Abstract
The major green tea polyphenolic component, (-) -epigallo catechin gallate (EGCg), has been shown to exhibit noticeable inhibition of angiotensin I-converting enzyme (ACE) activity. A study was conducted to determine whether this effect in vitro is reflected in the blood pressure of animals following oral feeding. Crude catechins (extracted from green tea and composed mainly of EGCg) were fed in the diet to spontaneously hypertensive rats (SHR) or stroke-prone SHR (SHRSP), and their blood pressure was measured by the tail cuff method. The mean systolic blood pressure of SHR fed a diet containing 0.5% crude catechins from the age of 5 weeks increased with time, but remained significantly lower than that in the control group (p<0.05). At the age of 16 weeks, the diets of the two groups were exchanged. As a result, the blood pressure curves of the two groups crossed in 2 weeks, and this situation persisted. In SHRSP given 1% saline as drinking water, addition of 0.5% crude catechins to the diet not only tended to suppress the blood pressure to a non-significant extent relative to the control group, but also clearly prolonged the survival period before death due to stroke.
