Anthocyanin

Anthocyanins (from Ancient Greek anthos 'flower' and kuaneos 'dark blue'), also called anthocyans, are water-soluble vacuolar pigments that, depending on their pH, may appear red, pink, purple, blue, or black. In 1835, the German pharmacist Ludwig Clamor Marquart named a chemical compound that gives flowers a blue color, Anthokyan.. Anthocyanins are derived from anthocyanidins by adding sugars. Anthocyanins may be used as pH indicators because their color changes with pH\; they are red or pink in acidic solutions (pH < 7), purple in neutral solutions (pH 7), greenish-yellow in alkaline solutions (pH > 7). Anthocyanidins are an important subclass of the polymethine dyes and flavonoids