Antioxidant activity of teas obtained from leaves of Camellia sinensis (L.) Kuntze in course of various production processes available on Polish market
Introduction: The leaves of Camellia sinensis (L.) Kuntze are used to produce many types of tea; this variety results from the production process. The extracts, especially from teas rich in polyphenols, are also used in the prevention and treatment of certain diseases, in addition to their application for consumption. Objective: The aim of the study was to compare the antioxidant activity and total phenolic content in extracts from the following types of tea: white, green, oolong, black and Pu-erh. Methods: The aqueous and methanolic extracts from the teas were analysed by spectrophotometric methods. The method with the Folin-Ciocalteu reagent was used to determine total phenolic content; the antioxidant activity was investigated by means of the reaction with the DPPH radical. Results: Total phenolic content and the antioxidant activity of examined extracts differed significantly. The alcoholic and aqueous extracts from white and green tea of the highest content of polyphenols (97.1–84.4 mg GAE/g) showed the greatest antioxidant activity (IC50 0.263–0.329 mg/ml), similar to that of BHA. The methanolic extracts from black and Pu-erh tea demonstrated much weaker activity. Conclusions: The antioxidant activity of extracts from investigated teas is closely correlated with content of polyphenolic compounds, which depends on the type of tea and the solvent used for extraction.