Resveratrol (resorcinol) is the polyphenol found in wine. It is a powerful antioxidant synthesized and stored in the skin of the red grape
Vitamin A is a fat-soluble vitamin.
Vitamin A is derived from two sources, the preformed retinoids and the provitamin carotenoids.
Retinoids, (retinal and retinoic acid) are found in animal sources like liver, kidney, eggs, and dairy produce. Carotenoids (beta-carotene) on the other hand, are found in plants like dark or yellow vegetables and carrots.
Retinoids are present in all living organisms, either as preformed vitamin A or as one of the carotenoids. Retinoids are required for vision and cellular growth. A major biologic function of vitamin A (as the metabolite retinal) is in the visual cycle.
"Retinol is one of the animal forms of vitamin A. It is a diterpenoid and an alcohol. It is convertible to other forms of vitamin A, and the retinyl ester derivative of the alcohol serves as the storage form of the vitamin in animals.
When converted to the retinal (retinaldehyde) form, vitamin A is essential for vision, and when converted to retinoic acid, is essential for skin health, teethremineralization and bone growth. These chemical compounds are collectively known as retinoids, and possess the structural motif of all-trans retinol as a common feature in their structure. Structurally, all retinoids also possess a β-ionone ring and a polyunsaturated side chain, with either an alcohol, aldehyde, acarboxylic acid group or an ester group. The side chain is composed of four isoprenoid units, with a series of conjugated double bonds which may exist in trans- or cis-configuration.
Retinol is produced in the body from the hydrolysis of retinyl esters, and from the reduction of retinal. Retinol in turn is ingested in a precursor form; animal sources (liver and eggs) contain retinyl esters, whereas plants (carrots, spinach) contain pro-vitamin A carotenoids (these may also be considered simply vitamin A). Hydrolysis of retinyl esters results in retinol, while pro-vitamin A carotenoids can be cleaved to produce retinal by carotene dioxygenase in the intestinal mucosa. Retinal, also known as retinaldehyde, can be reversibly reduced to produce retinol or it can be irreversibly oxidized to produce retinoic acid, which then cannot function as the vitamin in the eye."