flavanoleja

Flavanols, also known as flavan-3-ols, are a class of flavonoids, a broad group of polyphenolic compounds found in many plants. They exist as monomers—catechin, epicatechin, gallocatechin, and epigallocatechin—and as polymers called proanthocyanidins or condensed tannins.

Natural occurrence and dietary sources include tea (green and black), cocoa and chocolate, grapes and red wine, apples, berries, and some nuts. These compounds contribute to the astringency and color of foods and beverages and can accumulate in edible seeds and skins.

Chemical properties and classification: flavanols have a saturated C-ring with a hydroxyl group at position 3. They occur as monomers or as oligomers and polymers, with the polymeric forms collectively referred to as proanthocyanidins. They are a subset of flavonoids distinct from other groups such as flavonols.

Biosynthesis and plant function: flavanol biosynthesis arises from the phenylpropanoid pathway in plants, joining the flavonoid biosynthetic branch that produces various polyphenols. In plants, flavanols contribute to defense against pests and pathogens and can affect pigment formation.

Absorption, metabolism, and bioavailability: monomeric flavanols are partially absorbed in the small intestine, while larger polymers reach the colon where gut microbiota metabolize them to smaller phenolic metabolites. These metabolites are excreted in urine and may exert systemic effects.

Health implications and research status: flavanols exhibit antioxidant activity in vitro and have been studied for potential cardiovascular and metabolic benefits in humans. Clinical results are mixed and appear to depend on dose, bioavailability, and food matrix; more research is needed to define definitive health effects and optimal intake.