Photolytic mechanism of riboflavin.

One of the most characteristic properties of riboflavin (I) is its extraordinary photosensitivity. Therefore, many investigations (1-11) have been carried out on the photolytic reaction of riboflavin and related compounds. According to Karrer et al. (2) and Kuhn et al. (3), the type of decomposition by light is dependent on the pH of the solution. When irradiated in neutral or acidic solution, riboflavin is converted into lumichrome (II), while the main photo decomposition product of the vitamin in an alkaline medium is lumiflavin