Astaxanthin (3,3’-dihydroxy-beta,beta-carotene-
4,4’-dione) belongs to the xanthophyll subclass of
carotenoids. It has oxygen in its molecular structure,
which sets it apart from beta-carotene and
other molecules of the carotene subclass.5 The
astaxanthin molecule has an extended shape, with
a polar structure at either end of the molecule and
a nonpolar zone in the middle (Figure 1). The polar
structures are ionone rings that have potent
capacity for quenching free radicals or other
oxidants.