Antihypertensive Effects of Hydrolysates of Wakame <i>(Undaria pinnatifida)</i> and Their Angiotensin-I-Converting Enzyme Inhibitory Activity

Abstract

Aim: The angiotensin-I-converting enzyme (ACE) inhibitory and antihypertensive activities of wakame hydrolysates have been investigated in several studies. Methods: Wakame (Undaria pinnatifida) was hydrolyzed using 17 kinds of proteases and the inhibitory activity of the hydrolysates for ACE was measured. Of these hydrolysates 4 with potent ACE inhibitory activity were administered singly and orally to spontaneously hypertensive rats (SHR). Results: The systolic blood pressure of SHR decreased significantly after single oral administration of protease S ‘Amano’ and proleather FG-F hydrolysates (10 mg protein/kg body weight). In a long-term feeding experiment, 7-week-old SHR were fed standard chow supplemented with protease S ‘Amano’-derived 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. Conclusions: The hydrolysates derived from wakame by protease S ‘Amano’ have a powerful ACE-inhibitory activity (IC₅₀ = 86 µg protein/ml) and were effective in spite of their slight bitterness as ‘physiologically functional food’ with antihypertensive activity.

The role of nutrition and nutraceutical supplements in the treatment of hypertension

“…The primary effect of Wakame appears to be through its ACEI activity from at least four parent tetrapeptides and possibly their dipeptide Houston M. Hypertension, nutrition, nutritional supplements, cardiovascular disease and tripeptide metabolites, especially those containing the amino acid sequence Val-Tyr, Ile-Tyr, Phe-Tyr and Ile-Try in some combination [251,254,255] . Its long-term use in Japan has demonstrated its safety.…”

Functional and Nutraceutical Ingredients from Marine Macroalgae

“…Seaweeds have also proven to be good sources of antihypertensive peptides. In particular, peptides derived from the brown seaweed U. pinnatifida (wakame) and the red algae Porphyra yezoensis have been demonstrated to be potent inhibitor of ACE [42][43]. Controlled enzymatic hydrolysis is one of the most appropriate methods in the production of tailor-made peptides from parent protein with enhanced ACE inhibitory properties.…”

“…However, peptides of peptic digest of wakame showed pronounced bitter taste, which limited their use as functional food ingredients. In another screening test, the authors compared the antihypertensive effects of 17 different protease hydrolysates of wakame, among which the hydrolysate made with protease S 'Amano' exhibited marked antihypertensive effect in both the single oral administration and long-term feeding test to SHR [42]. Moreover, S 'Amano' was more effective than other enzymes to produce a hydrolysate with improved sensory properties and high solubility in water.…”

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

“…The brown alga protein was collected, concentrated and lyophilized. One gram of brown alga protein was dispersed in 25 mL of distilled water and mixedwith 10 mg of each protease and then hydrolyzed using various kinds of proteases at optimal pH and temperature for 18 h to obtain peptide mixture (Sato et al, 2002 b).…”