Investigation of antiradical potential of different kinds of teas and extracts from these teas using antiradical activity units (TAU).

INTRODUCTION Green, black and pu-erh teas are known to have strong antiradical properties in comparison to other plant raw materials. In this study fifteen different teas belonging to three types, green, black, and pu-erh tea (five of each kind), were investigated for their antiradical properties. Antiradical activity of extracts and raw materials was measured using DPPH and ABTS(•+) radicals. MATERIAL/METHODS The antiradical potential of teas was measured using DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS(•+) (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt). The TAU₅₁₅ and TAU₇₃₄ (antiradical activity units) were defined with the tests of DPPH and ABTS(•+), respectively, and the number of units was calculated per mg of extracts (TAU(515/mg) and TAU(734/mg)) and g of raw materials (TAU(515/g) and TAU(734/g)). RESULTS/DISCUSSION When the extracts were investigated, the highest number of antiradical units (TAU(515/mg); TAU(734/mg)) was found per mg of ethyl acetate extract obtained from green tea leaves assayed with DPPH and ABTS(•+): 57.7±0.8; 106±2.0, units respectively. When the number of antiradical units TAU(515/g) was calculated per g of raw material, the highest antiradical potential (7601±92) was observed for green tea leaves. The greatest TAU(734/g) value (14,303±354) was also calculated for green tea leaves. The lowest value of antiradical activity units TAU(515/g) (684±30) and TAU(734/g) (1870±180) was calculated for pu-erh tea leaves. A high positive correlation was found between the antiradical activity of the raw materials and the content of phenolic compounds in these raw materials.