DENIA VALLADAO

Dr. DENIA VALLADAO

orcid

Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 July 2020 in European Journal of Pharmaceutical Sciences
Verified
Journal Article
Closed access
JPJader Pires
Jader Pires
SCSimone Tasca Cargnin
Simone Tasca Cargnin
SCSuéllen Alves Costa
Suéllen Alves Costa
VSValéria Dornelles Gindri Sinhorin
Valéria Dornelles Gindri Sinhorin
ADAmílcar Sabino Damazo
Amílcar Sabino Damazo
SFStela Ferrarini
Stela Ferrarini

1 September 2019 in Acta Amazonica
Verified
Journal Article
Open access
MTMaycon de Paula Ribeiro Torres
Maycon de Paula Ribeiro Torres
RERhuan Vínicius de Freitas Esprendor
Rhuan Vínicius de Freitas Esprendor
SBSOLANGE MARIA BONALDO
SOLANGE MARIA BONALDO
ERElton Brito Ribeiro
Elton Brito Ribeiro
DVDENIA VALLADAO
DENIA VALLADAO
Advances in nanotechnology, combined with the use of natural products, represent a promissing research field. Brazil is a country of a rich biodiversity, especially in the Amazon forest. Fruits commonly used by local communities, such as bacaba (Oenocarpus bacaba), are potentially important for prospection of industrial applications of natural products. In nanotechnology, microemulsions stand out for providing a modified release to conveyed substances. This work aimed to develop microemulsionated formulations of bacaba oil, characterize them and evaluate their stability. We determined the HLB (hydrophile-lipophilic balance) of bacaba oil for formulation development. Six formulations were selected from pseudoternary diagrams, which indicated the proportions of surfactants, aqueous phase and bacaba oil. The viability of these formulations was evaluated through stability tests. We provided the rheological characterization of the formulations, evaluated their potential antioxidant activity through the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging method, and determined the hydrodynamic diameter of the droplets. The microemulsions were stable throughout the test period. Droplet diameter was below 200 nm, and the microemulsions were characterized as newtonian fluids, presenting an increase in antioxidant activity when compared with the diluted oil. Our results confirm the potential of bacaba oil in microemulsionated formulation as a suitable carrier for active compounds.

1 January 2020 in Ciência Rural
Verified
Journal Article
Open access
PDF file
ARAléxia Lorenzi Raiser
Aléxia Lorenzi Raiser
MTMaycon de Paula Ribeiro Torres
Maycon de Paula Ribeiro Torres
ERElton Brito Ribeiro
Elton Brito Ribeiro
DVDENIA VALLADAO
DENIA VALLADAO
This study analyzed the use of the ultrasound-assisted method as an alternative to obtain munguba oil. The extraction provided a 47.70 % yield of an oil with appropriate quality, evaluated by assessing the %FFA as oleic acid, iodine, peroxide, and saponification values, in addition to the refractive index and density. The oil presented thermal stability up to 300 °C, was constituted mainly by palmitic acid (C16:0), and presented a total phenolic content of 55.02 ± 1.872 µgEAG g-1. Results suggest that the ultrasound-assisted method has the potential to obtain vegetable oils without compromising their characteristics and quality, as well as optimize extraction time, solvent volume, and operational costs. Moreover, munguba oil presents itself as a suitable and sustainable alternative as an adjuvant in food products, pharmaceuticals, cosmetics, and biofuels.

1 January 2017 in Revista Árvore
Verified
Journal Article
Open access
PDF file
DUDeise Martins Uriu
Deise Martins Uriu
BGBruna Serpa de Almeida Godoy
Bruna Serpa de Almeida Godoy
LBLeandro Dênis Battirola
Leandro Dênis Battirola
CACARLA REGINA ANDRIGHETTI
CARLA REGINA ANDRIGHETTI
MMMarinez Marques
Marinez Marques
DVDENIA VALLADAO
DENIA VALLADAO
The total phenol concentration present in Vochysia divergens Pohl. (Vochysiaceae) leaves in the Pantanal was analyzed. Work was carried out between September/2012 and June/2013 which is made up by the dry season (September/2012), the beginning of the rising water (December/2012), the high water (March/2013) followed by the receding water period (June/2013). For the purpose of the research fifteen trees were selected, five from each sample area. The phenolic content in the leaves was obtained from the samples which were dried, steeped with ethanol: water and centrifuged. The extract was used to determine the concentration of total phenols using the Folin-Ciocalteu spectrometric method. There was no difference among the sampling areas; however the values were different in relation to seasonal periods. The lowest concentration was recorded in the dry season (young leaves) increasing gradually at the beginning of the rising water, with higher levels at the end of high water and receding water season. The highest concentration of phenols occurred during the receding water period (end of the life cycle of V. divergens leaves), followed by high and rising water periods. The increase in phenol concentration is associated with the Pantanal flood cycle, and related to the phenology of the V. divergens leaves.

1 January 2023 in Brazilian Journal of Biology
Verified
Journal Article
Open access
BDB. W. Debiasi
B. W. Debiasi
ARA. L. Raiser
A. L. Raiser
SDS. H. A. Dourado
S. H. A. Dourado
MTM. de P. R. Torres
M. de P. R. Torres
CACARLA REGINA ANDRIGHETTI
CARLA REGINA ANDRIGHETTI
DVDENIA VALLADAO
DENIA VALLADAO
Species of the genus Cordia have shown biological activities, such as anti-inflammatory, analgesic, antioxidant, antiviral, and antifungal activities. The species Cordia glabrata (MART) A.DC. Has no information concerning its phytochemical profile and possible biological activities. Thus, this study aimed to evaluate this profile in ethanolic extracts of young, adult and senescent leaves, as well as their antioxidant, photoprotective, antimicrobial, and virucidal potentials. Phytochemical analysis was performed by TLC (thin-layer chromatography) and showed the presence of flavonoids, tannins, and terpenes. The evaluation by UPLC-MS/MS (Ultra performance liquid chromatography - tandem mass spectrometer) evidenced the presence of caffeic (3.89 mgL-1), p-cumaric (6.13 mgL-1), and ferulic (0.58 mgL-1) acids, whilst, in GC/MS (Gas chromatography–mass spectrometry) analysis there was a greater amount of palmitic (51.17%), stearic (20.34%), linoleic (9.62%), and miristic (8.16%) fatty acids. The DPPH (2,2-Diphenyl-1-picrylhydrazyl) and ABTS+ (2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) radicals were used to verify the potential antioxidant activity, observing a better activity for the leaf extract in the adult phenological stage: 54.63 ± 1.06 µgmL-1 (DPPH) and 44.21 ± 1.69 mM (ABTS). The potential photoprotective activity of the extracts was determined by spectrophotometry and the in vitro values of SPF (Sun Protection Factor) in young and adult leaves (5.47 and 5.41, respectively) showed values close to the minimum SPF of 6.0 required by ANVISA (Brazilian Health Regulatory Agency). It was not observed an antimicrobial activity for Staphylococcus aureus with a minimum inhibitory concentration of 2000 μgmL-1, however the anti-herpetic assay against the Herpes simplex virus type 2 (HSV-2) showed a potent virucidal activity at the tested concentrations with CV50 value <0.195 μgmL-1 and a Selectivity Index (SI = CC50 / CV50) greater than 448. The results obtained in this study suggest that extracts of leaves of C. glabrata in their adult phenological stage have potential antioxidant, photoprotective and virucidal activity, considering in vitro test results.

1 January 2017 in Bioscience Journal
Verified
Journal Article
Closed access
PDF file
MMMárcia Regina Marcílio
Márcia Regina Marcílio
ARAlexia Lorenzi Raiser
Alexia Lorenzi Raiser
LFLigia Paula Fumagalli
Ligia Paula Fumagalli
RBRudy Bonfilio
Rudy Bonfilio
CACarla Regina Andrighetti
Carla Regina Andrighetti
DVDENIA VALLADAO
DENIA VALLADAO
Secnidazole, a 5-nitroimidazole, is a drug used in the treatment against protozoa, and several bacterial infections. This study purpose was to develop and validate a UV spectrophotometric method to determine secnidazole in pharmaceutical tablet dosage forms once there is no method reported in the pharmacopoeia yet. The quantification was performed using methanol as solvent at 325 nm (maximum wavelength) and three kinds of products marketed in Brazil (reference, generic and similar tablets) containing 1g of secnidazole. The method obeyed Beer’s law in the concentration range of 4 - 20 mgmL -1 respectively. The method was validated according to the International Conference on Harmonization (ICH) and Brazil National Health Surveillance Agency (ANVISA) guidelines, showing accuracy, precision, selectivity, robustness and linearity. Tests such as weight range, friability, disintegration, hardness and dissolution were carried out to check tablets’ quality and all the trials showed to be in accordance with the general test guidelines of the Brazilian Pharmacopoeia. The dissolution test was carried out and the developed method was applied. The method developed is suitable for the estimation of secnidazole in tablets without any interference from the excipients and can be used for routine in quality control. Still, it's a simple, fast and low cost method.