
Bilberry contains a variety of phenolic compounds, including flavonols (quercetin, catechins), tannins, ellagitannins, and phenolic acids, but anthocyanins make by far the largest contribution to its phytochemical mix.
The flavonol-O-glycosides in fresh bilberry juice and fruit include quercetin-3-rhamnoside (quercitrin), quercetin-3-glucoside (isoquercitrin), quercetin-3-galactoside (hyperoside), and kaempferol-3-glucoside (astragalin).
The following phenolic acids have been identified in fresh bilberry juice and unripe fruit: gallic, protocatechuic, m-and p-hydroxybenzoic, vanillic, chlorogenic, caffeic, syringic, o- m-, and p-coumaric, ferulic, and syringic acids.
Bilberry juice