Polysaccharides from Chinese tea: recent advance on bioactivity and function.

Tea (Camellia sinensis) has a long history of medicinal use in Asian countries such as China, Japan, India and Thailand as ancient as 500,000 years ago. Tea is globally one of the most popular and lowest cost beverages, next only to water. Tea leaves are popularly consumed with unfermented (green tea), semi-fermented (oolong tea), and fermented (black and puerh) forms. The chemical composition of tea mainly includes polyphenols (TPP), proteins, polysaccharides (TPS), chlorophyll, and alkaloids. Great advances have been made in chemical and bioactive studies of catechins and polyphenols from tea in recent decades. However, polysaccharides from tea materials have received much less consideration than TPP. Recently, TPS from tea leaves and flowers have attracted great interest. The number of relevant publications has increased rapidly in recent years. Herein, the bioactivities and function aspects of TPS from Chinese tea were reviewed.