Preface

Damage in biological compounds such as nucleic acid, protein, lipids, etc. occurs when the free radical encounters another molecule and seeks to find another electron to pair its unpaired electron. Free radicals can cause mutations in different biological compounds and lead to various diseases (cancer, cardiovascular disease, aging, etc.). Antioxidants are chemical substances that protect different human cells from free radical damage that can occur from exposure to certain chemicals, smoking, pollution, radiation, and as a by-product of normal metabolism. Most antioxidants come from natural sources, which include wild plants, herbs and spices, fruits and vegetables, aquatic organisms, and microorganisms, and from antioxidant compounds, including vitamins A, C, and E, carotenoids such as beta-carotene, minerals, phenolic compounds, and other natural chemicals with antioxidant properties. There is developing interest in the utilization of natural antioxidants for the preservation of different kinds of foods and in the management of a number of diseases and conditions. The implication of oxidative stress in the etiology and progression of several acute and chronic clinical diseases has led to the suggestion that antioxidant compounds can have health benefits as prophylactic agents. Several studies have consistently shown an inverse association between consumption of natural products (as fruits, vegetables, herbs, algae etc.), the risk of cardiovascular diseases, and certain kinds of cancer. Although the protective effects have been primarily attributed to well-known antioxidants, such as vitamins A, C and E and beta-carotene, plant phenolic compounds may also play a significant role. Moreover, restrictions on the consumption of synthetic antioxidants such as Butylated hydroxyl anisole and Butylated hydroxyl toluene in food further strengthen the concept of using naturally occurring compounds as antioxidants.

The aim of this book is to illustrate the definition of oxidative stress and antioxidant in addition to identifying antioxidant sources, mechanisms, its applications in different fields, and the relation between antioxidant compounds and their preventive effect against several diseases such as cancer, cardiovascular disease, inflammation, diabetes, atherosclerosis, etc.

The current book will be of interest to students, researchers, and scientists in the field of biological science and applications.

I would like to thank all the contributing authors for their time and great efforts in the careful construction of the chapters and for making this project realizable.

I am grateful to Ms. Sandra Maljavac (Author Service Manager) for her great efforts, encouragement, and guidance during the preparation of this book.

Finally, I would like to express my deepest gratitude towards my parents, my wife (Ghada M. Azzam), and my daughters (Hana, Farida, and Zaina) for their kind cooperation and encouragement, which helped me in completing this book.

**Dr. Emad Shalaby**

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Section 1

Antioxidants: Sources and

Modes of Actions

Professor of Biochemistry, Biochemistry Department, Faculty of Agriculture, Cairo University, Giza, Egypt Section 1
