Effects of two kinds of Koji on blood pressure in spontaneously hypertensive rats

The effect of koji prepared with Aspergillus oryzae and beni-koji prepared with Monascus pilosus on blood pressure of spontaneously hypertensive rats (SHR) was studied. Male adult SHR were fed semi-purified chow containing 1% NaCl with 5_??_10% koji or 3_??_10% beni-koji for 3 weeks. The blood pressure of the animals fed one of the kojis was 7.15% lower than that of the control group. Beni-koji had a stronger hypotensive effect than koji. Koji and beni-koji did not affect blood glucose, plasma cholesterol, plasma triglycerides, or mineral metabolism. These results suggested that koji and beni-koji suppress rises in blood pressure. The mechanism of the effect did not involve Na/K ion-exchange in the gastrointestinal tract, which would inhibit Na absorption.