What is it? Riboflavin is the well known Vitamin B2, it can be found in food and used as a dietary supplement. It is a water-soluble yellow compound that used to be called lactochrome or Vitamin G. It was discovered in 1920, isolated un 1933 and first made in 1935. It can be synthesized by plants, yeasts, and procaryotic cells, while mammals can obtain it by consuming plant-based foods. Chemical Structure The name "Riboflavin" comes from ribose (the sugar whose reduced form, ribitol, appears in structure) and flavus which means yellow in Latin, because of the ring-moiety (Isoalloxazine ring) which imparts the yellow color to the oxidized molecule. The isoalloxazine ring is a focal point for electron transfers, which allow riboflavin to take its three redox forms (fully oxidized/quinone, one-electron reduced/semi-quinone and two electrons reduced/hydroquinone). Additionally, riboflavin is the precursor of flavin mononucleotide (FMN) and flavin adenine dinucleot