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Dive into the research topics where Erika M. de O. Ribeiro is active.

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Featured researches published by Erika M. de O. Ribeiro.


Journal of the Brazilian Chemical Society | 2016

Rosmarinic and Cinnamic Acid Derivatives of in vitro Tissue Culture of Plectranthus ornatus: Overproduction and Correlation with Antioxidant Activities

Héctor H. Medrado; Edlene O. dos Santos; Erika M. de O. Ribeiro; Jorge M. David; Juceni P. David; José Fernando Araújo; Ademir E. do Vale; Moema Cortizo Bellintani; Hugo Neves Brandão; Paloma R. Meira

This work describes the tissue culture of Plectranthus ornatus Codd. (Lamiaceae) on Murashige and Skoog (MS) medium with naphthalene acetic acid (NAA) (1.0, 2.0 and 4.0 mg L-1) and 6-benzylaminopurine (BAP) (1.0, 2.0 and 4.0 mg L-1) as growth regulators to obtain the overproduction of rosmarinic acid. The content of rosmarinic acid and its biosynthetic precursors were determined by high performance liquid chromatography (HPLC). The antioxidant activities (AA) of the extracts were also evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The best growing condition was observed with the addition of 1.0 mg L-1 of both NAA and BAP in the culture medium yielded an increase of 94 times of rosmarinic acid comparing with the wild plant. All extracts diplayed antioxidant activity, as evidenced by the DPPH free radical scavenging assay. However, those with 2.0 mg L-1 NAA and, 1.0 mg L-1 NAA and BAP in culture medium showed the lowest EC50 (26.0 and 29.8 µg mL-1, respectively). At concentration higher than 10 µg mL-1 of rosmarinic acid it was not observed the correlation with AA, suggesting some other anti-oxidant mechanism acting.


Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy | 2015

Validation of LED spectrofluorimeter for determination of both biodiesel and nontransesterified residual cooking oil in diesel samples

Marilena Meira; Cristina M. Quintella; Pedro Ramos da Costa Neto; Iuri Muniz Pepe; Erika M. de O. Ribeiro; Weidson Leal Silva; Alexandre Lopes Del Cid; Alexandre Kamei Guimarães

This paper presents the results of the validation of a LED spectrofluorimeter patented for the analysis of biodiesel in diesel and non-transesterified residual cooking oil (RCO) in diesel. Detection limit, quantification limit and sensitivity were determined from the regression lines. The spectrofluorimeter validated in this study was adequate for quantifying the amount of biodiesel in diesel in the range from 2% to 45% (B02-B45) with an R-squared value of 0.9962 and a detection limit of 3%. For the analysis of non-transesterified RCO in diesel, the linear range was from 2% to 20% with an R-squared value of 0.9872 and a detection limit of 2%. The accuracy of the equipment for the analysis of biodiesel in diesel and non-transesterified RCO in diesel was evaluated using Students t-test for paired data. With 95% confidence level there was no significant difference between the actual values and those determined by the equipment.


Journal of the Brazilian Chemical Society | 2015

Determination of Adulterants in Diesel by Integration of LED Fluorescence Spectra

Marilena Meira; Cristina M. Quintella; Erika M. de O. Ribeiro; Humbervânia Reis Gonçalves da Silva; Alexandre Kamei Guimarães; Saionara Luna; Weidson Leal Silva; Irlane J. de Brito

This paper describes a simple and rapid methodology for determining the content of adulterants in diesel by the integration of fluorescence spectra. The procedure consists of constructing analytical curves using the concentrations of each adulterant in diesel and the relative change in the fluorescence area of each blend with respect to the fluorescence area of the diesel. The results indicated that the proposed method can be used to determine adulterants such as non-transesterified residual cooking oil, kerosene, and turpentine in diesel. The detection limits were 3, 4 and 5% for non-transesterified residual cooking oil, kerosene and turpentine in diesel, respectively. The method was also successfully used to determine the non-transesterified residual cooking oil content in B5 biodiesel-diesel blend (5% biodiesel) in the range of 0-70%, with a limit of detection of 4%.


Biomass Conversion and Biorefinery | 2015

Overview of the challenges in the production of biodiesel

Marilena Meira; Cristina M. Quintella; Erika M. de O. Ribeiro; Humbervânia Reis Gonçalves da Silva; Alexandre Kamei Guimarães


Phytochemistry Letters | 2013

A new tropane alkaloid and other constituents of Erythroxylum rimosum (Erythroxylaceae)

Erika M. de O. Ribeiro; Luciano S. Lima; Jorge M. David; Ademir E. do Vale; Lucia Maria Xavier Lopes; Juceni P. David


International Journal of Chemistry | 2014

Identification of Adulteration of Olive Oil with Other Edible Oils by LED-induced Fluorescence and Multivariate Calibration

Marilena Meira; Cristina M. Quintella; Erika M. de O. Ribeiro; Mariana Andrade Santos; Saionara Luna; Alexandre Lopes Del Cid


Biochemical Systematics and Ecology | 2013

Ent-labdane and beyerane diterpenes from Erythroxylum betulaceum Mart

Erika M. de O. Ribeiro; Juceni P. David; Jorge M. David; Maria Lenise Silva Guedes; Lucia Maria Xavier Lopes; Zuzana Kršková; Jaroslav Dušek


Phytochemistry Letters | 2017

Abiotic factors influencing podophyllotoxin and yatein overproduction in Leptohyptis macrostachys cultivated in vitro

Paloma R. Meira; Juceni P. David; Erika M. de O. Ribeiro; José Raniere Ferreira de Santana; Hugo N. Brandão; Lenaldo Muniz de Oliveira; Jorge M. David; Héctor H. Medrado; José Floriano Barêa Pastore


Biomass Conversion and Biorefinery | 2015

Gaussian fit to the fluorescence spectra for determination of adulteration to diesel by addition of residual oil

Marilena Meira; Cristina M. Quintella; Erika M. de O. Ribeiro; Weidson Leal Silva


American Journal of Analytical Chemistry | 2013

Prediction of Concentration of Animal Fat in Mixture with Vegetable Oil by Multivariate Calibration Associated with Spectrofluorimetry

Marilena Meira; Cristina M. Quintella; Erika M. de O. Ribeiro; Alexandre Kamei Guimarães; Mariana Andrade Santos; Gabriela Silva Cerqueira; Alexandre Lopes Del Cid; Saionara Luna; Weidson Leal Silva

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Weidson Leal Silva

Federal University of Bahia

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Saionara Luna

Federal University of Bahia

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Jorge M. David

Federal University of Bahia

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Juceni P. David

Federal University of Bahia

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Marilena Meira

Bahia Federal Institute of Education

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Ademir E. do Vale

Federal University of Bahia

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