Effect of Porphyra extract on blood pressure in spontaneously hypertensive rats

Abstract

The effect of Porphyra extract (PE), containing 10.5% of γ-aminobutyric acid (GABA), on blood pressure in spontaneously hypertensive rats (SHRs) was examined. Single dose oral administration of PE (2 mg/kg of rat weight) in SHRs showed a significant reduction in systolic blood pressure. SHRs fed a diet containing PE at the level of 0.003% for 35 days showed a significantly lowered blood pressure compared to the control group. Moreover, these same rats showed lowered angiotensin I-converting enzyme (ACE) activities in the serum, abdominal aorta and lung. On the other hand, the concentration of PE producing 50% inhibition of rabbit lung ACE activity in vitro was 0.47 mg/ml. These results suggest that the lowered blood pressure of SHRs was due to GABA and some ACE inhibitory components in PE.