In vitro antioxidative and anticancer activities of tea glycoprotein in green tea

Abstract

In this paper, the antioxidative and anticancer activities of tea glycoprotein (TGP) in green tea were studied. TGP was extracted from coarse old green tea and purified by Sephadex G-100 gel filtration, and its purity was determined by high performance gel permeation chromatography (HPGPC). The antioxidative activity of the TGP was evaluated by determining the change of the values of the heat-induced oxidation in a linoleic acid system with β-carotene, the decoloration of the 1,1-diphenyl-2-picrylhydrazyl (DPPH), and the superoxide generated from autoxidation of pyrogallol. The results show that the TGP possesses distinctive antioxidative activity. Furthermore, the anticancer activity of the TGP at different concentrations was evaluated by the MTT assay using two kinds of colon cancer cell lines (HCT-15, Caco-2). Dose-dependently TGP exhibited good antiproliferation activity to HCT-15, whereas exhibited very weak antiproliferation activity to Caco-2. Only at a very high concentration (409.6 μmol L−1), the TGP obviously inhibited the proliferation of Caco-2. Whether there is a correlation between the antioxidative and the anticancer activity of the TGP, should be studied further.