Potentials of Encapsulated Flavonoids in Biologics: A Review

Flavonoids are a versatile class of natural polyphenolic compounds that represent secondary metabolites from higher plants. Their basic structures consists of fifteen-carbon skeleton consisting of two benzene rings (A and B) linked via a heterocyclic pyrane ring (C) to produce a series of subclass compounds such as flavones, flavonols, flavanones, isoflavones, flavanols or catechins and anthocyanins. Their biological activities are dependent on the structure, chemical nature and degree of hydroxylation, substitutions, conjugation and degree of polymerization. A brief description of flavonoids, its source and classification have been described. Although flavonoids are integral in nutraceutical, pharmaceutical, medicinal, cosmetic and other applications their bioavailability to the target tissues and cells are restricted due to poor water solubility and enzymatic degradation. To increase effectiveness, currently encapsulation of the drug candidate in biological material that are able to enhance the potential health benefits by increasing the water solubility and targeted delivery are being achieved. Biodegradable natural, synthetic and semi-synthetic material/ polymers approved by the US Food and Drug Administration (FDA) for use in the preparation of nanodrugs as well as the applied encapsulation technique are discussed that prevent against oxidation, isomerization and degradation of the flavanoids. The aim of this review is to identify specific flavonoids that exhibit increased pharmacological and biological efficiencies on encapsulation. Thus, these potential drugs may help in preventing many chronic diseases and lead to future research directions.