ABSTRACT
Flavonoids are a major group of phenolic compounds that occur ubiquitously in foods of plant origin; herbs, fruits, vegetables, and soybeans are the major natural sources. Due to variations in the hydroxylation pattern and in the heterocyclic ring C structure, flavonoids can be classified as flavan-3-ol, flavanones, isoflavones, flavones, flavonols, anthocyanins, or chalcones. These basic structures of flavonoids are called aglycones; however, in plants, most of these compounds exist in forming conjugates with other functional groups. Conjugation of flavonoids modified their physicochemical properties and, therefore, their ability to be absorbed after consumption and, later, biotransformed in potential bioactive forms. More investigation is required to elucidate the relationship between conjugation patterns of flavonoids and their bioavailability and biological activities.
