... and aqueous ethanol, and are bitter. Tea polyphenols Tea polyphenols are natural compounds extracted from tea leaves,and contain flavanols,flavanones,flavonols and ... component, made up 60%-80% of total amount of polyphenols.Catechins of several single catechins including EGC,DL-C,EC ... ,EGCG,GCG,ECG etc.Catechins with special molecular structure are easy to oxidize, which leads ...