includes monomeric flavanols, flavanones, anthocyanidins, flavones, Isoflavonoid and Neoflavanoids. It is very probable that a number of herbal remedies, whose constituents are yet unknown, will be shown to contain active flavonoids, quercetin and rutin in plant Trigonella foenum seed, they are known for its anti-inflammatory properties. Most flavonoids have anti-tumor properties. Flavonoids are powerful antioxidant. Extract from onion contain quercetin which induce the cellular antioxidant system. The main aim of this review was to give an overview of the research in the field of flavonoids. The potential valuable working mechanisms of flavonoids are discussed, followed by present knowledge on the absorption, conjugation, and toxicity of these substances. The potential clinical applications of flavonoids are also discussed.