Comparison of the Antioxidative Activities and Bioactive Compound Contents of Green Tea, Roasted Green Tea, and Black Tea

Abstract

This study compared the antioxidative activities and bioactive compound contents of three different teas [green tea (GT), roasted green tea (RGT), and black tea (BT)]. GT showed higher antioxidative activity than RGT and BT according to in vitro assays of 1,1-diphenyl-2-picrylhydrazyl radical and reducing power. RGT had more effective radical-scavenging and reducing power than BT (p<0.05). GT showed significantly higher total phenolic, total flavonoid, and individual and total catechin contents than RGT and BT. Compared to GT, RGT showed lower contents of (-)-epicatechins, including (-)-epicatechin, (-)-epigallocatechin, (-)-epicatechin gallate, and (-)-epigallocatechin gallate, but higher contents of catechins, including (+)-catechin, (+)-gallocatechin, (+)-gallocatechin gallate, and (+)-catechin gallate. In addition, the caffeine content in RGT was lower than that in GT. These results provide useful information on the antioxidative activity and content of bioactive compounds in roasted green tea.