Suchergebnisse

Graphene oxide (GO) is used to enhance the photocatalytic activity of ZnO nanoparticles for the degradation of vanillic acid (VA) under simulated solar light and visible-LED (λ > 430 nm). ZnO-GO composites are prepared by a mixing and sonication process with different GO loadings (i.e., from 1.8 to 6.5 wt.%). The materials are extensively characterized by thermogravimetric analysis (TGA), physisorption of N2 , X-ray diffraction (XRD), infrared spectroscopy (FTIR), scanning electron microscopy (SEM), point of zero charge (pHPZC), and UV-Vis diffuse reflectance spectroscopy (DRUV). The presence of GO increases the photocatalytic activity of all the prepared composites in comparison with the pristine ZnO. The highest photocatalytic activity is found for the composite containing 5.5 wt.% of GO (i.e., ZnO-GO5.5), reaching a VA degradation of 99% and 35% under solar light and visible-LED, respectively. Higher TOC removal/VA degradation ratios are obtained from the experiments carried out under visible-LED, indicating a more effective process for the mineralization of VA than those observed under simulated solar light. The influence of hole, radical, and non-radical scavengers is studied in order to assess the occurrence of the reactive oxygen species (ROS) involved in the photocatalytic mechanism. The study of the photo-stability during three reuse experiments indicates that the presence of GO in the composites reduces the photocorrosion in comparison with pristine ZnO. ; Spanish Project ref. RTI 2018-099224-B100 funded by ERDF/Ministry of Science, Innovation and Universities ; State Research Agency and the Nano4Fresh project (ref. PCI2020-112045), as part of the PRIMA Programme supported by the European Union

AbstractCharacterizing uranium (U) mine water is necessary to understand and design an effective bioremediation strategy. In this study, water samples from two former U-mines in East Germany were analysed. The U and sulphate (SO42−) concentrations of Schlema-Alberoda mine water (U: 1 mg/L; SO42−: 335 mg/L) were 2 and 3 order of magnitude higher than those of the Pöhla sample (U: 0.01 mg/L; SO42−: 0.5 mg/L). U and SO42− seemed to influence the microbial diversity of the two water samples. Microbial diversity analysis identified U(VI)-reducing bacteria (e.g. Desulfurivibrio) and wood-degrading fungi (e.g. Cadophora) providing as electron donors for the growth of U-reducers. U-bioreduction experiments were performed to screen electron donors (glycerol, vanillic acid, and gluconic acid) for Schlema-Alberoda U-mine water bioremediation purpose. Thermodynamic speciation calculations show that under experimental conditions, U(VI) is not coordinated to the amended electron donors. Glycerol was the best-studied electron donor as it effectively removed 99% of soluble U, 95% of Fe, and 58% of SO42− from the mine water, probably by biostimulation of indigenous microbes. Vanillic acid removed 90% of U, and no U removal occurred using gluconic acid.

Oat (Avena sativa L.) has rich phenolic contents with nutritional and therapeutic health benefits. The objective of the present work was to perform a cell cytotoxicity assay of three South Asian oat cultivars to determine their suppressive effect on intracellular reactive oxygen species (ROS). Oat cultivars were firstly examined for total phenolic content, 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity, and phenolic acid profiling through HPLC. Total phenolic contents of oat cultivars ranged from 167.57 to 198.41 mg GAE/100 g, and DPPH scavenging activity was IC50 = 18.81 to 13.18 mg/mL. Oat cultivars displayed average content of phenolic acids such as vanillic acid (0.33 µg/g), syringic acid (6.70 µg/g), caffeic acid (4.16 µg/g), ferulic acid (2.06 µg/g), p-coumaric acid (20.22 µg/g), with the highest being gallic acid (74.32 µg/g). Cell cytotoxicity assay of oat polyphenolic extracts revealed that 10 and 15 µg/mL concentrations had non-significant differences when compared with their respective control treatments. Oat extracts suppressed ROS in Caco-2-cells, with or without hydrogen peroxide stimulation from 65.20 - 86.13%, and 56.36 - 79.56% with 10 and 15 µg/mL concentrations, respectively. In conclusion, oat is a rich source of polyphenols which have strong antioxidant behaviour to suppress the ROS activity.

AbstractThis work is focused on the effect of lethal and sub-lethal copper (Cu) concentrations on the free amino acid and polyphenol production by the marine diatom Phaeodactylum tricornutum (P. tricornutum) after 12, 18, and 21 days of exposure. The concentrations of 10 amino acids (arginine, aspartic acid, glutamic acid, histidine, lysine, methionine, proline, valine, isoleucine, and phenylalanine) and 10 polyphenols (gallic acid, protocatechuic acid, p-coumaric acid, ferulic acid, catechin, vanillic acid, epicatechin syringic acid, rutin, and gentisic acid) were measured by RP-HPLC. Under lethal doses of Cu, free amino acids reached levels significantly higher than those in the control cells (up to 21.9 times higher), where histidine and methionine showed the highest increases (up to 37.4 and 65.8 times higher, respectively). The total phenolic content also increased up to 11.3 and 5.59 times higher compared to the reference cells, showing gallic acid the highest increase (45.8 times greater). The antioxidant activities of cells exposed to Cu were also enhanced with increasing doses of Cu(II). They were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging ability (RSA), cupric ion reducing antioxidant capacity (CUPRAC), and ferric reducing antioxidant power (FRAP) assays. Malonaldehyde (MDA) exhibited the same tendency: cells grown at the highest lethal Cu concentration yielded the highest MDA level. These findings reflect the involvement of amino acids and polyphenols in protective mechanisms to overcome the toxicity of copper in marine microalgae.
Graphical Abstract

In this thesis, three species of African plants belonging to three different families were investigated from a phytochemical and pharmacological point standpoint. These were Anisophyllea dichostyla (Rhizophoraceae) and Annona caneata (Annonaceae) encountered in the democratic Republic of Congo. The isolation of all the compounds was conducted using different chromatographic techniques.The final elucidation of the structures was by spectroscopic means. chemical methods (hydrolysis,d erivatization) were also used to confirm some of the structures. In the essential oil of A, cuneata stem barks, 25 compounds were identified and characterized by their retention times, their masses and their Kovats Index. Z-sabinene is the major component. In addition 13 polyphenolic compounds, mainly simple phenols were identified namely (p-hydroxy benzoic acid, dihydroxybenzoic acid, ferulic acid, vanillic acid along with syringialdehyde, vanillin and vanillic alcohol). The physicochemical index such as the peroxides, p-anisidine and conjugated dienes values were compared according to the time of storage, to measure the rancidity of the argan oils. A study by NMR made it possible to locate the triglyceridic regiospecificity of the profile of oil. Use of HPLC, GC-MS and LC/MS allowed the identification of additional compounds for the first time in the oil of A, spinosa. The phenolic antioxidants ferulic, vanillic, syringicacids along with tyrosol were detected. The major phytosterol detected in argan oil was squalene with lower amounts of schottenol and spinasterol. However the major tocopherol was found to be gamma-tocopherol and not alpha-tocopherol. The unsaponifiable fractions of the oils showed antioxidant activity at 100mg/l. 26 compounds were detected and identified in A. dichostyla, comprising catechin and ellagic acid derivatives respectively. he total methanolic extract showed a very remarkable antioxidant inhibitor of xanthine oxidase in vitro model. A triterpene (bryonolic acid was also isolated and identified in this ...

In this thesis, three species of African plants belonging to three different families were investigated from a phytochemical and pharmacological point standpoint. These were Anisophyllea dichostyla (Rhizophoraceae) and Annona caneata (Annonaceae) encountered in the democratic Republic of Congo. The isolation of all the compounds was conducted using different chromatographic techniques.The final elucidation of the structures was by spectroscopic means. chemical methods (hydrolysis,d erivatization) were also used to confirm some of the structures. In the essential oil of A, cuneata stem barks, 25 compounds were identified and characterized by their retention times, their masses and their Kovats Index. Z-sabinene is the major component. In addition 13 polyphenolic compounds, mainly simple phenols were identified namely (p-hydroxy benzoic acid, dihydroxybenzoic acid, ferulic acid, vanillic acid along with syringialdehyde, vanillin and vanillic alcohol). The physicochemical index such as the peroxides, p-anisidine and conjugated dienes values were compared according to the time of storage, to measure the rancidity of the argan oils. A study by NMR made it possible to locate the triglyceridic regiospecificity of the profile of oil. Use of HPLC, GC-MS and LC/MS allowed the identification of additional compounds for the first time in the oil of A, spinosa. The phenolic antioxidants ferulic, vanillic, syringicacids along with tyrosol were detected. The major phytosterol detected in argan oil was squalene with lower amounts of schottenol and spinasterol. However the major tocopherol was found to be gamma-tocopherol and not alpha-tocopherol. The unsaponifiable fractions of the oils showed antioxidant activity at 100mg/l. 26 compounds were detected and identified in A. dichostyla, comprising catechin and ellagic acid derivatives respectively. he total methanolic extract showed a very remarkable antioxidant inhibitor of xanthine oxidase in vitro model. A triterpene (bryonolic acid was also isolated and identified in this ...

Modern people have embraced plants as a source of useful bioactive compounds. As such, plants with medicinal properties have become essential components in human life. The purpose of this study was to investigate the phytochemical profile of the extract of Dioscorea steriscus tubers obtained from Zimbabwe. Phytochemicals were extracted from tubers of D. steriscus using aqueous acetone. UV-Visible Spectrophotometry, Fourier transform infrared (FTIR) spectrometry and highperformance liquid chromatography (HPLC) techniques were used to determine the phytochemical profile of the tuber extract. The yield of phytochemicals extracted from D. steriscus tubers was found to be 6.38 %. The presence of bioactive compounds possessing phenyl, organic hydroxyl, amine, carboxyl, carbonyl, acyl, alkyl and aromatic functional groups was confirmed using UVVisible and FTIR analysis. The presence of substantial amounts of vanillic acid and kaempferol in D. steriscus tubers was confirmed using HPLC analysis. In support of the ethnobotanical values of Dioscorea species, the study confirmed the presence of potent phytochemicals in the extract of D. steriscus tubers obtained from Zimbabwe.

Truffles are very precious and expensive mushrooms owing to their distinctive aroma and great flavor. The present study was carried out to survey the nutritional value of Tuber nitidum, a wild edible mushroom belonging to Tuber genus. It was analyzed for fatty acid content, phenolic and volatile compounds and amino acid profile. The chemical composition of the studied mushroom species showed that this wild edible fungus is one of a rich phenolic and amino acid source. The characteristic mushroom odor compounds, 1-octen-3-ol (14.81%) and 1-octen-3-one (11.19%), have been also detected. However, it has been reported that p-hydroxy benzoic acid, gentisic acid, vanillic acid were found in ethyl acetate extract as phenolic ingredient. In the lipidic extract, it has been determined that 76.94% linoleic acid (C18:2n6c), 12.38% palmitic acid (C16:0), 6.38% oleic acid (C18:1n9c), 2.54% stearic acid (C18:0). The wild edible mushroom, Tuber nitidum, a wild edible mushroom, may be of value and importance in the food and pharmaceutical industry as a natural healthy product source. ; Trüfler, karakteristik aromaları ve leziz tadı nedeniyle çok değerli ve pahalı mantarlardır. Bu çalışma Tuber cinsine ait yabani yenilebilir bir mantar olan Tuber nitidum'un besin değerini araştırmak için yürütülmüştür. Yağ asidi içeriği, fenolik ve uçucu bileşikleri ve amino asit profili analiz edildi. Çalışılan mantarın kimyasal bileşimi, bu yabani yenilebilir mantarın zengin fenolik ve amino asit kaynağı olduğunu gösterdi. Karakteristik mantar koku bileşikleri, 1-okten-3-ol (.81) ve 1-okten-3-on (.19) da tespit edilmiştir. Bununla birlikte, fenolik bileşen olarak etil asetat ekstraktında p-hidroksi benzoik asit, gentisik asit, vanilik asit bulunmuştur. Lipid özütünde, .94 linoleik asit (C18:2n6c), .38 palmitik asit (C16:0), %6.38 oleik asit (C18:1n9c), %2.54 stearik asit (C18:0) olduğu tespit edilmiştir. Yabani yenilebilir mantar olan Tuber nitidum, doğal sağlıklı bir ürün kaynağı olarak gıda ve ilaç sektöründe bir değer olarak önemlidir.

10 Pags., 5 Tabls., 3 Figs. ; Phenolic compounds have a high importance in olive oil because of their effect on shelf life and sensory properties. This study reports on the HPLC profiles of the phenolic compounds of virgin olive oils obtained from Arbequina olives from the harvesting in a super-intensive orchard under a linear irrigation system. In addition, phenolic content, carotenoid and chlorophyllic pigments, and oxidative stability were analyzed. Total phenol content and 3,4-DHPEA-EDA increased up to a maximum throughout the ripening process. The simple phenols tyrosol and hydroxytyrosol acetate increased throughout the ripening process, however, there was not found a clear trend in hydroxytyrosol content. Minor constituents such as vanillic acid and p-coumaric acid increased up to a maximum and then decreased, since vanillin decreased progressively throughout the time of harvest. 3,4-DHPEA-EDA and lignans were present in considerable amounts in the studied samples, while oleuropein aglycone was present in a low amount. Total phenol content and oil stability followed the same trend throughout the study, so a very good correlation was established between them. Total secoiridoids and, specifically, 3,4-DHPEA-EDA seemed to be responsible for oil stability. The pigment content decreased during ripening, and not a positive correlation was found between pigments and oil stability. ; This work was made possible by a predoctoral fellowship awarded to Marta Benito and the PI 170/09 project given by the Aragon government. ; Peer reviewed

Background: Ethno-medicinal survey of herbal recipes used in managing sickle cell disease in Ile-Ife, Osun-State, Nigeria was carried out and two recipes selected for antisickling studies. Materials and Methods: Information was obtained using semi-structured questionnaires and open interview from respondents consisting of herb sellers, traditional medical practitioners, artisans and tradersin two local government areas of Ife. Two recipes from the survey were selected for antisickling studies. Aqueous extract of each recipe was obtained by boiling the constituents in water for 1 h while the hydro ethanolic extracts were obtained by maceration in 70% ethanol for 72 h. Inhibitory and reversal antisickling properties were assessed using sodium metabisulphite as deoxygenating agent, vanillic acid (inhibitory agent), para-hydroxybenzoic (reversal agent) acid as positive controls while phosphate buffered saline was employed as negative control. Results: Fifty four recipes comprising forty six plants were obtained from the ethno-medicinal survey. The respondents comprised of 44% men and 56% women. The most frequently and commonly used plants belong to family Fabaceae. The inhibitory and reversal activities of the aqueous extract of recipe 1 (81.37± 1.09%, 88.56 ±1.38% respectively) were significantly (p < 0.05) higher than recipe 2 (78.51 ± 0.78% inhibition and 79.8 ± 2.16% reversal) at same concentration. The hydro-alcoholic extracts of recipes 1 and 2 gave highest inhibitory activities at 0.5 mg/mL (69.25 ±1.30% and 68.28 ±2.78% respectively). Conclusion: This study documented the medicinal plants and recipes used in Ile-Ife for managing sickle cell disease, and validated the ethno-medicinal claim of two recipes.