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Objective: Glucosyl hesperidin (G-hesperidin), a water-soluble hesperidin derivative, has antihypertensive effects. A detailed understanding of the mechanism of the blood pressure-lowering effect, however, remains obscure. The aim of this work was to investigate the underlying mechanisms involved in the hypotensive effect of G-hesperidin in spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto rats (WKYs)., Methods: Fourteen-week-old SHRs and WKYs were fed a control or G-hesperidin (50 mg/kg) diet for 8 wk. Blood pressure was recorded weekly. After 8 wk, the vasodilatory responses of isolated aortas to acetylcholine and sodium nitroprusside were assessed. Expression of mRNAs related to regulation of blood pressure and vascular tone in the aorta also was investigated. Urinary 8-hydroxy-2'-deoxyguanosine, an oxidative stress marker, was measured. Cardiac and vascular hypertrophies were observed., Results: In SHRs, the ingestion of G-hesperidin inhibited the development of hypertension. G-hesperidin enhanced endothelium-dependent vasodilation in response to acetylcholine, but had no effect on endothelium-independent vasodilation in response to sodium nitroprusside. G-hesperidin decreased mRNA expression of nicotinamide adenine dinucleotide phosphate oxidase subunits in aorta, which are the main source of superoxide anion in the vasculature; endothelial nitric oxide synthase expression was unchanged. Urinary 8-hydroxy-2'-deoxyguanosine was reduced significantly by G-hesperidin treatment. G-hesperidin suppressed cardiac and vascular hypertrophies. In contrast, G-hesperidin had no effects in WKYs., Conclusion: Continuous ingestion of G-hesperidin reduces oxidative stress by inhibiting nicotinamide adenine dinucleotide phosphate oxidase expression in the vasculature, thereby ameliorating endothelial dysfunction and hypertension in SHRs.

Background and Objectives: Epidemiologic studies indicate that ingestion of vegetables and fruit inhibits the development of cardiovascular disease. Chlorogenic acids are abundant phenolic compounds contained in vegetables and fruits, but the impact of dietary chlorogenic acids on vascular function in hypertension is not known. We therefore examined the effects of 5-caffeoylquinic acid (CQA), a representative chlorogenic acid, on blood pressure and vascular function in age-matched normotensive Wistar-Kyoto rats and spontaneously hypertensive rats., Methods and Results: A single ingestion of CQA (30-600 mg/kg) reduced blood pressure in spontaneously hypertensive rats, an effect that was blocked by administration of a nitric oxide synthase inhibitor, N(G)-nitro-L-arginine methyl ester. When spontaneously hypertensive rats were fed diets containing 0.5% CQA for 8 weeks (approximately 300 mg/kg per day), the development of hypertension was inhibited compared with the control diet group. CQA ingestion increased urinary excretion of nitric oxide metabolites and decreased urinary excretion of hydrogen peroxide; decreased NADPH-dependent superoxide anion production in the aorta, suggesting that dietary CQA inhibited vascular NADPH oxidase activity; significantly improved acetylcholine-induced endothelium-dependent vasodilation in the aorta; and markedly reduced the degree of immunohistochemical staining for nitrotyrosine and media hypertrophy in aorta sections. In contrast, CQA had no effects in Wistar-Kyoto rats., Conclusions: Dietary CQA reduces oxidative stress and improves nitric oxide bioavailability by inhibiting excessive production of reactive oxygen species in the vasculature, and leads to the attenuation of endothelial dysfunction, vascular hypertrophy, and hypertension in spontaneously hypertensive rats.

Epidemiological studies indicate that habitual coffee consumption lowers the risk of diabetes and cardiovascular diseases. Postprandial hyperglycemia is a direct and independent risk factor for cardiovascular diseases. We previously demonstrated that coffee polyphenol ingestion increased secretion of Glucagon-like peptide 1 (GLP-1), which has been shown to exhibit anti-diabetic and cardiovascular effects. We hypothesized coffee polyphenol consumption may improve postprandial hyperglycemia and vascular endothelial function by increasing GLP-1 release and/or reducing oxidative stress. To examine this hypothesis, we conducted a randomized, acute, crossover, intervention study in healthy male adults, measuring blood parameters and flow-mediated dilation (FMD) after ingestion of a meal with or without coffee polyphenol extract (CPE). Nineteen subjects consumed a test meal with either a placebo- or CPE-containing beverage. Blood biomarkers and FMD were measured at fasting and up to 180 minutes postprandially. The CPE beverage led to a significantly lower peak postprandial increase in blood glucose and diacron-reactive oxygen metabolite, and significantly higher postprandial FMD than the placebo beverage. Postprandial blood GLP-1 increase tended to be higher after ingestion of the CPE beverage, compared with placebo. Subclass analysis revealed that the CPE beverage significantly improved postprandial blood GLP-1 response and reduced blood glucose increase in the subjects with a lower insulinogenic index. Correlation analysis showed postprandial FMD was negatively associated with blood glucose increase after ingestion of the CPE beverage. In conclusion, these results suggest that coffee polyphenol consumption improves postprandial hyperglycemia and vascular endothelial function, which is associated with increased GLP-1 secretion and decreased oxidative stress in healthy humans. [ABSTRACT FROM AUTHOR]