Definition of quercetin in US English:



  • A yellow crystalline pigment present in plants, used as a food supplement to reduce allergic responses or boost immunity.

    A flavone derivative; chemical formula: C₁₅H₁₀O₇

    • ‘Green, red, and purple grapes all contain important plant chemicals, like quercetin and catechins.’
    • ‘Tomatoes provide two valuable phytochemicals: the carotenoid lycopene and the flavonoid quercetin.’
    • ‘This reduction of quercetin potentially gives QC the same anticancer effects of quercetin with the hydrophilic effect of a chalcone.’
    • ‘In a Japanese study of mast cells from nasal mucosa of individuals with perennial allergic rhinitis, quercetin significantly inhibited antigen-stimulated histamine release.’
    • ‘Due to the poor bioavailability of quercetin, this author utilizes a water-soluble quercetin analogue - quercetin chalcone.’


Mid 19th century: probably from Latin quercetum ‘oak grove’ (from quercus ‘oak’) + -in.