A novel high-throughput image based rapid Folin-Ciocalteau assay for assessment of reducing capacity

This is the peer reviewed version of the following article: Talanta 152 (2016): 82-89, which has been published in final form at http://dx.doi.org/10.1016/j.talanta.2016.01.051The aim of the presented work was to develop a novel high-throughput rapid Folin-Ciocalteau assay for the quantification of reducing capacity based on image scanner (Image-F-C assay). The original rapid F-C assay using a 96-well plate was improved by adding a neutralization step that stabilizes the formed color, enabling image acquisition using a flatbed scanner. The effects of reaction volume, scanning orientation and model of flatbed scanner were assessed based on linearity, sensitivity and reproducibility of gallic acid standard curve. Euclidean distance calculated from R (Red), G (Green) and B (Blue) values was chosen, based on linearity and sensitivity, in order to quantify the reducing capacity. An in-house program using free ImageJ macro language was written to calculate automatically the RGB values of each well. The Image-F-C assay is linear within the range of 0-20 mg L-1 of gallic acid (R2 ≥ 0.9939). The reducing capacity of herbal infusions using the new method was: tymus (251 ± 11), digestive (166 ± 9), sen (88 ± 7), chamomile (54 ± 3), green tea (615 ± 12), lemon black tea (143 ± 4), coffee (576 ± 20), and fruit juices Biofrutas mediterraneo (939 ± 35), pineapple juice (520 ± 27) and apple juice (226 ± 17) and an inter-day relative standard error < 8% was observed. Bland-Altman and correlation analyses showed that there were no significant differences between the reducing capacity values measured by the new Image-F-C and the original rapid F-C assay.We are grateful for the Universidad Autónoma de Madrid (Project UAM-60), for supporting this wor

Inulin extraction from common inulin-containing plant sources

Currently there is a growing interest from the food industry in obtaining inulin for its possible use in the elaboration of functional foods. A set of optimum extraction conditions was developed for the recovery of inulin plus fructo-oligosaccharides (FOS) from several common inulin-containing plant sources, like chicory roots (Cichorium intybus L.) and Jerusalem artichoke tubers (Helianthus tuberosus L.), as well as from novel sources like globe artichoke inflorescence (Cynara cardunculus L.) and its by-product. Optimal conditions for temperature (60−80 °C), time (20−60 min) and solvent to solid ratio (10−40 mL/g) were estimated in order to maximize inulin plus FOS extraction by using response surface methodology (RSM) with a Box-Behnken design. Inulin plus FOS were estimated colorimetrically by difference between total carbohydrate and reducing sugar contents for the optimization. Moreover, the profile of inulin and low molecular weight carbohydrates was studied in optimized plant extracts by HPLC. Inulin in raw samples and optimal extracts were further characterized by Fourier Transformed Infrared spectroscopy. According to response surface methodology model, optimal conditions for inulin plus FOS extraction depended on plant source and were achieved at a solvent to solid ratio of 27.8–37.4 mL/g, from 62−80 °C and a variable time of 22−60 min. The highest inulin plus FOS contents were achieved in chicory root (70.5 g/100 g dry weight) and Jerusalem artichoke tuber (81.1 g/100 g dry weight), and the lowest ones were attained in globe artichoke by-product (4.2 g/100 g). Nevertheless, its high availability and low cost would support this novel globe artichoke by-product as an alternative and valuable source of inulin and FOS for the food industry. At the same time their reuse as potential prebiotic ingredients would contribute to the circular economy

Imbalance between pro and anti-oxidant mechanisms in perivascular adipose tissue aggravates long-term high-fat diet-derived endothelial dysfunction

Background: The hypothesis of this study is that long-term high-fat diets (HFD) induce perivascular adipose tissue (PVAT) dysfunction characterized by a redox imbalance, which might contribute to aggravate endothelial dysfunction in obesity. Methods and Results: C57BL/6J mice were fed either control or HFD (45% kcal from fat) for 32 weeks. Body weight, lumbar and mesenteric adipose tissue weights were significantly higher in HFD animals compared to controls. The anticontractile effect of PVAT in mesenteric arteries (MA) was lost after 32 week HFD and mesenteric endothelial-dependent relaxation was significantly impaired in presence of PVAT in HFD mice (Emax = 71.0±5.1 vs Emax = 58.5±4.2, p<0.001). The inhibitory effect of L-NAME on Ach-induced relaxation was less intense in the HFD group compared with controls suggesting a reduction of endothelial NO availability. Expression of eNOS and NO bioavailability were reduced in MA and almost undetectable in mesenteric PVAT of the HFD group. Superoxide levels and NOX activity were higher in PVAT of HFD mice. Apocynin only reduced contractile responses to NA in HFD animals. Expression of ec-SOD and total SOD activity were significantly reduced in PVAT of HFD mice. No changes were observed in Mn-SOD, Cu/Zn-SOD or catalase. The ratio [GSSG]/([GSH]+[GSSG]) was 2-fold higher in the mesenteric PVAT from HFD animals compared to controls. Conclusions: We suggest that the imbalance between pro-oxidant (NOX, superoxide anions, hydrogen peroxide) and antioxidant (eNOS, NO, ecSOD, GSSG) mechanisms in PVAT after long-term HFD might contribute to the aggravation of endothelial dysfunctionThis work was supported by grants from Ministerio de Ciencia e Investigación (BFU2011-25303), Ministerio de Economía y Competitividad (SAF2009- 09714, SAF2011-25303, BFU2012-35353), Grupos Universidad Complutense de Madrid (UCM; GR-921641), Fundación Universitaria San Pablo-CEU, Fundación Mutua Madrileña and Sociedad para el Estudio de la Salud Cardiometabólica (SESCAMET). MGO and CFG-P are supported by Ministerio de Educación y Cienci

Fetal undernutrition is associated with perinatal sex-dependent alterations in oxidative status

This is the published version of a work that was accepted for publication in The Journal of Nutritional Biochemestry. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in The Journal of Nutritional Biochemestry 26.12 (2015). DOI: 10.1016/jnubio.2015.09.004Intrauterine growth retardation predisposes to hypertension development, known as fetal programming. Females are less susceptible, which has been mainly attributed to estrogen influence. We hypothesize that perinatal differences in oxidative status might also contribute. We studied 21-day-old (prepuberal) and 6-month-old male and female Intrauterine growth retardation predisposes to hypertension development, known as fetal programming. Females are less susceptible, which has been mainly attributed to estrogen influence. We hypothesize that perinatal differences in oxidative status might also contribute. We studied 21-day-old (prepuberal) and 6-month-old male and female offspring from rats fed ad libitum during gestation (Control) or with 50% of Control daily intake from day 10 to delivery (maternal undernutrition, MUN). We assessed in vivo blood pressure and the following plasma biomarkers of oxidative status: protein carbonyls, thiols, reduced glutathione (GSH), total antioxidant capacity, superoxide anion scavenging activity (SOSA) and catalase activities; we calculated a global score (oxy-score) from them. Estradiol and melatonin concentration was measured in young rats. Prepuberal MUN males were normotensive but already exhibited increased carbonyls and lower thiols, GSH, SOSA and melatonin; oxy-score was significantly lower compared to Control males. Prepuberal MUN females only exhibited reduced SOSA compared to Control females. Adult rats from all experimental groups showed a significant increase in carbonyls and a decrease in antioxidants compared to prepuberal rats; oxy-score was negative in adult rats suggesting the development of a prooxidative status as rat age. Adult MUN males were hypertensive and exhibited the highest increase in carbonyls despite similar or even higher antioxidant levels compared to Controls. Adult MUN females remained normotensive and did not exhibit differences in any of the biomarkers compared to Controls. The better global antioxidant status developed by MUN females during perinatal life could contribute to their protection against hypertension programming.offspring from rats fed ad libitum during gestation (Control) or with 50% of Control daily intake from day 10 to delivery (maternal undernutrition, MUN). We assessed in vivo blood pressure and the following plasma biomarkers of oxidative status: protein carbonyls, thiols, reduced glutathione (GSH), total antioxidant capacity, superoxide anion scavenging activity (SOSA) and catalase activities; we calculated a global score (oxy-score) from them. Estradiol and melatonin concentration was measured in young rats. Prepuberal MUN males were normotensive but already exhibited increased carbonyls and lower thiols, GSH, SOSA and melatonin; oxy-score was significantly lower compared to Control males. Prepuberal MUN females only exhibited reduced SOSA compared to Control females. Adult rats from all experimental groups showed a significant increase in carbonyls and a decrease in antioxidants compared to prepuberal rats; oxy-score was negative in adult rats suggesting the development of a prooxidative status as rat age. Adult MUN males were hypertensive and exhibited the highest increase in carbonyls despite similar or even higher antioxidant levels compared to Controls. Adult MUN females remained normotensive and did not exhibit differences in any of the biomarkers compared to Controls. The better global antioxidant status developed by MUN females during perinatal life could contribute to their protection against hypertension programming.This work was supported by Ministerio de Economía y Competitividad Spain (grant number FEM2012-37634-C03-01 to S. M. Arribas) and Universidad Autónoma de Madrid Banco - Santander (Interuniversity Cooperation Project, Center for Latin American Studies, Santander, USA 2013–2014 to M. A. Martín-Cabrejas)

Design of polyphenol-rich diets in clinical trials: A systematic review

Most randomized clinical trials of polyphenols focus on individual foods. Nevertheless, due to their presence in many foods and in order to reflect a real situation, clinical trials based on polyphenol-rich diets are particularly important. This systematic review explores the characteristics of the polyphenol-rich diets used in intervention studies. The bibliography search for English-language scientific papers was performed in the Elsevier Scopus Database and PUBMED in March 2020, and focused on intervention studies with whole polyphenol-rich diets, establishing several exclusion criteria. In studies fulfilling the requirements, information on the design of the polyphenol-rich diet and associated polyphenol intake was extracted and compared. A total of 5 studies were selected. Among them, substantial differences were found in the design of the polyphenol-rich diets, regarding specific instructions and concerning the foods provided. Similarly, although a median daily polyphenol intake of 2,564 mg/day (17,945 mg/week) was obtained from the studies, which corresponds to a nutritional dose, intake values varied widely both for total polyphenols (the difference between studies reached threefold), and for individual polyphenol intake (for hydroxycinnamic acids, a tenfold difference was found between percentile 25 and percentile 75 values). These differences made the comparison of results difficult and may affected the observed health effects. Thus, despite the relevance of studying polyphenol-rich diets as a whole, this systematic review found substantial differences between the studies performed, making direct comparisons difficult.Miss Christina Gazi was the recipient of an Erasmus+grant, a programme from the European Union.Peer reviewe

Improved evaporative light scattering detection for carbohydrate analysis

© 2015 Elsevier Ltd. All rights reserved. Optimization and validation of evaporative light scattering detector (ELSD), aided by response surface methodology (RSM), has been developed for the liquid chromatography analysis of a wide molecular weight (MW) range of carbohydrates, including polysaccharides and oligosaccharides. Optimal experimental parameters for the ELSD detection were: 88.8 °C evaporator temperature, 77.9 °C nebulizer temperature and 1.1 standard litres per minute nitrogen flow rate. Optimal ELSD detection, used together with high performance size exclusion chromatography (HPSEC) of carbohydrates, gave a linear range from 250 to 1000 mg L-1 (R2 > 0.998), with limits of detection and quantitation of 4.83-11.67 and 16.11-38.91 mg L-1, respectively. Relative standard deviation was lower than 1.8% for intra-day and inter-day repeatability for apple pectin, inulin, verbascose, stachyose and raffinose. Recovery ranged from 103.7% to 118.3% for fructo-oligosaccharides, α-galacto-oligosaccharides and disaccharides. Optimized and validated ELSD detection is proposed for the analysis of high- to low-MW carbohydrates with high sensitivity, precision and accuracy.This research was supported by project AGL2014-52572-R from the Spanish MINECO.Peer Reviewe

Molecular mobility and concentration of plant cells intracellular compartments, as derived from ice crystal size measured on cryo-SEM micrographs

Abstract presented at CRYO2022.Peer reviewe