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Molecules ; 26(10)2021 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-34069720


The phytochemical analysis of Vinca minor, V. herbacea, V. major, and V. major var. variegata leaf extracts showed species-dependent antioxidant, antibacterial, and cytotoxic effects correlated with the identified phytoconstituents. Vincamine was present in V. minor, V. major, and V. major var. variegata, while V. minor had the richest alkaloid content, followed by V. herbacea. V. major var. variegata was richest in flavonoids and the highest total phenolic content was found in V. herbacea which also had elevated levels of rutin. Consequently, V. herbacea had the highest antioxidant activity followed by V. major var. variegata. Whereas, the lowest one was of V. major. The V. minor extract showed the most efficient inhibitory effect against both Staphylococcusaureus and E. coli. On the other hand, V. herbacea had a good anti-bacterial potential only against S. aureus, which was most affected at morphological levels, as indicated by scanning electron microscopy. The Vinca extracts acted in a dose-depended manner against HaCaT keratinocytes and A375 melanoma cells and moreover, with effects on the ultrastructure, nitric oxide concentration, and lactate dehydrogenase release. Therefore, the Vinca species could be exploited further for the development of alternative treatments in bacterial infections or as anticancer adjuvants.

Antibacterianos/farmacologia , Antineoplásicos Fitogênicos/farmacologia , Antioxidantes/farmacologia , Extratos Vegetais/farmacologia , Folhas de Planta/química , Vinca/química , Linhagem Celular Tumoral , Cromatografia Líquida de Alta Pressão , Humanos , Testes de Sensibilidade Microbiana
Food Funct ; 11(6): 5293-5307, 2020 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-32458896


Quercetin, one of the most abundant flavonoids in plant-based foods, commonly occurs in nature in various glycosylated forms. There is still a less explored aspect regarding the cause of diversity of its glycosides, depending on the sugar moiety attached. This work focuses on four wide-spread quercetin glycosides-hyperoside, isoquercitrin, quercitrin and rutin-by testing the property-tuning capacity of different sugar moieties and thus explains and predicts some of their functions in plant-based foods. The electron paramagnetic spectra of the semiquinone anion radicals of these glycosides were interpreted in terms of hyperfine coupling constants and linewidths, highlighting a clear link between spin density trends, the identity of the bound sugar, and their reactivity corroborated with their modelled structures. Redox potential and lipophilicity were connected to a specific flavonoid-enzyme interaction and correlated with their prooxidant reactivity assessed by oxidation of ferrous hemoglobin. Hyperoside and isoquercitin-galactose and glucose glycosides-exhibit the highest prooxidant reactivity owing to their lowest redox potential and lipophilicity whereas rutin and quercitrin-rutinose and rhamnose glycosides-behave vice versa. The ability of the tested glycosides to undergo HAT or SET-type reactions has also been tested using five different analytical assays, including inhibition of cytochrome c-triggered liposome peroxidation. In most cases, rutin proved to be the most unreactive of the four tested glycosides considering either steric or redox reasons whereas the reactivity hierarchy of the other three glycosides were rather assay dependent.

Glicosídeos/química , Quercetina/análogos & derivados , Rutina/química , Antioxidantes/química , Espectroscopia de Ressonância de Spin Eletrônica , Elétrons , Sequestradores de Radicais Livres/química , Hidrogênio/química , Lipídeos/química , Oxidantes/química , Oxirredução , Quercetina/química , Rutina/farmacologia
Spectrochim Acta A Mol Biomol Spectrosc ; 233: 118158, 2020 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-32143172


Among others, amino acids can inhibit oxidative processes through multiple pathways including inactivation of reactive oxygen species, scavenging free radicals, chelation of pro-oxidative transition metals, as well as reduction of hydroperoxides. Moreover, they can be a major target for oxidants as a result of their abundance in biological systems. The purpose of the present study is to examine the radical scavenging, reducing power and chelating capacity of the free proteinogenic amino acids, using several analytical assays based on different mechanisms and monitored via molecular UV-vis absorption spectrophotometry. In most of the assays, the highest antioxidant activity is rendered by Cys and Trp, known for their involvement in physiological radical reactions, followed by Tyr, Asn and Arg. The least reactive amino acids with respect to both radical scavenging and reducing power principle were Ala, Met, Thr and Val. The hierarchy of the amino acids based on their antioxidant activity is shifting, depending on the analytical assay employed. Results from the multivariate exploratory techniques-hierarchical cluster analysis and principal component analysis-could point out the methods that are most similar and best connected to each other, thus classifying the investigated amino acids according to their activity. Considering the results of chemometric techniques, the antioxidant methods that best discriminate between amino acids are DPPH bleaching and SORS assays. Not only the comprehensive study of antioxidant activity of amino acids is novel in this study but also the application of the sum of ranking differences to compare and rank the various antioxidant capacity assays. The obtained results will support the development of amino acids based multifunctional formulations with important physiologically relevant implications for both humans and animals, with a possible future use in the food industry.

Aminoácidos/química , Quelantes/química , Sequestradores de Radicais Livres/química , Oxirredução , Espectrofotometria
Free Radic Biol Med ; 146: 189-197, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31705959


Superoxide radical is one of the main players when it comes to oxidative stress. Even if in itself is moderately reactive and can cause the degradation of very few biologically relevant macromolecules, it can dismutate to hydrogen peroxide followed by a possible conversion to hydroxyl radical. In order to protect the internal environment against reactive oxygen species, plants have evolved a line of defence made from secondary metabolites with versatile redox properties, such as flavonoids and phenolic acids. Their characteristics are highly modulated by pH, as they turn into prooxidant compounds as it increases. Reported here are the behaviour and clear patterns in reactivity towards superoxide anion radical of four classes of plant phenolics as a pH function. The reactivity towards superoxide radical in acidic conditions has been studied by use of oscillating Briggs-Rauscher reaction with a new spectroelectrochemical experimental setup, by recording the absorbance in high quality for the first time. Some mechanistic intricacies have also been explored with regard to this method. Reactivity modulation at neutral and slightly basic pH has been assayed by superoxide radical scavenging ability using nitroblue tetrazolium as a substrate. For stronger alkaline pHs studies, Electron Paramagnetic Resonance was exploited. Hydroxybenzoic acids tend to be the least reactive species at all tested pH values. Hydroxycinnamic acids have their activity towards superoxide radical decreased as the pH increases, whereas flavonoids act vice versa.

Polifenóis , Superóxidos , Sequestradores de Radicais Livres , Radical Hidroxila , Fenóis , Espécies Reativas de Oxigênio
BMC Complement Altern Med ; 19(1): 289, 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31664997


BACKGROUND: Natural extracts with beneficial biological activities are nowadays of high interest, in various treatment or prophylaxis. Hypericum capitatum has been known for its curative effects for centuries and its extracts have become of interest due to their distinct activity among other Hypericaceae members. In this study, further light is aimed to be shed on the secondary-metabolites composition of H. capitatum extracts, using chromatographic techniques and Electron paramagnetic resonance profiles in alkaline medium. Considering that no previous works explored the anti-inflammatory activity of H. capitatum, here, an in vivo study is also designed in order to evaluate this property by assessing the impact of one of H. capitatum extracts in ameliorating turpentine oil-induced inflammation on rats and to quantify their blood antioxidants level. METHODS: Chromatographic techniques and Electron paramagnetic resonance spectroscopy were used in order to describe the chemical profile in different parts of the plant. The in vivo study on turpentine-oil induced inflammation in rats included three doses of H. capitatum extract expressed in rutin concentration. Oxidative stress was measured using total oxidative status, total antioxidant capacity, oxidative stress index, 3-nitrotyrosine, nitric oxide, malondialdehyde, superoxide dismutase, catalase and the inflammatory response was evaluated by performing a complete blood cells count and C reactive protein. RESULTS: The extract was remarkably rich in rutin; however, other polyphenolic-like minor components appeared important in explaining the observed biological properties. The tested extract prevents the increase of inflammation-induced white blood cell count, number of neutrophils, and serum nitric oxide, and did so in a dose-dependent manner, similarly to the positive control-diclofenac. In addition, the same extract appeared to be a good alternative to diclofenac to restore total oxidative status, thiobarbituric active reactive species, total proteins and C reactive proteins. Moreover, antioxidant enzymes such as catalase, superoxide dismutase and total serum thiol concentration were significantly increased by the tested extract. CONCLUSIONS: Due to its powerful reservoir rich in rutin, H. capitatum extract depicted its in vivo antioxidant and anti-inflammatory effects indicating it to be a good alternative to conventional drugs for oxidative stress protection.

Anti-Inflamatórios/administração & dosagem , Hypericum/química , Inflamação/tratamento farmacológico , Extratos Vegetais/administração & dosagem , Rutina/administração & dosagem , Animais , Anti-Inflamatórios/química , Catalase/metabolismo , Feminino , Humanos , Inflamação/induzido quimicamente , Inflamação/metabolismo , Masculino , Malondialdeído/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/química , Ratos , Ratos Wistar , Rutina/análise , Superóxido Dismutase/metabolismo , Terebintina/efeitos adversos
PLoS One ; 13(7): e0200022, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29969484


Galium verum is a well-known medicinal plant which is used in various pathologies. G. verum extracts are characterized here using chromatography, where among the rich pool of phenolic acids of flavonoids two known anti-stress modulators, chlorogenic acid and rutin are identified in high quantities. Additionally, the extracts are characterized using a series of in vitro assays (EPR, DPPH, TPC and TEAC). Considering the chemical findings, the potential beneficial effects of the G. verum extract are explored here in a living organism exposed to stress induced oxidative damages. Thus, the biochemical-modulatory and antioxidant roles of two doses of G. verum extract are examined in animals exposed to acute restraint and dark stress (S). The animals were divided in groups [control, S, SG1 (exposed to 25 mg G. verum extract), SG2 (50 mg extract)]. Increased levels of lipid peroxidation (TBARS from 4.43 to 8.06 nmol/mL), corticosterone from 0.43 to 1.96 µg/dL and epinephrine from 44.43 to 126.7 µg/mL, as well as decreased antioxidant enzymes activities (SOD/CAT) were observed in the S group. The G. verum extract afforded a near-normal equilibrium within the biochemical parameters of animals exposed to RS, by reducing oxidative damage (TBARS at a 3.73 nmol/mL; CS at 0.90 µg/dL; EP at 63.72 µg/mL) and by restoring the antioxidant balance.

Antioxidantes/farmacologia , Escuridão/efeitos adversos , Galium/química , Extratos Vegetais/farmacologia , Espécies Reativas de Oxigênio/farmacologia , Restrição Física/psicologia , Estresse Psicológico/metabolismo , Alanina Transaminase/metabolismo , Animais , Aspartato Aminotransferases/metabolismo , Colesterol/metabolismo , Corticosterona/sangue , Relação Dose-Resposta a Droga , Epinefrina/sangue , Feminino , Peroxidação de Lipídeos/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Polifenóis/farmacologia , Ratos , Ratos Wistar , Estresse Psicológico/sangue , Estresse Psicológico/enzimologia , Estresse Psicológico/etiologia