Resumo em Português:

Chlorophyll is the most abundant green pigment on the planet, it is unstable and decomposes naturally. Mate-herb is a traditional native plant in the southern region of South America, and its tea is part of the local culture and extractive agriculture. The mate-herb industry generates as a by-product a resinous material rich in chlorophyll whose use is proposed to be a natural pigment. The chlorophyll extraction method uses ethanol as a solvent; its structural modification leads to the obtainment of derivatives like pheophytin, Co-pheophytin, Ni-pheophytin, and Zn-pheophytin. The samples were analyzed by electronic (VISIBLE) and vibrational (FTIR) spectroscopy, and energy-dispersive X-ray fluorescence spectrometry (EDXRF). Color analysis (CIE L*a*b*) was performed by decomposition in grayscale and the classification of the samples by the supervised machine learning (ML) algorithm Random Forest (RF), showing adequate accuracy for this type of matrix. The pigments were dispersed in synthetic enamel paint to study color stability when exposed to lighting. It was verified that Co-pheophytin and Ni-pheophytin are the most stable. The chlorophyll extracted from the resin presents an economically viable use for residues from mate-herb industries, whose family farmers benefit, with the bias of environmental and social sustainability, within the circular economy.

Resumo em Português:

LN-1 and LN-2 are two Ru(II) complexes coordinated to the phosphine and amines simultaneously, each with two chlorides. PPh3 is the phosphine and the amine is piperidine (LN-1) and perhydroazepine (LN-2). The two compounds are complexes five-coordinated square pyramidal geometry, with the amine in the axial plane. LN-1 and LN-2 were tested for the first time as initiator for piperine self-metathesis olefin. The system variables chosen to this study were the reactional time (24, 48 and 72 h), catalyst:substrate ratio (1:1 and 1:10 mol) and temperature (25 e 50 ºC). Results were analyzed by GC-ME. None olefin metathesis product was noted in the experiments to 25 ºC for until 72 h, in any catalyst:substrate ration. However, to 50 ºC for 72 h, olefin metathesis product from piperine was observed. LN-1 presented yield of c.a. 29% of product in the mixture and LN-2 were c.a. 39%. The product is interesting and unheard, it has two 1,3-benzildiaxine groups, interleaved for one unsaturated carbon chain. In the experiments with catalyst:substrate ratio of 1:10 mol there was no product formation. The results were discussed in function of the electronic and steric properties of the ancillary ligand of LN1 and LN-2.

Resumo em Português:

This work reports the use of the Octave, a free computational software, to optimize the experimental design in the synthesis of ethyl oleate from oleic acid and ethanol catalyzed by a native lipase from Aspergillus niger. The central composite factorial design (CCD) was performed with 2 levels and 3 variables (temperature, mass of native A. niger lipase and oleic acid:ethanol molar ratio) in conjunction with response surface methodology (RSM). The results indicate that variable 1 (oleic acid:ethanol molar ratio; X1) and 2 (mass of A. niger lipase, X2), as well as the interaction between them, are statistically significant. The optimal reaction condition was estimated using ANOVA data and the response surface. The experimental results are consistent with those estimated, and thus, ethyl oleate was obtained with conversion (> 90%) using oleic acid and ethanol in a 1:2 molar ratio, A. niger lipase (8,00 mg) and temperature of 45 °C in 6 hours of reaction.

Resumo em Inglês:

The control of fungal species in agriculture is mainly conducted with the use of contact or systemic fungicides. However, environmental and human health concerns and increased resistance of fungal species to existing fungicides have increased the pressure on researchers to find new active ingredients for fungal control which present low toxicity to non-target organisms, are environmentally safe, and can be applied at very low concentrations. It is herein described the synthesis of eleven glycerol triazole containing compounds (ten of them fluorinated derivatives) and evaluation of their fungicidal activity. Eight out of eleven synthesized compounds are novel and all of the glycerol derivatives were characterized using infrared (IR), nuclear magnetic ressonance (NMR), and mass spectrometry (MS) techniques. Theoretical calculations were also carried out and the results are discussed. Starting from glycerol, the triazole derivatives were prepared in four steps. Evaluation of them against Colletrotricum gloesporioides showed that compound 1-((2,2-dimethyl-1,3 dioxolan-4-yl)methyl)-4-(2-fluorophenyl)-1H-1,2,3-triazole (4d) (ED50 = 59.14 µg mL-1) was slightly more active than commercial fungicide tebuconazole (61.35 µg mL-1). Compound 4d presented attractive physicochemical features for agrochemical purposes as revealed by the calculated physicochemical parameters. It is believed that glycerol-fluorinated triazole derivatives can be explored towards the development of new chemicals for the control of fungal species.

Resumo em Inglês:

Exposure to heavy metals has been documented to induce changes in the expression of plant proteins. Phaseolus vulgaris L., represents a great source of nutrition for millions of people, and is the second most important legume crop. The present study aimed to investigate the effects of Hg stress on germination rate and identify the gene expression profiling of U1-70 kDa by using SDS-PAGE analysis. Seeds of black beans (P. vulgaris L.) variety Jamapa were used. The study was performed in the municipality of Guadalupe in Zacatecas, México; August 2009 to 2011. Embryos were exposed to 10 µmol L-1 HgCl2. Expression and detection of U1-70 kDa was affected by mercury. It was possible to amplify the cDNA for U1-70 kDa in all tested samples, there were also found variations in the mRNA of embryos bean seeds for western blot analysis. Mercury does not affect the germination of bean seeds P. vulgaris L.; there is variation in the expression of the U1-70 kDa protein at different hours of exposure to 10 µmol L-1 of mercury. The presence of U1-70 kDa is identified for the first time in early stages of germination of bean seeds P. vulgaris L.

Resumo em Inglês:

The genus Chamaecrista comprises more than 330 species, with only a few studies on their chemical composition and biologic activities. In this study, the phytochemical profile of leaf, stems, and fruits extracts of the C. duckeana were examined by UPLC ESI HRMS analysis to determine possibly bioactive constituents. The antioxidant activity was carried out through in vitro assay, by the sequestration of the free radical DPPH. To evaluate the cytotoxic activity of the extracts, an MTT assay was used and the IC50 was determined against HL60 and RAJI cell lines. The metabolic profiles of the botanical parts are dominated by flavonoid class, highlighting isoflavonoids such as daidzin and ononin. All these compounds are reported for the first time in C. duckeana. The extracts presented antioxidant potential, and the activity of the stems extract was higher than the standard butylated hydroxytoluene. In the cytotoxic assay, only HL60 line (leukemia) had growth inhibition over 80%. The stems presented more expressive cytotoxicity with IC50 of 137.3 (104.6-180.1) and 106.8 (96.52-118.3) μmol. L-1 for HL60 and RAJI, respectively. In conclusion, the present work provides an in-depth knowledge about the chemical profile of C. duckeana, a species rich in bioactive secondary metabolites with cytotoxic activity.

Resumo em Português:

Biodiesel is a renewable fuel, a substitute for fossil diesel, which is important for reducing GHG in Brazil. Therefore, this work aims to synthesize and characterize the catalyst using the support of natural zeolite impregnated with K2O and apply it in the production of biodiesel through the transesterification reaction. Through the analysis of characterizations such as XRD, characteristic peaks of Clinoptilolite and Mordenite zeolites were verified in the natural zeolite, in addition to evidencing the characteristic peaks of KI and K2O in this microporous support. Thermal and FTIR analyzes revealed the presence of KI and K2O in the presence of the decomposition region of composite compounds (500 to 800 °C) and corresponding vibration bands, while EDS analysis indicated the efficiency of KI to K2O conversion after calcination. To evaluate the application of the catalyst in the production of biodiesel, the following reaction conditions were studied: percentage of catalyst in relation to oil mass (6% and 8%), methanol:oil mass ratio (15: 1 and 30: 1) and temperature (60 °C and 90 °C). The catalyst presents good results reaching a conversion of 98.96% in esters using 6% catalyst, mass ratio oil:methanol 1:30 and reaction temperature of 90 °C.

Resumo em Inglês:

Failure or loss of human tissues and organs due to illness or injury requires the partial or even total transplantation. Although transplantation is a successful intervention, donor availability and immune rejections represent still the main drawbacks. In addition, the fast and proper recovery of the patient is nowadays more than necessary to prevent infection, chronic inflammation, and other complications during the tissue/organ healing process. There is still a tremendous interest of alternatives to transplantation, such as scaffold-based tissue engineering, that may contribute to practical outcomes for the worldwide health concern related to severe tissue injuries. Herein, we explore the features, benefits and scaffold designs applied for biotechnological sciences, particularly for tissue engineering. The great potential to transform biocompatible polymers in three-dimensional matrix, assimilating the extracellular matrix (ECM), makes them attractive for cells adhesion and proliferation. On the basic of relevant results recently reported in the literature, along with the pioneering works, we discuss specific issues and challenges such as matrix-cell interactions, strategies to design scaffolds with homogeneous nano/microscales using different techniques, e.g., hydrogels, electrospinning, and rotary jet spinning, as well as the combination of some of these techniques.

Resumo em Português:

Artemisinin, a natural sesquiterpene isolated from the Artemisia annua L. plant, represents a remarkable achievement in the treatment against malaria. Since its discovery in the 1970’s, researchers readily started synthesizing this complex natural product containing an unusual endoperoxide fragment. Despite various total syntheses reported, only in the last decade the production jumped from extraction/bench scale to industrial manufacturing. In this sense, the objective of this contribution is to highlight the discovery, the most representative works towards the synthesis of artemisinin and its main derivatives used worldwide against malaria, and the path to the industrial production of these compounds.

Resumo em Português:

Aromatic amines are important intermediates in the industry to produce a wide array of products, and the reduction of aromatic nitro compounds is the main methodology for their preparation. Considering this fact, the objective of this review is to describe the development of sustainable methodologies for the reduction of aromatic nitro compounds for their respective amines from 2017 to 2020. Thus, throughout the text, the reaction conditions and the various reagents, solvents and catalysts used in the synthesis of aromatic amines are presented, along with the main advantages of the methodologies described.

Resumo em Inglês:

Agathisflavone is a natural biflavone with restricted occurrence in plants. This biflavone presents several biological activities and can be important to developing new drugs. Obtaining such a molecule on a large scale for in vivo tests is a challenge. To date, there are no reports regarding its synthesis; thus, it is important to improve and develop methods for the purification of this bioactive compound from natural sources. Previous studies indicated that the leaves of Poincianella pyramidalis (Leguminosae) had agathisflavone predominantly. However, obtaining this compound requires some steps of chromatographic procedures and extraction with organic solvents. This paper compares four procedures for the purification of agathisflavone from its leaves, two by traditional chromatographic techniques and by complexation with inorganic bases. The purification in the automatic flash chromatography in two steps provides a high-yield extraction; the two procedures using alkaline extraction and the traditional method reduced to three steps provided the compound with similar yields. The biflavone was identified by TLC, and HPLC analysis showed that it was isolated with > 99% of purity. Thus, the applied methodologies provided the purification of this compound employing less volume of solvents, the number of chromatographic column procedures, and time-consuming, with increased yields.

Resumo em Inglês:

Dispersive liquid-liquid microextraction (DLLME) is a fast and simple technique and applicable procedure for the analysis of xenobiotics in different biological matrices. We have developed a DLLME method for the determination of benzodiazepines in plasma samples using liquid chromatography-diode-array detection (LC-DAD). During method validation, relative standard deviation values of more than 20% were observed for both intra and inter-day associated with precision and accuracy. So, full method validation was unsuccessful. Critical aspects and flaws associated with DLLME for benzodiazepines determination in biological matrices has never been addressed. The majority of previous studies involving DLLME for benzodiazepines analysis either did not carry out a full method validation or they do not share any details regarding their full validation procedure. The current study has focused on the issues and pitfalls encountered upon method validation so that scientific groups worldwide can avoid unnecessary experiments and benefit from the present discussion. These observations reinforce the need to carry out such a process to guarantee the reliability of the results, even more so if one is intending its application for real case samples in the field of toxicological analysis. Indeed, full, and satisfactory method validation is paramount to provide adequate and trustworthy analytical results.

Resumo em Português:

Being part of the Pharmacy course curriculum, Organic Chemistry emphasizes the fundamentals of Organic Synthesis, reaction mechanisms, as well as the methods for separation, purification and identification of organic compounds. However, students do not always realize the direct association between this knowledge and their future working field. In an effort to make such association more explicit, we proposed a case of possible intoxication, inviting students of Experimental Organic Chemistry to play the role of laboratory workers and seek evidence to resolve the case within a one-week period. By analyzing the proposed resolution, we verified that the students sought information about the substances involved, employed techniques studied in the discipline, and indicated possible poisoning culprits. Despite some limitations, the students involvement with the case and the search for information enlightened the direct relationship between the techniques addressed in the discipline and their future activity.

Resumo em Português:

Considering the recent expansion and democratization of access to Higher Education in Brazil, this article aims to characterize and compare the socioeconomic profiles of students who are entering the Bachelor (BAC), teacher education degree (LIC) and Chemical Engineering (ENG) at UNESP - Araraquara. A quantitative, longitudinal study was performed according to sociological interpretation of Pierre Bourdieu. The data stands for a socioeconomic questionnaire and the performance on the entrance exam of 1544 students between 2003 and 2018. A Socioeconomic Index was built through a Factorial Analysis and a Multiple Correspondence Analysis was performed to compare the profile of students of three courses. The results show that the students’ profiles are different, despite becoming similar in recent years, and the demand for these courses has been decreasing since 2016. There are three factors that explain these changes: i) young people’s lack of interest in scientific careers; ii) low attractiveness of the teaching career; iii) the creation of a new course modality in the institution (the ENG). Studies like this can contribute to identify, evaluate, and implement actions to democratize the access and permanence of students in Higher Education.

Resumo em Português:

The subject of the present article is a Brazilian chemist who lived and worked in the nineteenth century and who is hardly known today. He was the first person in Brazil, still in the first half of the nineteenth century, to write chemical equations in the description of actual reactions, and also the first to use equations in order to perform stoichiometric calculations. Although commonplace and trivial today, these were quite innovative in the 1840’s. He had a diploma from the École Centrale des Arts et Manufactures of Paris, from which he graduated in 1845 as a “chemical civil engineer”. Back in Brazil he continued his career, pioneering different aspects of chemistry in the country, and publishing continuously for a number of years on several chemical topics, as well as in other technical subjects. After what seemed to be a meteoric career, he became disillusioned with many setbacks, mostly political, and took up a different career, as a mathematician.