Covalent anthocyanin-flavonol complexes from the violet-blue flowers of Allium 'Blue Perfume'

► Covalent anthocyanin-flavonol complexes were isolated from the violet-blue flowers of Allium. ► Covalent anthocyanin-flavonol complexes were based on delphinidin 3-glucoside. ► The violet-blue flower color of Allium was exhibited by strong intramolecular copigmentation.