[Evaluation of the hypoglycemic effect of a peptide fraction of chia seeds (Salvia hispánica L.) in male Wistar rats induced with alloxan]. / Evaluación del efecto hipoglucemiante de una fracción peptídica de las semillas de chía (Salvia hispanica L.) en ratas macho Wistar inducidas con aloxano.

INTRODUCTION: Introduction: diabetes research with peptides from foods has been conducted in animal experiments to be later applied to humans. Objective: the main purpose of this work was to evaluate in rats the hypoglycemic effect of a peptide fraction of chia seeds derived by enzymatic hydrolysis. Materials and methods: from chia flour a protein-rich fraction was obtained, which was hydrolyzed with pepsin-pancreatin system enzymes to yield a peptide fraction (> 10 kDa) by ultrafiltration. Five rat groups (one normoglycemic and four diabetized with alloxan) were used. A sucrose tolerance curve was performed, providing the disaccharide before measurement. Blood was taken from the tip of the tail at 0 (before sugar), 30, 60, 90, and 120 minutes. Results: the protein content of chia flour was 49.51 %. The peptide fraction (> 10 kDa) had 91 % of protein. A dose of 50 mg/kg showed in rats a tendency to decrease blood glucose within the first hour, but no significance was found between the target and the doses evaluated. There was no decrease in glucose absorption vs. the reference drug. At 120 min postprandial, no differences were found between doses, water, and acarbose, showing a return to the baseline status. The tolerance curve in diabetic rats was opposite to that of acarbose, so there was no relationship between the drug's mechanism of action and this analyzed effect. Conclusion: the peptide fraction of chia of > 10 kDa showed no hypoglycemic effect at the single dose that was administered.

INTRODUCCIÓN: Introducción: se han realizado investigaciones sobre la diabetes con péptidos de diferentes fuentes alimentarias en animales experimentales para aplicarse después en los seres humanos. Objetivo: la finalidad de este trabajo fue evaluar en ratas el efecto hipoglucemiante de una fracción peptídica de chía obtenida por hidrólisis enzimática. Materiales y métodos: de la harina de chía se obtuvo una fracción rica en proteína que fue hidrolizada con pepsina-pancreatina, generándose una fracción peptídica (> 10 kDa) por ultrafiltración. Se utilizaron cinco grupos de ratas (uno de normoglucémicas y cuatro de diabetizadas con aloxano). Se realizó una curva de tolerancia a la sacarosa, proporcionándoles el disacárido antes de la medición. La sangre se tomó de la punta de la cola a los 0, 30, 60, 90 y 120 minutos. Resultados: el contenido proteico de la harina fue del 49,51 %. La fracción peptídica (> 10 kDa) presentó un 91 % de proteína; de esta se suministró una dosis de 50 mg/kg que demostró una tendencia a la disminución de la glucosa sanguínea en la primera hora, aunque no se encontró significancia entre el blanco y las dosis evaluadas. No hubo disminución de la absorción de glucosa frente al fármaco de referencia. A los 120 min del periodo postprandial no se encontraron diferencias entre las dosis, el blanco y la acarbosa, lo que denota un retorno al estado basal. Los valores en las ratas diabetizadas fueron opuestos a los de la acarbosa, por lo que no existió relación entre el mecanismo de acción del fármaco con el efecto analizado. Conclusión: las fracciones peptídicas de chía de > 10 kDa no presentaron efecto hipoglucemiante con la dosis única suministrada.

A Cecropia peltata ethanolic extract reduces insulin resistance and hepatic steatosis in rats fed a high-fat diet.

ETHNOPHARMACOLOGICAL RELEVANCE: Cecropia peltata L. (CP) leaves have been used in Latin American traditional medicine by its purported hypoglycemic, anti-inflammatory and antioxidant properties. PURPOSE: The aim of this study was to evaluate the metabolic effects of an ethanolic extract of CP leaves in rats fed a high-fat diet and 10% of sugar in water (HFD). METHODS: Male Wistar rats were randomly divided into four groups: group 1 was fed a control diet; groups 2, 3 and 4 were fed a HFD. In addition, group 3 was co-administered with 10 mg/kg/day of CP extract (HFD + CP) and group 4 with a solution of 5 mg/kg/day metformin (HFD + M) for 90 days. RESULTS: Body weight gain and serum triglycerides were significantly decreased in the HFD + CP group compared with the HFD and HFD + M groups. Glucose tolerance increased in the HFD + CP compared with the HFD group. Administration with CP extract reduced adipose tissue lipolysis and lipid accumulation in liver of HFD + CP rats with respect to HFD and HFD + M groups. Histological examinations showed that the area of the adipocytes in WAT and the area of lipid vesicles in BAT were significantly smaller in the HFD + CP group than in the HFD and HFD + M groups. CONCLUSION: Administration of a CP extract prevented glucose intolerance and hepatic lipid accumulation in rats fed a HFD in association with reduced adipocyte hypertrophy, demonstrating potential antidiabetic properties.

[Inhibitory effect of peptide fractions derivatives from chia (Salvia hispanica) hydrolysis against α-amylase and α-glucosidase enzymes]. / Efecto inhibitorio de fracciones peptídicas derivadas de la hidrólisis de semillas de chía (Salvia hispanica) sobre las enzimas α-amilasa y α-glucosidasa.

INTRODUCTION: biopeptides are amino acid sequences with biological functions about metabolism and carbohydrates absorption. OBJECTIVE: the aim of this study was the evaluation of the inhibitory effect of peptide fractions derivatives of the hydrolysis of Salvia hispanica against α-amylase and α-glucosidase enzymes to know their activity on the carbohydrates metabolism. MATERIAL AND METHODS: the fraction rich in protein was hydrolyzed by two enzymatic systems: Alcalase®-Flavourzyme® and pepsin-pancreatine. The grade of hydrolysis was determined for the samples. The hydrolyzed samples were centrifuged and the soluble portion was ultra-filtered using different cut membranes. The content of protein was determined for each fraction. An in vitro analysis was made, measuring the percentage of inhibition of the Salvia hispanica fractions against α-amylase and α-glucosidase. RESULTS: the enzymatic system showing the highest grade of hydrolysis (63.53%) was pepsin-pancreatine. From the ultrafiltration, five peptide fractions were obtained: 10 kDa, 5-10 kDa, 3-5 kDa, 1-3 kDa and 1 kDa. The highest protein content was for these fractions: 10 kDa and 5-10 kDa, (0.90 and 0.93 mg/ml, respectively) for pepsin-pancreatine. The inhibition percentages obtained were 85.61% and 79.19% for the 10 kDa and 5-10 kDa fractions, respectively, for the α-amylase enzyme. With respect to the α-glucosidase enzyme, the highest inhibition was for the 10 kDa fraction, with 96.91%. CONCLUSION: the peptide fractions obtained from the chia may increase the natural sources for the preparation of functional foods important for the diabetic patient's diet.

Introducción: los biopéptidos son secuencias aminoacídicas que pueden ejercer funciones biológicas sobre el metabolismo y la absorción de carbohidratos.Objetivo: la finalidad de este estudio fue evaluar el efecto inhibitorio de fracciones peptídicas derivadas de la hidrólisis de Salvia hispanica sobre las enzimas α-amilasa y α-glucosidasa, para comprobar su actividad en el metabolismo glucídico. Material y métodos: se obtuvo una fracción rica en proteína, la cual fue hidrolizada mediante dos sistemas enzimáticos: Alcalasa®-Flavourzima® y pepsina-pancreatina. A las muestras obtenidas se les determinó el grado de hidrólisis. El hidrolizado fue centrifugado y la porción soluble fue ultrafiltrada, utilizando diferentes membranas de corte. A cada fracción se le determinó el contenido de proteína. Se realizó un análisis in vitro midiendo el porcentaje de inhibición de las fracciones de Salvia hispanica sobre α-amilasa y α-glucosidasa.Resultados: el sistema enzimático que presentó el mayor grado de hidrólisis (63,53%) fue la pepsina-pancreatina. De la ultrafiltración se obtuvieron cinco fracciones peptídicas: > 10 kDa, 5-10 kDa, 3-5 kDa, 1-3 kDa y < 1 kDa. El mayor contenido de proteína lo presentaron las fracciones de > 10 kDa y 5-10 kDa (0,90 y 0,93 mg/ml, respectivamente) para pepsina-pancreatina. Los porcentajes de inhibición obtenidos fueron de 85,61% y 79,19% para las fracciones de > 10 kDa y 5-10 kDa, respectivamente para la enzima α-amilasa. Para la enzima α-glucosidasa, el mayor porcentaje de inhibición fue para la fracción de > 10 kDa, con 96,91%.Conclusión: los péptidos obtenidos de la chía podrían incrementar las fuentes naturales para la elaboración de alimentos funcionales importantes para la dieta de pacientes diabéticos.

Evaluation of Hypotensive and Antihypertensive Effects of Velvet Bean (Mucuna pruriens L.) Hydrolysates.

Hypertension could cause significant worldwide health problems that affect 15-20% of all adults; according to National Health and Nutrition Examination Survey, about 29% of the adult population in the United States are hypertensive. Recent research has shown that peptides derived from the hydrolysis of food proteins can decrease blood pressure. This study was carried out to evaluate the hypotensive and antihypertensive potential of Mucuna pruriens protein hydrolysates in in vitro and in vivo models. M. pruriens protein concentrate was prepared by wet fractionation and enzymatically hydrolyzed using Alcalase®, Flavourzyme®, and the sequential system Alcalase-Flavourzyme at different times (5-120 min). The biological potential was measured in vitro based on the IC50 value as well as in vivo effect, measuring the systolic (SBP) and diastolic (DBP) blood pressure in normotensive and antihypertensive Wistar-Kyoto rats by the tail-cuff method. Hydrolysis of M. pruriens protein concentrates with commercial enzymes generated extensive hydrolysates with angiotensin-converting enzyme (ACE-I) inhibitory activity (IC50: 0.589-0.993 mg/mL) and hypotensive (SBP: 0.6-47.43%, DBP: 1.94-43.47%) and antihypertensive (SBP: 8.84-27.29% DBP: 16.1-29.37%) effect. These results indicate that Mucuna pruriens protein hydrolysate (MPPH) could be used as a functional ingredient to prevent blood pressure increase.

Evaluation of the Antihyperglycemic Effect of Minor Steviol Glycosides in Normoglycemic and Induced-Diabetic Wistar Rats.

Steviol glycosides are a family of compounds found in Stevia rebaudiana Bertoni that are responsible for sweetness capacity. The antihyperglycemic effect of the two major steviol glycosides, Rebaudioside A and Stevioside, has been studied and it has been found that despite having the same common structure, only Stevioside exerts an antihyperglycemic effect. Although other steviol derivatives are found in smaller amounts (minor steviol glycosides) in S. rebaudiana, whether or not they possess antihyperglycemic activity has not been evaluated. The aim of this study was to evaluate the antihyperglycemic effect of minor steviol glycosides in normoglycemic and diabetic (streptozotocin/nicotinamide) Wistar rats. Rats were subjected to an intraperitoneal glucose tolerance test (IPGTT) both before and after chronic treatment (28 days). After 6 h of fasting, IPGTT was conducted in pentobarbital-anesthetized rats using 1 g/kg of glucose plus 20 mg/kg of the minor glycoside (Dulcoside A, Rebaudioside B, C, D, or Steviolbioside) or control treatment (distilled water, glibenclamide, or metformin); the blood of the tip of the tail was collected at time 0, 15, 30, 60, and 120 min.; and blood glucose was measured, and its net area under the curve (AUCnet) was calculated. After 28-day chronic oral administration, IPGTT was again performed. Differences were considered significant at P < .05 by one-way ANOVA. Acute intraperitoneal or chronic oral administration of 20 mg/kg of minor steviol glycosides had no antihyperglycemic effect in normoglycemic or induced-diabetic Wistar rats. Considering the dose tested, it is unlikely that these glycosides have an effect on glucose in diabetic or normoglycemic humans.

ACE-I Inhibitory Activity from Phaseolus lunatus and Phaseolus vulgaris Peptide Fractions Obtained by Ultrafiltration.

The involvement of angiotensin-I-converting enzyme (ACE-I) as one of the mechanisms controlling blood pressure is being studied to find alternative means of control of hypertension on human beings. On the market there are synthetic drugs that can control it, but these can cause undesirable health side effects. In this work was assessed the fractionation by ultrafiltration of the Lima bean (Phaseolus lunatus) and Jamapa bean (Phaseolus vulgaris), protein hydrolysates obtained with Alcalase(®) and Flavourzyme(®) on ACE-I inhibitory activity. Four membranes of different molecular cutoffs (10, 5, 3, and 1 kDa) were used. Fractions that had a higher inhibitory activity in both legumes were denominated as E (<1 kDa) with IC50 of 30.3 and 51.8 µg/mL values for the P. lunatus with Alcalase and Flavourzyme, respectively, and for the Phaseolus vulgaris with Alcalase and Flavourzyme with about 63.8 and 65.8 µg/mL values, respectively. The amino acid composition of these fractions showed residues in essential amino acids, which make a good source of energy and amino acids. On the other hand, the presence of hydrophobic amino acids such as V and P is a determining factor in the ACE-I inhibitor effect. The results suggest the possibility of obtaining and utilizing these peptide fractions in the development and innovation of a functional product that helps with treatment and/or prevention of hypertension.

Angiotensin-I converting enzyme inhibitory and antioxidant activities of peptide fractions extracted by ultrafiltration of cowpea Vigna unguiculata hydrolysates.

BACKGROUND: Enzymatic proteolysis of food proteins is used to produce peptide fractions with the potential to act as physiological modulators. Fractionation of these proteins by ultrafiltration results in fractions rich in small peptides with the potential to act as functional food ingredients. The present study investigated the angiotensin-I converting enzyme (ACE-I) inhibitory and antioxidant activities for hydrolysates produced by hydrolyzing Vigna unguiculata protein extract as well as ultrafiltered peptide fractions from these hydrolysates. RESULTS: Alcalase(®), Flavourzyme(®) and pepsin-pancreatin were used to produce extensively hydrolyzed V. unguiculata protein extract. Degree of hydrolysis (DH) differed between the enzymatic systems and ranged from 35.7% to 58.8%. Fractionation increased in vitro biological activities in the peptide fractions, with IC(50) (hydrolysate concentration in µg protein mL(-1) required to produce 50% ACE inhibition) value ranges of 24.3-123 (Alcalase hydrolysate, AH), 0.04-170.6 (Flavourzyme hydrolysate; FH) and 44.7-112 (pepsin-pancreatin hydrolysate, PPH) µg mL(-1), and TEAC (Trolox equivalent antioxidant coefficient) value ranges of 303.2-1457 (AH), 357.4-10 211 (FH) and 267.1-2830.4 (PPH) mmol L(-1) mg(-1) protein. CONCLUSION: The results indicate the possibility of obtaining bioactive peptides from V. unguiculata proteins by means of a controlled protein hydrolysis using Alcalase(®), Flavourzyme(®) and pepsin-pancreatin. The V. unguiculata protein hydrolysates and their corresponding ultrafiltered peptide fractions might be utilized for physiologically functional foods with antihypertensive and antioxidant activities.

Effect of extrusion conditions and lipoxygenase inactivation treatment on the physical and nutritional properties of corn/cowpea (Vigna unguiculata) blends.

The influence of lipoxygenase inactivation and extrusion cooking on the physical and nutritional properties of corn/cowpea (Vigna unguiculata) blends was studied. Corn was blended in an 80:15 proportion with cowpea flour treated to inactivate lipoxygenase (CI) or non-inactivated cowpea flour (CNI). Extrusion variables were temperature (150 degrees C, 165 degrees C and 180 degrees C) and moisture (15%, 17% and 19%). Based on their physical properties, the 165 degrees C/15% corn:CNI, and 165 degrees C/15% corn:CI, and 150 degrees C/15% corn:CI blends were chosen for nutritional quality analysis. Extrudate chemical composition indicated high crude protein levels compared with standard corn-based products. With the exception of lysine, essential amino acids content in the three treatments met FAO requirements. Extrusion and lipoxygenase inactivation are promising options for developing corn/cowpea extruded snack products with good physical properties and nutritional quality.