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

Parsley is high in flavonoids (a type of antioxidant), which may help protect against heart disease and cognitive decline (difficulty with memory and focusing).131415 Citrus fruits, like lemons, oranges, and grapefruits, are common superfoods. —Jillian Kubala, Health, 25 June 2025

Less well known is the fact that the flavonoids in cocoa can help mitigate the stress response from the adrenal glands and the subsequent release of cortisol. —Alessandra Signorelli, Vogue, 23 June 2025

Why Drinking Coffee Might Help You Age Better Coffee contains more than 100 unique bioactive compounds, many of which are antioxidants such as phenolic acids, flavonoids, and carotenoids. —Stephanie Anderson Witmer, Health, 4 June 2025

These foods are high in a range of antioxidants, such as carotenoids and flavonoids, which fight free radicals and oxidative stress, protecting the neurons in the brain. —Alessandra Signorelli, Vogue, 3 June 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