Biochemical role of antioxidants in the living system

INTRODUCTION

Oxygen is an indispensable element for life. Oxidative property of oxygen plays a vital role in various biological phenomena; being essential for life, oxygen can also aggravate the damage within the cell by oxidative events. Oxygen is used by the cell to generate energy and free radicals are formed as a consequence of ATP (adenosine triphosphate) production by the mitochondria. Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are the by-products resulting from the cellular redox process. These reactive species play a dual role in human as both toxic and beneficial compounds. The delicate balance between their two opposite effects is undoubtedly a key aspect of life. At low or moderate levels, reactive species exert beneficial effects on cellular redox signalling and immune function, but at high concentrations, they produce oxidative stress, a harmful process that can damage cell function and structures.

TABLE OF CONTENTS

TABLE OF CONTENTS

CHAPTER ONE

1.1Introduction 1

1.2What are Antioxidants?1

CHAPTER TWO

2.1Sources Of Antioxidants3

2.1.1Antioxidants in Dietary Food 3

2.1.2Dietary Antioxidants 3

2.1.3Antioxidants in algae 4

2.1.4Natural antioxidants 4

2.2Classification Of Antioxidants 5

2.2.1Natural Antioxidants7

2.2.1.1Enzymatic Antioxidants 7

2.2.1.2Nonenzymatic Antioxidants 9

2.2.2Synthetic Antioxidants 9

2.3Reactive Oxygen Species 9

2.3.1Biological Role of Reactive Oxygen Species/ Free Radicals 11

2.4Concept Of Oxidative Stress And Molecular Damage 12

2.4.1Lipids    13

2.4.2Proteins   14

2.4.3DNA 14

2.4.4Carbohydrates 15

2.5Mechanism Of Action Of Antioxidants 16

2.5.1Antioxidants and natural defense from ROS induced damages  16

CHAPTER THREE

3.1Antioxidants Against Disease 17

3.1.1Cardiovascular Disease  17

3.1.2Cancer  18

3.1.3Diabetes 19

3.1.4Rheumatoid Arthritis 20

3.1.5Neurodegenerative Diseases  21

3.1.6Renal Disorders 23

3.1.7 Pulmonary disorders24

3.1.8Eye Disorders  25

CHAPTER FOUR

4.1Antioxidant Supplementation  27

4.2Limitations of antioxidant supplementation  27

4.3Conclusion  28

REFERENCES29