Suchergebnisse

1. The Mechanism of Antioxidant Action in vitro -- 2. Detection, Estimation and Evaluation of Antioxidants in Food Systems -- 3. Chemistry and Implications of Degradation of Phenolic Antioxidants -- 4. Natural Antioxidants Exploited Commercially -- 5. Natural Antioxidants not Exploited Commercially -- 6. Biological Effects of Food Antioxidants -- 7. Toxicological Aspects of Antioxidants Used as Food Additives.

XXIII Encontro Nacional da Sociedade Portuguesa de Química. Aveiro, 12-14 de Junho 2013. ; Artemisia gorgonum (Asteraceae) known as "losna or lorna" is used in Cape Verde in traditional medicine to treat inflammation, fever and gastroenteritis. The antioxidant activity of methanol, 70% ethanol, chloroform-methanol and chloroform extracts from A. gorgonum leaves was evaluated using the DPPH assay and the results presented. ; Thanks are due to the University of Aveiro, Portuguese Foundation for Science and Technology (FCT), European Union, QREN, FEDER and COMPETE for funding the QOPNA research unit (project PEst-C/QUI/UI0062/2011), the CICECO (PEst-C/CTM/LA0011/2011-FCT) and CESAM.

28 Pags.- 2 Figs. the definitive version is available at: http://onlinelibrary.wiley.com/journal/10.1111/%28ISSN%291399-3054 ; Reactive oxygen species are a ubiquitous danger for aerobic organisms. This risk is especially elevated in legume root nodules due to the strongly reducing conditions, the high rates of respiration, the tendency of leghemoglobin to autoxidize, the abundance of nonprotein Fe and the presence of several redox proteins that leak electrons to O(2). Consequently, nodules are particularly rich in both quantity and diversity of antioxidant defenses. These include enzymes such as superoxide dismutase (EC 1.15.1.1) and ascorbate peroxidase (EC 1.11.1.11) and metabolites such as ascorbate and thiol tripeptides. Nodule antioxidants have been the subject of intensive molecular, biochemical and functional studies that are reviewed here. The emerging theme is that antioxidants are especially critical for the protection and optimal functioning of N(2) fixation. We hypothesize that this protection occurs at least at two levels: the O(2) diffusion barrier in the nodule parenchyma (inner cortex) and the infected cells in the central zone. ; Work in the laboratory of M. B. was supported by grants PB98-0522, 2FD97-1101 and HB98-163 from Dirección General de Enseñanza Superior e Investigación Científica, Comisión Interministerial de Ciencia y Tecnología, and the European Union. Work in the laboratory of D. A. D. was supported by National Science Foundation grants DCB-8903254, IBN-9206453 and IBN-9507491. ; Peer Reviewed

Abstract
The aim of the study was to characterise antioxidative properties and antiradical activity of the herbal tea collection in Latvia. High-pressure liquid chromatography and spectrophotometry methods were used to characterise antioxidant properties of herbal tea. Antiradical activity was determined spectrophotometrically. The antiradical scavenging activity was measured by the DPPH (2,2-diphenyl-1-picrylhydrazyl) reaction. The herbal tea antiradical scavenging activity was estimated as the broken down quantity of DPPH on 100 grams of the herbal tea. Individual polyphenols in the herbal tea were identified and determined by liquid chromatography. Antiradical scavenging activity of the herbal tea was found to be 104 mol 100 g-1 tea. The following polyphenols were identified chromatographically in herbal tea: gallic, caffeic, chlorogenic, ferulic acids, rutin, catechin, vanillin, and epicatechin. Altogether 12 different varieties of herbal tea samples were analyzed. The results showed that different types of herbal tea substantially differed in composition. Polyphenol content of herbal teas was in the range of 1 mg in 100 g of tea up to 8 g per 100 g of tea. In the case of virus-related disease, infections and weakness of the organism, it is recommended to use tea with high content of rutin, as in Verbascum thapsiforme Schr., Alchemilla vulgaris L., Comarum palustre L. herbal tea.

Sulfur mustard (SM) is a chemical weapon that targets the skin, eyes, and lung. It was first employed during World War I and it remains a significant military and civilian threat. As a bifunctional alkylating agent, SM reacts with a variety of macromolecules in target tissues including nucleic acids, proteins and lipids, as well as small molecular weight metabolites such as glutathione. By alkylating subcellular components, SM disrupts metabolism, a process that can lead to oxidative stress. Evidence for oxidative stress in tissues exposed to SM or its analogs include increased formation of reactive oxygen species, the presence of lipid peroxidation products and oxidized proteins, and increases in antioxidant enzymes such as superoxide dismutase, catalase, and glutathione-S-transferase. Inhibition of antioxidant enzymes including thioredoxin reductase by SM can also disrupt cellular redox homeostasis. Consistent with these findings, SM-induced toxicity has been shown to be reduced by antioxidants in both in vitro and in vivo models. These data indicate that drugs that target oxidative stress pathways may represent important candidates for reducing SM-induced tissue injury.

The genus Camellia presents a wide geographic distribution in which three species can be highlighted: Camellia japonica for ornamental purposes, Camellia oleifera for essential oil production, and Camellia sinensis for tea production. Among them, C. japonica is characterized by its associated high socioeconomic impact in Galicia (NW Spain) due to its abundance in gardens, since, to date, its use continues to be almost exclusively ornamental. However, different chemical characterizations carried out on Camellia genus have indicated a similar composition among different species, so it would be expected that C. japonica could be used for additional purposes [1]. These applications will be determined by the chemical composition of the part used, which in turn will be influenced by the variety of camellia and environmental factors (growing area, climate, soil). One of the parts of greatest interest are the flowers since it has been shown that the petals of C. japonica have a high content of phenolic compounds that make them potential sources of bioactive compounds for medicinal and cosmetic use [2]. In this work, a standard extraction (maceration) was carried out using a methanol: water mixture (60:40) as solvent to evaluate the bioactivity of the flowers of different varieties of C. japonica. Among the 8 varieties analyzed, two of them (Elegans variegated and Grandiflora Superba) were characterized by having a high antioxidant capacity, as observed in terms of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of 136.5 and 86.8 μg/mL respectively. Overall, it can be concluded that camellias are a potential source of antioxidants with application in food and nutraceutical industries. ; The research leading to these results was supported by MICINN supporting the Ramón y Cajal grant for M.A. Prieto (RYC-2017-22891) and Juan de la Cierva Formation grant for T. Oludemi (FJC2019-042549-I); by Xunta de Galicia for supporting the program EXCELENCIA-ED431F 2020/12 and the pre-doctoral grant A.G. Pereira (ED481A-2019/0228). Authors are grateful to Ibero-American Program on Science and Technology (CYTED—AQUA-CIBUS, P317RT0003), to the Bio Based Industries Joint Undertaking (JU) under grant agreement No 888003 UP4HEALTH Project (H2020-BBI-JTI-2019) that supports the work of P. Garcia-Perez. The JU receives support from the European Union's Horizon 2020 research and innovation program and the Bio Based Industries Consortium. The project SYSTEMIC Knowledge hub on Nutrition and Food Security, has received funding from national research funding parties in Belgium (FWO), France (INRA), Germany (BLE), Italy (MIPAAF), Latvia (IZM), Norway (RCN), Portugal (FCT), and Spain (AEI) in a joint action of JPI HDHL, JPI-OCEANS and FACCE-JPI launched in 2019 under the ERA-NET ERA-HDHL (n° 696295). ; info:eu-repo/semantics/publishedVersion