Vitamins are essential organic nutrients required in minute amounts for the body's optimal functioning. They could be water soluble or fat soluble. Water soluble vitamins include; vitamins Band C, while the fat soluble vitamins are; Vitamins A, D,E,K. Vitamin A was the first fat soluble Vitamin to be discovered in 1913.
Vitamin A's structure is depicted to the right. Retinol is the precursor of of retinal and retinoic acid. Both are active metabolites of retinol. Retinal plays an important role in vision while retinoic acid is the intracellular messenger which affects the transcription of some gene( Bates ...