Black And Green Tea Polyphenols For Blood Pressure

May 28, 2008 by  
Filed under All, Science, Tea

Research in stroke-prone spontaneously hypertensive rats demonstrated benefits from both black and green tea polyphenols. Oxidative stress is reportedly involved not only in cardiovascular disease but also in hypertension. Using continuous monitoring of blood pressure, both green tea polyphenols and black tea polyphenols significantly reduced both systolic and diastolic blood pressure compared with controls. “These data demonstrate that both black and green tea polyphenols attenuate blood pressure increases through their antioxidant properties. Furthermore, because the amounts of polyphenols used in this experiment correspond to those in 1 liter of tea, the regular consumption of black and green tea may also provide some protection against hypertension in humans.”
The Journal of Nutrition, January 1, 2004. Ikeda, Katsumi; Njelekela, Marina; Xu, Jin-Wen; Negishi, Hiroko
Oxidative stress was reported to be involved not only in cardiovascular diseases, but also in hypertension. Epidemiologic studies indicated that tea consumption slightly reduces blood pressure. We conducted two studies to determine whether black and green tea can lower blood pressure (BP) in stroke-prone spontaneously hypertensive rats (SHRSP). Male SHRSP (n = 15) were allowed to recover for 2 wk after a transmitter for measuring BP was implanted in the peritoneal cavity. The rats were divided into three groups: the control group consumed tap water (30 mL/d); the black tea polyphenol group (BTP) consumed water containing 3.5 g/L thearubigins,0.6 g/L theaflavins, 0.5 g/L flavonols and 0.4 g/L catechins; and the green tea polyphenol group (GTP) consumed water containing 3.5 g/L catechins, 0.5 g/L flavonols and 1 g/L polymetric flavonoids. The telemetry system was used to measure BP, which were recorded continuously every 5 min for 24 h. During the daytime, systolic and diastolic BP were significantly lower in the BTP and GTP groups than in the controls. Protein expressions of catalase and phosphorylated myosin light chain (MLC-p) were measured in the aorta by Western blotting. GTP significantly increased catalase expression, and BTP and GTP significantly decreased MLC-p expression in the aorta. These data demonstrate that both black and green tea polyphenols attenuate blood pressure increases through their antioxidant properties in SHRSP. Furthermore, because the amounts of polyphenols used in this experiment correspond to those in ~1 L of tea, the regular consumption of black and green tea may also provide some protection against hypertension in humans. J. Nutr. 134: 38-42, 2004.

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