Erika M. de O. Ribeiro
Federal University of Bahia
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Erika M. de O. Ribeiro.
Journal of the Brazilian Chemical Society | 2016
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
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
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
Marilena Meira; Cristina M. Quintella; Erika M. de O. Ribeiro; Humbervânia Reis Gonçalves da Silva; Alexandre Kamei Guimarães
Phytochemistry Letters | 2013
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
Marilena Meira; Cristina M. Quintella; Erika M. de O. Ribeiro; Mariana Andrade Santos; Saionara Luna; Alexandre Lopes Del Cid
Biochemical Systematics and Ecology | 2013
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
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
Marilena Meira; Cristina M. Quintella; Erika M. de O. Ribeiro; Weidson Leal Silva
American Journal of Analytical Chemistry | 2013
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