ABSTRACT
Carotenoids are a large family of plant pigments that may have specific biological
activities in humans. More than 600 carotenoids have been isolated from nature.
Substantial research has been done regarding the biological functions and
metabolism of carotenoids, particularly for the major carotenoids (b-carotene, a-carotene, lycopene, cryptoxanthin, lutein, and zeaxanthin) found in human plasma and tissues. These carotenoids are important food components and there
exists strong epidemiological evidence for their health benefits in terms of
prevention of chronic diseases (e.g., cancer, cardiovascular disease, and age-related
macular degeneration). The information on retinoid activity as the most important
function of provitamin A carotenoids continues to accumulate. Other functions of
carotenoids have also been defined, including antioxidant capabilities, enhance-
ment of cellular gap junction communication, modulation of the immune system,
inhibition of growth factor-induced cell proliferation, induction of apoptosis, and
blocking of neoplastic transformation of normal cells. Several excellent chapters in
this book will discuss these functions of carotenoids in detail.
