Vitamin A (CAS 79-81-2)

Vitamin A is a fat-soluble vitamin and an essential nutrient for humans. It is a group of organic compounds that includes retinol, retinal, (also known as retinaldehyde), retinoic acid, and several provitamin A carotenoids (most notably beta-carotene (β-carotene). Vitamin A has multiple functions: it is essential for embryo development and growth, for maintenance of the immune system, and for vision, where it combines with the protein opsin to form rhodopsin – the light-absorbing molecule necessary for both low-light (scotopic vision) and color vision.