ABSTRACT
The plant kingdom boasts of a great number of species consumed by humans in various ways: fresh, dry, cooked, processed, or as decoctions. These are fruits, vegetables, herbs and spices, olive and olive oil, grapes and wines, and juices and beverages, which contain in their chemical composition more or less antioxidant compounds classified to structurally different categories. Phenols and polyphenols constitute one of the most numerous and widely distributed group of secondary metabolites in the plant kingdom. This group of compounds is characterized by the presence of at least one phenolic ring to their chemical structure, and is divided into subgroups that may differ significantly in stability, bioavailability, and physiological functions in relation to human health. Phenolic acids are usually found in plant tissues in the form of ester, salt, or glycosides, constituting the aglycone part of the compound.
