Abstract Agro-industrial processing activities generate by-products that are discarded at high economic and environmental costs; however, many of them still contain high levels of bioactive compounds (BCs) such as dietary fiber (DF) and phenolic compounds (PCs), which, when combined, are known as antioxidant dietary fiber (ADF). These BCs have properties that are beneficial to our health, among them anti-inflammatory, antioxidant and cardioprotective. Moreover, DF can regulate glucose and cholesterol levels. The mechanism of ADF action depends on its chemical structure and the interactions between the DF and PCs in it. Recent studies have reported the incorporation of several of these by-products on a diet through food products consumed worldwide, such as bread. This review describes the chemical characteristics of the ADF complex and the effect of its molecular interactions on sensory, nutritional and health-promoting properties of functional bakery goods.

Abstract Grape pomace (GP) and pecan shell (PS) are agro-industrial by-products rich in healthy bioactives, mainly phenolic compounds (PC) and dietary fiber (DF). Raw GP and PS were chemically characterized, and the adsorption isotherms of their PC-insoluble DF (IDF) complexes were evaluated. GP and PS statistically differed (p < 0.05) in chemical and physicochemical properties. Total PC, total flavonoids, and IDF were higher in GP. Thirteen and eight PC were identified in GP and PS by HPLC-MS/MS chromatography, finding isoquercetin and type B dimer and trimer procyanidins as the most abundant compounds. PC-IDF (phenolic compounds-insoluble dietary fiber) adsorption isotherms were determined by both spectroscopic (Freundlich) and HPLC-MS/MS (Freundlich/Langmuir) techniques, observing that PS IDF presented higher PC adsorption at all tested concentrations. Epicatechin, isoquercetin, and quercetin were the main identified PC in both by-products, and were able to fit to both Langmuir and Freundlich isotherm by HPLC-MS/MS.

Abstract Pancreatic lipase is a key enzyme in lipid metabolism. Flavonoids are bioactive compounds obtained from vegetables with big relevance, due to their intrinsic interaction with digestive enzymes. Pancreatic lipase activity was evaluated in the presence of flavonoids, through UV-Vis spectroscopy. All tested flavonoids showed a mixed-type inhibition, except catechin, which showed a uncompetitive inhibition. The best inhibitor was quercetin followed by rutin > luteolin > catechin > hesperetin, with IC50 values of 10.30, 13.50, 14.70, 28.50 and 30.50 µM, respectively. The flavonoids inhibitory capacity was related to structural properties shared between the different flavonoids, such as the hydroxylation at C5, C7 (ring A), C2’ and C3’ (ring B), and the double bond between C2 and C3 (ring C). The inhibition results are in agreement with the extrinsic fluorescence analysis. Molecular docking studies indicated that the interaction between pancreatic lipase and flavonoids was mainly through hydrophobic interactions (pi-stacking). The interactions of all flavonoids, except rutin, occurred at the same enzyme site (subsite 1). Instauration between C2 and C3 was decisive for the arrangement of flavonoids with the enzyme, mainly due to pi-stacking interactions.

Resumen Lipasa pancreática es una enzima clave en el metabolismo de lípidos. Los flavonoides son compuestos bioactivos de gran relevancia debido a sus interacciones con enzimas digestivas. Se evaluó la actividad de lipasa pancreática en presencia de flavonoides. Mediante espectroscopía UV Visible se determinó que el mejor inhibidor fue quercetina, seguido de rutina > luteolina > catequina > hesperetina, con valores de IC50 de 10.30, 13.50, 14.70, 28.50 y 30.50 µM, respectivamente. Todos los flavonoides mostraron una inhibición mixta, excepto catequina que mostró una inhibición acompetitiva. La capacidad inhibitoria de los flavonoides se relacionó con propiedades estructurales compartidas entre los distintos flavonoides, como la hidroxilación en las posiciones C5, C7 (anillo A), C2’ y C3’ (anillo B), y el doble enlace entre C2 y C3 (anillo C). Los resultados de inhibición coincidieron con el análisis de la fluorescencia extrínseca. Los estudios de docking molecular indicaron que la interacción entre lipasa pancreática y los flavonoides fue principalmente mediante interacciones hidrofóbicas (pi-stacking). Las interacciones de todos los flavonoides, excepto rutina, se dieron en el mismo sitio (subsitio 1) de la enzima. La insaturación entre C2 y C3 fue determinante para el acomodo de los flavonoides con la enzima, principalmente por interacciones de pi-stacking.

Summary Polyphenolic compounds are antioxidant compounds present mainly in plants. Concentrations may differ in the same species located at different growing points since plants produce these compounds for protection against oxidative stress as a result of environmental factors that could affect them. This study determined the proximate composition, the concentration of polyphenolic compounds and the antioxidant activity in fruits of Lycium berlandieri collected in the three locations of the municipality of Juárez, Chihuahua (Riveras del Bravo, San Isidro and San Agustín), with the aim of evaluating the effect of inorganic nitrogen, alkalinity and salinity of the soil on the content of total phenolic and flavonoids compounds. The moisture content in the fruits of L. berlandieri ranged from 78.2 to 93.3%; the proximal composition of the fruit in dry weight indicated ash content of 3.6 to 5.3%, fats 0.9 to 6.7%, protein 9.0 to 15.4% and total carbohydrates 75.2 to 85.7%. In terms of polyphenolic compounds (in dry weight), fruits from San Agustín had the highest concentration of these compounds, particularly in total phenols 12 mg EAG (P = 0.002) and 9.02 mg EC in flavonoids (P = 0.001). Results of soil analysis indicated that the soil of San Agustín had the highest concentration of nitrates (88.51 mg kg-1) and a more saline soil (6.04 dS m-1). Overall, the results obtained showed that the differences in concentration of polyphenolic compounds in the fruits of L. berlandieri are related to soil salinity and availability of nitrates. Therefore, the soil of San Agustín in Ciudad Juárez, Chihuahua is optimal for the cultivation of L. berlandieri.

Resumen Los compuestos fenólicos son compuestos antioxidantes inocuos de las plantas, cuyas concentraciones pueden variar entre plantas de la misma especie cultivadas en diferentes zonas geográficas, debido a que las plantas producen estos compuestos para protegerse contra el estrés oxidativo a consecuencia de los factores ambientales que le pudieran afectar. La presente investigación tuvo como objetivos determinar la composición proximal, la concentración de compuestos fenólicos y actividad antioxidante en frutos de Lycium berlandieri colectados en las tres localidades del municipio Juárez, Chihuahua (Riveras del Bravo, San Isidro y San Agustín), con la finalidad de evaluar el efecto del contenido de nitrógeno inorgánico, alcalinidad y salinidad del suelo de los sitios de colecta de los frutos de L. berlandieri con el contenido de compuestos fenólicos y flavonoides totales. El contenido de humedad en los frutos de L. berlandieri se ubicó entre 78.2 a 93.3%; la composición proximal del fruto en peso seco indicó un contenido de cenizas de 3.6 a 5.3%, en grasas de 0.9 a 6.7%, en proteínas de 9.0 a 15.4% y de 75.2 a 85.7% en carbohidratos totales. En compuestos fenólicos en peso seco, los frutos provenientes de San Agustín mostraron la mayor concentración de estos compuestos, particularmente en fenoles totales 12.82 mg EAG (P = 0.002) y 9.02 mg EC en flavonoides (P = 0.001). Los resultados del análisis de suelo indicaron que el suelo de San Agustín tiene una mayor concentración de nitratos (88.51 mg kg-1) y un suelo más salino (6.04 dS m-1). En conjunto los resultados obtenidos permiten atribuir que las diferencias de concentración de los compuestos fenólicos en los frutos de L. berlandieri, está correlacionado con la salinidad del suelo y la disponibilidad de nitratos, por lo que el suelo de San Agustín en Ciudad Juárez, Chihuahua es óptimo para el cultivo de L. berlandieri.

Abstract Harpin protein was used as an elicitor in green (butterhead) and red (oak leaf type) varieties of hydroponically grown lettuce (Lactuca sativa L.). Its impact on polyphenolic content and antioxidant capacity was evaluated. Harpin protein was sprayed three days before harvesting in concentrations of 45, 60, and 120 mg/L. Green lettuce samples showed a positive response to Harpin by significantly increasing its phenolic content from 12 (control) to 16.43 mg gallic acid equivalents (GAE)/100 g dry weight (DW) (120 mg/L Harpin treatment) which means a 36.9% increase. Chlorogenic acid was the only phenolic compound that increased its concentration after lettuce induction with Harpin treatment. Antioxidant capacity, evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH˙) and ferric reducing antioxidant power (FRAP) methods, also showed a significant increase (46.5 and 64.3%, respectively) in Harpin-treated green lettuce. The red lettuce variety showed none or a negative response to Harpin treatment for all parameters evaluated. These results show that elicitation may be an effective strategy to enhance phenolic content in lettuce varieties.

Abstract Background Globally, snake envenomation is a well-known cause of death and morbidity. In many cases of snakebite, myonecrosis, dermonecrosis, hemorrhage and neurotoxicity are present. Some of these symptoms may be provoked by the envenomation itself, but others are secondary effects of the produced oxidative stress that enhances the damage produced by the venom toxins. The only oxidative stress effect known in blood is the change in oxidation number of Fe (from ferrous to ferric) in hemoglobin, generating methemoglobin but not in other macromolecules. Currently, the effects of the overproduction of methemoglobin derived from snake venom are not extensively recorded. Therefore, the present study aims to describe the oxidative stress induced by Crotalus molossus nigrescens venom using erythrocytes. Methods Human erythrocytes were washed and incubated with different Crotalus molossus nigrescens venom concentrations (0–640 μg/mL). After 24 h, the hemolytic activity was measured followed by attenuated total reflectance-Fourier transform infrared spectroscopy, non-denaturing PAGE, conjugated diene and thiobarbituric acid reactive substances determination. Results Low concentrations of venom (<10 μg/mL) generates oxyhemoglobin release by hemolysis, whereas higher concentrations produced a hemoglobin shift of valence, producing methemoglobin (>40 μg/mL). This substance is not degraded by proteases present in the venom. By infrared spectroscopy, starting in 80 μg/mL, we observed changes in bands that are associated with protein damage (1660 and 1540 cm−1) and lipid peroxidation (2960, 2920 and 1740 cm−1). Lipid peroxidation was confirmed by conjugated diene and thiobarbituric acid reactive substance determination, in which differences were observed between the control and erythrocytes treated with venom. Conclusions Crotalus molossus nigrescens venom provokes hemolysis and oxidative stress, which induces methemoglobin formation, loss of protein structure and lipid peroxidation.

Considering the extensive use of hot peppers and spicy sauces in the Mexican cuisine, in the present paper, three widely consumed Mexican condiments (mole sauce, achiote, and pasilla hot pepper) were analyzed for their total phenols, flavonoids and proanthocyanidins, antioxidant activity, and protective effect against lipid oxidation in chopped pork meat. All samples were extracted first with methanol and then with acetone, and the extracts were compared. Pasilla pepper showed the highest phenolic and flavonoid content in both solvents, followed by mole and achiote. Achiote showed the highest proanthocyanidin concentration. All samples showed high antioxidant activity, and good correlations with phenolic compounds and flavonoids, while no correlation was observed in the case of condensed tannins. Mole sauce methanolic extract showed the highest inhibition of pork meat oxidation, followed by pasilla pepper, and finally achiote paste extracts. These results suggest that these condiments are useful to prevent meat lipid oxidation during storage.

Fourier transform infrared microspectroscopy (FTIRM) is a recent technique that, over the last decade, has become more popular for the study of biological systems. It is the result of the union between FTIR spectroscopy and optical microscopy. The use of synchrotron radiation offers a significant gain in terms of brightness but recent developments on optics (ATR) and detectors (FPA) allow as well an important expansion of the technique in laboratories. In both cases, micrometric resolution can be reached. The generated optical image allows studying a particular area and uses the mid-infrared radiation (2.5 to 15 µm/ 4000 to 650 cm-1) to detect vibrational movements from the molecular groups present in biological samples. FTIRM results allow us to observe the biochemical state of a sample, and provide us with information about all molecules present therein, allowing identification, semi-quantification and precise localization of one or more relevant molecules. In this way it is possible to identify cells from different species or in different metabolic stages, or to analyze the biochemical changes generated in the samples under diverse experimental conditions. This review aims to inform about FTIRM, giving a general prospect of the technique and citing several studies made with it in various biological systems.

La microespectroscopía de infrarrojo con transformada de Fourier (FTIRM) es una técnica reciente que ha cobrado auge en el estudio de sistemas biológicos. Esta técnica es el resultado de la unión de la espectroscopia de infrarrojo (FTIR) con la microscopia óptica. El uso de la radiación de sincrotrón ofrece ventajas significativas en términos de brillantez, pero los recientes desarrollos en óptica (ATR) y en detectores (FPA) han permitido la expansión de esta técnica en los laboratorios. En ambos casos se pueden alcanzar resoluciones en la escala de los micrómetros. La imagen óptica generada permite delimitar un área de estudio y se usa a la radiación del infrarrojo medio (2.5 a 15 µm/ 4000 a 650 cm-1) para detectar los movimientos vibracionales de los grupos moleculares presentes en muestras biológicas. Los resultados que se obtienen permiten observar el estado bioquímico de una muestra, además de obtener información de todas las moléculas presentes en la misma lo cual permite la identificación, semi-cuantificación y precisa localización de una o varias moléculas de interés al interior de la célula o tejido. De esta manera se pueden identificar células de diferentes especies o en diversos estados metabólicos también se pueden analizar las variaciones bioquímicas generadas bajo diversas condiciones a las que sea sometida una muestra. Esta revisión informa sobre la FTIRM, dando un panorama general de la técnica y citando a varios estudios realizados con la misma en diversos sistemas biológicos.