Is ß-carotene an antioxidant?

ß -carotene is a human nutrient found in plants or animals. It is also can be synthesized chemically. It is lipid-soluble, and is yellow, orange or red in color. ß-Carotene can be cleaved into vitamin A in vivo. The most abundant form of ß-carotene in human serum is trans isomer; cis isomers such as 9-cis ß-carotene, 13-cis ß-carotene, and 15-cis ß-carotene are only present in trace amounts. ß-carotene is a versatile antioxidant: it prevents both singlet oxygenand free radical-mediated damage. It is believed to exert its antioxidant function at low oxygen tension. The chemical and physical mechanisms to scavenge reactive species have been proposed in a number of papers. The structure, metabolism, and possible mechanisms to scavenge reactive oxygen species are briefly reviewed in this paper. Jianfang Hu β-carotene 3