Green tea: Biochemical and biological basis for health benefits

Abstract

Publisher Summary Green tea beverages originated many thousands of years ago as a medicinal tonic. The historically long use of many folk remedies does not necessary prove their medical usefulness. However, recent evidence based on modern scientific evaluations of green tea appears to support the possibility that green tea compounds, especially catechins, are medically valuable. The chapter focuses on green tea and green tea catechins rather than on fermented teas or catechin by-products that are produced during fermentation. Theaflavins and thearubigins, a complex mixture of catechin condensation products with a heterogeneous molecular weight distribution, are major fermentation products in black tea, which, like catechins, have antioxidant and antitumorigenic activities. Experimental studies on the physiological effects of some polyphenolic tannins from other plants indicate that they also may be beneficial for decreasing serum lipids, reducing blood pressure, and modulating immune responses and for use as antitumorigenic and antibacterial agents and use in food preservation. The chapter discusses that tea polyphenols are widely used as natural antioxidants for prevention of oxidation of edible oils or discoloring of foods.