Person: León González, María Eugenia De
Loading...
First Name
María Eugenia De
Last Name
León González
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Química Analítica
Area
Química Analítica
Identifiers
17 results
Search Results
Now showing 1 - 10 of 17
Item 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 YolandaObtaining 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.Item Anti-inflammatory activity of ethyl acetate and n-butanol extracts from Ranunculus macrophyllus Desf. and their phenolic profile(Journal of Ethnopharmacology, 2021) Deghima, Amirouche ; Righi, Nadjat; Rosales Conrado, Noelia; León González, María Eugenia De; Baali, Faiza; Gómez Mejía, Esther; Madrid Albarrán, María Yolanda; Bedjou, FatihaEthnopharmacological relevance: The members of the genus Ranunculus have counter-irritating properties and thus, they are traditionally used for treating anti-inflammatory disorders and other skin conditions. Ranunculus macrophyllus Desf. is a wild medicinal plant growing in Algeria and traditionally used to treat some cutaneous skin disorders. Aim: The aim of this study was to characterize the composition of the ethyl acetate and n-butanol extracts from Ranunculus macrophyllus Desf. as well as to elucidate and to compare their effect against acute skin inflammation. Moreover, both the antioxidant activity and the acute toxicity of the plant extracts were also studied. Materials and methods: Spectrophotometric and chromatographic methods were employed to identify and quantify phenolic compounds and triterpenoids from R. macrophyllus Desf. fractions. The antioxidant activity was estimated using the phosphomolebdenum, DPPH, reducing power and β-carotene bleaching assays. The ethyl acetate and n-butanol extracts were screened for their anti-inflammatory activities using ex-vivo membrane stabilizing assays and in-vivo acute skin inflammation model. Results: Ethyl acetate fraction showed the highest amounts of total phenolic compounds (413 ± 4 μg GAE/mg extract) and triterpenoids (70.4 ± 1.8 μg UAE/mg extract). Rutin, hesperidin, myricetin and kaempferol were the major compounds identified in the different fractions. Ethyl acetate fraction exhibited strong DPPH• radical scavenging ability (IC50 1.6 ± 0.2 μg/mL), high total antioxidant capacity (447 ± 7 μg AAE/mg extract) and reducing power (514 ± 8 μg AAE/mg extract). Ethyl acetate fraction inhibited (73.4 ± 0.3) % of linoleic acid peroxidation. Ethyl acetate and n-butanol fractions did not have any visible toxicity at 2000 mg/kg and presented excellent membrane stabilizing ability. The inhibition of xylene induced ear inflammation was (38 ± 4) % and (46 ± 1) % for RM-B and RM-EA, respectively. Conclusions: The high content of both phenolic compounds and triterpenoids combined with the remarkable antiinflammatory effect and antioxidant activity of ethyl acetate and n-butanol extracts from R. macrophyllus Desf. support the wide spread use of this traditional plant on some skin disorders (inflammatory skin disorders).Item 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 YolandaDue 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.Item Valorisation of the green waste parts from large-leaved buttercup (Ranunculus macrophyllus Desf.): phenolic profile and health promoting effects study(Waste and biomass valorization, 2020) Deghima, Amirouche; Righi, Nadjat; Rosales Conrado, Noelia; León González, María Eugenia De; Baali, Faiza; Gómez Mejía, Esther; Madrid Albarrán, María Yolanda; Bedjou, Fatiha; SpringerDue to the extensive use of Ranunculus macrophyllus Desf. roots for medicinal purposes, most of the leafy green parts are just wasted. The aim of this work is to valorize the leafy green parts and promote their application in different modern industries. Methods For this purpose, we studied the phenolic profile of R. macrophyllus Desf. (RM-B) using chromatographic and spectrophotometric methods and we tested the in-vitro antioxidant activity and the in-vivo effect of RM-B on plasma and liver antioxidant statuts. Results RM-B contained high amounts of polyphenols (675 mg GAE/100 g dry weigh dw) and flavonoids (105 mg QE/100 g dw). In-vitro, RM-B exhibited promising radical scavenging activity against 2,2′-azino-bis(3-éthylbenzothiazoline-6-sulphonique) (ABTS+·) (IC50: 247 µg/mL), hydrogen peroxide radicals (IC50: 626 µg/mL) and inhibited oxidative red blood cells hemolysis (IC50: 120 µg/mL), RM-B also showed strong reducing power (982 µM FeSO4/mg extract). In-vivo, RM-B improved the radical scavenging ability and reducing power of plasma and enhanced liver antioxidant status by increasing catalase and reduced glutathione levels and decreasing malondialdhyde levels without altering the key serum biochemical parameters reflecting liver and kidney functions. Polyphenols identified using capillary LC-DAD and LC–MS/MS analyses like hesperidin (131.2 mg/100 g dw), rutin (29.0 mg/100 g dw) and p-coumaric acid (5.8 mg/100 g dw), may be responsible for the health promoting effects of RM-B. Conclusion We may conclude that R. macrophyllus Desf. is a good source of beneficial polyphenols with strong antioxidant, anti-hemolytic and health-promoting effects, which promotes its use in pharmaceutical, medicinal and nutraceutical industries.Item In vivo quantification of volatile organoselenium compounds released by bacteria exposed to selenium with HS-SPME-GC-MS. Effect of selenite and selenium nanoparticles(Talanta, 2021) Moreno Martín, Gustavo; Sanz Landaluce, Jon; León González, María Eugenia De; Madrid Albarrán, María Yolanda; ElsevierQuantification of volatile organoselenium species released by Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), after their growth in the presence of 1 and 2 mg Se⋅L-1 as both selenite and chitosan modified selenium nanoparticles (Ch-SeNPs), was achieved by the application of a method based on headspace solid-phase microextraction (HS-SPME) and in-fiber internal standardization, combined with gas chromatography coupled to mass spectrometry (GC-MS). This method consisted of an initial extraction of the released volatile organoselenium compounds on the SPME fiber, followed by the extraction of internal standard (IS), deuterated dimethyl sulfide (d6-DMS), on the same fiber before its desorption at the injection port of GC-MS. The results showed that the biotransformation of selenite and Ch-SeNPs into volatile organoselenium compounds was dependent on both the type of bacterial species and the chemical form of selenium (Se) administered. In this sense, E. coli was able to biotransform both selenite and Ch-SeNPs into dimethylselenium (DMSe) and dimethyldiselenium (DMDSe) while S. aureus, biotransformed selenite into DMSe and DMDSe and, Ch-SeNPs only into DMDSe. Additionally, the formation of a volatile mixed sulfur/selenium compound, dimethyl selenenyl sulfide (DMSeS), from Se in nanoparticulated form has been detected for the first time.Item 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 CHEMISTRYThe 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.Item Valorisation of black mulberry and grape seeds: Chemical characterization and bioactive potential(Food Chemistry, 2021) Gómez Mejía, Esther; Lobo Roriz, Custódio ; Heleno, Sandrina ; Calhelha, Ricardo ; Dias, Maria Inês ; Pinela, José; Rosales Conrado, Noelia; León González, María Eugenia De; Ferreira, Isabel; Barros, LillianGrape (Vitis vinifera L. var. Albariño) and mulberry (Morus nigra L.) seeds pomace were characterized in terms of tocopherols, organic acids, phenolic compounds and bioactive properties. Higher contents of tocopherols (28 ± 1 mg/100 g fw) were obtained in mulberry, whilst grape seeds were richer in organic acids (79 ± 4 mg/100 g fw). The phenolic analysis of hydroethanolic extracts characterised grape seeds by catechin oligomers (36.0 ± 0.3 mg/g) and mulberry seeds by ellagic acid derivatives (3.14 ± 0.02 mg/g). Both exhibited high antimicrobial activity against multiresistant Staphylococcus aureus MIC = 5 mg/mL) and no cytotoxicity against carcinogenic and non-tumour primary liver (PLP) cells. Mulberry seeds revealed the strongest inhibition (p < 0.05) against thiobarbituric reactive substances (IC50 = 23 ± 2 µg/mL) and oxidative haemolysis (IC50 at 60 min = 46.0 ± 0.8 µg/mL). Both seed by-products could be exploited for the developing of antioxidant-rich ingredients with health benefits for industrial application.Item 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; ElsevierA 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.Item Neuroprotective activity of selenium nanoparticles against the effect of amino acid enantiomers in Alzheimer’s disease(Analytical and Bioanalytical Chemistry, 2022) Vicente Zurdo, David; Rodríguez-Blázquez, Sandra; Gómez Mejía, Esther; Rosales Conrado, Noelia; León González, María Eugenia De; Madrid Albarrán, María YolandaAlzheimer’s disease (AD), the most prevalent neurodegenerative disease, is characterized by extracellular accumulation of amyloid-beta protein (Aβ), which is believed to be the very starting event of AD neurodegeneration. In this work, D-Phe, D-Ala, and D-Glu amino acids, which are the non-occurring enantiomeric form in the human body, and also D-Asp and DL-SeMet, have proved to be amyloidogenic regarding Aβ42 aggregation in TEM studies. These amyloidogenic amino acid enantiomers also widened Aβ42 fibrils up to 437% regarding Aβ42 alone, suggesting that Aβ42 aggregation is enantiomerically dependent. To inhibit enantiomeric-induced amyloid aggregation, selenium nanoparticles stabilized with chitosan (Ch-SeNPs) were successfully synthesized and employed. Thus, Ch-SeNPs reduced and even completely inhibited Aβ42 aggregation produced in the presence of some amino acid enantiomers. In addition, through UV–Vis spectroscopy and fluorescence studies, it was deduced that Ch-SeNPs were able to interact differently with amino acids depending on their enantiomeric form. On the other hand, antioxidant properties of amino acid enantiomers were evaluated by DPPH and TBARS assays, with Tyr enantiomers being the only ones showing antioxidant effect. All spectroscopic data were statistically analysed through experimental design and response surface analysis, showing that the interaction between the Ch-SeNPs and the amino acids studied was enantioselective and allowing, in some cases, to establish the concentration ratios in which this interaction is maximum.Item The potential of plum seed residue: unraveling the effect of processing on phytochemical composition and bioactive properties(International Journal of Molecular Science, 2024) Rodríguez-Blázquez, Sandra; Pedrera-Cajas, Laura; Gómez Mejía, Esther; Vicente Zurdo, David; Rosales Conrado, Noelia; León González, María Eugenia De; Rodríguez Bencomo, Juan José; Miranda Carreño, RubénBioactive compounds extracted from plum seeds were identified and quantified, aiming to establish how the brandy manufacturing process affects the properties and possible cascade valorization of seed residues. Extraction with n-hexane using Soxhlet has provided oils rich in unsaturated fatty acids (92.24–92.51%), mainly oleic acid (72–75.56%), which is characterized by its heart-healthy properties. The fat extracts also contain tocopherols with antioxidant and anti inflammatory properties. All the ethanol–water extracts of the defatted seeds contain neochlorogenic acid (90–368 µg·g−1), chlorogenic acid (36.1–117 µg·g −1), and protocatechuate (31.8–100 µg·g−1) that have an impact on bioactive properties such as antimicrobial and antioxidant. Anti-amyloidogenic activity (25 mg·mL−1) was observed in the after both fermentation and distillation extract, which may be related to high levels of caffeic acid (64 ± 10 µg·g −1m). The principal component analysis showed that all plum seed oils could have potential applications in the food industry as edible oils or in the cosmetic industry as an active ingredient in anti-aging and anti-stain cosmetics, among others. Furthermore, defatted seeds, after both fermentation and distillation, showed the greatest applicability in the food and nutraceutical industry as a food supplement or as an additive in the design of active packaging.