**8. Conclusion**

Tea, which is consumed all over the world, is thought to be not only a popular beverage but also can be an antioxidative agent that is readily available in everyday life. Polyphenols such as theaflavins and thearubigins, as well as catechins, which are major constituents of tea, are thought to be primarily responsible for several beneficial effects. Tea's antioxidant properties include its ability to inhibit free radical generation, scavenge free radicals, and chelate transition metal ions. It is clear that, despite extensive research, the composition of tea is still unknown. Only 20% of the approximately 2.5 million metric tonnes of dried tea produced is green tea, and less than 2% is oolong tea. Green tea is primarily consumed in China, Japan, and a few North African and Middle Eastern countries. Fresh tea leaf is unusually high in catechins, a flavanol group of polyphenols that can account for up to 30% of the dry leaf weight. Other polyphenols include flavonols and their glycosides, as well as depsides like chlorogenic acid, coumarylquinic acid, and theogallin, which is unique to tea (3-galloylquinic acid). Caffeine is present in an average concentration of 3%, with very small amounts of the other common methylxanthines, theobromine and theophylline also present. Teas used in pharmacological studies should be classified according to their type, source, and method of production. It would be preferable to include analytical information such as caffeine and catechin content. Methods of preparation should be specified when using tea extracts or fractions. Tea polyphenols can also reduce the risk of certain types of cancer by inducing phase I and phase II metabolic enzymes that increase the formation and excretion of carcinogen-detoxified metabolites. The research interest in tea components may provide a method to reduce the incidence and mortality from a variety of diseases. In general, tea is a more affordable natural beverage than modern beverages such as soft drinks.
