vitamin B2 Any member of a group of vitamers that belong to the chemical structural class called flavins that exhibit biological activity against vitamin B<small>₂</small> deficiency. Symptoms associated with vitamin B<small>₂</small> deficiency include glossitis, seborrhea, angular stomaitis, cheilosis and photophobia. The vitamers include riboflavin and its phosphate derivatives (and includes their salt, ionised and hydrate forms). Any member of a group of vitamers that belong to the chemical structural class called flavins that exhibit biological activity against vitamin B2 deficiency. Symptoms associated with vitamin B2 deficiency include glossitis, seborrhea, angular stomaitis, cheilosis and photophobia. The vitamers include riboflavin and its phosphate derivatives (and includes their salt, ionised and hydrate forms). B vitamin