Comparative Study on Total Polyphenol Content and Total Antioxidant Activity of Tea (Camellia sinensis)

Total polyphenol content (TPC) and total antioxidant activity (TAA) of seventeen types of tea samples were evaluated and their relationship examined. TPC of tea was measured by the standard Folin-Ciocalteu method and a new enzymatic procedure involving the use of horseradish peroxidase and 4-aminoantipyrine, a chromagenic agent. TAA in tea samples was assessed using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and ferric reducing antioxidant power (FRAP) assays. The highest content of polyphenol and strongest antioxidant activity was detected in green teas, followed by oolong teas and then black teas. The comparison of the above methods revealed the relationship between TPC and TAA of teas. Discrepancies in the results maybe explained by the different chemical principles upon which these assays are built. Moreover, use of a variery of standard compounds, along with a new enzymatic method, showed significant differences in the used TPC of teas, indicating need for further standardization of TPC and TAA methods.