ABSTRACT
Introduction 640
Green Tea Polyphenols and Photoprotection 641
Photoprotective Effects of Green Tea Polyphenols in Skin Cancer 642
Green Tea Polyphenols and the Different Stages of Photocarcinogenesis 643
Photoprotective Effects of Green Tea Polyphenols on the Acute
UV-Induced Sunburn Response 644
Photoprotective Effects of Green Tea Polyphenols on Photoaging 645
Protective Effects of Green Tea Polyphenols in UV-Induced
Immunosuppression 646
Mechanisms of Action of Green Tea Polyphenols 647
Cellular Effects 647
Apoptosis 647
Proliferation of Keratinocytes 647
Inflammatory Cell Infiltration 647
Molecular Effects 648
DNA Damage 648
Reactive Oxygen Intermediates 648
Proteasome Activation 649
Biochemical Activities 649
Conclusions 650
Acknowledgments 651
References 651
INTRODUCTION
The relationship that humans have with sun exposure is delicately balanced
between the positive effects that this form of radiant energy provides and the
negative aspects that overexposure engenders. The benefits of sun exposure
include its positive psychological actions, the role it plays in vitamin D metab-
olism, and the value it has as a therapeutic agent in cutaneous and systemic
disease. The adverse consequences of overexposure include acute UV-induced
erythema (i.e., a sunburn), nonmelanoma skin cancer (cutaneous squamous cell
and basal cell carcinoma), melanoma, photoaging of the skin, and UV-induced
immunosuppression.
