The effects of a water-soluble green coffee bean extract (GCE) on blood pressure were investigated using spontaneously hypertensive rats (SHR). There was a dose-dependent reduction in blood pressure after a

Ferulic acid (4-hydroxy-3-methoxycinnamic acid) is a phenolic compound contained in rice bran and other plants. The effect of ferulic acid on blood pressure (BP) was investigated in spontaneously hypertensive rats (SHR). After oral administration of ferulic acid (1 to 100 mg/kg) to SHR, systolic blood pressure (SBP) significantly decreased in a dose-dependent manner. When oral ferulic acid (50 mg/kg) was administered to SHR, BP was lowest at 1 h and returned to basal levels at 6 h. There was a significant correlation between SHR plasma ferulic acid and changes in the SBP of the tail artery, suggesting that absorbed ferulic acid reduces BP. When 7-week-old SHR were given 10 and 50 mg/kg/d of ferulic acid for 6 weeks, increases in BP were significantly attenuated compared to SHR on the control diet. Intravenous injection of ferulic acid dose dependently reduced carotid arterial pressure in anesthetized SHR. Furthermore, the depressor effect of intravenous ferulic acid (1 mg/kg) was significantly attenuated by pretreatment of SHR with the nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME; 3 mg/kg, administered intravenously). These data suggest that the hypotensive effect of ferulic acid in SHR is associated with NO-mediated vasodilation.

Our previous study revealed the antihypertensive effects of green coffee bean extract (GCE) ingestion in spontaneously hypertensive rats. We suggested that this antihypertensive action was due to the fact that

No abstract

Recent studies suggest that chlorogenic acids, which are the main components of the polyphenol class in coffee, decrease blood pressure, and that hydroxyhydroquinone (HHQ), which is generated by roasting coffee beans, inhibits the antihypertensive effect of chlorogenic acids in brewed coffee. Here, we examined the vasoreactivity and antihypertensive effects of HHQ-reduced coffee in mild hypertension. The study design was a double blind, randomized, placebo-controlled intervention study, with a 4-week run-in period, followed by an 8-week test beverage ingestion period. The subjects were Japanese men and women with mild hypertension and vascular failure, who were not taking any antihypertensive drugs. During the test beverage ingestion period, the subjects ingested either active or placebo HHQ-reduced coffee (chlorogenic acids per 184 ml of coffee: active, 300 mg; and placebo, 0 mg) daily. Subjects were randomly divided into two groups: active group (n¼9) and placebo group (n¼12). In the active beverage group, endothelium-dependent, flow-mediated vasodilation impairment was significantly ameliorated and systolic blood pressure was significantly decreased from the baseline, but not in the placebo group. There were no test beverage consumption-related changes in other parameters that may influence blood pressure, such as pulse, cardiac output, body weight or 24-h urine volume. Ingestion of the active beverage significantly decreased urinary isoprostane levels, suggesting a reduced oxidative stress. These findings indicate that HHQ-reduced coffee decreased blood pressure in subjects with mild hypertension. The decreased blood pressure was associated with improved vascular endothelial function.