Figure 1.

Phenolic family compound basic skeletal structure and their classification in subclasses as stated by [50]. There are two major groups: flavonoids and non-flavonoids. Flavonoids have six subclasses: anthocyanidins, flavonols, flavanones, flavanols, flavones and isoflavones. Anthocyanidins become anthocyanins when sugars are linked in their chemical structures. Non-flavonoids are subdivided into four subclasses: stilbenes, tannins, coumarins and phenolic acids. Tannins are categorized into condensed, hydrolysable and complex. For phenolic acids, a more specified classification is to divide them into three groups: hydroxybenzoic, hydroxyphenylacetic and hydroxycinnamic acids. Created using licensed BioRender (2022).