Vitamin A is a group of unsaturated nutritional organic compounds that includes retinol, retinal, retinoic acid, and several provitamin A carotenoids (most notably bet a-carotene). It is also known as anti-dry eye vitamin, is one of the essential nutrients for humans. The precursor of vitamin A is carotene present in various plants.
Functions and Applications
1. It is important for growth and development, for the maintenance of the immune system and good vision.
2. It is needed by the retina of the eye in the form of retinal, which combines with protein opsin to form rhodopsin, the light-absorbing molecule necessary for both low-light (scotopic vision) and color vision.
3. It also functions in a very different role as retinoic acid (an irreversibly oxidized form of retinol), which is an important hormone-like growth factor for epithelial and other cells.