91 research outputs found
Contribuições da história da matemática para a construção dos saberes do professor de matemática
Evaluation of reducing power and radical scavenging activities of water and ethanol extracts from sumac (Rhus coriaria L.)
The purpose of this study was to determine the reducing power, metal chelating, and radical scavenging capabilities of water and ethanol extracts of sumac (Rhus coriaria L.), comparatively. The water and ethanol extracts of sumac were evaluated for their radical scavenging activities by means of the DPPH and DMPD assays. Water extract of sumac (R. coriaria L.) scavenged radicals effectively with EC50 values of 36.4?g/ml for DPPH free radical and 44.7?g/ml for DMPD cation radical. Similarly, the total reducing power of water extract was found higher than ethanol extract in both potassium ferricyanide reduction (FRAP) and cupric ions reduction capacity methods (CUPRAC). 2,2'-Bipyridine was used to determine the metal chelating activity and the result of water extract was found higher than ethanol extract. Total phenolic and total flavonoid contents of both extracts were studied as well. The values of water extract were found to be higher than that of ethanol extract. The present study found that water extracts of sumac (R. coriaria L.) have effective antioxidant and radical scavenging activities as compared to ethanol extracts. © 2010 Elsevier Ltd
UHPLC-MS/MS phenolic profiling and in vitro antioxidant activities of inula graveolens (L.) Desf
PubMed ID: 28697630Inula graveolens (L.) Desf. is an annual aromatic herb which has various uses on alternative medicine in many region of the world. In this study, antioxidant activities of ethanol and water extracts of the plant leaves were determined by in vitro DPPH method and phenolic composition of the plant sample was determined by LC-MS/MS analysis. The results showed that chlorogenic acid, quinic acid, hyperoside, protocatechuic acid and quercetin were the major phenolic compounds among the 27 standard compounds. The significant antioxidant capacity of the plant might be related with the high abundance of phenolic compounds. © 2017 Informa UK Limited, trading as Taylor & Francis Group
Polyphenol contents and in vitro antioxidant activities of lyophilised aqueous extract of kiwifruit (Actinidia deliciosa)
The aim of this study was to determine the antioxidant potency and total phenolic and flavonoid contents of kiwifruit (Actinidia deliciosa) in vitro by analysing the radical scavenging activity of lyophilised water extract from kiwifruit (LEK) for 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picryl-hydrazyl (DPPH), N,N-dimethyl-p-phenylenediamine (DMPD), and superoxide anion radical (O2-) as well as the total reducing power by FRAP and CUPRAC assays and the metal chelating activities. LEK showed efficient radical scavenging activity with DPPH, ABTS, DMPD, and O2- radicals; ferric (Fe3+) and cupric (Cu2+) ion reducing power and metal chelating activities. Moreover, the amounts of phenolic compounds, such as caffeic acid, ferulic acid, syringic acid, ellagic acid, catechol, pyrogallol, p-hydroxy benzoic acid, vanillin, p-coumaric acid, gallic acid, quercetin, ?-tocopherol and ascorbic acid, in LEK were quantified by LC-MS-MS. The results show that pyrogallol (2070.0mg/kg LEK) is the main phenolic compound responsible for the antioxidant and radical scavenging activities of LEK. Finally, total phenolic and flavonoid contents were determined as gallic acid (GAE) and quercetin equivalents (QE). The GAE and QE values in LEK were 16.67±2.83?g GAE/mg and 12.95±0.52?g QE/mg, respectively. The results suggest that consumption of kiwifruit (A. deliciosa) can be beneficial effects due to its antioxidant properties. © 2011 Elsevier Ltd.BAP-2008/75The authors thank to Dr. Yusuf Kaya, Atatürk University, Sciences Faculty, Department of Biology for identification of kiwifruit ( A. deliciosa ) that we used in the studies. Also, the authors would like to express their gratitude to the Research Fund of the Atatürk University for the funding of project ( BAP-2008/75 )
False profile radiography for the evaluation of Legg-Calvé-Perthes disease.
False profile radiography (FPR), as proposed by Lequesne and de Sèze, depicts the pathology on the anterolateral acetabular wall and femoral head. A study was conducted to find out the differences between normal anteroposterior radiography and FPR. Twenty-seven patients with Legg-Calvé-Perthes disease who had not been operated on previously and 50 recruits without any pathology were studied for the acetabulum-head index of Heyman-Herndon (HHI) and center-edge angles (CEs) in antero-posterior radiographs and VCA angles in FPR. The VCA angle is most useful to detect anterolateral coverage of the femoral head in lateral pillar C hips. FPR is an easy, reliable and cheap technique to evaluate the anterolateral parts of the femoral head, and the acetabulum
Evaluation of antioxidant capacity of endemic plant Marrubium astracanicum subsp. macrodon: Identification of its phenolic contents by using HPLC-MS/MS
PubMed: 29842794Antioxidant properties of Marrubium astracanicum subsp. macrodon solvent extracts were measured by both cupric ion reducing antioxidant capacity (CUPRAC) and ferric reducing antioxidant power (FRAP) methods. According to the results, ethanol extract of the plant has high potential of reducing antioxidant activity on CUPRAC method. However, water extract of the plant has lower antioxidant potential. Furthermore, both water and ethanol extracts showed lower reducing antioxidant activity compare to standards on FRAP method. Moreover, the composition and content of plant leaves were detected by UHPLC-ESI-MS/MS. High concentrations of quinic acid, p-coumaric acid and malic acid were determined. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group
UHPLC-ESI-MS/MS analyses for quantification of phenolic compounds of Nepeta nuda subsp. Lydiae
Phenolic compounds of Nepeta nuda subsp. Lydiae leaves were identified by UHPLC-ESI-MS/MS. To the best of our knowledge, phenolic compounds in N. nuda subsp. Lydiae are reported for the first time. Chlorogenic acid, rosmarinic acid and quinic acid, were found to be the most abundant compound in the methanol extract of N. nuda subsp. Lydiae, among the twenty-seven compounds studied by LC-MS/MS. Also, smaller amounts of kaempferol, p-coumaric acid, tr-caffeic acid, apigenin, luteolin and rhamnetin were identified, quantitatively. In conclusion, leaves of N. nuda subsp. Lydiae have high potential of phenolic contents that mainly attributed with biological activities. © 2016 Abdulmelik Aras et al
Purification and characterization of peroxidase from sweet gourd (Cucurbita moschata Lam. Poiret)
Peroxidase (EC 1.11.1.7; donor: hydrogen peroxide oxidoreductase) is an oxidoreductase enzyme found in many fruits and vegetables. This enzyme was purified from sweet gourd (Cucurbita moschata Lam. Poiret) by ammonium sulphate precipitation and CM-Sephadex ion-exchange chromatography. Furthermore, optimum pH, optimum temperature, optimum ionic strength, stable pH, and stable temperature conditions were determined as 7.2, 50°C, 0.4 M, 8.0, and 40°lC, respectively. The molecular weight (MW) of the enzyme was estimated to be 85 kDa by SDS-PAGE method. The values of Km and Vmax were calculated from the Lineweaver-Burk graph for guaiacol/H2O2 substrate patterns. © 2012 Copyright Taylor and Francis Group, LLC
Spectroscopic, Thermal and Antioxidant Properties of Novel Mixed Ligand-Metal Complexes Obtained from Saccharinate Complexes and Azo Dye Ligand (Mnppa)
The novel mixed ligand-metal complexes with a general formula [M(Sac)2(H2O)2L2]-nH2O] [M = Mn(II), Co(N), Ni(II), Cu(II) and Cd(N), L = 5-Methly-4-(4-nitrophenylazo)-2H-pyrazole-3-ylamine (mnppa)] have been synthesized and characterized by elemental analyses, IR, UV-VIS, magnetic susceptibility mass spectra and thermogravimetry-differential thermal analysis (TGA-DTA). Each metal (II) ion is octahedral coordinated by two sac, two mnppa and two aqua ligands. The antioxidant properties of mixed ligand-metal complexes were determined by different in vitro methods such as ABTS, DPPH, FRAP and CUPRAC assays. The results of metal complexes were compared with standard antioxidant compounds. © 2016 Nevin Turan etai
Exciton absorption in quantum-well wires under the electric field
The binding energy of excitons, and interband optical absorption in quantum-well wires of GaAs surrounded by Ga1-xAlxAs is calculated in effective-mass approximation, using a variational approach. Results obtained show that the exciton binding energies, and optical absorption depend on the sizes of the wire and strength of the electric field. The additional confinement of particles in quantum well wire offers greater variety of electric field dependence in comparison to bulk materials and quantum well structures. (C) 2002 Elsevier Science B.V. All rights reserved
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