Debora Luana Monego | UFSM - Universidade Federal de Santa Maria (original) (raw)
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Papers by Debora Luana Monego
ACS Nano, 2020
We report on the colloidal stability of nanoparticles with alkanethiol shells in apolar solvents.... more We report on the colloidal stability of nanoparticles with alkanethiol shells in apolar solvents. Small angle X-ray scattering and molecular dynamics simulations were used to characterize the interaction between nanoparticles in linear alkane solvents ranging from hexane to hexadecane, including 4 nm gold cores with hexadecanethiol shells and 6 nm cadmium selenide cores with octadecanethiol shells. We find that the agglomeration is enthalpically driven and that, contrary to what one would expect from classical colloid theory, the temperature at which the particles agglomerate increases with increasing solvent chain length. We demon-1
Journal of Applied Pharmaceutical Science, 2016
This paper presents an overview on the chemical composition and biological activity of plants fou... more This paper presents an overview on the chemical composition and biological activity of plants found in the Brazilian Amazon-Bauhinia variegata, Cecropia obtusa, Cecropia palmata, Connarus perrottetti var. angustifolius, Chrysobalanus icaco and Mansoa alliacea. The lack of information regarding these species, along with their importance given their pharmacological and nutritional use in Latin American folk medicine, justifies the demand for this study. However, various interesting and important actions, as antioxidant, antibacterial, cytotoxic, hypoglycemic, antifungal, antiangiogenic, antitumor, anti-inflammatory, antiulcer, and chemopreventive have been modestly reported so far. In other words, these species can play a very important role in terms of biological and chemical activity, but their pharmacology is still poorly investigated. Accordingly, the discovery of molecules that could play a role against the major diseases of modern society could be achieved by paying more attention to plants used daily in some regions of our country.
Ciência e Natura, 2016
Perfil cromatográfico e atividade antioxidante frente aos radicais peroxila (ROO•), superóxido (O... more Perfil cromatográfico e atividade antioxidante frente aos radicais peroxila (ROO•), superóxido (O2•-) e DPPH da folha, flor, ramo e inflorescência da Plectranthus barbatus. Chromatographic profile and antioxidant activity front peroxyl radical (ROO•), superoxide (O2•-) and DPPH of the leaf, flower, twig and inflorescence of Plectranthus barbatus.
Ciência e Natura, 2016
Este trabalho teve como objetivo avaliar a atividade antioxidante (ROO • , O 2 •e DPPH) e o perfi... more Este trabalho teve como objetivo avaliar a atividade antioxidante (ROO • , O 2 •e DPPH) e o perfil cromatográfico de compostos fenólicos da folha, flor, ramo e inflorescência da Achilea millefolium. Os extratos etanólicos das diferentes partes da planta obtidos através de extração por ultrassom foram caracterizados por cromatografia líquida acoplada a um detector UV-HPLC-UV. Além disso, avaliou-se a atividade antioxidante frente aos radicais DPPH, superóxido e peroxil. Como resultado, a maioria dos extratos apresentou atividade antioxidante frente aos radicais investigados, além de que foram identificados os compostos quercetina, quercetrina, flavona, ácido cafeico e canferol nas partes investigadas da planta. Por fim, o estudo demonstrou que é de extrema importância se saber qual parte da planta está sendo avaliada, visto que estas apresentam diferenças na atividade antioxidante e na composição química.
Waste and Biomass Valorization, 2016
The recovery of residual oil from palm kernel cake by supercritical carbon dioxide (CO2) and comp... more The recovery of residual oil from palm kernel cake by supercritical carbon dioxide (CO2) and compressed liquefied petroleum gas (LPG) was evaluated. Extractions were carried out in order to investigate how pressure and temperature affect the extraction yield, chemical composition and antioxidant activity of the product. Even though the maximum yield was similar for both solvents (about 9.0 wt%), the extraction rate for compressed LPG was 27 times higher than for supercritical CO2. The steady state for extractions carried out with supercritical CO2 was reached at about 75 min, whereas for compressed LPG this time was much shorter, of 3–4 min. Therefore, compressed LPG represents a better option than supercritical CO2 concerning the extraction of oil from palm kernel cake. Therefore, this solvent can be a promising alternative for fast extractions of vegetable oils at mild operational conditions.
The Journal of Supercritical Fluids, 2016
Abstract Compressed liquefied petroleum gas (LPG) and CO2 were used for the extraction of bioacti... more Abstract Compressed liquefied petroleum gas (LPG) and CO2 were used for the extraction of bioactive compounds from palm pressed fiber (Elaeis guineensis). The influence of temperature and pressure on extraction yield, chemical composition, antioxidant activities towards superoxide and hydroxyl radicals and the sun protection factor were studied for each solvent. Maximum extraction yield was 4.55 wt% using supercritical CO2 at 60 °C and 25 MPa, which was about three times higher than the yield using compressed LPG. The highest antioxidant activities and sun protection factor were also obtained at this condition. The chemical profiles were similar for both solvents, where lauric, palmitic and oleic acids corresponded to 80% of the total fatty acids determined in the extract. Antioxidant compounds such as α-tocopherol, squalene, β-carotene and β-sitosterol were also determined. CO2 was the best solvent for extraction of bioactive compounds from pressed fiber palm, due to the highest extraction yield, antioxidant activities and sun protection factor.
ACS Nano, 2018
Being able to predict and tune the colloidal stability of nanoparticles is essential for a wide r... more Being able to predict and tune the colloidal stability of nanoparticles is essential for a wide range of applications, yet our ability to do so is currently poor due to a lack of understanding of how they interact with one another. Here, we show that the agglomeration of apolar particles is dominated by either the core or the ligand shell, 1
Liquefied petroleum gas palm pressed fiber a b s t r a c t Compressed liquefied petroleum gas (LP... more Liquefied petroleum gas palm pressed fiber a b s t r a c t Compressed liquefied petroleum gas (LPG) and CO 2 were used for the extraction of bioactive compounds from palm pressed fiber (Elaeis guineensis). The influence of temperature and pressure on extraction yield, chemical composition, antioxidant activities towards superoxide and hydroxyl radicals and the sun protection factor were studied for each solvent. Maximum extraction yield was 4.55 wt% using supercritical CO 2 at 60 • C and 25 MPa, which was about three times higher than the yield using compressed LPG. The highest antioxidant activities and sun protection factor were also obtained at this condition. The chemical profiles were similar for both solvents, where lauric, palmitic and oleic acids corresponded to 80% of the total fatty acids determined in the extract. Antioxidant compounds such as-tocopherol, squalene,-carotene and-sitosterol were also determined. CO 2 was the best solvent for extraction of bioactive compounds from pressed fiber palm, due to the highest extraction yield, antioxidant activities and sun protection factor.
A summary of the various quantum chemical analyses that have been employed to evaluate the free r... more A summary of the various quantum chemical analyses that have been employed to evaluate the free radical scavenger capacity of carotenoid molecules are tabulated in this review and the most important observations are discussed. These molecules are able to interact with reactive oxygen species through singlet oxygen scavenging, electron transfer, hydrogen atom abstraction and radical adduct formation. Most studies employ density functional theory to compare the antiradical capacity of different carote-noids with the ones that are most explored theoretically, such as lycopene and b-carotene. A significant number of these applications have been directed towards understanding the electron transfer mechanism , and a useful tool called the FEDAM (full-electron donor-acceptor map) was developed to better evaluate this mechanism. Important aspects that may affect the radical scavenging capacity of carote-noids, such as synergistic effects and solubility, are sometimes overlooked, and a greater number of such compounds should be explored.
ACS Nano, 2020
We report on the colloidal stability of nanoparticles with alkanethiol shells in apolar solvents.... more We report on the colloidal stability of nanoparticles with alkanethiol shells in apolar solvents. Small angle X-ray scattering and molecular dynamics simulations were used to characterize the interaction between nanoparticles in linear alkane solvents ranging from hexane to hexadecane, including 4 nm gold cores with hexadecanethiol shells and 6 nm cadmium selenide cores with octadecanethiol shells. We find that the agglomeration is enthalpically driven and that, contrary to what one would expect from classical colloid theory, the temperature at which the particles agglomerate increases with increasing solvent chain length. We demon-1
Journal of Applied Pharmaceutical Science, 2016
This paper presents an overview on the chemical composition and biological activity of plants fou... more This paper presents an overview on the chemical composition and biological activity of plants found in the Brazilian Amazon-Bauhinia variegata, Cecropia obtusa, Cecropia palmata, Connarus perrottetti var. angustifolius, Chrysobalanus icaco and Mansoa alliacea. The lack of information regarding these species, along with their importance given their pharmacological and nutritional use in Latin American folk medicine, justifies the demand for this study. However, various interesting and important actions, as antioxidant, antibacterial, cytotoxic, hypoglycemic, antifungal, antiangiogenic, antitumor, anti-inflammatory, antiulcer, and chemopreventive have been modestly reported so far. In other words, these species can play a very important role in terms of biological and chemical activity, but their pharmacology is still poorly investigated. Accordingly, the discovery of molecules that could play a role against the major diseases of modern society could be achieved by paying more attention to plants used daily in some regions of our country.
Ciência e Natura, 2016
Perfil cromatográfico e atividade antioxidante frente aos radicais peroxila (ROO•), superóxido (O... more Perfil cromatográfico e atividade antioxidante frente aos radicais peroxila (ROO•), superóxido (O2•-) e DPPH da folha, flor, ramo e inflorescência da Plectranthus barbatus. Chromatographic profile and antioxidant activity front peroxyl radical (ROO•), superoxide (O2•-) and DPPH of the leaf, flower, twig and inflorescence of Plectranthus barbatus.
Ciência e Natura, 2016
Este trabalho teve como objetivo avaliar a atividade antioxidante (ROO • , O 2 •e DPPH) e o perfi... more Este trabalho teve como objetivo avaliar a atividade antioxidante (ROO • , O 2 •e DPPH) e o perfil cromatográfico de compostos fenólicos da folha, flor, ramo e inflorescência da Achilea millefolium. Os extratos etanólicos das diferentes partes da planta obtidos através de extração por ultrassom foram caracterizados por cromatografia líquida acoplada a um detector UV-HPLC-UV. Além disso, avaliou-se a atividade antioxidante frente aos radicais DPPH, superóxido e peroxil. Como resultado, a maioria dos extratos apresentou atividade antioxidante frente aos radicais investigados, além de que foram identificados os compostos quercetina, quercetrina, flavona, ácido cafeico e canferol nas partes investigadas da planta. Por fim, o estudo demonstrou que é de extrema importância se saber qual parte da planta está sendo avaliada, visto que estas apresentam diferenças na atividade antioxidante e na composição química.
Waste and Biomass Valorization, 2016
The recovery of residual oil from palm kernel cake by supercritical carbon dioxide (CO2) and comp... more The recovery of residual oil from palm kernel cake by supercritical carbon dioxide (CO2) and compressed liquefied petroleum gas (LPG) was evaluated. Extractions were carried out in order to investigate how pressure and temperature affect the extraction yield, chemical composition and antioxidant activity of the product. Even though the maximum yield was similar for both solvents (about 9.0 wt%), the extraction rate for compressed LPG was 27 times higher than for supercritical CO2. The steady state for extractions carried out with supercritical CO2 was reached at about 75 min, whereas for compressed LPG this time was much shorter, of 3–4 min. Therefore, compressed LPG represents a better option than supercritical CO2 concerning the extraction of oil from palm kernel cake. Therefore, this solvent can be a promising alternative for fast extractions of vegetable oils at mild operational conditions.
The Journal of Supercritical Fluids, 2016
Abstract Compressed liquefied petroleum gas (LPG) and CO2 were used for the extraction of bioacti... more Abstract Compressed liquefied petroleum gas (LPG) and CO2 were used for the extraction of bioactive compounds from palm pressed fiber (Elaeis guineensis). The influence of temperature and pressure on extraction yield, chemical composition, antioxidant activities towards superoxide and hydroxyl radicals and the sun protection factor were studied for each solvent. Maximum extraction yield was 4.55 wt% using supercritical CO2 at 60 °C and 25 MPa, which was about three times higher than the yield using compressed LPG. The highest antioxidant activities and sun protection factor were also obtained at this condition. The chemical profiles were similar for both solvents, where lauric, palmitic and oleic acids corresponded to 80% of the total fatty acids determined in the extract. Antioxidant compounds such as α-tocopherol, squalene, β-carotene and β-sitosterol were also determined. CO2 was the best solvent for extraction of bioactive compounds from pressed fiber palm, due to the highest extraction yield, antioxidant activities and sun protection factor.
ACS Nano, 2018
Being able to predict and tune the colloidal stability of nanoparticles is essential for a wide r... more Being able to predict and tune the colloidal stability of nanoparticles is essential for a wide range of applications, yet our ability to do so is currently poor due to a lack of understanding of how they interact with one another. Here, we show that the agglomeration of apolar particles is dominated by either the core or the ligand shell, 1
Liquefied petroleum gas palm pressed fiber a b s t r a c t Compressed liquefied petroleum gas (LP... more Liquefied petroleum gas palm pressed fiber a b s t r a c t Compressed liquefied petroleum gas (LPG) and CO 2 were used for the extraction of bioactive compounds from palm pressed fiber (Elaeis guineensis). The influence of temperature and pressure on extraction yield, chemical composition, antioxidant activities towards superoxide and hydroxyl radicals and the sun protection factor were studied for each solvent. Maximum extraction yield was 4.55 wt% using supercritical CO 2 at 60 • C and 25 MPa, which was about three times higher than the yield using compressed LPG. The highest antioxidant activities and sun protection factor were also obtained at this condition. The chemical profiles were similar for both solvents, where lauric, palmitic and oleic acids corresponded to 80% of the total fatty acids determined in the extract. Antioxidant compounds such as-tocopherol, squalene,-carotene and-sitosterol were also determined. CO 2 was the best solvent for extraction of bioactive compounds from pressed fiber palm, due to the highest extraction yield, antioxidant activities and sun protection factor.
A summary of the various quantum chemical analyses that have been employed to evaluate the free r... more A summary of the various quantum chemical analyses that have been employed to evaluate the free radical scavenger capacity of carotenoid molecules are tabulated in this review and the most important observations are discussed. These molecules are able to interact with reactive oxygen species through singlet oxygen scavenging, electron transfer, hydrogen atom abstraction and radical adduct formation. Most studies employ density functional theory to compare the antiradical capacity of different carote-noids with the ones that are most explored theoretically, such as lycopene and b-carotene. A significant number of these applications have been directed towards understanding the electron transfer mechanism , and a useful tool called the FEDAM (full-electron donor-acceptor map) was developed to better evaluate this mechanism. Important aspects that may affect the radical scavenging capacity of carote-noids, such as synergistic effects and solubility, are sometimes overlooked, and a greater number of such compounds should be explored.