ABSTRACT
The central cleavage of b-carotene 1 is most likely the major pathway by which mammals produce the required retinoids (1), in particular, retinal 2, which is essential for vision and is subsequently oxidized to retinoic acid 3 and reduced to
retinol 4. An alternative excentric cleavage of 1 has been reported involving
scission of the double bond at C-70/C-80 producing b-80-apocarotenal 5, which subsequently undergoes bond scission and b oxidation leading to 3 (Fig. 1) (2). The significance of carotene metabolites such as 2, 3, and 4 to embryonic
development and other vital processes such as skin and membrane protection is
discussed elsewhere in this book.
