Angiotensin-1 converting enzyme (ACE) inhibitory activity of peptides isolated from bovine milk fermented with Lactobacillus helveticus NCDC-288.

摘要

Hypertension is a major risk factor for cardiovascular diseases, such as coronary heart disease, congestive heart failure and stroke. By lowering high blood pressure with antihypertensive treatment; the incidence and severity of these complications can be decreased. Several casein-derived peptides are able to lower blood pressure. This study investigated the ability of casein-derived peptides obtained from Lactobacillus helveticus NCDC 288 fermented buffalo milk to inhibit angiotensin-1 converting enzyme (ACE) activity. Buffalo skim milk was fermented with L. helveticus NCDC 288 (1, 2 or 3% inoculum and incubation for 8, 16 or 24 h). After incubation, the curd was mixed to break up large particles and centrifuged. The peptides produced were separated using Sephadex G-25 gel filtration and HPLC using a C18 column. These peptides were tested in vitro for ACE inhibition and found to be effective ACE inhibitors. Results show that of the 6 peaks resolved by HPLC the peptide fraction obtained from the 3rd and 4th peaks showed 58 and 75% ACE inhibition, respectively. In addition, a method is proposed for measuring ACE inhibitory activity which is based on following colour development caused by specific binding of 2,4,6-trinitro benzene sulfonate (TNBS) to the primary amine His-Leu formed on hydrolysis of Hip-His-Leu by ACE.