The health benefits of green tea for a wide variety of ailments, including different types of cancer, heart disease, and liver disease, were reported. Many of these beneficial effects of green tea are related to its catechins, particularly epigallocetachin-3-gallate content. There is evidence from research the green tea has various there pentic potentials.

TABLE OF CONTENTS

Title page - - - - - - - - i

Dedication - - - - - - - - ii

Table of content - - - - - - - iii

Abstract - - - - - - - - - iv

CHAPTER ONE

1.0 Introduction - - - - - - - 1

CHAPTER TWO

2.0 The composition of green tea and the extraction processes - - - - - - - 7

2.1 Composition of GREEN TEA - - - - 7

2.2 Production and extraction process of GREEN TEA- - - - - - - - 11

CHAPTER THREE

3.0Health benefits of Green Tea - - - 15

3.1 Mechanism of Antioxidants on free Radical -24

CHAPTER FOUR

4.0 Antioxidants in Green Tea and adverse Effect of

Green Tea - - - - - - - - 28

4.1 antioxidants in Green Tea - - - - 28

4.2 adverse effects of Green Tea- - - -29

CHAPTER FIVE

5.0 Conclusion - - - - - - 32

References - - - - - - - 33

CHAPTER ONE

1.0 INTRODUCTION

Tea is generally consumed in the form of black, oolory, or green tea; which are all preparations originating from Camellia Sinensis, a small plant grown mainly in China and Southeast Asia (Mckay and Blumber, 2002).

In recent years, the health benefits of consuming green tea, including the prevention of cancer and cardiovascular diseases, the anti-inflammatory, antiarthritic, anti-bacterial, antiangiogenic, antioxidative, antiviral, neuroprotetcive and cholesterol – lowering effects of green tea and isolated green tea constituents are under investigation. However, adding green tea to the diet has beneficial effect on human health (Roomi et al., 2007). The health –promoting effects its poly-phenol content, particularly flavonols and flavonols which represents 30% of fresh leaf dry weight. Recently many of the fore mentioned beneficial effects of green tee were attributed to its most abundant catechin-epigallocatechin -3-gallate (EACG). Green tea extract are more stable than pure epigallocatechin gallate, one of the major constituent of green tea, because of the presence of other antioxidant constituent in the extract (Babu et al., 2006).

Green tea has become the raw material extracts used in various beverages, dietary supplement, and cosmetics items. Many varieties of green tea have been created in the countries where it is grown. These varieties can differ substantially due to variable growing conditions horticulture, production processing and harvesting time

(Chen et al., 2001).

Many claims have been made from a number of sources for the beneficial health effects of green tea consumption, but they have generally not been borne out by scientific investigation; excessive consumption is associated with some harmful health effects but moderate, regular consumption is safe (Khokhar and Mangnus 2002).

The first green tea was exported from India to Japan during the 17^th century. Green tea was first brewed in 2737BC during the reign of Emperor shennog in China (Dona et al., 2003).

Green tea contains a variety of enzymes, amino acids, carbohydrates, lipids, sterols, dietary minerals and photochemical such as polyphenols, flavonols and caffeine. Polyhenols found in green tea include Epigallocatechin (EGC), epigellocatechin gellate (EGCG), epicatechin gellate, and epicatechin, flavonols such as kaempferol, quercetin and myricitin are also found in green tea (Chen et al., 2001).

Green tea been used as a medicine for thousands of years, originating in China but widely used throughout Asia this bererage has a multitude of uses from lowering blood pressure to preventing cancer. The reason that green tea has more health benefits attached to it than black tea is due to the processing. Black tea is processed in a way that allows fermentation whereas green tea processing avoids the fermentation process. As a result green tea redeems maximum amount of antioxidants and poly-phenols the substances that saves green tea its many health benefits. To produce green tea, freshly harvested leaves are immediately steamed to prevent fermentation, yielding a dry stable product; this steaming process destroys the enzymes responsible for breaking down the color pigment in the leaves and allows the tea to maintain its green color during the subsequent rolling and drying processes. These processes preserve natured polyphones with respect to the health-promoting properties. As green tea is fermented to oolory and then black tea, polyphone compound (catching) in green tea are dimerized to form a variety of the a flavins, such that these teas may have different biological activates (Babu et al., 2006).