quercetin

noun

quer·​ce·​tin ˈkwər-sə-tən 

: a yellow crystalline pigment C₁₅H₁₀O₇ occurring usually in the form of glycosides in various plants

Examples of quercetin in a Sentence

Recent Examples on the Web

Blackberries Blackberries are rich in antioxidant compounds, including vitamin C, vitamin E, anthocyanins, ellagic acid, quercetin, and terpenoids. —Brian Mastroianni, Health, 5 Dec. 2025

Potato peels also contain quercetin, a type of flavonol, which may help support the immune system by reducing inflammation. —Barbie Cervoni, Verywell Health, 24 Nov. 2025

Vaccine developers can profit from their products, but designing and testing a vaccine is a lot more work than selling a plant flavonol called quercetin as a treatment for COVID, and supplements are not subject to the same kind of regulatory oversight as drugs. —Rivka Galchen, New Yorker, 27 June 2025

Word History

Etymology

International Scientific Vocabulary, from Latin quercetum oak forest, from quercus oak — more at fir

First Known Use

1856, in the meaning defined above

Medical Definition

quercetin

noun

quer·​ce·​tin ˈkwər-sət-ən 

: a yellow crystalline pigment C₁₅H₁₀O₇ occurring usually in the form of glycosides in various plants