dihydroflavonol

Dihydroflavonols are a class of flavonoids in which the C2-C3 bond of the central heterocyclic ring is saturated, yielding a 2,3-dihydroflavonol skeleton with a carbonyl group at position 4. This saturation distinguishes them from flavonols, which retain a C2-C3 double bond. Like other flavonoids, dihydroflavonols consist of two aromatic rings (A and B) joined by a dihydropyran ring, with various hydroxyl or other substituents that vary among compounds.

Natural occurrence: Dihydroflavonols occur in a range of plants as intermediates in secondary metabolism and, in some cases, as pigments. Notable members include dihydroquercetin (taxifolin), dihydrokaempferol, and dihydromyricetin (ampelopsin). They are found in fruits, vegetables, and other plant-derived foods and beverages, contributing to biochemistry and color pathways in plants.

Biosynthesis and role: In plants, dihydroflavonols are formed in the flavonoid pathway by hydroxylation of flavanones followed by reduction. They serve as substrates for dihydroflavonol 4-reductase, which converts them to leucoanthocyanidins, precursors to anthocyanidins and ultimately to anthocyanins. This branch influences pigment production, UV protection, and signaling in plants.

Properties and applications: Dihydroflavonols generally exhibit antioxidant activity and contribute to the health-promoting attributes associated with flavonoids. Some derivatives, such as taxifolin, have been investigated for anti-inflammatory, antimicrobial, and cardioprotective effects. Bioavailability and metabolism vary among compounds, and while they are of interest in nutraceuticals and research, clinical evidence varies.