Antihypertensive peptides from skimmed milk hydrolysate digested by cell-free extract of Lactobacillus helveticus JCM1004

In the present experiments, the proteinase, aminopeptidase and x-prolyl-dipeptidyl aminopeptidase activitives were measured at 513 ± 11.9, 376 ± 9.3 and 23.6 ± 1.6 units per gramme of cell-free extract of Lactobacillus helveticus JCM1004. ACE-inhibitory activity of skimmed milk hydrolysate produced by cell-free extract of L. helveticus JCM1004 was determined, and the optimum pH and hydrolysis time for the production of ACE-inhibition substances from skimmed milk were 6.5–7.0 and 6–10 h, respectively. Peptides of Val-Pro-Pro and Ile-Pro-Pro with potent ACE inhibitor and antihypertensive activitives were purified from the hydrolysate by three step-reverse-phase high-performance liquid chromatography. The IC50 values of Val-Pro-Pro and Ile-Pro-Pro were 9.13 ± 0.21 and 5.15 ± 0.17 μM, respectively. Significant decrease (p < 0.01) in SBP of SHR was measured after a single gastric intubation of Val-Pro-Pro or Ile-Pro-Pro at 8 or 4 h, respectively.