Oxidative Metabolites of Lycopene and Their Biological Functions - Carotenoids: Physical, Chemical, and Biological Functions and Properties - page 417

20 Oxidative Metabolites

of Lycopene and Their
Biological Functions

Jonathan R. Mein and Xiang-Dong Wang

CONTENTS
20.1 Introduction .......................................................................................................................... 417
20.2 Formation of Lycopene Metabolites In Vitro ....................................................................... 418
20.2.1 Chemical Oxidation of Lycopene ............................................................................. 418
20.2.2 Enzymatic Cleavage of Lycopene............................................................................. 419
20.2.2.1 Carotene-15,15 ′ -Oxygenase and Lycopene ................................................ 419

-Oxygenase and Lycopene ................................................. 419
20.2.2.3 Regulation of Carotene Oxidases .............................................................. 421
20.3 Formation of Lycopene Metabolites In Vivo ........................................................................ 422
20.4 Biological Activity of Lycopene Metabolites ....................................................................... 423
20.4.1 Antioxidant Properties.............................................................................................. 423
20.4.2 Gap Junction Communication .................................................................................. 424
20.4.3 Retinoid Activity.......................................................................................................424
20.4.4 Induction of Phase II Enzymes................................................................................. 425
20.4.5 Interference with Growth Factors............................................................................. 427
20.4.6 Cell Proliferation and Apoptosis .............................................................................. 427
20.5 Summary .............................................................................................................................. 429
Acknowledgments .......................................................................................................................... 429
Abbreviations ................................................................................................................................. 429
References ...................................................................................................................................... 430

20.2.2.2 Carotene-9 ′ ,10 ′

20.1 INTRODUCTION
Considerable interest and research efforts have been expended in an effort to uncover the potential
roles of carotenoids in human health and disease. While early studies focused on provitamin A caro-
tenoids, more recent research efforts have focused on the potential roles of the non-provitamin A
carotenoids (e.g., lycopene) in the health and the disease. Lycopene has been implicated as having a
potential benei cial impact in a number of chronic diseases including cancer. Although evidence from
epidemiological and animal studies supports a potential chemopreventive role of lycopene (Boileau
et al. 2003, Canene-Adams et al. 2007, Giovannucci 1999b, Giovannucci and Clinton 1998, Siler et
al. 2004), the biochemical mechanisms behind such benei cial effects have, as of yet, not been well-
dei ned. Several reports have demonstrated the potential benei cial effects of lycopene especially
in respect to antioxidant function, enhanced cellular gap junction communication, the induction of
phase II enzymes through the activation of the antioxidant response element (ARE) transcription
system, the suppression of insulin-like growth factor (IGF)-1 stimulated cell proliferation by induced

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