Characterization of the constituents and antioxidative activity of cocoa tea (Camellia ptilophylla)

Three main types of cocoa tea derived from Camellia ptilophylla, white cocoa tea (WCT), green cocoa tea (GCT) and black cocoa tea (BCT) were prepared. A comparison between cocoa tea and commonly consumed tea Biluochun cha (BLC), Longjing cha (Lj), Qimenhong cha (Qmh) and Yinghong 9# (Yh9) was studied. Levels of catechins and purine alkaloids were determined by HPLC. Total polyphenol contents were determined by ferrous tartrate assay. Antioxidative activity was evaluated using ABTS decolorization assay, DPPH radical assay and ferric thiocyanate (FTC) method. The results showed that WCT contained the highest polyphenol content and showed the highest antioxidative activity. The radical scavenging ability of the tea extracts followed this order: WCT > GCT > Blc > Lj > BCT > Yh9 > Qmh. Tea extracts measured by the linoleic acid system also showed the same patterns of activity as the ABTS and DPPH method. A high correlation between polyphenol content and antioxidative activity of tea extracts was observed.