The biological, physicochemical, and environmental properties of
substances are anticipated by utilizing structure-activity relationships (SARs). A SAR
is a (qualitative) correlation between a chemical substructure and the potential for one
of the chemicals in the substructure to have a particular biological property or effect.
We are familiar with the term SAR which is a powerful concept in the discovery of any
active pharmaceutical ingredient with both qualitative and quantitative associations that
relate to the chemical structure and biological activity of any chemical compound. Due
to their safety and medicinal efficacy, plant-derived functional foods are of great
interest. In this chapter, the different types of biologically active compounds, their
chemistry and SAR, and the different biologically active compounds from daily dietary
supplements, foods, and fruits, which contain polyphenolic compounds, have been
discussed. SAR of flavonoids like anthocyanidins, which is the principal component of
the majority of fruits, vegetables, and flower petals, flavonols, usually called catechins,
and isoflavones, are also discussed. Other polyphenolic compounds like tannins with
their subtypes like hydrolysable and non-hydrolysable tannins are well covered.