Polyphenol-containing azuki bean (Vigna angularis) extract attenuates blood pressure elevation and modulates nitric oxide synthase and caveolin-1 expressions in rats with hypertension.
OBJECTIVE
Azuki beans (Vigna angularis) contain polyphenols such as proanthocyanidins that exhibit potential radical scavenging activities. We herein investigated the effects of polyphenol-containing azuki bean extract (ABE) on elevated blood pressure, nitric oxide (NO) production, and expressions of endothelial NO synthase (eNOS), inducible NOS (iNOS), and caveolin-1 proteins in the aorta and kidney of chronically hypertensive rats.


RESULTS
Spontaneously hypertensive rats (SHRs/Izm) with approximately 200 mm Hg systolic blood pressure (SBP) were randomly divided into 2 groups fed either 0% or 0.9% ABE-containing diet. Age-matched normotensive Wistar-Kyoto rats were used as the control. The content of 24-h urinary nitrate/nitrite (NOx) excretion was measured to evaluate NO production. After 8 weeks of treatment, the eNOS, iNOS, and caveolin-1 protein expressions in the aorta and kidney were analyzed by western blotting. The SBP of the ABE-treated SHR was significantly lower than that of the untreated SHR. The level of 24-h urinary NOx excretion was significantly higher in the ABE-treated SHR than in the untreated SHR. The eNOS and iNOS expressions in the aorta and kidney were remarkably upregulated in the untreated SHR but suppressed in the ABE-treated SHR. The vascular and renal caveolin-1 expressions were upregulated in the ABE-treated SHR.


CONCLUSIONS
ABE reduced the elevated blood pressure and increased NO production in long-term treatment. It may be associated with the modulation of eNOS and iNOS protein expressions in the aorta and kidney during the development of hypertension.
Mukai
Y
Y
Department of Life Sciences, Graduate School of Health Sciences, Aomori University of Health and Welfare, Mase 58-1, Hamadate, Aomori 030-8505, Japan.
Sato
S
S
D000818:Animals; D001013:Aorta, Thoracic / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects*; D015153:Blotting, Western; D051242:Caveolin 1 / Q000096:biosynthesis*; D002908:Chronic Disease; D007887:Fabaceae / Q000737:chemistry*; D005419:Flavonoids / Q000737:chemistry / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D006973:Hypertension / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D007668:Kidney / Q000378:metabolism / Q000473:pathology; D008297:Male; D009569:Nitric Oxide / Q000652:urine; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D010636:Phenols / Q000737:chemistry / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology; D059808:Polyphenols; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
D051242:Caveolin 1; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts; D059808:Polyphenols; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III