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, 2017, 1691568

Protective Effect of Green Tea ( Camellia sinensis (L.) Kuntze) Against Prostate Cancer: From In Vitro Data to Algerian Patients

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Protective Effect of Green Tea ( Camellia sinensis (L.) Kuntze) Against Prostate Cancer: From In Vitro Data to Algerian Patients

Somia Lassed et al. Evid Based Complement Alternat Med.

Abstract

Green tea (GT) has been studied for its effects as antioxidant and cancer-preventive agent. Epidemiological studies showed that GT consumption decreases the risk for prostate cancer (PC). To investigate whether erythrocyte oxidative stress (OS) is associated with PC and whether daily consumption of GT improves the oxidative phenotype, we performed a study in a group of Algerian PC patients, preceded by an in vitro study to characterize composition and antioxidant/antiproliferative activities of the GT used. This contained a high content of phenolic and flavonoid compounds, demonstrating in vitro antioxidant activity and significant antiproliferative effect on human prostate cancer PC-3 cell line. Seventy PC patients and 120 age-matched healthy subjects participated in the study, with glutathione (GSH), malondialdehyde (MDA), and catalase activity evaluated before and after GT consumption. The results showed a reduced GSH and catalase activity and a high level of MDA in erythrocytes from PC patients. The consumption of 2-3 cups per day of GT during 6 months significantly increased GSH concentration and catalase activity and decreased MDA concentration. In conclusion, GT significantly decreased OS in Algerian PC patients. Regular consumption of GT for a long period may prevent men from developing PC or at least delay its progression.

Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Figure 1
Figure 1
Total phenolic and flavonoid content of green tea extracts, measured as described in Materials and Methods. Concentrations of total phenolic compounds are expressed as μg of gallic acid equivalent (GAE) per mg of extract and total flavonoids are expressed as μg of quercetin equivalent (QE) per mg of extract. Values are means ± SD (n = 3).
Figure 2
Figure 2
Chromatograms of green tea extracts. (a) Chromatogram of chloroformic (CHCl3) green tea extract. (b) Chromatogram of ethyl acetate (EtOAc) green tea extract. (c) Chromatogram of n-butanol (n-BuOH) green tea extract. The chromatographic conditions were described in Materials and Methods. The phenols detected by HPLC-TOF/MS analysis are expressed as numbers from 1 to 23.
Figure 3
Figure 3
Antioxidant activity of green tea extracts. (a) DPPH scavenging activities of green tea extracts and vitamin C, measured as described in Materials and Methods. (b) Effect of green tea extracts and vitamin C on inhibition of FeSO4-induced lipid peroxidation of egg vitellose, measured as previously described in Materials and Methods. Values are mean ± SD (n = 3).
Figure 4
Figure 4
Effects of green tea extracts on prostate cancer PC-3 and fibroblast BJ cell mass. The control value (vehicle only) was determined as 100% to account for the differential proliferation of cell lines. Data are expressed as the means ± SEM of four different experiments, p < 0.05, ∗∗∗∗p < 0.0001 versus control, nontreated cells.
Figure 5
Figure 5
Effect of green tea consumption on lipid peroxidation and antioxidants status in erythrocytes from controls individuals and PC patients. (a) Effect of green tea consumption in erythrocytes GSH level in controls and PC patients. (b) Effect of green tea consumption in erythrocyte catalase activity in controls and PC patients. (c) Effect of green tea consumption in erythrocyte MDA level in controls and PC patients. T0: PC patients before green tea consumption; 3 months: PC patients after 3 months of green tea consumption; 6 months: PC patients after 6 months of green tea consumption; C − tea: control individuals who rarely or never drank tea; C + green tea: control individuals who usually drank 1 to 3 cups of green tea per day. Data are expressed as the means ± SD of three to four different experiments; p < 0.05, ∗∗p < 0.01, and ∗∗∗∗p < 0.0001, compared to T0. +++p < 0.005, +p < 0.05, compared to C − tea.

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