RESUMEN
This research aimed to determine the biofunctional properties of wheat flour (WF) protein fractions and modifications to the antioxidant, anti-α-amylase and anti-angiotensin-I converting enzyme (ACE) activities induced by the action of digestive endopeptidases in vitro. A molecular characterization of the most abundant protein fractions, i.e., albumins, glutelins-1, glutelins-2 and prolamins, showed that low- and high-MW polypeptides rich in cysteine, glutamic acid and leucine were present in albumins and glutelins, whereas low-MW subunits with a high proportion of polar amino acids prevailed in prolamins. Prolamins exhibited the second-highest water holding capacity (54%) after WF (84%), while albumins provided superior foam stability (76%). Prolamins, glutenins-1 and globulins demonstrated the highest antioxidant activity (up to 95%, 68% and 59%, respectively) both before and after hydrolysis with pepsin (P-H) or trypsin-chymotrypsin (TC-H). Prolamins, globulins and WF strongly inhibited α-amylase (>90%) before and after TC-H, and before P-H (55-71%). Moreover, P-H significantly increased α-amylase inhibition by albumins from 53 to 74%. The fractions with strong ACE inhibitory activity (70-89%) included prolamins and globulins after TC-H or P-H, as well as globulins before TC-H and WF before P-H. This novel evidence indicates that WF protein fractions and their peptide-enriched P and TC hydrolysates are excellent sources of multifunctional bioactives with antioxidant, antihyperglycemic and antihypertensive potential.
Asunto(s)
Antioxidantes , Triticum , Antioxidantes/farmacología , alfa-Amilasas , Harina , Albúminas , Glútenes , Fármacos GastrointestinalesRESUMEN
One of the most striking aspects of the primary structure in the hydrophobic domains of the tropoelastin molecule is the occurrence of the VAPGVG repeating sequence. Since the N-terminal tripeptide VAP of VAPGVG showed a potent ACE inhibitory activity, the ACE inhibitory activity of various derivatives of VAP was examined in vitro. The results showed that VAP derivative peptides VLP, VGP, VSP, GAP, LSP, and TRP exhibited potent ACE inhibitory activities, while the non-derivative peptide APG showed only weak activity. In in silico studies, the docking score S value showed that VAP derivative peptides VLP, VGP, VSP, LSP, and TRP had stronger docking interactions than APG. Molecular docking in the ACE active pocket showed that TRP, the most potent ACE inhibitory peptide among the VAP derivatives, had a larger number of interactions with ACE residues in comparison with APG and that the TRP molecule appeared to spread widely in the ACE pocket, while the APG molecule appeared to spread closely. Differences in molecular spread may be a reason why TRP exhibits more potent ACE inhibitory activity than APG. The results suggest that the number and strength of interactions between the peptide and ACE are important for the ACE- inhibitory potency of the peptide.
Asunto(s)
Inhibidores de la Enzima Convertidora de Angiotensina , Peptidil-Dipeptidasa A , Animales , Porcinos , Inhibidores de la Enzima Convertidora de Angiotensina/farmacología , Inhibidores de la Enzima Convertidora de Angiotensina/química , Simulación del Acoplamiento Molecular , Peptidil-Dipeptidasa A/química , Elastina , Péptidos/farmacología , Péptidos/químicaRESUMEN
This study aimed to assess the biological properties of peptide fractions isolated from dried fermented dairy products (jameed) as influenced by processing. Peptide fractions were separated by reversed-phase high-performance liquid chromatography (RP-HPLC) from salted (Sa) and unsalted (Us) cow milk jameed after drying the fermented curd by sun drying (Sd) or freeze-drying (Fd) and were characterized for their antioxidant capacity and inhibitory activity toward angiotensin I-converting enzyme (ACE) and α-amylase. Sd samples showed more numerous peptide peaks in RP-HPLC chromatograms than Fd samples, regardless of the salt content. High antioxidant activity was evidenced in several peptide fractions from FdUs jameed (including fractions 1, 2, 4, 7, 8, 9, and 10), SdUs jameed (1, 2, 5, 7, and 9), and FdSa jameed (2, 5, 6, and 9). By contrast, peptide fractions from SdSa (1, 2, 3, 5, 8, and 9), SdUs (4, 5, and 10), and FdUs (5, 6, and 8) jameed displayed the highest ACE inhibitory activity. Similarly, the highest inhibition of α-amylase was obtained with fractions from SdSa (1, 2, 3, 4, 5, 6, 8, and 9), SdUs (2 and 6), and FdUs (1, 7 and 9) jameed. A significant negative correlation was evidenced between antioxidant activity and anti-α-amylase activity of peptide fractions from SdSa jameed. These findings demonstrate that cow milk jameed is a source of bioactive peptides with antioxidant, anti-ACE, and anti-α-amylase properties in vitro, which can be tailored by adjusting the salt content and the drying conditions. PRACTICAL APPLICATION: This study shows that cow milk jameed, a staple fermented food in several Mediterranean countries, can serve as a useful source of multifunctional bioactive peptides with potential antioxidant, hypotensive, and hypoglycemic effects, which may help prevent and manage chronic health conditions such as hypertension, type 2 diabetes, and the metabolic syndrome. The bioactivities of certain peptide fractions were enhanced by lowering the salt content of jameed or by the drying method. The relatively simple RP-HPLC method described in this study can be used to isolate the peptide fractions of interest for further characterization and use as functional ingredients.
Asunto(s)
Aminoácidos/análisis , Inhibidores de la Enzima Convertidora de Angiotensina/farmacología , Antihipertensivos/farmacocinética , Antioxidantes/farmacología , Productos Lácteos Cultivados , Hipoglucemiantes/farmacología , Leche/química , Fragmentos de Péptidos/farmacología , Inhibidores de la Enzima Convertidora de Angiotensina/química , Animales , Antihipertensivos/química , Antioxidantes/química , Bovinos , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Hipertensión/tratamiento farmacológico , Hipoglucemiantes/química , Fragmentos de Péptidos/química , Peptidil-Dipeptidasa A/metabolismoRESUMEN
Whey protein hydrolysates (WPHs) are one of the most promising sources of biofunctional peptides with such beneficial properties as antioxidant, antihypertensive, anti-inflammatory and others. WPHs also could be used as foaming agents for aerated products (e.g., milk shake type drinks). However, WPH alone has a bitter taste and foamed WPH should be stabilized by additional ingredients. Here, we present a composition including WPH and three polysaccharides-pumpkin pectin, sodium alginate and ι-carrageenan-used as foam stabilizers. Polysaccharide content was selected according to foaming, organoleptic antioxidant and angiotensin-I-converting enzyme inhibitory characteristics of the resulted composition. Further, the hypotensive, antioxidant and hepatoprotective properties of the composition were proved by in vivo tests performed in spontaneously hypertensive rats and Wistar rats with CCl4-induced hepatic injury.
Asunto(s)
Hipotensión/dietoterapia , Polisacáridos/farmacología , Proteína de Suero de Leche/metabolismo , Alginatos , Inhibidores de la Enzima Convertidora de Angiotensina/farmacología , Animales , Antiinflamatorios/farmacología , Antihipertensivos/farmacología , Antioxidantes/farmacología , Cucurbita , Carbohidratos de la Dieta , Modelos Animales de Enfermedad , Masculino , Estrés Oxidativo/efectos de los fármacos , Pectinas , Péptidos , Peptidil-Dipeptidasa A , Hidrolisados de Proteína , Ratas , Ratas WistarRESUMEN
The mechanism of action of food-derived angiotensin-I-converting enzyme (ACE) inhibitory peptides has not been completely elucidated. In the present study, ion-exchange chromatography, gel filtration chromatography, reverse phase-high performance liquid chromatography, and liquid chromatography-electrospray ionization-tandem mass (LC-ESI-MS/MS) were employed for purifying and identifying the ACE inhibitory peptides from hazelnut. To understand the mode of action of these peptides, ACE inhibition kinetics, in vitro and in vivo bioavailability assays, active site analysis, and interaction between the inhibitory peptides and ACE were investigated. The results identified novel ACE inhibitory peptides Ala-Val-Lys-Val-Leu (AVKVL), Tyr-Leu-Val-Arg (YLVR), and Thr-Leu-Val-Gly-Arg (TLVGR) with IC50 values of 73.06, 15.42, and 249.3⯵M, respectively. All peptides inhibited the ACE activity via a non-competitive mode. The binding free energies of AVKVL, YLVR, and TLVGR for ACE were -3.46, -6.48, and -7.37â¯kcal/mol, respectively. The strong inhibition of ACE by YLVR may be attributed to the formation of cation-pi interactions.
Asunto(s)
Inhibidores de la Enzima Convertidora de Angiotensina/metabolismo , Corylus/química , Péptidos/metabolismo , Peptidil-Dipeptidasa A/metabolismo , Proteínas de Plantas/química , Secuencia de Aminoácidos , Inhibidores de la Enzima Convertidora de Angiotensina/química , Animales , Hidrólisis , Peso Molecular , Péptidos/química , Unión ProteicaRESUMEN
To enhance the γ-aminobutyric acid (GABA) content, the optimized fermentation of soybean with added sea tangle extract was evaluated at 30°C and pH 5.0. The medium was first inoculated with Aspergillus oryzae strain FMB S46471 and fermented for 3 days, followed by the subsequent inoculation with Lactobacillus brevis GABA 100. After fermentation for 7 days, the fermented soybean showed approximately 1.9 g/kg GABA and exhibited higher ACE inhibitory activity than the traditional soybean product. Furthermore, several peptides in the fraction containing the highest ACE inhibitory activity were identified. The novel fermented soybean enriched with GABA and ACE inhibitory components has great pharmaceutical and functional food values.
Asunto(s)
Inhibidores de la Enzima Convertidora de Angiotensina/metabolismo , Aspergillus oryzae/metabolismo , Glycine max/metabolismo , Kelp/metabolismo , Levilactobacillus brevis/metabolismo , Ácido gamma-Aminobutírico/metabolismo , Aspergillus oryzae/crecimiento & desarrollo , Técnicas de Cocultivo , Fermentación , Concentración de Iones de Hidrógeno , Levilactobacillus brevis/crecimiento & desarrollo , TemperaturaRESUMEN
Angiotensin-I-converting enzyme (ACE) plays an important role in blood pressure regulation. In this study, an ACE-hexapeptide inhibitor (Asp-Glu-Asn-Ser-Lys-Phe) designated as chebulin was produced from the fruit protein of Terminalia chebula Retz. by pepsin digestion, ultrafiltrated through a 3 KDa cut-off membrane, a reverse-phase high-performance liquid chromatography, and nano-liquid chromatography tandem mass spectrometry analysis. Chebulin was found to inhibit ACE in a noncompetitive manner, as supported by the structural model. It bounds to ACE by the hydrogen bond, hydrophobic and ionic interactions via the interactions of C-terminal Phe (Phe-6), and N-terminal residues (Asp-1 and Glu-2) with the amino acid residues on noncatalytic sites of the ACE. The results showed that chebulin derived from fruits of T. chebula Retz. is a potential ACE-peptide inhibitor that could be used as a functional food additive for the prevention of hypertension and as an alternative to ACE inhibitor drug.