Abstract
The purpose of this study was to investigate the influence of watercress intake on blood pressure and lipid metabolism in rats. Spontaneously hypertensive rats (SHRs) were divided into control and watercress groups, and the latter were fed a 2.5% watercress diet. After feeding for 11 weeks, the systolic blood pressure of the SHRs fed watercress was significantly lower than that of the control SHRs. The antihypertensive mechanism of watercress was then studied using the Magnus method. An aqueous extract of watercress inhibited angiotensin-I-converting enzyme in vascular smooth muscle, and showed weak antagonism towards the AT1 receptor. Ethanol and methanol extracts of watercress showed weak inhibition of voltage-dependent calcium channels and the α-adrenergic receptor. The SHRs fed watercress showed significantly decreased serum levels of total cholesterol, LDL-cholesterol, and triglycerides, and the total cholesterol content of the liver showed a tendency to decrease. Although the watercress-fed SHRs showed significantly high liver triglyceride levels, their serum aspartate aminotransferase and alanine aminotransferase levels remained unchanged. These results suggest that daily consumption of watercress efficiently improves lipid metabolism and lowers blood pressure.
