Examinando por Autor "Recio, Isidra"
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Ítem ACE-inhibitory and antihypertensive properties of a bovine casein hydrolysate(Elsevier Ltd., 2009-01-01) Miguel, Marta; Contreras, María del Mar; Recio, Isidra; Aleixandre, AmayaThe aim of this study was to investigate the potential angiotensin converting enzyme (ACE)-inhibitory activity and the antihypertensive effect, after a single oral administration, of a pepsin hydrolysed bovine casein (HBC) and a fraction with molecular mass lower than 3000 Da (HBC < 3000). ACE-inhibitory activity was measured by spectrophotometric assay. These products were orally administered by gastric intubation. The systolic (SBP) and the diastolic blood pressure (DBP) were measured in spontaneously hypertensive rats by the tail cuff method before administration and also 2, 4, 6, 8, and 24 h post-administration. HBC showed a potent ACE-inhibitory activity. This activity was 10 times higher in HBC < 3000. HBC and HBC < 3000 decreased the arterial blood pressure of the rats. The decrease in the SBP observed for HBC (400 mg/kg) or HBC < 3000 (200 mg/kg) was less pronounced than that caused by 50 mg/kg of captopril (antihypertensive positive control). However, the maximal decreases in DBP caused by HBC or HBC < 3000 were as high as the maximum decrease observed for captopril. The antihypertensive effect of these products was transient and reverted 24 h after the administration. HBC and HBC < 3000 exert antihypertensive effect caused by small peptides with ACE-inhibitory activity.Ítem Acute and repeated dose (4 weeks) oral toxicity studies of two antihypertensive peptides, RYLGY and AYFYPEL, that correspond to fragments (90–94) and (143–149) from αs1-casein(Elsevier Ltd., 2010-07) Anadón, Arturo; Martínez-Caballero, María Aranzazu; Ares, Irma; Ramos-Alonso, Eva; Martínez-Larrañaga, María Rosa; Contreras-Gámez, María Mar; Ramos-González, Mercedes; Recio, IsidraThe Lowpept® is a powdered casein hydrolysate containing the antihypertensive peptides RYLGY and AYFYPEL, two sequences that correspond to αs1-casein f (90–94) (RYLGY) and αs1-casein f (143–149) (AYFYPEL). To support the safety, Lowpept® has been examined in an acute and in a 4-week repeated dose oral toxicity studies in rats. Powdered casein hydrolysate administered in a single oral gavage dose of 2000 mg/kg resulted in no adverse events or mortality. Also, casein hydrolysate administered as a daily dose of 1000 mg/kg for 4 weeks by gavage resulted in no adverse events or mortality. No evidence or treatment-related toxicity was detected during both studies. Data analysis of body weight gain, food consumption, clinical observations, blood biochemical, haematology, organ weight ratios and histopathological findings did not show significant differences between control and treated groups. It is concluded that the casein hydrolysate containing the peptides RYLGY and AYFYPEL orally administered to rats was safe and that not treatment-related toxicity was detected even at the highest doses investigated in both acute (2000 mg/kg of body weight) and repeated dose (4 weeks) oral (1000 mg/kg of body weight) toxicity studies.Ítem Application of mass spectrometry to the characterization and quantification of food-derived bioactive peptides(Oxford University Press, 2008-07-01) Contreras, María del Mar; López-Expósito, Iván; Hernández-Ledesma, Blanca; Ramos, Mercedes; Recio, IsidraBiologically active peptides are of particular interest in food science and nutrition because they have been shown to play different physiological roles, including antihypertensive, opioid, antimicrobial, and immunostimulating activities. Because these peptides are generated by protein hydrolysis or fermentation, they can represent only minor constituents in a highly complex matrix and therefore, identification of biologically active peptides in food matrixes is a challenging task in food technology. In this context, mass spectrometry (MS) has developed into a necessary tool to assess quality and safety of food and, more recently, to determine the presence and behavior of functional components such as these bioactive peptides. This review highlights the existing methods based on MS to identify, characterize, and quantify food-derived biologically active peptides, taking into account the different ionization sources used for the analysis of these high-value food components. The quantitative determination of bioactive peptides in food products or biological fluids is also discussed.Ítem Milk versus caseinophosphopeptides added to fruit beverage: Resistance and release from simulated gastrointestinal digestion(Elsevier Inc., 2010-04) García-Nebot, María José; Alegría, Amparo; Barberá, Reyes; Contreras, María del Mar; Recio, IsidraThe influence of simulated gastrointestinal digestion on caseinophosphopeptides (CPPs) formation in milk-based fruit beverage was evaluated, together with resistance of a pool of CPPs added to fruit beverage. In milk-based fruit beverage, four CPPs were identified that can be justified by their presence in raw milk or due to processing. When it was subjected to simulated gastrointestinal digestion, 10 CPPs were identified, and only 1 presented the cluster (SpSpSpEE) (3 phosphoseryl group followed by 2 glutamic acid residues), which corresponded to αs2-CN(1–19)4P. CPPs added to fruit beverage are resistant to simulated gastrointestinal digestion, and 16 CPPs were identified originating from the fragmentation of added CPPs, and with a greater presence of the cluster compared with CPPs originating from milk-based fruit beverage. This could justify the use of CPPs as functional ingredients, and offer a good alternative to milk-based fruit beverage for improving mineral bioavailability.Ítem Monitoring the large scale production of antihypertensive peptides RYLGY and AYFYPEL by HPLC-MS(Springer Nature, 2010-04-01) Contreras-Gámez, María Mar; Gómez-Sala, Beatriz; Martín-Álvarez, Pedro Jesús; Amigo, Lourdes; Ramos-González, Mercedes; Recio, IsidraThis work reports the quantitative analysis of two novel antihypertensive peptides αs1-CN f(90-94), with sequence RYLGY, and αs1-CN f(143-149), with sequence AYFYPEL, by high-performance liquid chromatography–mass spectrometry in food-grade hydrolysates of milk proteins. The method was validated and showed sufficient specificity, reproducibility, linearity and recovery. Linear calibrations of the molecular ions m/z 671.2 and 902.3 were selected for the determination of the peptides RYLGY and AYFYPEL, respectively, and showed good statistical results (R 2 ≥ 0.995 and with no significant lack-of-fit). The simplicity of RP-HPLC-MS method allowed the automated quantification of both antihypertensive peptides without any sample pretreatment. The application of this method permitted the evaluation of some hydrolysis variables, i.e., substrate, temperature, hydrolysis time or enzyme/substrate ratio, on the formation of antihypertensive peptides. The quantitative analysis of RYLGY and AYFYPEL showed that ultrafiltration was not effective to improve the content in active peptides, containing the hydrolysates and their respective permeates similar peptide amounts.Ítem Novel casein-derived peptides with antihypertensive activity(Elsevier Ltd., 2009-10) Contreras, María del Mar; Carrón, Rosalía; Montero, María José; Ramos, Mercedes; Recio, IsidraIn this study, we report novel casein-derived peptide sequences with angiotensin converting enzyme (ACE)-inhibitory activity and antihypertensive activity demonstrated in spontaneously hypertensive rats (SHR). The peptides were obtained by enzymatic hydrolysis of total isoelectric casein with pepsin. To identify ACE-inhibitory peptides, the casein hydrolysate was fractionated by semi-preparative high performance liquid chromatography, and 44 (CN) peptides contained in the active fractions were sequenced by using an ion trap mass spectrometer. Among the identified peptides, three sequences, that corresponded to αs1-CN f(90–94) (RYLGY), αs1-CN f(143–149) (AYFYPEL), and αS2-CN f(89–95) (YQKFPQY), showed IC50 values as low as 0.71 μm, 6.58 μm, and 20.08 μm, respectively. These three peptides also exerted antihypertensive activity when they were orally administered to SHR at a dose of 5 mg kg−1 of body weight. The activity of peptides RYLGY and AYFYPEL in SHR was similar to that found for tripeptide VPP when orally administered at the same dose.Ítem Production of antioxidant hydrolyzates from a whey protein concentrate with thermolysin: Optimization by response surface methodology(Elsevier Ltd., 2011-01) Contreras-Gámez, María Mar; Hernández-Ledesma, Blanca; Amigo, Lourdes; Martín-Álvarez, Pedro Jesús; Recio, IsidraWhey protein concentrate (WPC) enriched in β-lactoglobulin (β-Lg) was hydrolyzed using Corolase PP® and thermolysin to produce hydrolyzates with antioxidant activity. The optimization of the main experimental variables involved in the process, such as type of enzyme, and hydrolysis conditions, concretely enzyme to substrate ratio, time and temperature, were evaluated using response surface methodology. A central composite circumscribed (CCC) design was employed to study the effect of the experimental variables on the antioxidant activity determined by radical scavenging potency. The parameters of the model were estimated by multiple linear regression, and the highest radical scavenging activity (2.57 μmol Trolox/mg protein) was found in WPC hydrolyzed with thermolysin after 8 h at 80 °C and an enzyme/substrate ratio of 0.10 (w/w). Nineteen β-Lg derived peptides were identified by RP-HPLC-MS/MS in this hydrolyzate. Of special interest are peptides LQKW f(58–61) and LDTDYKK f(95–101), which amino acid composition makes them potential contributors on the radical scavenging activity detected.Ítem Stability to gastrointestinal enzymes and structure–activity relationship of β-casein-peptides with antihypertensive properties(Elsevier Inc., 2009-10) Quirós, Ana; Contreras-Gámez, María Mar; Ramos-González, Mercedes; Amigo, Lourdes; Recio, IsidraPhysiological digestion plays a key role in the formation and degradation of angiotensin-converting enzyme (ACE)-inhibitory peptides. In this study, we evaluated the impact of a simulated gastrointestinal digestion on the stability of eight peptides previously identified in fermented milk with antihypertensive activity. Two of these identified peptides with sequences LHLPLP and LVYPFPGPIPNSLPQNIPP, possess ACE-inhibitory activity in vitro and antihypertensive activity in vivo. The results showed that LHLPLP was resistant to digestive enzymes. In contrast, LVYPFPGPIPNSLPQNIPP was totally hydrolyzed and its activity decreased after incubation with pepsin and a pancreatic extract. The peptide LHLPLP was incubated with ACE and was found to be a true inhibitor of the enzyme and to exhibit a competitive inhibitor pattern. A structure–activity relationship study of this peptide was carried out by synthesizing several modified peptides related to the sequence LHLPLP. The substitution of amino acid Leu in the penultimate position by Gly improved the ACE-inhibitory activity twofold and the substitution of Pro at C-terminal position by Arg increased the activity twofold, with an IC50 of LHLPLR as low as 1.8 μM.