Effect of solvent-temperature extraction conditions on the initial antioxidant activity and total phenolic content of muitle extracts and their decay upon storage at different pH [Efecto de las condiciones de extraccio ́ n solvente-temperatura en la actividad antioxidante y contenido de fenoles totales en extractos de muitle y su pérdida durante el almacenamiento a diferentes valores de pH]
Garcia-Marquez E.,Metropolitan Autonomous University |
Roman-Guerrero A.,Metropolitan Autonomous University |
Perez-Alonso C.,National Autonomous University of Mexico |
Cruz-Sosa F.,Metropolitan Autonomous University |
And 2 more authors.
Revista Mexicana de Ingeniera Qumica | Year: 2012
The effect of solvent and extraction temperature on the initial antioxidant activity (AA) and total phenolic content (TPC) of Muitle (Justicia spicigera) extracts and their decay upon storage at different pH values was studied. Extraction with aqueous solvents, at either 25 or 60 °C, produced fresh extracts (pH 7.4) with higher initial TPC and AA. Extracts were adjusted to different pH's displayed different TPC and AA decay rates upon storage. TPC had first order decay kinetics, characterized by a relatively quick constant (k 1) at relatively short storage times followed by a relatively slow constant (k 2) at relatively large storage times. ABTS and DPPH assays estimated different AA in the extracts, attributed to compatibility differences between the bioactive species and the free radicals.
Carrillo-Ocampo D.,Autonomous University of the State of Morelos |
Bazaldua-Gomez S.,Autonomous University of the State of Morelos |
Bonilla-Barbosa J.R.,Autonomous University of the State of Morelos |
Aburto-Amar R.,University la Canada |
Rodriguez-Lopez V.,Autonomous University of the State of Morelos
Molecules | Year: 2013
Castilleja tenuiflora (Orobanchaceae) has been used in Mexican traditional medicine as a treatment for cough, dysentery, anxiety, nausea and vomiting as well as hepatic and gastrointestinal diseases. The ethanolic extract of the aerial parts of Castilleja tenuiflora was separated by silica gel column chromatography. The fractions were evaluated using the induced edema acetate 12-O-tetradecanoylphorbol (TPA) anti-inflammatory activity model. The most active fraction was subjected to medium-pressure liquid chromatography (MPLC) with UV detection at 206 and 240 nm. The following iridoids were isolated: geniposidic acid, aucubin, bartioside, 8-epi-loganin, mussaenoside, and the phenylpropanoid verbascoside. The most active iridoid was geniposidic acid, which was more active than the control (indomethacin), and the least active iridoid was mussaenoside. 8-epi-Loganin, and mussaenoside have not been previously reported to be anti-inflammatory compounds. The results of these investigations confirm the potential of Mexican plants for the production of bioactive compounds and validate the ethnomedical use of Castilleja tenuiflora-like anti-inflammatory plants. © 1996-2013 MDPI AG.
Fernandez V.M.J.,University of Veracruz |
Paxtian Z.J.H.,University la Canada
International Journal of Circuits, Systems and Signal Processing | Year: 2011
In this paper a digital circuit architecture dedicated to median filtering of grayscale images is presented. The architecture emerges from a sorting network based median algorithm which effectiveness is verified by Matlab programming and its hardware implementation tested on a Spartan-3E FPGA device. The median pixel computation is approached by a sorting network scheme which is constituted by seven three-data comparator modules and hierarchically composed by twenty one switch/compare circuits. The successful operation of the threedata comparator module is demonstrated by transistor level SPICE simulations using 0.5μm CMOS technology.
Medina-Torres L.,National Autonomous University of Mexico |
Vernon-Carter E.J.,Metropolitan Autonomous University |
Gallegos-Infante J.A.,Durango Institute of Technology |
Rocha-Guzman N.E.,Durango Institute of Technology |
And 3 more authors.
Journal of the Science of Food and Agriculture | Year: 2011
BACKGROUND: The process of convective drying was evaluated in terms of the bioactive compounds contained in nopal samples before and after dehydration. Total polyphenol, flavonoid, flavonol, carotene and ascorbic acid contents were determined in undehydrated and dehydrated samples. Two drying temperatures (45 and 65 °C) and two air flow rates (3 and 5 m s-1) were evaluated. The rheology of samples under the best drying conditions was also studied, since it provides important information regarding processing (mixing, flow processing) as well as the sensory attributes (texture) of rehydrated samples. RESULTS: Non-Newtonian shear-thinning behaviour was observed for samples dried at 45 °C, while samples dried at 65 °C showed shear-thickening behaviour, possibly caused by thermal chain scission of high-molecular-weight components. CONCLUSION: The best conditions for bioactive compound preservation were a drying temperature of 45 °C and an air flow rate of 3 m s-1, resulting in 40.97 g phenols, 23.41 g flavonoids, 0.543 g β-carotene and 0.2815 g ascorbic acid kg-1 sample as shown in table 3. © 2011 Society of Chemical Industry.
Jimenez-Fernandez V.M.,University of Veracruz |
Dominguez-Chavez J.A.,University of Veracruz |
Vazquez-Leal H.,University of Veracruz |
Gallardo Del Angel A.,University of Veracruz |
Hernandez-Paxtian Z.J.,University la Canada
Revista Mexicana de Fisica E | Year: 2012
The physical realization of memristor, achieved by the Hewlett Packard Laboratories in 2008, has become this novel device into an important topic under study in the Electronics Engineering area. However, in spide of the existence of several papers, theses, book chapters, and technical reports about this topic found in databases, it is unfortunate the lack of references written in spanish and furthermore references that approach it under a perspective which let an easy understanding with the only academic background requirement of basic concepts of electromagnetism. Taking in account this fact as motivation, this paper emerges with the objective of being an introductory reference for undergraduate students in Physics, Electrical Engineering or Electronics Engineering that could be interested in beginning a study about the memristor electrical model. The model proposed by Hewlett-Packart has been taken as reference and its verification has been performed through Maple Realease 13.0 and PSpice simulations.