title: Investigation of antiradical potential of different kinds of teas and extracts from these teas using antiradical activity units (TAU).
abstract: BACKGROUND
  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.
  
  
  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)).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Pharmacognosy, Wrocław Medical University, Wrocław, Poland.
authors.forename: Damian
authors.initials: D
authors.lastname: Wojciechowski
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Sroka
authors.forename: Andrzej
authors.initials: A
authors.lastname: Gamian
mesh_terms: D000975:Antioxidants / Q000032:analysis / Q000737:chemistry*; D028241:Camellia sinensis / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000032:analysis / Q000737:chemistry*; D010636:Phenols / Q000032:analysis / Q000737:chemistry*; D010936:Plant Extracts / Q000032:analysis / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry; D013223:Statistics as Topic; D013662:Tea / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D010636:Phenols; D010936:Plant Extracts; D013662:Tea