Publicaciones 2011-2020

@article{RN286,
title = {Secondary Metabolites in Ramalina Terebrata Detected by Uhplc/Esi/Ms/Ms and Identification of Parietin as Tau Protein Inhibitor},
author = { A. Cornejo and F. Salgado and J. Caballero and R. Vargas and M. Simirgiotis and C. Areche},
url = {/brokenurl#<Go to ISI>://WOS:000382337900115},
doi = {10.3390/ijms17081303},
issn = {1422-0067},
year = {2016},
date = {2016-01-01},
journal = {International Journal of Molecular Sciences},
volume = {17},
number = {8},
abstract = {Liquid chromatography coupled with mass spectrometry is an outstanding methodology for fast analysis of phenolic compounds in biological samples. Twenty two compounds were quickly and accurately identified in the methanolic extract of the Antarctic lichen Ramalina terebrata for the first time using ultra high pressure liquid chromatography coupled with photodiode array detector and high resolution mass spectrometry (UHPLC-PDA-Q/Orbitrap/MS/MS). In addition, the extract and the four compounds isolated from this species were tested for the inhibitory activity of tau protein aggregation, which is a protein involved in Alzheimer's disease (AD). All compounds showed null activity with the exception of parietin, which it was able to inhibit aggregation process of tau in a concentration range between 3 mu g/mL (10 mu M) to 28 mu g/mL (100 mu M). In addition, we show how parietin interact with tau (306)VQIVYK(311) hexapeptide inside of the microtubule binding domain (4R) with the help of molecular docking experiments. Finally, the constituents present in the methanolic extract could possibly contribute to the established anti-aggregation activity for this extract and this in-depth analysis of the chemical composition of R. terebrata could guide further research into its medicinal properties and potential uses.},
keywords = {alzheimer's alzheimers-disease, biological disease, docking, evaluation, fibril filaments, formation helical lichen lichens, liquid-chromatography, mass-spectrometry, molecular paired parietin, phenolic-compounds, protein, ramalina, tau uhplc-q/orbitrap/ms/ms, uhplc/ms, xanthoria-parietina},
pubstate = {published},
tppubtype = {article}
}

@article{RN287,
title = {Phenolic Compounds in Chilean Mistletoe (Quintral, Tristerix Tetrandus) Analyzed by Uhplc-Q/Orbitrap/Ms/Ms and Its Antioxidant Properties},
author = { M.J. Simirgiotis and C. Quispe and C. Areche and B. Sepulveda},
url = {/brokenurl#<Go to ISI>://WOS:000373802200140},
doi = {10.3390/molecules21030245},
issn = {1420-3049},
year = {2016},
date = {2016-01-01},
journal = {Molecules},
volume = {21},
number = {3},
abstract = {Mass spectrometry has become a method of choice to characterize bioactive compounds in biological samples because of its sensitivity and selectivity. Hybrid ultra-HPLC hyphenated with Orbitrap mass analyzer is an innovative state of the art technology that allows fast and accurate metabolomic analyses. In this work the metabolites of a Chilean mistletoe endemic to the VIII region of Chile were investigated for the first time using UHPLC mass analysis (UHPLC-PDA-HESI-Orbitrap MSn). The anthocyanins, together with the non-pigmented phenolics were fingerprinted and correlated with the antioxidant capacities measured by the bleaching of the DPPH radical, the ferric reducing antioxidant power (FRAP), the superoxide anion scavenging activity assay (SA), and total content of phenolics, flavonoids and anthocyanins measured by spectroscopic methods. Six anthocyanins were identified, and among them, the 3-O-glycosides of delphinidin and cyanidin were the major ones. In addition, several phenolic acids (including feruloylquinic acid, feruloyl glucose, chlorogenic acid) and several flavonols (luteolin, quercetin, apigenin, isorhamnetin and glycoside derivatives) were also identified. The mistletoe leaves showed the highest antioxidant activity as measured by the DPPH radical bleaching, ferric reducing antioxidant power and superoxide anion scavenging activity tests (13.38 +/- 0.47 mu g/mL, 125.32 +/- 5.96 mu molTE/g DW and 84.06 +/- 4.59 at 100 mu g/mL, respectively).},
keywords = {anthocyanins, antioxidants, bioactive chile, components, del esi-ms, extracts flavonoids, fruits, hplc-dad, hplc-ms, l., liquid-chromatography, mass-spectrometry, medicinal-plants, muerdago, northern phenolic quintral ultra},
pubstate = {published},
tppubtype = {article}
}

@article{RN174,
title = {Determination and Co-Estimate of the Chlormadinone Acetate and 17 Alpha-Ethinyl Estradiol in Pharmaceutical Formulation and Drinking Water Samples by Digital Derivative Spectophotometry},
author = { C. Soto and R. Otipka and M.I. Toral and D. Pino and D. Contreras and J. Yanez},
url = {/brokenurl#<Go to ISI>://WOS:000342613100019},
doi = {10.4067/S0717-97072014000200019},
issn = {0717-9707},
year = {2014},
date = {2014-01-01},
journal = {Journal of the Chilean Chemical Society},
volume = {59},
number = {2},
pages = {2485-2489},
abstract = {In this work are presented two methods for the simultaneous determination of 17 alpha-ethinylestradiol (EEL) and chlormadinone acetate (CMA) by second order derivative spectrophotometry., The first analytical method proposed is based in the dissolution and extraction of both drugs in acetonitrile. The solution was directly evaluated by second order derivative spectrophotometry with a smoothing factor of 8,000 and a scale factor of 10,000. The determination of EEL and CMA was carried out to 296,6 and 291.8 nm, respectively. The detection limits (3.3 sigma criterion) for EEL and CMA were 6.9 x 10(-7) and 9.8 x 10(-8) mol/L, respectively., Furthermore, a study of the effect of the excipients containing in the pharmaceutical formulation was included. Polyvidone presents greater tendency to produce interference, but its spectral bands are located between 215 and 240 nm, so these bands do not interferes spectrally in the simultaneous determination of EEL and CMA. Both drugs were extracted from the pharmaceutical formulation with acetonitrile, obtaining a good recovery relative to the nominal content., The second method is a screening method and was applied in fortified drinking water. In this method, drugs were extracted in chloroform, which was then removed with N-2 and the residue was redissolved in acetonitrile. Due to the difference in the procedure in relation to the pharmaceutical formulation a new analytical parameters were obtained. For EEL this parameters were very similar to those obtained directly in solution, however these were higher for CMA, which could be attributed to that under these conditions was found a higher standard deviation of the blank. Recoveries of fortified samples were 81.8 +/- 1.5% and 101.1 +/- 0.73% for EEL and CMA, respectively.},
keywords = {alpha-ethinyl chlormadinone derivative electrode estradiol, ethinylestradiol, formulations, gestodene, human least-squares, liquid-chromatography, mass-spectrometry, method, oral-contraceptives, performance pharmaceutical plasma, screening spectrophotometry, tandem},
pubstate = {published},
tppubtype = {article}
}

@article{RN182,
title = {Hplc-Uv-Ms Profiles of Phenolic Compounds and Antioxidant Activity of Fruits from Three Citrus Species Consumed in Northern Chile},
author = { A. Brito and J.E. Ramirez and C. Areche and B. Sepulveda and M.J. Simirgiotis},
url = {/brokenurl#<Go to ISI>://WOS:000345564300019},
doi = {10.3390/molecules191117400},
issn = {1420-3049},
year = {2014},
date = {2014-01-01},
journal = {Molecules},
volume = {19},
number = {11},
pages = {17400-17421},
abstract = {Peels and edible pulp from three species of citrus including Citrus aurantifolia (varieties pica and sutil) and Citrus x lemon var. Genova widely cultivated and consumed in Northern Chile (I and II region) were analyzed for phenolic compounds and antioxidant activity for the first time. A high performance electrospray ionization mass spectrometry (HPLC-UV-ESI-MS) method was developed for the rapid identification of phenolics in extracts from peels and juices of all species. Several flavonoids including one kaempferol-O-hexoside (peak 16) and one hesperidin derivative (peak 22) three quercetin derivatives (peaks 4, 19 and 36), five isorhamnetin derivatives (peaks 5, 23, 24, 26 and 29) four luteolin derivatives (peaks 14, 25, 27 and 40), seven apigenin derivatives (peaks 2, 3, 12, 20, 34, 35 and 39), seven diosmetin derivatives (peaks 7-9, 17, 21, 31 and 37), three chrysoeriol derivatives (peaks 10, 18 and 30), and four eryodictiol derivatives (peaks 6, 13, 15 and 38) were identified in negative and positive mode using full scan mass measurements and MSn fragmentations. Ascorbic acid content was higher in the pulps of the varieties Genova and Sutil (60.13 +/- 1.28 and 56.53 +/- 1.06 mg ascorbic acid per g dry weight, respectively) while total phenolic content was higher in Pica peels followed by Sutil peels (34.59 +/- 0.81 and 25.58 +/- 1.02 mg/g GAE dry weight, respectively). The antioxidant capacity was also higher for Pica peels (10.34 +/- 1.23 mu g/mL in the DPPH assay and 120.63 +/- 2.45 mu M trolox equivalents/g dry weight in the FRAP assay). The antioxidant features together with the high polyphenolic contents can support at least in part, the usage of the peel extracts as nutraceutical supplements, especially to be used as anti-ageing products.},
keywords = {antioxidants, caenorhabditis-elegans, capacity, chilean dad, damage, de detection, diode-array endemic esi-qtof, fruits, harvest hplc-ms, identification lemon, limon liquid-chromatography, mass-spectrometry, oxidative performance pica pica, poliphenolics, quantitation, species, tandem time},
pubstate = {published},
tppubtype = {article}
}

@article{RN186,
title = {Anthocyanin Characterization, Total Phenolic Quantification and Antioxidant Features of Some Chilean Edible Berry Extracts},
author = { A. Brito and C. Areche and B. Sepulveda and E.J. Kennelly and M.J. Simirgiotis},
url = {/brokenurl#<Go to ISI>://WOS:000341502600014},
doi = {10.3390/molecules190810936},
issn = {1420-3049},
year = {2014},
date = {2014-01-01},
journal = {Molecules},
volume = {19},
number = {8},
pages = {10936-10955},
abstract = {The anthocyanin composition and HPLC fingerprints of six small berries endemic of the VIII region of Chile were investigated using high resolution mass analysis for the first time (HR-ToF-ESI-MS). The antioxidant features of the six endemic species were compared, including a variety of blueberries which is one of the most commercially significant berry crops in Chile. The anthocyanin fingerprints obtained for the fruits were compared and correlated with the antioxidant features measured by the bleaching of the DPPH radical, the ferric reducing antioxidant power (FRAP), the superoxide anion scavenging activity assay (SA), and total content of phenolics, flavonoids and anthocyanins measured by spectroscopic methods. Thirty one anthocyanins were identified, and the major ones were quantified by HPLC-DAD, mostly branched 3-O-glycosides of delphinidin, cyanidin, petunidin, peonidin and malvidin. Three phenolic acids (feruloylquinic acid, chlorogenic acid, and neochlorogenic acid) and five flavonols (hyperoside, isoquercitrin, quercetin, rutin, myricetin and isorhamnetin) were also identified. Calafate fruits showed the highest antioxidant activity (2.33 +/- 0.21 mu g/mL in the DPPH assay), followed by blueberry (3.32 +/- 0.18 mu g/mL), and arrayan (5.88 +/- 0.21), respectively.},
keywords = {activity, antioxidants, arrayan, berberis-microphylla berries, blueberry, calafate, capacity, chequen, chile, cultivars endemic fruits, hplc-ms, inhibitory liquid-chromatography, luma, mass-spectrometry, meli, murtilla, myrtaceae, oxidase poliphenolics, polyphenols, quantitation, southern vegetables},
pubstate = {published},
tppubtype = {article}
}

@article{RN111,
title = {Parallel Determination of Desogestrel and 17 Alpha-Ethinylestradiol in Pharmaceutical Formulation by Derivative Spectrophotometry},
author = { M.I. Toral and F. Nacaratte and F. Nova-Ramirez and R. Otipka},
url = {/brokenurl#<Go to ISI>://WOS:000331237700031},
issn = {0717-9707},
year = {2013},
date = {2013-01-01},
journal = {Journal of the Chilean Chemical Society},
volume = {58},
number = {2},
pages = {1779-1784},
abstract = {This work presents a rapid and simple method for the parallel determination of Desogestrel (DSG) and 17 alpha-Ethinylestradiol (EE2) by second order derivative spectrophotometry and its application in pharmaceutical formulations. Study of the effect of the solvents, excipients and spectral behavior is also included. Acetonitrile was selected as a solvent; subsequently the samples were evaluated by second order derivatives, using a smoothing factor of 8,000 and a scale factor of 10(4). The EE2 determination was carried out using the graphical method at 288 nm and DSG by the zero-crossing method at 220 nm. The determination ranges were found to be between 1.5.10(-6) and 5.10(-4) mol/L and 1.7.10(-7) to 1.0.10(-3) mol/L for DSG and EE2, respectively., The homogenized tablets are divided in two fractions, the first, called sample A, was dissolved in acetonitrile, which contains the absorbents species that is polyvidone, DGS and EE2, the latter is determined directly at 288 nm. Meanwhile, in the second fraction (sample B), after extract with water the polyvidone and partially EE2, it is possible determine DGS at 220 nm. When the pharmaceutical formulation contains Vitamin E (Vit. E) is necessary to use an equations system to be evaluated in sample B.},
keywords = {desogestrel, estradiol, estrogens, ethinyl ethinylestradiol, formulations, gestodene levonorgestrel, mass-spectrometry, oral-contraceptives, pharmaceutical povidone, spectral study},
pubstate = {published},
tppubtype = {article}
}