Production of the blood pressure lowing peptides from brown alga, Wakame (Undaria pinnatifida)

摘要

Wakame (Undaria pinnatifida) was treated by alginate lyase and then hydrolyzed using 17 kinds of proteases and the inhibitory activity of the hydrolysates for the angiotensin- I -converting enzyme (ACE) was measured. Of these hydrolysates 4 with potent ACE inhibitory activity were administered singly and orally to spontaneously hypertensive rats (SHR). The systolic blood pressure of SHR decreased significantly after single oral administration of protease S 'Amano'(from Bacillus stearothermophilus) hydrolysates (wakame hydrolysates) at the concentration 10 mg protein/kg body weight. In long-term feeding experiment, 7-week-old SHR were fed standard chow supplemented with the wakame hydrolysates for 10 weeks. In SHR fed the 1 and 0.1% wakame hydrolysates, elevation of systolic blood pressure was still significantly suppressed for 7 weeks. To elucidate the active components, the wakame hydrolysates were fractionated by 1-butanol extraction and HPLC on a reverse-phase column. Seven kinds of ACE inhibitory peptides were isolated and identified by amino acid composition analysis, sequence analysis, and LC-MS, as Val-Tyr, Ile-Tyr, Ala-Trp, Phe-Tyr, Val-Trp, Ile-Trp, and Leu-Trp. Each peptide was determined to have an antihypertensive effect after a single oral administration in SHR. The wakame hydrolysates were also confirmed to decrease the blood pressure in human.