The antioxidant activity of green tea has been extensively studied; however, the results obtained from dietary intervention studies are controversial probably due to the differences in the population’s studied and in experimental protocols.
Consumption of green tea has been correlated with supporting good health where oxidative stress seems to be involved: a higher dietary intake of antioxidant compounds might be considered preventive in the onset of ROS (Reactive Oxygen Species)-related human conditions by increasing the antioxidant potential of subjects (1).
The effectiveness of a moderate intake of Greenselect® (green tea extract) on the antioxidative status, on healthy blood profiles, addressing to oxidative stress as well as the activity of antioxidant enzymes on lymphocytes have been investigated (2-4). The importance of demonstrating the antioxidant effects of tea in human beings is emphasized by the evidence that catechins are extensively metabolized in vivo and that the antioxidant and biological activities of their metabolites may differ from those of their original compound.
Epidemiological data also indicate that green tea consumption may help weight management by improving energy expenditure.
The weight loss promotion appears to be sustained by the thermogenic effect exerted by galloyl catechinic derivatives (5). Greenselect® Phytosome® has been tested on a multicentric trial against a low calorie diet alone (5) to assess its capability to promote weight loss.
Clinical studies on Greenselect® Phytosome®
Effect of Greenselect® on peroxide level measured by Carr Units
Effect of Greenselect® on total antioxidant activity in plasma
Clinical studies on Greenselect® Phytosome®
Weight loss promotion of Greenselect® Phytosome® on overweight patients (5).
One hundred overweight patients affected by obesity have been treated with 150 mg of Greenselect® Phytosome® twice daily (300 mg/day). Along the study all patients (treated and placebo) were put onto a low calories diet (1250-1350 Kcal for women and 1650-1750 Kcal for men) distributed in at least 4 meals per day. Parameters such as body weight, body mass index, waistline, total cholesterol, basal glycemia and total triglycerides have been measured at the beginning, after 45 days and after 90 days (end of the study). The average weight loss was of 6 kg in the diet only group and 14 kg in the treated group. Accordingly, relevant results have been reported in terms of body mass index, waistline and blood parameters. Greenselect®Phytosome® provides clinically demonstrated support in weight management.
Clinical studies on Greenselect®
Effectiveness of Greenselect® on improvement of antioxidant defenses in plasma(4).
Greenselect® was administered at a dosage of 160 mg/b.i.d. (320 mg/day) to 24 healthy female volunteers held on a controlled diet, for six weeks’ treatment.
At the end of the treatment, the subjects treated with Greenselect® had a significantly lower LDL cholesterol level, while the Total Antioxidant Activity (TAA) was significantly increased compared to control subjects.
It is noticeable that blood samples were obtained 12 hours after the last consumption, indicating that the effect on the antioxidative status of plasma persists at least for that period of time. When tea consumption is regular, in fact, the mean plasma concentration of catechins reaches a steady state significantly higher than the baseline levels, and remains for at least 12 hours after the last ingestion.
The results of this study suggest that a moderate intake of Greenselect® in healthy subjects improves antioxidant defenses in plasma and protects lymphocytes from DNA oxidative damage.
- Weisburger J. H., Chung F. L., “Mechanisms of chronic disease causation by nutritional factors and tobacco products and their prevention by tea polyphenols”, Food Chem. Toxicol. 40, 1145-1154 (2002)
- Pietta P. G., Simonetti P.,Mauri P., “Antioxidant activity of selected medicinal plants”, J. Agric. Food Chem. 46, 4487-4490, (1998)
- Erba D, Riso P, Colombo A, Testolin G., Supplementation of Jurkat T cells with green tea extract decreases oxidative damage due to iron treatment., J Nutr. 1999 Dec;129(12):2130-4
- Erba D., Riso P., Bordoni A., Foti P., Biagi P.L., Testolin G., Effectiveness of moderate green tea consumption on antioxidative status and plasma lipid profile in humans, J. Nutrit. Biochem. 16, 144-149 (2005)
- Di Pierro F, Menghi AB, Barreca A, Lucarelli M, Calandrelli A. “Greenselect Phytosome as an adjunct to a low-calorie diet for treatment of obesity: a clinical trial “, Altern Med Rev. Jun;14(2):154-60. (2009)