Ciência e Natura

Drying study and phytochemical profile of the aqueous extract of the scaly leaf bulb of Allium cepa L (var.roxa)

Cassiano Vasques Frota Guterres — 2024-04-10

The objective of this study was to evaluate the phytochemical profile, predict drying kinetics, and quantify the content of total phenolics and flavonoids present in the aqueous extract of the bulb of scamiform leaves of Allium cepa L. The plant material was collected in the municipality of São Luís (MA). For the preparation of the aqueous extract, the cold maceration process was used using distilled water as a solvent. For the study of the drying kinetics, 10 g of the material in natura was submitted to a convective air oven at 45 °C/4h. The statistical parameters were determined by nonlinear regression using the Statistica 10.0software, using the Quasi-Newton method. To determine the total phenolic content, the Folin-Ciocalteu methodology was used. And for the total flavonoids, the aluminum complexation assay was used. The determination of phenolics and total flavonoids revealed significant quantities in the extract, with values of 106.54 mg EAT g-1 and 26.36 mg EAT g-1, respectively. According to the prediction of the statistical data, it was verified that the mathematical methods of Midilli-Kucuk and Verma proved to be adequate to describe the drying process of Allium cepa L. Through the results obtained, the mathematical model was determined for the drying kinetics of the squamous leaf bulb Allium cepa L, in addition to attesting the presence of secondary metabolites, thus making the product fit for biologically active activities.

Chemical profile and therapeutic potential of the essential oil and nanoemulsions of Citrus x sp (Tanja Lemon)

Wivianni Karinne Chaves Ferreira — 2024-07-29

The objective of this study was to evaluate the chemical profile and therapeutic potential of the essential oil and nanoemulsions of Citrus x sp (Tanja Lemon). Hydrodistillation was used to extract the essential oil. Gas Chromatography coupled to Mass Spectrometry (GC/MS) was used for the analysis of chemical constituents. The phenolic content (CFT) was analyzed by the Folin-Ciocalteau assay, and flavonoids (CFLT) by complexation with aluminum. The nanoemulsions were formulated by the phase inversion method. The antioxidant activity was evaluated by a hydroxyl radical assay and the anti-inflammatory activity by protein denaturation, and antiarthritic activity by a cyclooxygenase inhibition assay in bovine albumin serum. By means of GC/MS, limonene was identified as the major component (70.25%). The determination of CFT and CFLT quantified 227.645 mg EAT g^-1 and 86.57 mg EQ g^-1. For antioxidant capacity, nanoemulsions have EC₅₀ values of 9.10-11.28 mg L^-1. In anti-inflammatory activity, synergies quantified 4.63-11.03 mg L^-1. For the antiarthritic activity, it is noted that among the nine synergies formulated, some manifested excellent antiarthritic activity, with EC₅₀ values of 1.9-1.98 mg L^-1. It can be affirmed that the formulations produced from Citrus x sp presented satisfactory results, evidencing the efficacy of their properties.

Eco-friendly strategies for the graphene oxide reduction

Leonardo Vidal Zancanaro — 2024-04-26

The reduced graphene oxide (rGO) is a nanomaterial derived from graphene, which exhibits a high surface area, chemical stability, and extensive diffusion of π-conjugated bonds. Graphene oxide (GO) can be reduced to rGO through different protocols, however, commonly applied methodologies involving the use of chemical reagents may have disadvantageous effects on the environment. Considering the excellent properties of rGO, this study aimed to reduce GO through sustainable green strategies using carrots, oranges, and beets as reducing agents. The characterization of GO and rGO was carried out by X-ray diffraction spectroscopy (XRD), Fourier-transform infrared spectroscopy (FTIR) and scanning electronic microscopy (SEM), which revealed a reduction in the spacing between the layers of GO, indicating the formation of rGO. Due to the outstanding results obtained, future studies will explore the properties of this nanomaterial as an adsorbent for contaminants of emerging concern.

Potentiation of the anti-inflammatory effect of Attalea speciosa (babassu) oil microemulsions through the incorporation of Citrus x aurantium L. (sour-orange) essential oil.

Marille do Carmo Marinho Bogéa — 2024-07-29

This study analyzed the anti-inflammatory activity of a microemulsion of A. speciosa oil with incorporation of the essential oil of Citrus × aurantium (sour orange). The plant material used in this research was collected in the region of São Luís-MA. The essential oil was extracted by hydrodistillation. The chemical constituents were identified by Gas Chromatography coupled with Mass Spectrometry (GC/MS). The microemulsions were formulated with A. speciosa oil, Citrus × aurantium and Tween 20. The total phenolic content was determined by the Folin-Ciocalteu spectrophotometric method. The anti-inflammatory activity was evaluated using the protein denaturation method with calculation of the 50% Efficient Concentration (EC₅₀). The total phenolic content and refractive index were found, respectively, for the oil of A. speciosa and for the essential oil of C. aurantium, being 238.01; 1.454 and 232.2; 1,470. It was observed that the oil of A. speciosa has greater anti-inflammatory activity than the essential oil of C. aurantium, while the formulated microemulsion showed greater anti-inflammatory activity than both tested individual oils. Finally, it is concluded that the microemulsion was effective in the anti-inflammatory process, indicating that the incorporation of the essential oil of C. aurantium to the microemulsion of A. speciosa increased its anti-inflammatory potential, confirming the possibility of its use with anti-inflammatory action.

Nanoemulsions of plant-based bioactive compounds with antimicrobial applications: a review

Júlio César Sousa Prado — 2024-04-10

The search for alternative antimicrobial agents is attracting increasing scientific interest. Natural products of plant origin are sources of several substances with proven biological activities, including antimicrobial activity. The encapsulation of these products in the form of a nanoemulsion seeks to overcome problems inherent to these products, such as instability and degradation. Based on these considerations, we carried out a bibliographical survey of nanoemulsions produced from plant-derived substances, such as essential oils and extracts, with antimicrobial potential, focusing on antibacterial, antifungal and antiviral activities. Articles and documents published in scientifically relevant journals, as well as keywords classified from Health Sciences Descriptors, were used. All documents relevant to this search reported that nanoemulsions loaded with essential oils and plant extracts from different botanical species had in vitro antimicrobial activity against different microorganisms of medical importance, in addition to enhancing the antimicrobial effects of these bioproducts. Therefore, nanostructured antimicrobials with essential oils and plant extracts can be considered treatment options for microbial diseases: due to their physicochemical properties, they act as better delivery vehicles for natural products with good bioavailability, by reducing toxicity and prolonging the useful life of these natural antimicrobials, thus enhancing treatment for infectious human diseases.

Polyurethanes Thermal, Hydrolytic and Soil Degradation: Systematic Literature Review

Amanda Schueng Lima — 2024-05-27

A search in the Scopus and Web of Science databases covering the period from 2016 to 2021 was carried out and used to update the methodology of polyurethanes hydrolytic, thermal and soil degradation assessment. To that effect, three groups of search words were used: (1) polymer degradation AND “hydrolytic degradation” AND polyurethane; (2) polymer degradation AND “thermal degradation” AND polyurethane; and (3) polymer degradation AND “soil degradation” AND polyurethane. It was observed that the studies on the degradation of polymers are disseminated in different research groups and on a continuous basis during the survey period. The main methodologies found to perform the degradation of polymers were: method of immersion of samples in aqueous solution to evaluate hydrolytic degradation, thermogravimetric analysis, differential exploratory calorimetry and accelerated weathering to evaluate thermal degradation and inoculation of the polymer in soils with different characteristics, such as pH, moisture and organic load to assess soil degradation. Polymers can become a biodegradable solution to the environmental issues generated by plastic waste.

Chemical characterization and biotechnological potential of Salvia rosmarinus Spenn essential oil nanoemulsions

Karen Caroline Cantanhede Chaves — 2024-07-29

This study aimed to determine the total phenolic compounds, evaluate the antioxidant and anti-inflammatory activities of nanoemulsions (O/W) and essential oils (EOs) from Salvia rosmarinus (rosemary). The plant material was obtained in the city of São Luís (MA). The EO was obtained by the hydrodistillation technique in a modified Clevenger extractor and the NOE's by phase inversion. The chemical constituents of EO were determined by GC-MS. The determination of total phenolic compounds (TPC) was performed by the Folin-Ciocalteu method. The anti-inflammatory activity was performed by the method of protein denaturation and the antioxidant activity by the spectrophotometric method of scavenging hydroxyl radicals. The GC-MS allowed quantifying 1,8-cineol (30.22%), α-pinene (22.14%), camphor (18.33%) and camphene (10.36%) as major components of the EO. The TPC of the EO was quantified at 26.74 mg EAT g^-1 and the refractive index at 1.466 nD 25°. In the antioxidant activity test, an EC₅₀ of 80.33 mgL^-1 was obtained for the EO and from 19.56 to 408.85 mg L^-1 for the nanoemulsions. In the anti-inflammatory activity assay, an EC₅₀of 62.46 mgL^-1 was obtained for EO and 64.96 to 4220.25 mg L^-1 for NOE's. Finally, the pharmacological activities tested showed efficient values for EC_50, therefore considered active. This activity is attributed to its chemical compounds present, thus encouraging studies with this species aiming at its potential application in a formulated bioproduct.

The use of magnetic nanocomposites containing carbon derivatives and biopolymer for aquatic contaminants removal

Franciane Batista Nunes — 2024-06-24

Anthropogenic activities and industrial development are consequences of the increase in the world population occurred in the last century. The result is more generation of waste through textile and metal-mechanic industries mainly by carrying out improper disposal, without proper treatment directly in the environment. This practice is criminal and causes irreversible damages to humans and other animals affected by the contaminants. As a result, the exploration, research, and development of new materials with “green” characteristics as well as new compounds, which is the case of magnetic nanocomposites containing graphene oxide and chitosan in their structure. The present review approaches these materials and their application in process for adsorption of metallic contaminants and dyes. The combination of these nanomaterials presents a potential and promising characteristic in the adsorption processes, demonstrating high efficiency, easy handling, and reusable capacity due their magnetic characteristic and combined properties.

Graphene oxide assessment on the germination of Persian clover and buckwheat seeds

Raquel Stefanello — 2024-04-10

The increase in the use of graphene oxide (GO) allows different studies in several fields, and raise concerns about its possible toxic effect on the environment, especially in the early growth of plants. Thus, this study aimed to evaluate the effect of GO on the germination of Persian clover and buckwheat seeds. The seeds were placed on germitest paper in different concentrations of graphene oxide (0, 125, 250, and 500 mg L^-1) and kept in a germination chamber at 20 °C (photoperiod of 12 hours). The evaluated parameters were seed germination and seedling growth (length and dry mass). Graphene oxide did not show toxic effects on seed germination and initial growth of both species up to 500 mg L^-1. In this context, understanding the role of graphene oxide in the germination process and the development of plants will be able to contribute positively to understanding its possible environmental impacts when used in large quantities in ecosystems.

Aflatoxin M1 in milk and dairy products in Brazil: a review of characteristics, contamination, human exposure and health risks

Cesar Vinicius Toniciolli Rigueto — 2024-04-10

This paper aimed to present a review of the presence of aflatoxin M1 in milk and dairy products in Brazil, along with its characteristics and potential risks to human health. Overall, most studies analyzed during the defined period of this review (2013 to May 2023) reported average concentrations of AFM1 within the limits established by Brazilian legislation for milk, powdered milk, and cheese. However, considering the consumption of milk and dairy products by more vulnerable groups, such as children, two studies reported levels of AFM1 above the limits established for aflatoxins in different regions of Brazil. Thus, a more rigorous inspection by the responsible Brazilian authorities is necessary. Furthermore, since AFM1 is the only mycotoxin present in milk relevant to public health, it is important to continue conducting studies on the detection and determination of aflatoxins in milk and dairy products. This is necessary to monitor these contaminants and estimate the levels to which the population is exposed.

Adsorption study of micropollutants by biosorbents from different rice harvest residues for large scale applications

Patricia da Rosa Lira — 2024-04-10

A large-scale removal of micropollutants from residual waters is an urgent problem to be tackled. In this work, three biomasses from agricultural residues, produced by different processes, were compared in terms of the adsorption efficiency of toxic species in water. The biosorbents used were rice husk ashes (RHA), leached rice husk silica (SRHA), and rice straw ashes (RSA). Two representatives of the most common micropollutants present in the effluent waters, 2-nitrophenol and the pesticide 2,4-dichlorophenoxyacetic acid (2,4-D), were chosen as probing molecules. The biosorbents were characterized by SEM, X-Ray FRX, FT-IR, BET, pHcpz, and hydrophobicity; surface areas of 175.81 m2 g-1(SRHA), 66.11 m2 g-1 (RHA) and 42.77 m2 g-1 (RSA) were found, together with a microporous morphology. Firstly, the efficiency of removal was evaluated through adsorption isotherms: RHA and SRHA proved to be more efficient, with an adsorption capacity of 29.14 mg g-1 and 23.75 mg g-1 of 2-nitrophenol and 10.82 mg g-1 and 10.55 mg g-1 for 2,4-D. In particular, the removal of more than 90% for both 2-Nitrophenol and 2,4-D stands out as a very promising result. In light of these results, pillow-shaped filters with RHA were fabricated and tested for the first time for 2-Nitrophenol removal on a larger scale. The positive outcome (removal efficiency of 73%) demonstrates the possibility of producing filters based on sustainable and cheap biosorbents that could be implemented industrially to improve water purification as well as to implement the concept of circular economy.

LID Implementation in an urban basin: a Brazilian case study

Camilla Pires dos Santos Câmara — 2024-08-09

Problems related to urban drainage systems and the disorderly growth of large urban centers have led to the search for alternative drainage techniques. These techniques have been called Low Impact Development (LID), and generally influence the reduction of peak flow and runoff volume. In an urban sub-basin in the city of Recife, PE, the hypothesis of replacing existing roofs with a green roof (GR) was considered in three scenarios: (1) pre-urbanized, (2) current, (3.1) 30% of GR, (3.2) 50% of GR, (3.3) 75% of GR, (3.4) 100% of T.V. For this, simulations were carried out in PCSWMM based on the current urbanization situation. Linimetric readings were taken for calibration, obtaining 0.61 NSE and 0.903 R². Validation was carried out using images at two points within the basin. The reduction in peak flow values ranged from 0.74 to 2.10 m³/s, in addition to the time being delayed from 31 to 90 minutes. As for river level values, the variation was between 4 and 13 cm, while volume reductions recorded values between 67.42 and 190.81 m³. Overall, this proposed methodology can help stormwater managers better evaluate the performance of LID techniques at different hydrological scales, showing the importance of prioritizing urban adaptation and green infrastructure implementation.

Use of green vegetable barriers as environmental noise attenuators: a case study in Irati, Parana

Jhenifer Spliethoff — 2024-04-10

The present study aims to evaluate the potential of the Secondary Mixed Ombrophilous Forest as a vertical noise-attenuating green barrier. The methodology calls for the development of an analysis of proximity between sampling points of omnidirectional noise monitoring to be measured at various distances from the source from the beginning of the barrier and inside the forest. A sound source reproducing amplified pink noise was used. In this research, an experimental strategy was used to prove the influence of this type of green plant barrier as a noise attenuator as one enters the interior of a fragment of Mixed Ombrophilous Forest, carrying out successive measurements of the sound pressure level at distances from the proximity of the source and the distances from the edge towards the interior of the forest that can prove the significant attenuating function of this type of green vertical barrier. In fact, the analyses performed for LZeq A and Z (dB) confirm a significant correlation for distance from the source regardless of the sound amplitude for measurements performed outside the barrier (in front of the source, 6 m behind the source, 6 meters in front of the source), as noise attenuation occurs as the sound propagates. However, the analyses inside the barrier (at 12m, 18m and 24m) present a negative correlation for distance, confirming the hypothesis of the effectiveness of the attenuation by the vegetal barrier.

Seasonal climatology of cold fronts in south-central South America from an automated detection system

Roseli de Oliveira — 2024-04-10

The cold fronts (CF) operating in south and south-central South America are the main ones responsible for heavy rain, thunderstorms with strong winds, and accentuated temperature drops. This study aimed to perform a seasonal climatology of CF’s displacement and intensity in the region above mentioned. A computational algorithm was developed called the Normalized Cold Front Detection Index (NCFI) for detecting and characterizing CFs through the CFSR and CFSv2 reanalysis data, using the meridional component of the wind at 10 meters and the air temperature at 2 meters. Ten areas were delimited: five coastal and five continentals. Seasonal climatology showed a higher frequency in winter, when these systems are more intense, averaging 20 per year. The patterns of displacement and intensity exhibited a decrease in CFs as they advanced toward lower latitudes. The synoptic analysis and the accumulated precipitation composites revealed that the CFs that act in the spring concentrated the accumulated precipitation in Santa Catarina’s western portion. In the summer, convection cells are responsible for storms and poorly distributed rain. In the autumn, rainfall is associated with CFs and maritime circulations, impacting Rio Grande do Sul and the west and north of Santa Catarina. In the winter, CFs dominate the precipitation pattern. According to the NCFI, spring, autumn, and winter cases are categorized as intense, while summer cases are moderate.

The use of maximum correlations of TSM of the Atlantic dipole and precipitation in the state of Ceará

Werbeson da Silva Freitas — 2024-04-26

It is known that the relationship between the ocean and the atmosphere is a major precursor of a wide range of meteorological events that influence the entire globe, including the rainfall regime in various regions. Understanding how these events explain precipitation is of constant interest. In this sense, the present work aimed to determine the maximum correlations between the Surface Sea Temperature (SST) anomalies in the Atlantic dipole region and precipitation in the State of Ceará. For this, we used observed and interpolated data of daily precipitation and SST anomalies from the National Oceanic and Atmospheric Administration (NOAA) for the period from 1982 to 2021. Using a tree algorithm between the maximum correlations of the Atlantic Dipole, based on in daily SST data, and precipitation we propose a methodological proposal to predict precipitation in the State of Ceará.

Spatial distribution of soil loss tolerance limits for the state of Paraíba using GIS

Paulo Roberto Megna Francisco — 2024-04-26

Changes in the physical and chemical attributes and biological processes of the soil over a long period of time lead to loss of ecosystem function and agricultural productivity. This work aimed to estimate, classify and map the soil loss tolerance limits for the lands of the State of Paraíba based on the values of the different soil classes, with variation in thickness of horizons and textural relationship, using modeling of geoprocessing data and techniques. The estimate was based on the effective depth, texture and density of the soils described in the 64 profiles from the Exploratory and Soil Recognition Survey and the Agricultural Zoning of the State of Paraíba and calculated using the Smith and Stamey (1964) method and using QGIS© for mapping. Soil loss tolerance followed the order of Oxisols > Cambisols > Argisols > Luvisols > Planosols > Neosols > Vertisols due to the influence of parameters such as effective soil depth and textural relationship between B and A horizons. Soil loss tolerance presented in the very high class an average of 20.08 t ha-1 yr-1 and are associated with Oxisols, Argisols, Cambisols, Planosols and Gleissoils. The upper class presented average losses of 10.56 t ha-1 yr-1 under Argisols. The tolerance limit for losses in the middle class was 6.59 t ha-1 yr-1 distributed under the Luvisols. The low class occurred in Luvisols, Planosols and Neosols distributed in 389 mapping units with an average limit of 3.90 t ha-1 yr-1; in the very low class it occurred under the Vertisols, Nátric Planosols and shallow Neosols with an average of 1.64 t ha-1 yr-1 of soil loss tolerance distributed in 362 mapping units.

Penny Circle: a study of the Quadratic Function

Marcia Falek Rocha — 2024-04-26

This work aims to present and discuss a pedagogical proposal involving the teaching of Quadratic Function, aimed at high school students. This is research with a qualitative approach, and is supported by the assumptions of mathematical research (Ponte et al., 2019). The activity arose from a reflection on the following question: how could the student recognize the graph of a Quadratic Function in a problem situation, using concrete material? Based on this proposal, the teacher can reflect on the teaching of functions and encourage the student to establish relationships between objects and mathematical problems that, through concrete material, allow experimentation and verification of conjectured results. In addition, review the contents of Affine Function, System Resolution, Radicals, Exponential Function, discuss the concepts of domain, codomain, range and properties of the graph of functions.

Cytotoxicity and genotoxicity of aqueous and hydroalcoholic extracts from Gallesia Integrifolia (Spreng) Harms

Sthefany Pereira Duarte — 2024-07-29

Gallesia integrifolia (Spreng) Harms is a medicinal plant commonly known in Brazil as pau-d'alho. This large tree species belongs to family Phytolaccaceae, which is widely distributed in several Brazilian states. Studies carried out with extracts deriving from different parts of this plant have evidenced its acaricidal, larvicidal, antifungal and bactericidal properties, among others. Thus, given its potential to be used as therapeutic alternative, the aim of the current study was to assess the cytogenetic and mutagenic effect of G. integrifolia, based on using the Allium cepa system and Random Amplified Polymorphic DNA (RAPD) as analysis tools, as well as on germination assay conducted with Lactuca sativa L. Results have indicated that aqueous and hydroalcoholic extracts from G. integrifolia leaves presented cytotoxic, genotoxic and mutagenic effects at the tested concentrations. The herein observed effects may be associated with phytochemical agents found in the tested extracts, as well as emphasize the importance of raising awareness about the indiscriminate use of medicinal plants. Thus, future research should be conducted to help isolating and better understanding the structure of components capable of inhibiting cell division.

APPLICATION OF THE BOOTSTRAP METHOD IN THE OPTIMIZATION OF BEET BETACYANIN EXTRACTION

Gabrielli Clímaco — 2024-07-31

The bootstrap method with resampling is a statistical tool that allows obtaining a greater confidence interval without the need for repetitions, as is the case with the RSM. The objective of this work was to apply this method in the extraction optimization of betacyanin from beet. Time and temperature were used in a second-order CCRD, and the response variable was the betacyanin content. The optimum extraction point was obtained by RSM, at 28min and 66°C. From the bootstrap analysis a reliable ellipse was constructed, and the maximum amounts were located at 20-35min and 60-65ºC, confirming the maximum extraction point. These results suggest that the bootstrap method is useful in evaluating the reliability of the optimization of betacyanin extraction from beet, predicted by RSM.