Isolation, purification and the anti-hypertensive effect of a novel angiotensin I-converting enzyme (ACE) inhibitory peptide from Ruditapes philippinarum fermented with Bacillus natto

Abstract

Hypertension is known as an important factor in cardiovascular disease. An angiotensin-I-converting enzyme (ACE) inhibitor is one of the synthetic drugs that is widely used to control hypertension. Here, we have prepared and investigated the ACE inhibitory peptide from Ruditapes philippinarum fermented with Bacillus natto. The fermented product obtained under optimized fermentation conditions exhibited ACE inhibitory activity. The ACE inhibitory peptides were purified by ultrafiltration, gel filtration chromatography and RP-HPLC, sequentially. A novel peptide with high ACE inhibitory activity (IC50 of 8.16 μM) was isolated and the amino acid sequence was identified to be Val-Ile-Ser-Asp-Glu-Asp-Gly-Val-Thr-His (VISDEDGVTH) by LC-MS/MS. The Lineweaver-Burk plots suggested that VISDEDGVTH acts as a competitive inhibitor against ACE. Our in vitro study indicated the stability of VISDEDGVTH against gastrointestinal proteases. An in vivo study in rats proved the significant anti-hypertension effect of the peptide. Furthermore, the cellular mechanism of VISDEDGVTH moderating hypertension was investigated. We found that VISDEDGVTH enhanced the release of NO, inhibited the secretion of EF-1, and scavenged ROS in human vascular endothelial cells. Our study suggests that VISDEDGVTH serves as an anti-hypertension and anti-inflammatory drug and as a beneficial ingredient in functional foods and pharmaceuticals.

Bioactive peptides from food fermentation: A comprehensive review of their sources, bioactivities, applications, and future development

“…Najafian & Babji (2018) mentioned that the high antioxidant activity of the peptides is attributed to the presence of high levels of hydrophobic amino acid residues and their interactions in the peptides. By using Bacillus natto to ferment Ruditapes philippinarum clams under the optimal conditions (5% inoculum, 1:25 solid-to-water ratio, and 10% additional sugar at 45 • C for 24 hr), Chen, Gao, et al (2018) The study showed that P1 demonstrated a higher antioxidant activity compared to P2. The presence of hydrophobic amino acids (Ile, Ala, and Pro) and basic amino acids (Lys) in the peptide sequences is believed to contribute to the high antioxidant activity of the fermented Loma fish.…”

“…By using Bacillus natto to ferment Ruditapes philippinarum clams under the optimal conditions (5% inoculum, 1:25 solid‐to‐water ratio, and 10% additional sugar at 45 °C for 24 hr), Chen, Gao, et al. (2018) managed to obtain a peptide (VISDEDGVTH) with high ACE‐I activity (IC 50 = 8.16 µM) after sequential fractionation. Due to its small molecular weight, the peptide was stable against simulated gastrointestinal digestion.…”

“…By observation, both peptides fulfilled the structure–activity requirement of branched hydrophobic amino acid (valine and isoleucine) at the N‐terminus and the presence of aromatic hydrophobic amino acid (proline) at the C‐terminus. Fermentation of R. philippinarum clam with B. natto GL‐12 produced a novel gastrointestinal‐stable peptide (VISDEDGVTH) with ACE‐I activity (IC 50 of 8.16 µM) (Table 4) (Chen, Gao, et al., 2018). Using Sprague‐Dawley rats, in vivo ACE‐I effect was also observed (Chen, Gao, et al., 2018).…”

“…Fermentation of R. philippinarum clam with B. natto GL‐12 produced a novel gastrointestinal‐stable peptide (VISDEDGVTH) with ACE‐I activity (IC 50 of 8.16 µM) (Table 4) (Chen, Gao, et al., 2018). Using Sprague‐Dawley rats, in vivo ACE‐I effect was also observed (Chen, Gao, et al., 2018). The presence of branched amino acid (valine) at the N‐terminus and aromatic amino acid (histidine) in the peptide could contribute to the ACE‐I effect.…”

Purification, Characterization and Evaluation of Inhibitory Mechanism of ACE Inhibitory Peptides from Pearl Oyster (Pinctada fucata martensii) Meat Protein Hydrolysate

“…The number of adults suffering from hypertension is estimated to increase to 1.6 billion worldwide by 2025 [2]. Angiotensin I converting enzyme (ACE) is regarded a crucial enzyme in regulating blood pressure by promoting the conversion of angiotensin I to angiotensin II in the circulatory or endocrine of human renin-angiotensin system [3,4]. In addition, ACE also converts the vasodilator bradykinin into an inactive peptide via kallikrein–kinin systems [5].…”