Composition of Polyphenols in Fresh Tea Leaves and Associations of Their Oxygen-Radical-Absorbing Capacity with Antiproliferative Actions in Fibroblast Cells

Abstract

The polyphenols in various parts of the tea plant used in manufacture of tea products (young leaves, old leaves, and stem) were analyzed by HPLC. The young leaves (apical bud and the two youngest leaves) were found to be richer (2.7-fold) in polyphenols than old leaves (from the tenth to the fifth leaf). Also, the tea polyphenols were found to be higher (1.4-fold) in summer than in spring. Ten different types of commercial tea (manufactured tea), including unfermented, semifermented, and fermented tea, were analyzed for their polyphenol compounds, and it was found that both yields of solids in tea water extracts (TWEs) and the amount of (-)-epigallocatechin 3-gallate (EGCG) in these products varied with different tea leaves and processing methods. Longjing tea (unfermented green tea) contained the highest concentration of EGCG and polyphenols, whereas Assam black tea (most fermented) contained the least. Longjing TWEs showed strong inhibitory effect on DNA synthesis in A-431 tumor cells. We also found that green tea polyphenols (GTPs) and EGCG strongly inhibited tumor cell DNA synthesis and peroxyl-radical generation. The evidence suggests that the strong antioxidative and antiproliferative activities of Longjing TWEs and GTPs are mainly due to the higher contents of tea polyphenols. EGCG (the major component of GTPs) showed strong inhibitory action on the growth of immortalized cells (NIH3T3) and tumor cells (S-180II) but almost no effect on the growth of normal cells (C3H10T1/2).

Comparison of antioxidant capacities of different types of tea using the spectroscopy methods and semi-empirical mathematical model

“…In general, the obtained results confirm the higher TEAC value of unfermented green tea than of fermented black tea, which is in line with data found in literature [12,13,25], although some studies indicate a reverse trend [15] or lack of differences in the antioxidant properties of teas manufactured via different technological processes [1,23]. In case of earl grey tea, earlier studies indicated a smaller polyphenol content compared to green and black tea [23], which can be explained by a lower total antioxidant potential of earl grey tea, despite the bergamot oil content, renowned for its antioxidant properties [26].…”

“…However, TEAC values obtained in this work are congruent with the values determined through the use of other research methods [1,10,23]. TEAC values found in literature varied between 143 and 3100 (µmol Trolox/100 mL) for black tea [1,10,16,21,24], between 480 and 6200 (µmol TE/100 mL) for green tea [16,17,21] and between 728 and 1205 (µmol Trolox/100 mL) for earl grey tea [17].…”

Effects of extraction solvents on concentration and antioxidant activity of black and black mate tea polyphenols determined by ferrous tartrate and Folin–Ciocalteu methods

“…Tea is the most widely consumed beverage worldwide and has become an important agricultural product (Benzie & Szeto, 1999;Lin, Juan, Chen, Liang, & Lin, 1996). Recent experimental studies have recognized that tea exhibits a significant health protecting activity due to its high polyphenol content (Manzocco, Anese, & Nicoli, 1998).…”

Protective Role of Vitamin C and Green Tea Extract on Malathion-Induced Hepatotoxicity and Nephrotoxicity in Rats

“…Malathion is also an ingredient in shampoos regulated by the United States Food and Drug Administration (FDA) to control head lice. The exposure to Malathion became an ongoing basis as there are residual amounts of organophosphorous pesticides have been detected in soil, vegetables, grains and other food products (Larc, 1983). Therefore, there is growing need to exogenous sources of antioxidant.…”

“…Certain catechins are the most biologically active group of the polyphenols in tea components (Lin et al, 1996). Much evidence indicates that tea polyphenols have various biological activities including antifungal, antiinflammation, antimutagenic, antioxidative, anticarcinogenic, antitumor, antidiabetic effects, the lowering of plasma cholesterol and triglyceride levels and reduction of blood pressure and platelet aggregation in several systems (Wang et al, 1989;Ho et al, 1992;Chisaka et al, 1988;Al-Attar and Abu Zeid, 2013).…”