flavonoid

noun

fla·​vo·​noid ˈflā-və-ˌnȯid 

: any of a large group of typically biologically active water-soluble plant compounds (such as the anthocyanins and flavones) that include pigments ranging in color from yellow to red to blue and occur especially in fruits, vegetables, and herbs (such as grapes, citrus fruits, peppers, and dill)

Flavonoids are effective scavengers of free radicals in the test tube (in vitro). However, even with very high flavonoid intakes, plasma and intracellular flavonoid concentrations in humans are likely to be 100 to 1000 times lower than concentrations of other antioxidants …

—Jane Higdon

The rich palette of dyes in butterflies' wings are all derived from chemicals called flavonoids, which the insects cannot make themselves and must sequester from their food plants.

—Nicholas Wade

see bioflavonoid

Examples of flavonoid in a Sentence

Recent Examples on the Web

Specifically, sunflower seed extracts' flavonoids, glycosides, and phytosterols had blood sugar-lowering properties and helped control blood sugar levels.3 9. —Cristina Mutchler, Verywell Health, 23 May 2025

Milk chocolate, on the other hand, contains more sugar and dairy, which dilutes the flavonoids—the compounds that give chocolate its health benefits. —Amy Brightfield, Better Homes & Gardens, 7 May 2025

Newsletter Sign up for our email newsletter for the latest science news Any chemical that’s called a flavonoid has to taste good. —Sam Walters, Discover Magazine, 7 May 2025

While the 2025 study focused on flavonoids, experts agree that aging well is also about overall dietary and lifestyle patterns. —Melissa Fleur Afshar, MSNBC Newsweek, 6 May 2025

Word History

Etymology

flavone + -oid

First Known Use

1947, in the meaning defined above

Medical Definition

flavonoid

1 of 2 adjective

fla·​vo·​noid ˈflāv-ə-ˌnȯid  ˈflav- 

: of, relating to, or being a flavonoid

flavonoid

2 of 2 noun

: any of a large group of typically biologically active, water-soluble, plant compounds (such as the flavones) that include pigments ranging in color from yellow to red to blue and occur especially in fruits, vegetables, and herbs (such as grapes, citrus fruits, peppers, and dill)

Tea contains substances called catechins (tea flavonoids) that may protect against heart disease and even cancer.

—UC Berkeley Wellness Newsletter

Flavonoids are effective scavengers of free radicals in the test tube (in vitro). However, even with very high flavonoid intakes, plasma and intracellular flavonoid concentrations in humans are likely to be 100 to 1000 times lower than concentrations of other antioxidants …

—Jane Higdon, An Evidence-Based Approach to Dietary Phytochemicals

Note: Flavonoids are polyphenolic 15-carbon compounds with a basic structure consisting of two benzene rings joined by a chain of 3 carbons.

see bioflavonoid