Three novel angiotensin I-converting enzyme (ACE) inhibitory peptides from cuttlefish (Sepia officinalis) using digestive proteases

The angiotensin I-converting enzyme (ACE) inhibitory activities of protein hydrolysates prepared from muscle of cuttlefish (Sepia officinalis) by treatment with various digestive proteases were investigated. The most active hydrolysate was obtained with the crude protease extract from the hepatopancreas of cuttlefish (64.47 ± 1.0% at 2 mg of dry weight/ml) with a degree of hydrolysis of 8%. By gel filtration on Sephadex G-25 and RP-HPLC on C18 column, three novel peptides with high ACE-inhibitory activity were purified and their molecular masses and amino acid sequences were determined. The three peptides Val-Tyr-Ala-Pro, Val-Ile-Ile-Phe and Met-Ala-Trp with IC50 values of 6.1, 8.7 and 16.32 μM, respectively, were novel ACE-inhibitory peptides. Lineweaver–Burk plots suggest that the three purified peptides act as non-competitive inhibitors against ACE. These results suggest that some peptides from cuttlefish could be a beneficial ingredient for nutraceuticals against hypertension.