Person:
León González, María Eugenia De

First Name

María Eugenia De

Last Name

León González

URI

https://hdl.handle.net/20.500.14352/76178

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Químicas

Department

Química Analítica

Area

Química Analítica

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Now showing 1 - 10 of 22

Effect of Storage and Drying Treatments on Antioxidant Activity and Phenolic Composition of Lemon and Clementine Peel Extracts
(Molecules, 2023) Gómez Mejía, Esther; Sacristán Navarro, Iván; Rosales Conrado, Noelia; León González, María Eugenia De; Madrid Albarrán, María Yolanda
Obtaining polyphenols from horticultural waste is an emerging trend that enables the valorization of resources and the recovery of value-added compounds. However, a pivotal point in the exploitation of these natural extracts is the assessment of their chemical stability. Hence, this study evaluates the effect of temperature storage (20 and −20 ◦C) and drying methods on the phenolic composition and antioxidant activity of clementine and lemon peel extracts, applying HPLC-DADMS, spectrophotometric methods, and chemometric tools. Vacuum-drying treatment at 60 ◦C proved to be rather suitable for retaining the highest antioxidant activity and the hesperidin, ferulic, and coumaric contents in clementine peel extracts. Lemon extracts showed an increase in phenolic acids after oven-drying at 40 ◦C, while hesperidin and rutin were sustained better at 60 ◦C. Hydroethanolic extracts stored for 90 days preserved antioxidant activity and showed an increase in the total phenolic and flavonoid contents in lemon peels, unlike in clementine peels. Additionally, more than 50% of the initial concentration was maintained up to 51 days, highlighting a half-life time of 71 days for hesperidin in lemon peels. Temperature was not significant in the preservation of the polyphenols evaluated, except for in rutin and gallic acid, thus, the extracts could be kept at 20 ◦C.
Diruthenium complexes as pH-responsive delivery systems: a quantitative assessment
(Inorganic Chemistry Frontiers, 2023) Coloma Manjón-Cabeza, Isabel; Cortijo Montes, Miguel; Mancheño Real, María José; León González, María Eugenia De; Gutierrez, Crisanto; Desvoyes, Bénédicte; Herrero Domínguez, Santiago; ROYAL SOCIETY OF CHEMISTRY
The controlled release of biologically active species from diruthenium compounds is crucial for the development of selective drug delivery systems based on such complexes, which in addition display antineoplastic properties by themselves. In the present work, we analyse in detail the kinetics of the pH-triggered release of the auxin-related hormones 2,4-D (2,4-dichlorophenoxyacetate) and NAA (1-naphthaleneacetate) from the metal–metal bonded tris(formamidinato) Ru25+ complexes [Ru2Cl(μ-DPhF)3(μ-2,4-D)](Ru2,4-D), [Ru2Cl(μ-DPhF)3(μ-NAA)] (RuNAA), [Ru2Cl(μ-DAniF)3(μ-2,4-D)] (Ru’2,4-D) and [Ru2Cl(μ-DAniF)3(μ-NAA)] (Ru’NAA) (DPhF = N,N’-diphenylformamidinate, DAniF = N,N’-bis(p-methoxy)phenylformamidinate). Moreover, the synthesis and complete characterisation of [Ru2Cl(μ-DAniF)3(μ-IAA)] (Ru’IAA, IAA = indole-3-acetate), Ru’2,4-D and Ru’NAA, including the crystal structure of the two latter ones, is reported. The release of auxins is studied through a fluorimetric quantitative assay, which allows determining the influence of different formamidinate ancillary ligands and the nature of the outgoing auxin ligand in the release process. Chemometrics is employed to evaluate the statistical significance of the variables. The release of auxins is slower at physiological pH and occurs faster at slightly acidic pH values. Compounds containing DPhF ancillary ligands and NAA outgoing ligand present a slower dissociation of the auxin, which is not complete in the first 24 h. The release rate is also correlated with the bond distance O1(auxin)–Ru1(hexacoordinated). A mechanism of the substitution reaction is tentatively proposed based on these findings. Overall, these results pave the way towards new systems for the controlled delivery of antineoplastic drugs under mild-acidic conditions like those surrounding solid tumours.
Screening the extraction process of phenolic compounds from pressed grape seed residue: Towards an integrated and sustainable management of viticultural waste
(LWT - Food Science and Technology, 2022) Gómez Mejía, Esther; Vicente Zurdo, David; Rosales Conrado, Noelia; León González, María Eugenia De; Madrid Albarrán, María Yolanda
The integrated valorisation of waste from the food chain to obtain value-added compounds with biological functionality will facilitate the transition to the era of a sustainable bioeconomy. To this end, an efficient matrix solid-phase dispersion (MSPD) extraction method was developed and optimized, using experimental factorial design and response surface methodology, for polyphenols recovery from pressed grape seeds obtained after the extraction of essential oils by cold pressing. Gallic, dihydroxybenzoic, p-coumaric and trans-ferulic acid, naringin, resveratrol, quercetin and kaempferol were quantified at 2.1–295 μg g−1 by capillary liquid chromatography coupled to a diode array detector and a mass analyser (cLC-DAD-MS). Furthermore, total antioxidant activity, free radical scavenging and lipid peroxidation suppression, together with the inhibition of beta-amyloid (Αβ42) protein aggregation, considered one of the main pathological effects of Alzheimer's disease, were evaluated. Potent lipid peroxidation inhibition (IC50 0.238 ± 0.003 ng g−1) was observed, along with the reduction of Αβ42 fibril width (9.4–54.8%) and aggregation. The results presented proved that the MSPD extraction method could be considered as an efficient and sustainable methodology to produce phenolic-rich extracts that may serve as an alternative antioxidant and neuroprotective ingredient for the food or pharmaceutical formulations, leading to the cascade valorisation of winery by-products.
Evaluation of the transformation of selenite and selenium nanoparticles to seleno-amino acids produced by Escherichia coli and Staphylococcus aureus by using liquid chromatography -inductively coupled plasma mass spectrometry and single-particle- inductively coupled plasma mass spectrometry and different sample treatments
(Spectrochimica Acta Part B: Atomic Spectroscopy, 2023) Moreno Martín, Gustavo; Espada-Bernabé, Elena; Gómez Gómez, Beatriz; León González, María Eugenia De; Madrid Albarrán, María Yolanda
Due to the scarce knowledge about the impact of selenium nanoparticles (SeNPs) on bacterial populations, the main objective of this work was focused on evaluating the transformations of SeNPs and selenite in Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). For this purpose, an analytical methodology based on bacteria cell wall disruption, carbamidomethylation, enzymatic hydrolysis and high-performance liquid chromatography couple to inductively coupled plasma mass spectrometry (HPLC-ICP-MS) and HPLC- electrospray tandem mass spectrometry (HPLC-ESI-MS/MS) measurements was developed, the latter for unambiguous identification of selenium species. Once bacteria were cultured in the presence of chitosan modified SeNPs (Ch-SeNPs) and selenite at 0, 1 and 2 mg L􀀀 1 Se for 24 h, an enzymatic disruption of the bacterial cell wall using lysozym followed by enzymatic hydrolysis with protease was applied. The use of lysozyme to extract selenium speciesprovided a better efficiency in the total selenium content (higher than 96%), compared to a mechanical disruption of the bacterial cell wall. Analysis of the extracts by anionic exchange HPLC-ICP-MS showed a strong influence of incubation time with protease (24, 48 and 72 h) on selenium chromatographic profile. The results showed that selenocysteine (SeCys) was the only Se species identified in both bacteria representing an 80% of total selenium accumulated. The confirmation of the identity of this Se species was carried out after performing a carbamidomethylation process, prior to enzymatic hydrolysis, and analyzing the extract by reversed phase HPLCESI- MS/MS. These analyses confirmed the presence of SeCys, and no relevant differences were found between the metabolic pathway of both forms of selenium. Moreover, the growth of both bacterial species in the presence of selenite resulted in the formation of biogenic SeNPs. Characterization by TEM before and after their separation from the culture medium showed spherical and monodispersed nanoparticles with an average size (155 ± 19) nm and (172 ± 20) nm for E. coli and S. aureus, respectively. Analysis by spICP-MS showed no significant differences in size with respect to TEM after considering the ionization efficiency of Se.
A combined analytical-chemometric approach for the in vitro determination of polyphenol bioaccessibility by simulated gastrointestinal digestion
(Analytical and Bioanalytical Chemistry, 2022) Gómez Mejía, Esther; Rosales Conrado, Noelia; León González, María Eugenia De; Valverde de la Fuente, Alejandro; Madrid Albarrán, María Yolanda
In this study, an integrated characterisation through polyphenol and cafeine content and antioxidant activity was combined with chemometric analysis to assess the efects of simulated in vitro gastrointestinal digestion on the bioaccessibility of these bioactive compounds from nine diferent tea infusions. Tea infusions were characterised based on total favonoids, total polyphenols and antioxidant activity, together with the determination of individual polyphenol content. Fourteen phenolic compounds, including phenolic acids, stilbenes and favonoids, were selected based on their reported bioactivity and high accessibility, attributed to their low molecular weight. Both polyphenols and cafeine were initially monitored in raw tea infusions and through the diferent digestion stages (salivary, gastric and duodenal) by capillary high performance liquid chromatography coupled to diode array detection (cHPLC-DAD) and/or HPLC coupled to a triple quadrupole mass analyser (HPLC–MS/MS). Multivariate analysis of the studied bioactives, using principal component analysis and cluster analysis, revealed that the decafeination process seems to increase the stability and concentration of the compounds evaluated during digestion. The greatest transformations occurred mainly in the gastric and duodenal stages, where low bioactivity indices (IVBA) were shown for resveratrol and cafeic acid (IVBA=0%). In contrast, the polyphenols gallic acid, chlorogenic acid and quercetin gave rise to their availability in white, green and oolong infusion teas (IVBA>90%). Furthermore, highly fermented black and pu-erh varieties could be designated as less bioaccessible environments in the duodenum with respect to the tested compounds.
A combined approach based on matrix solid-phase dispersion extraction assisted by titanium dioxide nanoparticles and liquid chromatography to determine polyphenols from grape residues
(Journal of Chromotography A, 2021) Gómez Mejía, Esther; Hartwig Mikkelsen, Line; Rosales Conrado, Noelia; León González, María Eugenia De; Madrid Albarrán, María Yolanda; Elsevier
A simple and eﬃcient low-cost matrix solid phase dispersion (MSPD) extraction assisted by TiO2 nanopar- ticles and diatomaceous earth has been developed for the extraction of phenolic compounds from grape and grape pomace wastes. Experimental conditions for MSPD extraction were optimized by a facto- rial design and a surface response methodology. The simultaneous identiﬁcation and quantiﬁcation of eight main natural polyphenols (caffeic, p-coumaric, dihydroxybenzoic and gallic acid, rutin, resveratrol, quercetin and catechin) was possible by combining MSPD and capillary liquid chromatography coupled to a diode array detection and a mass simple quadrupole analyzer (cLC-DAD-MS). Good linearity and acceptable LOD (0.05–62 μg· g −1 ) and LOQ (0.2–207 μg· g −1 ) were obtained. The quantities of extracted polyphenols were within 2.4 and 333 μg· g −1, with catechin and rutin the most abundant compounds in rape pomace and grape wastes, respectively. Furthermore, considering the prospective uses of the win- ery bioresidues, the extracts have been characterised in terms of bioactive properties (several antioxidant activities and bacterial inhibition against Staphylococcus aureus, Escherichia coli and Pseudomona aerugi- nosa) and parameters such as total polyphenol and total ﬂavonoid content. The high antioxidant activity (IC 50 5.0 ± 0.4 μg ·g −1 against DPPH radical) and antibacterial activity (2.2 ± 0.3 mg· mL −1 ) suggests that the methodology developed is eﬃcient, rapid and promising for the extraction of phenolic compounds with potential application as bioactive ingredients in food and cosmetic industries.
Valorization of citrus reticulata blanco peels to produce enriched wheat bread: phenolic bioaccessibility and antioxidant potential
(Antioxidants, 2023) Gómez Mejía, Esther; Sacristán, Iván; Rosales Conrado, Noelia; León González, María Eugenia De; Madrid Albarrán, María Yolanda
The fortification of foods with bioactive polyphenols aims to improve their functional properties and to provide health benefits. Yet, to exert their benefits, phenolic compounds must be released from the food matrix and absorbed by the small intestine after digestion, so assessing their bioaccessibility is crucial to determine their potential role. This work aims to incorporate Citrus reticulata Blanco peel extracts into wheat bread as a promising opportunity to increase their bioactive potential, along with supporting the sustainable management of citrus-industry waste. A control and a wheat bread enriched at 2% and 4% (w/v) with a phenolic extract from mandarin peels were prepared and analyzed for antioxidant activity and phenolic composition using LC-MS and UV-Vis spectrophotometry. In addition, in vitro digestion was performed, and the digested extracts were analyzed with HPLC-MS/MS. The results showed a significant increase in total flavonoid content (TFC, 2.2 ± 0.1 mg·g−1), antioxidant activity (IC50 = 37 ± 4 mg·g−1), and contents of quercetin, caffeic acid, and hesperidin in the 4% (w/v) enriched bread. Yet, most polyphenols were completely degraded after the in vitro digestion process, barring hesperidin (159 ± 36 μg·g−1), highlighting the contribution of citrus enrichment in the development of an enriched bread with antioxidant potential.
Ability of selenium species to inhibit metal-induced Aβ aggregation involved in the development of Alzheimer’s disease
(Analytical and Bioanalytical Chemistry, 2020) Vicente Zurdo, David; Romero Sánchez, Iván; Rosales Conrado, Noelia; León González, María Eugenia De; Madrid Albarrán, María Yolanda; Springer Heidelberg
Extracellular accumulation of amyloid beta peptide (Aβ) is believed to be one of the main factors responsible for neurodegeneration in Alzheimer’s disease (AD). Metals could induce Aβ aggregation, by their redox activity or binding properties to amyloid β fibrils, leading to their accumulation and deposition outside neurons. For this reason, metal chelation may have an acknowledged part to play in AD prevention and treatment. In the current work, the role of different selenium species, including selenium nanoparticles, in Aβ aggregation, was studied by evaluating their metal-chelating properties and their ability both to inhibit metal-induced Aβ1–42 aggregation fibrils and to disaggregate them once formed. Transition biometals such as Fe(II), Cu(II), and Zn(II) at 50 μM were selected to establish the in vitro models. The DPPH assay was used to determine the antioxidant capacity of the evaluated selenium species. Selenium nanoparticles stabilized with chitosan (Ch-SeNPs) and with both chitosan and chlorogenic acid polyphenol (CGA@ChSeNPs) showed the highest antioxidant properties with EC50 of 0.9 and 0.07 mM, respectively. UV–Vis and d1(UV–Vis) spectra also revealed that selenium species, in particular selenomethionine (SeMet), were able to interact with metals. Regarding Aβ1–42 incubation experiments, Fe(II), Cu(II), and Zn(II) induced Aβ aggregation, in a similar way to most of the evaluated selenium species. However, Ch-SeNPs produced a high inhibition of metal-induced Aβ aggregation, as well as a high disaggregation capacity of Aβ fibrils in both the presence and absence of biometals, in addition to reducing the length and width (20% of reduction in the presence of Zn(II)) of the generated Aβ fibrils.
Insights into the accumulation and transformation of Ch-SeNPs by Raphanus sativus and Brassica juncea: effect on essential elements uptake
(Science of the Total Environment, 2020) Moreno Martín, Gustavo; Sanz Landaluce, Jon; León González, María Eugenia De; Madrid Albarrán, María Yolanda
Selenium (Se) at very low doses has important functions for humans. Unfortunately, the low levels of Se in soils in various regions of the world have implemented the agronomic biofortification of crops by applying Se-enriched fertilizers (mainly based on selenate). Lately, the use of nanofertilizers is growing in interest as their low size reduces the amount of chemicals and minimizes nutrient losses in comparison with conventional bulk fertilizers. However, the knowledge on their fate and environmental impact is still scarce. This study aims to evaluate the biotransformation of chitosan-modified Se nanoparticles (Ch-SeNPs) as well as their effect on the metabolism of essential metals (Fe, Cu, Zn and Mo) when applied to hydroponic cultivation of R. sativus and B. juncea. In house-synthesized Ch-SeNPs were characterized in both synthesis and hydroponic culture media by transmission electron microscopy (TEM), dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA). The composition of one-tenth strength Hoagland's solution did not affect the size, shape and concentration in number of particles per mL of Ch-SeNPs. The plants were grown inside a box at 25 °C during the months of May–July in 2018. After a week of treatment with Ch-SeNPs, plants were harvested and divided into roots and aerial part. The biotransformation of Ch-SeNPs was evaluated through a process of enzymatic hydrolysis and subsequent analysis by HPLC-ICP-MS and HPLC-ESI-MS/MS. The results confirmed the transformation of Ch-SeNPs to seleno-amino acids: Selenomethionine (SeMet), Semethylselenocysteine (SeMetSeCys) and ɣ-glutamyl-Se-MetSeCys. Moreover, Multiple-way analysis of variance (ANOVA) and principal component analysis (PCA) showed that, regardless the plant species, Ch-SeNPs supplementation affected the absorption of Zn.
Phenolic profile, safety, antioxidant and anti-inflammatory activities of wasted Bunium ferulaceum Sm. aerial parts
(Food Research International, 2022) Deghima, Amirouche; Righi, Nadjat; Rosales Conrado, Noelia; León González, María Eugenia De; Baali, Faiza; Gómez Mejía, Esther; Madrid Albarrán, María Yolanda; Bedjou, Fatiha
The pharmaceutical and nutraceutical industries benefit greatly from recycling and transforming non-utilized parts of medicinal plants from agro-industrial operations into value added products. Hence, the aim of this work was to study the potential nutraceutical and pharmaceutical applications of Bunium ferulaceum Sm. aerial parts, in order to maximize their value. The phenolic profile of their hydromethanolic extract was determined and its antioxidant activity was evaluated in vitro and in vivo alongside with its anti-inflammatory activity and safety profile. The extract exerted an in vitro antioxidant activity mainly through radical scavenging (DPPH IC50: 14.0 ± 0.3 µg/ml) and iron chelating ability (24 ± 2 µg/ml), while, in vivo, the extract did not cause any mortality or visible signs of acute toxicity at high dose (2000 mg/kg body weight). The supplementation of the extract at different doses improved mice liver redox state by increasing catalase and reduced glutathione levels and reducing lipid peroxidation, without causing any toxicity. Moreover, the extract efficiently inhibited xylene induced ear inflammation (62 %). These different bioactivities were linked to the phenolic compounds present in the extract, particularly, chlorogenic acid (78 ± 6 mg/g extract), rutin (44 ± 2 mg/g extract) and hesperidin (56 ± 9 mg/g extract). However, further studies should be carried out on the isolated major compounds found in the extract to correlate the activity with these compounds or their mixture. The wasted aerial parts of Bunium ferulaceum Sm. proved to be a valuable source of polyphenols and exhibited interesting health promoting effects with no toxicity. Thus, Bunium ferulaceum Sm. aerial parts can be included in nutraceutical formulations or used as functional food and the extracted compounds may be used as an alternative food preservative.