Highest ACE-inhibitory Activity Research Articles

Isolation and characterization of antihypertensive peptides from soy bean protein

Proteins and peptides are the most diverse biomolecules found in nature and make our interest due to their wide applications in food and pharmaceutical industry. Angiotensin Converting Enzyme (ACE) plays a major role in controlling blood pressure. The inhibition of ACE with peptides is a main target in the regulation of hypertension. The objective of the present study was to investigate the therapeutic potential of soy bean. This was accomplished by isolation of ACE inhibitory peptides using response surface methodology (RSM) and characterization of these bioactive peptides by mass spectrometry. 31 hydrolyzed fractions were isolated and evaluated for their ACE inhibition potential. Hydrolyzed fraction having highest ACE inhibitory activity was characterized by liquid chromatography-mass spectrometry (LC-MS) technique. RSM results showed maximum ACE inhibition potential (64%) by hydrolyzate was obtained at 45 oC temperature, pH 8.0, E/S 0.2 in 2 hours hydrolysis time. Results of LC-MS analysis revealed Ser-Gly, Ser-Pro, Met-Ala, His-Ala, Lys-Pro, Phe-Thr, Met-Leu, Pro-Arg, Ala-Pro-Val, Pro-Ala-Leu, Val-Met-Gly, Pro-Leu-Val, Pro-Pro-Gln, His-Arg-Gly, Ser-Phe-Val-Leu, Ala-Val-His-Try, Arg-Thr-Val-Arg, His-His-Tyr-Leu-Val, Asp-Gly-Ala-Cys-Ser-Ala-Asn and MetVal-Thr-Gly-Pro-Gly-Cys-His bioactive peptides in hydrolyzed fraction of soy bean. Our data provide evidence that response surface methodology is a good approach for isolation of antihypertensive bioactive peptides with more potent activity as nutraceuticals or pharmaceuticals. Therefore soy bean can be use for industrial production of pharmaceutical grade natural medicines for handling high blood pressure.

Two novel potent ACEI peptides isolated from Pinctada fucata meat hydrolysates using in silico analysis: identification, screening and inhibitory mechanisms.

The aim of this study was to discover potent angiotensin-converting enzyme (ACE) inhibitory (ACEI) peptides from Pinctada fucata (P. fucata) for treating hypertension and to characterize them using in silico analysis. The P. fucata proteins were hydrolyzed by Alcalase®, a serine endopeptidase with broad selectivity, at various times (0, 2, 4, 6, 8, 10 h). The degree of hydrolysis (DH) and ACEI activity of the different hydrolysates were measured. Considering the molecular weight and ACEI activity, the 10 h hydrolysate was purified by a series of traditional separation methods, including ultrafiltration, gel G-25 chromatography, and reversed-phase high-performance liquid chromatography (RP-HPLC), with ACEI activity as a guide. The results showed two fractions, C17 and C18, eluted by means of semi-preparative RP-HPLC, and showed the highest ACEI activities of 80.33 ± 2.70% and 81.66 ± 0.29%, respectively, at 1 mg mL−1. The two fractions were then identified using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) and their MS/MS spectra data were subjected to de novo sequencing. Subsequently, the potential ACEI peptides were screened by in silico methods, namely, to analyze the average local confidence (ALC) value obtained from the sequencing software and the P-value from the Pepsite 2. In total, 13 potential ACEI peptide sequences were obtained and identified from the two fractions by LC-ESI-MS/MS, and two novel tetrapeptides, FRVW (607.3314 Da) and LPYY (555.2881 Da), were screened for synthesis according to the in silico analysis. The in vitro ACEI tests indicated that FRVW and LPYY had IC50 values of 18.34 and 116.26 μM, respectively. The Lineweaver–Burk plot showed that FRVW was a noncompetitive inhibitor, and LPYY was shown to be a mixed-mode type inhibitor. A stability study against ACE indicated that both peptides were hydrolyzed by ACE to some extent, the higher ACEI activity following incubation with ACE indicating that they should be classified as pro-drug substrates. Molecular docking results showed that hydrophobic amino acids (HAAs) within peptides formed vital interactions including hydrogen bonds, electrostatic forces, van der Waals forces and Pi–Pi interactions with ACE residues, which stabilized the enzyme–peptide complex. Furthermore, the docking results accorded with the inhibition kinetic mode. Our study demonstrated that FRVW and LPYY isolated from P. fucata have potential applications as antihypertensive agents.

Antioxidant, angiotensin-converting enzyme, and α-amylase inhibitory activities of protein hydrolysates of Leucaena leucocephala seeds

ABSTRACT The Leucaena leucocephala seeds (LLS) cotyledon proteins, globulins, and glutelins were independently hydrolyzed by Alcalase, Trypsin, and α-Chymotrypsin up to 180 min. The degree of hydrolysis (DH), antioxidant, ACE-inhibitory, and α-Amylase inhibition were assessed. The higher DH values were 76.75% and 82.71% for globulin α-Chymotrypsin, and glutelin Alcalase hydrolysates, respectively. The glutelin hydrolyzed with Trypsin showed the higher DPPH• antioxidant activity while the higher ABTS antioxidant activity was for globulin Alcalase hydrolysate after 180 min digestion. The highest ACE-inhibitory activity was 95.44% for globulin-Alcalase hydrolysate at 180 min; while, for the α-Amylase inhibition assay, glutelin-Alcalase showed the highest values at 100 min of reaction. LLS cotyledon protein concentrates and hydrolysates with relatively low mimosine content were obtained after protein extraction. Such findings indicate the possibility of getting bioactive peptides from LLS cotyledon proteins using enzyme digestions and might be utilized for functional foods with physiological enhancer effects.

Novel antioxidant and ACE inhibitory peptide identified from Arthrospira platensis protein and stability against thermal/pH treatments and simulated gastrointestinal digestion

In current study, novel antioxidant and ACE inhibitory peptides were screened from Arthrospira platensis protein hydrolysates (APH) generated by six different proteases, respectively. The purification steps including ultrafiltration membrane and chromatography were guided by ABTS radical scavenging activity (ARSA), hydroxyl radical scavenging activity (HRSA), ferrous ion chelation activity (FICA) and ACE inhibitory activity. A novel antioxidant peptide VTAGLVGGGAGK, which exhibited highest ARSA, HRSA and FICA with EC50 value of 1.08 mg/mL 1.35 mg/mL and 1.24 mg/mL, respectively, was identified from alcalase-APH. Meanwhile, a novel ACE inhibitory peptide PTGNPLSP with the highest ACE inhibitory activity (IC50 = 1.54 mg/mL) was identified from trypsin-APH. Both VTAGLVGGGAGK and PTGNPLSP had strong stability under thermal processing (25–100 °C) and diverse pH conditions (pH 3–11). In addition, the PTGNPLSP was more stable than VTAGLVGGGAGK during in vitro gastrointestinal digestion. Our findings will provide new knowledge for the development of novel natural antioxidants and ACE inhibitors as well as the high-value utilization of Arthrospira platensis protein.

Angiotensin-converting enzyme inhibitory and antibacterial activities of low molecular weight peptides derived from spent brewer’s yeast

According to the World Health Organization (WHO), hypertension is one of the most common chronic diseases. Cardiovascular disease causes 17.5 million deaths each year, in which hypertension is a direct cause to the death of up to 40%. This hypertension is caused by angiotensin-converting enzyme (ACE). ACE inhibitors consider as an effective therapy in hypertension treatment.Many ACE inhibitors are synthesized by chemical pathways to control high blood pressure, however, these drugs often cause side effects. Therefore, in the last two decades, many authors have been interested in studying and producing a variety of ACE inhibitory peptides, which are naturally derived (plants, animals, and microorganisms) that help reduces blood pressure and less cause side effects. On the other hand, biologically active peptides that are resistant to pathogenic bacteria are also of special interest. In this study, we refer to the limited hydrolysis of spent brewer's yeast by proteases to collect peptides with a molecular size of ≤ 10, 5 and 3 kDa. Peptide fraction with molecular size ≤ 10 kDa have ACE inhibitory activity. The results showed that smaller peptide fractions had higher ACE inhibitory activity. At concentration of 30 µg/mL, inhibitory activitiy of peptides with molecular sizes ≤ 10, 5, 3 kDa was 16.3, 27.7 and 32.7%, respectively, and the best IC50 was 48,85 µg/ml. The lowest peptide concentration for completely inhibition bacteria after 24 h of incubation was 30 mg/mL (V. cholerae), 35 mg/mL (E. coli) and 50 mg/mL (S. typhi).

Chemical characteristic, lactic acid bacteria population, and angiotensin converting enzyme inhibitory activity of traditional fermented beef ”cangkuk” by spontaneous fermentation with the addition of bamboo shoot

This research was conducted to examine the chemical properties, lactic acid bacteria (LAB) populationand angiotensin converting enzyme (ACE) inhibitory activity of fermented beef meat with the addition of bamboo shoots. This research used factorial completely randomized design.Factor A was the preparation method of bamboo shoots: chopped, ground, and extracted. Factor B was the ratio of meat and bamboo shoots (B) which was1:0.75,1:1, 1:1,25ratios. The chemical properties observed were total protein, soluble protein, hydrolysisdegree, pHandtitratableacidity value. The results showed that bamboo shoot preparation methods by ground and extracted were able to reduce total protein, and pH value. The ratio of meat and bamboo shoot (1:0.75 and 1:1) wereable to decreasedtotal protein but increased total titratable acidity. The interaction of the factors A and factor B only occurredin increasing hydrolysisdegree. Both of two factors (A and B) couldnot significantly effect to the number of LAB.The ACE inhibitory activity ranged from 36.5 to 79.6%. It can be concluded that the preparation methods ofbamboo shoots by ground and 1: 0.75 and 1: 1ofbeef : bamboo shoot ratio couldincreasehydrolysis degree and had highest ACE inhibitory activity.

Heterotrophic Microalgae Cultivation Using Jellyfish Protein Extract to Produce Bioactive Peptides

Jellyfish are often seen as a nuisance, and while attempts have been made to use jellyfish waste as fertilizer and food, they have not proved fruitful. In this study, proteins extracted from jellyfish (Aurelia aurita) are investigated as a novel nutrient source in culture medium and tested on aerial microalgae under heterotrophic condition. Results demonstrated that Vischeria helvetica KGU-Y001 heterotrophically grew in the extract-containing culture medium in the presence of light. Decomposition of the extracted protein in the culture medium containing V. helvetica cells was verified both in the presence and absence of light. The inhibitory activity of angiotensin I-converting enzyme (ACE) was measured in the culture medium when in the presence of light. The hydrolysates in the medium were separated using a gel filtration column and a peptide fraction with approximately 400 Da, and high ACE inhibitory activity (IC50 = 72 µg mL−1) was obtained. The results presented here will help to facilitate the development of culture systems with jellyfish waste as a resource for culture medium.

Metabolite dynamics and phytochemistry of a soy whey-based beverage bio-transformed by water kefir consortium

Integrated metabolomic and metagenomic techniques were used to study the metabolite dynamics and phytochemistry of a soy whey-based beverage bio-transformed by water kefir consortium. The UPLC- MS/MS and HPLC-ESI-MS metabolite quantification and the OPLS-DA result showed that the kefir consortium induced a significant change in the metabolite composition and altered the phytochemistry of the fermented beverage. Bioactive peptide analogues, flavonoids, and glycerophospholipids including N-acetyl-L-phenylalanine, acetyl-DL-leucine; tephcalostan, wogonin, pelargonin, genistein, daidzein, and glycerophosphoserines (PS), glycerophosphoethanolamines (PE) respectively were synthesized while flavonoid glycosides and soyasaponins were degraded in the novel beverage. Furthermore, the beverage showed high ACE inhibitory and DPPH radical scavenging activity of 92.31% and 87.51% respectively. Lactobacillus, Saccharomyces cerevisiae, and Pichia membranifaciens were the predominant microbial groups in the new beverage as revealed by the metagenomic sequence analysis. The study thus provides discrete data evidence that kefir consortium is a viable starter for transforming soy whey into a bioactive beverage.

Multifunctional hydrolysates from kenaf (Hibiscus cannabinus L.) seed protein with high antihypertensive activity in vitro and in vivo

Kenaf (Hibiscus cannabinus L.) seed is an underutilized protein-rich resource considered as a by-product of the kenaf fiber processing industry. Its high protein content (34%) makes it a promising candidate as a source of bioactive protein hydrolysates. In this study, the potential of enzymatically hydrolyzed kenaf seed protein to generate multifunctional bioactive peptides was evaluated. Kenaf seed protein concentrate was hydrolyzed using four different proteolytic enzymes (papain, alcalase, bromelain, and flavourzyme) at their respective optimum pH and temperature. The choice of enzyme affected the bioactivities to a certain degree as KSPH were shown to possess high ACE inhibitory activity and low-to-moderate DPP-IV and antioxidant activity. Papain KSPH showed the highest ACE inhibitory activity with 95% inhibition compared to other enzymatic hydrolysates, and therefore was chosen for further investigation of its antihypertensive activity. Papain KSPH was profiled for its hydrophobicity by RP-HPLC and revealed that the majority of late-eluting fractions exerted the highest ACE inhibitory activity. Spontaneously hypertensive rats showed a decrease of approximately 18–46 mmHg in their systolic blood pressure (BP) from 0 to 24 h after oral administration of papain KSPH at dosages of 100 mg/kg, 300 mg/kg, and 500 mg/kg. However, the effect was not dose-dependent. As a novel protein source, future research should aim to demonstrate the safety of kenaf seed protein and its hydrolysates, and validate its bioactivity through human intervention trials. Overall, kenaf seed protein has the potential to generate antihypertensive hydrolysates with multifunctional bioactivities as part of a functional food ingredient.

A comparative study of compositional, antioxidant capacity, ACE-inhibition activity, RP-HPLC peptide profile and volatile compounds of herbal artisanal cheeses

The effect of aromatic herbs on the RP-HPLC peptide profile, angiotensin I-converting enzyme-inhibitory (ACE-i) activity, antioxidant capacity and volatile compounds in artisanal cheeses was investigated. Three representative artisanal cheeses (white brined, beaten and Kashkaval cheeses) were produced using aromatic herbs (Mentha longifolia, Origanum vulgare, Thymus longicaulis, Alium sativum, Petroselinum crispum, Capsicum annuum). Compared with control group, herbal cheeses (except white cheese with garlic and parsley) revealed a significant increase in antioxidant activity. The highest ACE-i activity was noticed in 60 days of ripening with a mean value of 98.72% in goat beaten cheese and 97.78% in Kashkaval cheese enriched with peppers. One hundred and one volatile compounds, mainly acids, esters and alcohols, were identified in significantly higher amounts in cheeses made with herbs and contributed to the development of the overall aroma perception.

Comparative Study of Angiotensin I-Converting Enzyme (ACE) Inhibition of Soy Foods as Affected by Processing Methods and Protein Isolation

Angiotensin converting enzyme (ACE) converts angiotensin I into the vasoconstrictor angiotensin II and eventually elevates blood pressure. High blood pressure is a major risk factor for heart disease and stroke. Studies show peptides present anti-hypertensive activity by ACE inhibition. During food processing and digestion, food proteins may be hydrolyzed and release peptides. Our objective was to determine and compare the ACE inhibitory potential of fermented and non-fermented soy foods and isolated 7S and 11S protein fractions. Soy foods (e.g., soybean, natto, tempeh, yogurt, soymilk, tofu, soy-sprouts) and isolated proteins were in vitro digested prior to the determination of ACE inhibitory activity. Peptide molecular weight distribution in digested samples was analyzed and correlated with ACE inhibitory capacity. Raw and cooked soymilk showed the highest ACE inhibitory potential. Bacteria-fermented soy foods had higher ACE inhibitory activity than fungus-fermented soy food, and 3 day germinated sprouts had higher ACE inhibition than those germinated for 5 and 7 days. The 11S hydrolysates showed higher ACE inhibitory capacity than 7S. Peptides of 1–4.5 kDa showed a higher contribution to reducing IC50. This study provides evidence that soy foods and isolated 7S and 11S proteins may be used as functional foods or ingredients to prevent or control hypertension.

Separation and identification of ACE inhibitory peptides from defatted walnut meal

The peptide obtained from walnut protein enzymatic hydrolysate had high ACE inhibitory activity. Through centrifugation, ultrafiltration, gel chromatography and high performance liquid chromatography (HPLC), the walnut oligo-peptide, which was denoted as P4-c with high ACE inhibitory activity was obtained. Three novel ACE inhibitory peptides, GVVPHN, EHSLDPLK and KTLLNFGPN, were identified from P4-c by high-resolution ion mobility mass spectrometry (IM-MS). The three novel ACE inhibitory peptides possessed good ACE inhibitory activity and the fraction GVVPHN had high ACE inhibitory activity with 27.3 µmol L−1 of IC50. The molar percentage of hydrophobic amino acids in the peptide GVVPHN was 50% while the hydrophobic amino acid contents of EHSLDPLK and KTLLNFGPN were 37.5% and 44.4%, respectively, which indicates ACE inhibitory activities were hydrophobicity of amino acid-dependent.

Change in phenolic compound content, reductive capacity and ACE inhibitory activity in noni juice during traditional fermentation

Morinda citrifolia L., also known as noni, has a long history of traditional use in the Hawaiian and Taihitian islands as cure-all medicine. Recently, commercial noni juice products have been imported from different countries and delivered directly to consumers with claims of multiple health benefits, including anti-cancer and immuno-stimulating activities. In this study, phenolic compounds content, free radical and superoxide anion radical scavenging activities were determined in two noni juices with different extent of maturity from traditional fermentation process. Ripe noni fruits gave higher juice yield with a lighter color. In general, juice from ripe fruits contained higher total quantities of phenolic compounds, condensed tannins, flavonoids and scopoletin, and thus exhibiting better scavenging capacity for free radical, superoxide anion radicals and H2O2 and higher ACE inhibitory activity. Fermentation processing gave better juice recovery, whereas prolonged fermentation time reduced the reductive phytochemical content and some related bioactivities.

In vitro antioxidant and angiotensin I-converting enzyme inhibitory properties of peptides derived from corn gluten meal

Corn gluten meal (CGM) was hydrolyzed by Alcalase 2.4L and Protex 7L to obtain low-molecular-weight peptides. The antioxidant and angiotensin-I-converting enzyme (ACE) inhibitory activities of the peptides were determined by 2,2′-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) free radical scavenging activity, the JHH7 cell oxidative stress model, and the ACE inhibition assay, respectively. Corn peptides (CPs) had strong antioxidant capacity to scavenge ABTS radicals (1.44 ± 0.11 mmol/g), and significantly reduced reactive oxygen species and malondialdehyde levels in oxidized JHH7 cells, increasing superoxide dismutase, catalase, and glutathione peroxidase activities by 26.20%, 147.52%, and 43.20%, respectively, at the concentration of 800 μg/mL. CPs had high ACE inhibitory activity, with an IC50 value of 0.27 ± 0.05 mg/mL. Next, the CPs were separated by reverse-phase high-performance liquid chromatography. Twelve fractions were collected, and their ABTS free radical scavenging and ACE inhibitory activities were determined. Fractions 1, 2, 3, 4, and 9 showed higher ABTS free radical scavenging and ACE inhibitory activities. Twelve peptides were identified from active fractions by liquid chromatography–tandem mass spectrometry (LC–MS/MS) as Leu-Ser-Pro-Tyr, Leu-Asn-Ser-Pro-Ala-Tyr, Tyr-Gly-Pro-Gln, Pro-Pro-Tyr, Ala-Tyr-Pro-Glu, Thr-Tyr-Ser-Gly-Pro-Lys, Ala-Tyr-Pro-Gly-Pro-Gln, Leu-Ala-Tyr-Pro-Gln, Ala-Tyr-Leu-Gln-Gln-Gln, Ser-Ala-Pro, Asn-Ala-Pro, and Val-Asn-Ala-Pro. These peptides exhibited good ABTS free radical scavenging and ACE inhibitory activities. Therefore, CPs may have potential applications in the food industry as functional material additives.

Physicochemical Properties and Liposomal Formulations of Hydrolysate Fractions of Four Sea Cucumbers (Holothuroidea: Echinodermata) from the Northwestern Algerian Coast.

To promote the nutritional and pharmacological values of four sea cucumber species (Holothuria poli, H. tubulosa, H. arguinensis, and H. sanctori), harvested from the Algerian coast, we aimed to study their proximate composition, fatty acid profile and angiotensin-converting enzyme (ACE) inhibitory activity. Their phospholipids were also used to elaborate nanoliposomes and to encapsulate peptides obtained from the same source. After the physico-chemical characterization of nanoliposomes and peptides, in vitro analyses were realized. The four holothurian species showed a high amount of protein (49.26–69.34%), and an impressive lipid profile of 27 fatty acids, mainly composed of polar fatty acids (91.16–93.85%), with a high polyunsaturated fatty acids (PUFA) content (50.90–71.80%), particularly eicosapentaenoic acid (EPA) (5.07–8.76%) and docosahexaenoic acid (DHA) (4.86–7.25%). A high phospholipids amount was also found (55.20–69.85%), mainly composed of phosphatidylcholine (PC) (51.48–58.56%). Their peptide fractions exhibited a high ACE inhibitory activity (IC50 0.30 to 0.51 mg/mL). The results also showed that the nanoliposomes do not induce cytotoxicity and cell death in human MSCs and no perturbation of proliferation for all the times and the tested concentrations, as well as the combined nanoliposomes and hydrolysates (HTS) at a concentration of 0.1 mg/mL. All four sea cucumbers show potential as a new source for omega-3, omega-6, and bioactive peptides.

Angiotensin-I converting enzyme inhibitory peptide derived from the shiitake mushroom (Lentinula edodes).

Angiotensin-I converting enzyme (ACE) inhibitors are widely used to control hypertension. In this study, protein hydrolysates from shiitake mushroom were hydrolyzed to prepare ACE-inhibitory peptides. Optimum process conditions for the hydrolysis of shiitake mushrooms using Alcalase were optimized using response surface methodology. Monitoring was conducted to check the degree of hydrolysis (DH) and ACE inhibitory activity. In the results, the optimum condition with the highest DH value of 28.88% was 50.2°C, 3-h hydrolysis time, and 1.16 enzyme/substrate ratios. The highest ACE inhibitory activity (IC50 of 0.33μg/mL) was under 47°C, 3h 28min hydrolysis time, and 0.59 enzyme/substrate ratios. The highest activity was fractionated into 5 ranges of molecular weight, and the fraction below 0.65kDa showed the highest activity with IC50 of 0.23μg/mL. This fraction underwent purification using RP-HPLC, meanwhile the peak which offered a retention time of about 37min showed high ACE inhibitory activity. Mass spectrometry identified the amino acid sequence of this peak as Lys-Ile-Gly-Ser-Arg-Ser-Arg-Phe-Asp-Val-Thr (KIGSRSRFDVT), with a molecular weight of 1265.43Da. The synthesized variant of this peptide produced an ACE inhibitory activity (IC50) of 37.14μM. The peptide KIGSRSRFDVT was shown to serve as a non-competitive inhibitor according to the Lineweaver-Burk plot findings. A molecular docking study was performed, which showed that the peptide binding occurred at an ACE non-active site. The findings suggest that peptides derived from shiitake mushrooms could serve either as useful components in pharmaceutical products, or in functional foods for the purpose of treating hypertension.

Actividad inhibidora de la ECA y fijadora de metales producida durante la fermentación de la leche con tres cepas BAL potencialmente probióticas aisladas del queso doble crema de Chiapas

Some probiotic lactic acid bacteria could generate bioactive peptides during milk fermentation. The aim of this work was to evaluate the ACE inhibitory and mineral-binding (calcium and iron) activity during milk fermentation by three probiotic LAB strains (Lactobacillus plantarum, Lb. pentosus and Lb. acidipiscis) as well as mixed fermentation.  These strains were previously isolated from Chiapas double cream cheese. The fermentation that showed the highest microbial growth was performed by Lb. plantarum, followed by mixed fermentation and Lb. acidipiscis. However, the mixed fermentation had higher proteolysis. Milk fermentations performed with Lb. acidispiscis, Lb. pentosus and mixed showed high ACE-inhibitory activity (97%). The Lb. plantarum and mixed fermentations showed the higher iron-binding activity, 99 % and 97, respectively, whereas the Lb. acidipiscis and mixed fermentations had the highest calcium-binding activity. These results showed that probiotic microorganisms isolated from double cream cheese have great potential to be used in the production of functional foods.

Identification of novel angiotensin I‐converting enzyme inhibitory peptide from collagen hydrolysates and its molecular inhibitory mechanism

SummaryThe fish collagen protein was hydrolysed and further fractionated into four molecular weight ranges by ultrafiltration. Subsequently, the peptide fraction with the potent angiotensin I‐converting enzyme (ACE) inhibitory activity was identified. The potential inhibitory mechanism of the peptide was clarified by molecular docking. As a result, FCPH‐Ⅳ with molecular weight between 600 and 1000 Da exerted the high ACE inhibitory activity and was identified by de novo peptide sequencing. The peptide GHVGAAGS exhibited significant ACE inhibitory activity with the IC50 value of 407.28 ± 3.55 μm. In addition, the docking results showed the interactions between the amino acids at the four positions closest to the C‐terminal site of GHVGAAGS and the major active residues (GLN281, HIS353, LYS511 and HIS513) of ACE lead to the conformational change in ACE. This work indicates that fish collagen could be utilised to produce ACE inhibitory peptides and develop health products.

Effect of probiotic cultures on the angiotensin converting enzyme inhibitory activity of whey-based fermented beverages.

Fermented whey-based beverages were elaborated using commercial probiotics cultures (CHR HANSEN): BCT-1®, ABT-4®, ABC where A: Lactobacillus acidophilus, B: Bifidobacterium animalis subsp. lactis, C: Lactobacillus paracasei subsp. paracasei and T: Streptococccus thermophiles. Three treatments were prepared with these probiotics cultures and a treatment without cultures added as a control. All beverage were maintained at 4°C and evaluated during their shelf life at 0, 7, 14 and 21days. The variables analyzed were peptide concentration, proteolysis, ACE-inhibitory activity and, peptide and aromatic amino acid profiles. Principal component analysis (PCA) was conducted to assess the relationship between these variables. All whey-based fermented beverages added with probiotics presented ACE inhibitory activity (22-100%). However, whey-based beverage without probiotics added had the highest ACE inhibitory activity (100%), and it was maintained during its shelf life. Fermented beverage with ABT-4® culture had an ACE inhibitory activity from 80 to 100% during its shelf life. Thus can be attributed to the release of peptides during processing. Meanwhile, significative correlations were observed between variables varying this depending on the treatment, both, in magnitude and in direct or inverse direction (0.684-0.986). The ACE inhibitory activity was correlated to proteolysis and peptide and aromatic amino acids profiles. And, the IC50 was observed in the range of 0.01-0.055mg/mL.

Angiotensin I-converting Enzyme (ACE) Inhibitory Activity of Ace Inhibitory Peptides Produced during the Fermentation of Pigeon Pea (Cajanus cajan) Tempe

Fermentation products are common sources of angiotensin I-converting enzyme (ACE) inhibitory peptides used for hypertension treatment. This research investigated the effect of fermentation time on the ACE inhibitory activity produced during the fermentation of pigeon pea tempe and aimed to determine the optimal fermentation time to obtain pigeon pea tempe with the highest ACE inhibitory activity. Seeds were inoculated with Raprima® (0.02% w/w) containing Rhizopus oligosporus spores and fermented for 0-96 h. Protein pattern, degree of hydrolysis (DH), soluble protein content and ACE inhibitory activity were observed during fermentation. The result from SDS-PAGE shows that protein hydrolysis occurred after 12 h fermentation, marked by the appearance and greater intensity of protein bands with low-molecular-weight (60 kDa). An increase in DH and soluble protein content were detected during the fermentation and reached a maximum of 23.99% and 3.15 mg mL -1 at 96 h fermentation, respectively. The ACE inhibitory activity increased with fermentation time and pigeon pea tempe fermented for 48 h (76.14%) has the highest ACE inhibitory activity with IC 50 values of 0.65 mg mL -1 . It could be concluded that the optimal fermentation time to obtained pigeon pea tempe with the highest ACE inhibitory activity is for 48 h of fermentation.