Plant polyphenols are known for their limiting of adverse effects on reactive oxygen species (ROS) in biological systems. The photochemiluminescence (PCL) assay allows to evaluate the antiradical activity of a compound in the presence of a superoxide anion-radical (O •-), which is one of the ROS directly associated with the human body. In this work, determination of the superoxide anion radical scavenging activity of different tea extracts using the PCL assay was performed.
Investigations were conducted on different tea leaves extracts. The study included five kinds of tea leaves subjected to aqueous and ethanol extraction procedure. Catechins content was evaluated using HPLC. Antiradical activity of the samples was conducted with use of Photochem assay.
Analysis of total catechins content in tea aqueous extracts enabled them to be arranged as follows: yellow > green > white > red > black, while for ethanol extracts it was: yellow = green > white > red > black. The examined tea extracts were ranked from highest to lowest water-soluble antioxidative capacity (ACW) values as follows: yellow > green > white > red > black. The results of lipid-soluble antioxidative capacity (ACL) values for aqueous extracts were similar; however, were approximately 50% lower than those presented as ACW. The second examined group were ethanol extracts, which ranked for ACW values: yellow > green = red = white > black, while ACL values ranked as follows: yellow > white = black = red > green. PCL assay results were correlated with total catechin content in aqueous extracts.
Antiradical activity of different tea leaves extracts in PCL assay, showed that the highest activity was found in extracts of yellow tea; the lowest, however, was identified in black tea extracts.