Production of angiotensin I converting enzyme inhibitory (ACE-I) peptides during milk fermentation and their role in reducing hypertension

Total Fermented Dairy Food Intake Is Inversely Associated with Cardiovascular Disease Risk in Women

BACKGROUND

The relation between fermented dairy consumption and type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD) in an Australian population remains to be established.

OBJECTIVES

The aim of this study was to investigate the association between fermented dairy consumption and T2DM and CVD risk.

METHODS

The Australian Longitudinal Study on Women's Health included Australian women (aged 45-50 y) at baseline in 2001, who were followed up through 5 surveys until 2016. Dietary intake was assessed through the use of a validated 101-item FFQ at baseline. Main study outcomes were self-reported physician-diagnosed T2DM and CVD. Logistic regression models adjusted for sociodemographic and lifestyle factors were used to estimate the association between dairy intake and T2DM and CVD risk.

RESULTS

Of 7633 women free of diabetes at baseline, 701 (9.2%) developed T2DM during a maximum 15-y follow-up period. Women in the highest tertile of yogurt intake had lower adjusted odds of T2DM than those in the lowest tertile (OR: 0.81; 95% CI: 0.67, 0.99; P = 0.041). This relation became nonsignificant after adjustment for dietary variables and total energy intake (OR: 0.88; 95% CI: 0.71, 1.08; P = 0.21). Of 7679 women free of CVD at baseline, 835 (10.9%) cases of CVD were reported during follow-up. High intake of yogurt and total fermented dairy was associated with lower CVD risk (OR: 0.84; 95% CI: 0.70, 1.00; P = 0.05, 0.80; 0.67, 0.96; 0.017, respectively) than observed in the lowest tertile of dairy product intake. Additional adjustment attenuated the relation (OR: 0.87; 95% CI: 0.72, 1.04; P = 0.13, 0.83; 0.69, 1.00; 0.048, for yogurt and total fermented dairy, respectively). No associations were found with other dairy groups.

CONCLUSION

The findings from this population-based study of Australian women suggest an inverse association between total fermented dairy intake and CVD risk, which may partly be accounted for by other dietary components.

Preparation and Identification of ACE Inhibitory Peptides from the Marine Macroalga Ulva intestinalis

Angiotensin I-converting enzyme (ACE) inhibitory peptides derived from seaweed represent a potential source of new antihypertensive. The aim of this study was to isolate and purify ACE inhibitory peptides (ACEIPs) from the protein hydrolysate of the marine macroalga Ulva intestinalis. U. intestinalis protein was hydrolyzed by five different proteases (trypsin, pepsin, papain, α-chymotrypsin, alcalase) to prepare peptides; compared with other hydrolysates, the trypsin hydrolysates exhibited the highest ACE inhibitory activity. The hydrolysis conditions were further optimized by response surface methodology (RSM), and the optimum conditions were as follows: pH 8.4, temperature 28.5 °C, enzyme/protein ratio (E/S) 4.0%, substrate concentration 15 mg/mL, and enzymolysis time 5.0 h. After fractionation and purification by ultrafiltration, gel exclusion chromatography and reverse-phase high-performance liquid chromatography, two novel purified ACE inhibitors with IC₅₀ values of 219.35 μM (0.183 mg/mL) and 236.85 μM (0.179 mg/mL) were obtained. The molecular mass and amino acid sequence of the ACE inhibitory peptides were identified as Phe-Gly-Met-Pro-Leu-Asp-Arg (FGMPLDR; MW 834.41 Da) and Met-Glu-Leu-Val-Leu-Arg (MELVLR; MW 759.43 Da) by ultra-performance liquid chromatography-tandem mass spectrometry. A molecular docking study revealed that the ACE inhibitory activities of the peptides were mainly attributable to the hydrogen bond and Zn(II) interactions between the peptides and ACE. The results of this study provide a theoretical basis for the high-valued application of U. intestinalis and the development of food-derived ACE inhibitory peptides.

Identification of new bioactive peptides from Kefir milk through proteopeptidomics: Bioprospection of antihypertensive molecules

Kefir, a probiotic beverage prepared from fermented milk, has been associated with antihypertensive activity. However, the bioactive molecules responsible for this activity still remain unclear. Therefore, in this study we aim to evaluate the mechanisms of the antihypertensive effects of Kefir in the two-kidney one-clip hypertension model, and to bioprospect for bioactive peptides identified by proteomic methodologies. Treatment with Kefir was performed via gavage, and resulted in a 37 mmHg reduction in systolic arterial pressure and 19% inhibition of angiotensin converting enzyme (ACE) activity. For the proteopeptidomic study, the protein extract of Kefir beverage and non-fermented bovine milk were analysed by MALDI-TOF mass spectrometry, and their tryptic digestion products sequenced via Shotgun proteomics (Q-Exactive mass spectrometer). A list of 35 peptides with potential hypertensive activity due to ACE inhibition were identified. These results demonstrate the benefits of Kefir products, and may guide the design of new antihypertensive drugs.

Bioactive properties of fermented donkey milk, before and after in vitro simulated gastrointestinal digestion

Indigenous strains of lactic acid bacteria previously isolated from raw donkey milk samples were used to ferment donkey milk. Each sample was subjected to an in vitro simulated gastrointestinal digestion (SGID) and analysis of the digesta by HPLC-LTQ-Orbitrap XL was performed in order to obtain a comprehensive peptide profile of fermented donkey milk. Functional properties such as ACE-inhibitory, antimicrobial and antioxidant activities of the resulting fermented donkey milks, as well as characterization of the bioactive peptides produced by an in vitro SGID, were assayed. All bioactivities were found to be high in fermented milk and a further significant increase was observed after SGID. The Enterococcus faecium DM33 fermented milk exhibited the strongest antioxidant and the highest antimicrobial activities. The highest ACE-inhibitory activity was observed in milk fermented with Lactobacillus casei DM214. These findings will contribute to the development of a new functional dairy drink with anti-hypertensive, antimicrobial and/or antioxidant activities.

Analysis and Evaluation of the Inhibitory Mechanism of a Novel Angiotensin-I-Converting Enzyme Inhibitory Peptide Derived from Casein Hydrolysate

Casein hydrolysates exert various biological activities, and the responsible functional peptides are being identified from them continuously. In this study, the tryptic casein hydrolysate was fractionated by an ultrafiltration membrane (3 kDa), and the peptides were identified by capillary electrophoresis-quadrupole-time-of-flight-tandem mass spectrometry. Meanwhile, in silico methods were used to analyze the toxicity, solubility, stability, and affinity between the peptides and angiotensin-I-converting enzyme (ACE). Finally, a new angiotensin-I-converting enzyme inhibitory (ACEI) peptide, EKVNELSK, derived from α_s1-casein (fragment 35-42) was screened. The half maximal inhibitory concentration value of the peptide is 5.998 mM, which was determined by a high-performance liquid chromatography method. The Lineweaver-Burk plot indicated that this peptide is a mixed-type inhibitor against ACE. Moreover, Discovery Studio 2017 R2 software was adopted to perform molecular docking to propose the potential mechanisms underlying the ACEI activity of the peptide. These results indicated that EKVNELSK is a new ACEI peptide identified from casein hydrolysate.

Antihypertensive activity of fish protein hydrolysates and its peptides

The rising interest to utilize nutritionally exorbitant fish proteins has instigated research activities in fish waste utilization. The development of newer technologies to utilize fish waste has fostered use of bioactive value-added products for specific health benefits. Enzymatically obtained Fish Protein Hydrolysate (FPH) is a rich source of biologically active peptides possessing anti-oxidant, anticancer, antimicrobial and anti-hypertensive activity. Isolating natural remedies to combat alarming negative consequences of synthetic drugs has been the new trend in current research promoting identification of antihypertensive peptides from FPH. In this review, we aim to culminate data available to produce antihypertensive peptides from FPH, its composition and potential to be used as a therapeutic agent. These purified peptides are known to be rich in arginine, valine and leucine. Reports reveal peptides with low molecular weight (<1 kDa) and shorter chain length (<20 amino acids) exhibited higher antihypertensive activity. As these peptides have proven Angiotensin Converting Enzyme - I inhibitory activity in vitro and in vivo, their potential to be used as antihypertensive drugs is outrageous. However, current focus on research in the field of molecular docking is necessary to have improved understanding of interaction of the peptides with the enzyme.

Identification and the molecular mechanism of a novel myosin-derived ACE inhibitory peptide

The objective of this work was to identify a novel ACE inhibitory peptide from myosin using a number of in silico methods.

Systems biology of lactic acid bacteria: For food and thought

Lactic acid bacteria (LAB) ferment plants, fish, meats and milk and turn them into tasty food products with increased shelf life; other LAB help digesting food and create a healthy environment in the intestine. The economic and societal importance of these relatively simple and small bacteria is immense. In this review we hope to show that their adaptations to nutrient-rich environments provides fascinating and often puzzling behaviours that give rise to many fundamental evolutionary biological questions in need of a systems biology approach. We will provide examples of such questions, compare the (metabolic) behaviour of LAB to that of other model organisms, and provide the latest insights, if available.

Yogurt and Cardiometabolic Diseases: A Critical Review of Potential Mechanisms

Associations between yogurt intake and risk of diet-related cardiometabolic diseases (CMDs) have been the subject of recent research in epidemiologic nutrition. A healthy dietary pattern has been identified as a pillar for the prevention of weight gain and CMDs. Epidemiologic studies suggest that yogurt consumption is linked to healthy dietary patterns, lifestyles, and reduced risk of CMDs, particularly type 2 diabetes. However, to our knowledge, few to no randomized controlled trials have investigated yogurt intake in relation to cardiometabolic clinical outcomes. Furthermore, there has been little attempt to clarify the mechanisms that underlie the potential beneficial effects of yogurt consumption on CMDs. Yogurt is a nutrient-dense dairy food and has been suggested to reduce weight gain and prevent CMDs by contributing to intakes of protein, calcium, bioactive lipids, and several other micronutrients. In addition, fermentation with bacterial strains generates bioactive peptides, resulting in a potentially greater beneficial effect of yogurt on metabolic health than nonfermented dairy products such as milk. To date, there is little concrete evidence that the mechanisms proposed in observational studies to explain positive results of yogurt on CMDs or parameters are valid. Many proposed mechanisms are based on assumptions that commercial yogurts contain strain-specific probiotics, that viable yogurt cultures are present in adequate quantities, and that yogurt provides a minimum threshold dose of nutrients or bioactive components capable of exerting a physiologic effect. Therefore, the primary objective of this review is to investigate the plausibility of potential mechanisms commonly cited in the literature in order to shed light on the inverse associations reported between yogurt intake and various cardiometabolic health parameters that are related to its nutrient profile, bacterial constituents, and food matrix. This article reviews current gaps and challenges in identifying such mechanisms and provides a perspective on the research agenda to validate the proposed role of yogurt in protecting against CMDs.