polyphenolics

Polyphenolics are a broad and diverse class of plant-derived secondary metabolites that share multiple phenolic rings. They are abundant in the human diet and include simple phenolic acids as well as large polymeric tannins.

Major groups include phenolic acids (hydroxybenzoic and hydroxycinnamic acids), flavonoids (flavonols like quercetin, flavones, flavanones, catechins), stilbenes (resveratrol), lignans, and tannins (condensed tannins and hydrolyzable tannins).

Dietary sources include fruits, vegetables, tea, coffee, wine, cocoa, nuts, and whole grains.

In plants polyphenolics arise through the phenylpropanoid pathway, beginning with phenylalanine. Enzymes such as phenylalanine ammonia-lyase catalyze early steps; downstream reactions yield diverse structures involved in pigmentation, structural support, defense against pathogens, and UV protection.

In humans they can act as antioxidants and may influence inflammation and cell signaling. Observational studies associate polyphenol-rich foods with reduced risk of some chronic diseases, but results for isolated compounds and supplements are inconsistent.

Bioavailability varies; many polyphenols are poorly absorbed and extensively metabolized by the liver and gut microbiota, generating metabolites that may contribute to biological effects.

Analytically, total polyphenol content is often estimated with the Folin–Ciocalteu assay, while individual compounds are identified by chromatography. Research assesses cardiovascular, metabolic, and anticancer potential, with heterogeneous human findings.

Dietary intake from polyphenol-rich foods is generally safe; high intakes or supplements may interfere with mineral absorption or interact with drugs, underscoring the need for balanced consumption.