Table 1.

The main classes of phenolic compounds according to their carbon chains.

Class	Carbon Skeleton	Examples
C6	Simple phenols and benzoquinones	Catechol, 2,6-dimethoxybenzoquinone, hydroquinone, phenol, pirocatechol
C6–C1	Benzoic acids	Gallic, p-hydroxybenzoic, salicylic, siringic and vanillic acids
C6–C2	Phenylacetic acids and acetophenones	3-Acetyl-6-methoxybenzaldehyde, tyrosol, p-hydroxyphenylacetic acid
C6–C3	Cinnammic acids and phenylpropanoids	Caffeic, ferulic, p-coumaric, sinapic acids, aesculetin, bergenon, eugenin, myristicin
C6–C4	Naphtochinones	Juglone, plumbagin
C6–C1–C6	Xanthones	Mangiferin, mangostin
C6–C2–C6	Stilbenes and anthraquinones	Astringin, resveratrol, viniferin, chrysophanol, emodin
C6–C3–C6	Flavonoids and isoflavonoids	Catechin, cyanidin, epigallocatechin-3-gallate, naringenin, quercetin, myricetin, genistein
(C6–C3)2	Lignans and neolignans	Lariciresinol, pinoresinol, eusiderin, magnolianin
(C6)n	Catechol melanins
(C6–C1)n	Hydrolysable tannins
(C6–C2)n	Lignin, cutin and suberin
(C6–C3–C6)n	Condensed tannins (proanthocyanidins)