Repositório RCAAP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Current methods of controlling weeds have caused a dissatisfaction of social order, for putting at risk the quality of food for human or animal. Faced with this problem, associated with the appearance of more resistant species to current herbicides, it is necessary to find new methods of control. This paper describes a phytotoxic evaluation of diclorometanólico extract of leaves of Curatella americana (lixeira) in order to evaluate their efficiency in relation to the inhibition of seed germination of Panicum maximum (capim-colonião), in boxes Gerbox and greenhouse and the subsequent Panicum maximum characterization of allelopathic compounds responsible for inhibition. Were conducted germination, with a photoperiod of 10 hr for 7 days and with solutions of the extracts at concentrations of 0, 50, 100, 150, 200 and 250 ppm. The extract showed a high potential phytotoxic at concentrations similar to those used by commercial herbicides. In the qualitative identification of secondary metabolites present in the extract diclorometanólico sheet Curatella americana L. identificate flavonoids, anthraquinone aglycones, triterpenes, steroids, polyphenols and tannins. Identification the extract in Cromatography Gas: 3,7,11,15-Tetramethyl-2-hexadecen-1-ol, 2-Hexadeciloxirano; 1-(+)-ascorbic acid2,6-dihexadecanoate, Ethyl-hexadecanoate, and Ethyl-octadecanoate and Tetrapentacontano.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

This work had the aim to assess some biological eects of the Bidens sulphurea (Asterace ) (also know as Cosmos sulphureus), assessed eects were: cytotoxicity, antibiotic and phototoxicity. The phototoxicity was ephasized, since the primary aim of this work was to evaluate if this plant\'s pigments could be used as photosensitizers in the photodynamic therapy, in a non invasive way, using light emitted by LED, for treatment of dermatosis, particularly, onicomicosis. The conclusion of this work is that, of the two Bidens sulphurea varieties studied, the one that bear the greater photodynamic activity, when irradiated with white light, or red light ( 600 nm) and did showed greater antibiotic eect (in the dark) was the orange variety. The orange variety did showed an increase in the toxicidy to the Artemia salina nauplii, when irradiated with red light.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

This study aims to understand how the Programa Institucional de Bolsa de Iniciação à Docência da Universidade Federal de Uberlândia influences in formation of chemistry teachers in the subproject Pibid|Química|UFU. The methodology adopted for the development in the research - beyond the study of art about teacher training and programs that encourage this training it was performed a qualitative research, being a case study of ethnographic perspective, wherever was if made a fieldwork in the participants schools of Pibid|Química|UFU, who owned the subproject in chemistry area. We verified that the work done in subproject allowed the narrowing of the actions of UFU with the public schools, putting forth the knowledge for teacher training through negotiations performed in the participating schools, as well as the proposition of specific actions to be developed in the educational environment. The Pibid|Química|UFU, in this case, proved to be an important instrument of teaching professionalization, although the limitations and difficulties encountered during this investigation.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

In this work was carried out chemical analysis, identification of volatile components, the determination of antioxidant activity and antibacterial activity of wood, bark and leaves of Cordiera sessilis (Vell) Kuntze, known as marmelinho. This study is justified because the analysis of chemical species Cordiera sessilis (Vell) Kuntze had not been studied so far. Ethanol extracts of leaves, bark and wood were prepared and subjected to chemical analysis, seeking to identify, quantify and therefore determine the applicability of vegetable medicinal use. The percentages obtained for the macromolecular constituents of the bark and wood are within the acceptable range for hardwood trees. The content of Klason lignin was found to be 28.55 % and 24.00 % holocellulose content was 20.0 % and 72.0 % for the shell and timber, respectively. This work presents the first identification by gas chromatography-mass spectrometry (GC-MS) of essential oil from leaves, bark and wood. 31 were identified components for the sheets, in most organic acids, totaling 46 % of oil, especially the n-hexadecanoic acid (24.73 %) and linolenic acid (6.91 %). Linalool, α-Terpineol, (E)-Geraniol and Phytol were only found oxygenated monoterpenes and diterpenes respectively, corresponding to 5.84 % of total oil. Even if include short chain alcohols (such as cyclohex-4-en-1-ol, hex-3-en-1-ol, Hex-2-en-1-ol, 1-hex-1-anol ), totaling 23 % of oil, and aldehydes (such as (E)-2-hex-2-enal (5.31 %)), totaling 12 % of total oil. To the shells 18 have identified components, the majority of long chain fatty acids, total 88.4% of oil, especially the hexadecanoic acid (40.11 %) and octadecadienoic acid (33.2 %). In the wood was identified 18 components, we have again the predominance of long chain fatty acids, especially hexadecanoic Acid (32.23 %) and n-nonadecanoic acid (18.53 %), and this time was found sesquiterpene trans-Caryophyllene (0.72 %). For analysis of total phenols by Folin-Ciocalteau found 42.12 ± 0.93 mg g-1 sample to the leaves and 35.23 ± 0.46 mg g-1 sample to the shells. The content of proanthocyanidins found by the method of Vanillin was 133.6 ± 0.021 mg ECAT g -1 sample to the sheets and 111.1 ± 0.023 mg ECAT g-1 sample for the peel. In determining the antioxidant activity of EC50 values found for the leaves were 38.94 ± 2.59 mg mL-1 for the crude ethanolic extract, 79.67 ± 4.19 mg mL-1 for cyclohexane partition, 38.165 ± 5, 92 mg ml-1 for the partition dichloromethane, 17.97 ± 2.72 mg mL-1 to the partition ethyl acetate, and 15.79 ± 1.017 mg ml-1 for the partition methanol. As for the shells found EC 50 values are 39.73 ± 5.01 mg mL-1 for crude ethanol extract, 415.55 ± 0.83 mg mL-1 for the partition cyclohexane and 33.24 ± 0.75 g ml-1 for the partition dichloromethane. The extracts from the leaves and barks and its partitions showed antibacterial activity against the micro-aerobic and anaerobic organisms, especially the partitions in cyclohexane and dichloromethane leaf with values of minimum inhibitory concentrations (MIC) of 50 mg mL-1 for anaerobic micro-organisms. The partition of cyclohexane shells with MIC of 25 mg ml-1 and the other partitions of the leaves had minimum inhibitory concentrations ranging from 200 to 400 mg mL-1 for aerobic micro-organisms, and values between 100-400 mg ml-1 for micro anaerobic organisms. The partitions shells ranged from 25-400 mg ml-1 for the aerobic and anaerobic for the values are higher than 400 mg mL-1. Compared with other studies of cerrado plants MIC values for the extracts and partitions of the leaves are considered very relevant to the continuing search for other characterizations.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

The oleaginosa Macauba (Acrocomia aculeata) stands out as a feedstock for biodiesel production because it is a non-edible oil and so does not compromise the oils that are used in human food. The fruit of Macauba consists of two oil sources : the mesocarp / flesh and almonds, two sources that have high oil content, which can be used to produce biodiesel. In this work, it was previously to analyze the physical chemical properties of raw crude, and from there, was made choice of a catalyst to be performed. For the transesterification reaction was used alcohols: methanol and ethanol in the presence of catalysts: acid and basic. When comparing the chemical and physical characteristics of the oils Macauba, it was observed that the oil of almonds has better features than the mesocarp oil, the same was evident when comparing their biodieseis. These facts can be attributed to the presence of ligneous endocarp that surrounds the kernel performs the function of protection against degradation processes. The best features of almond oil are also reflected in its cost of buying which is three times larger than the mesocarp oil. In order to take advantage of the raw material of lesser value, we analyzed the reaction conditions to obtain the maximum yield of biodiesel from oil Macauba the mesocarp, the route was evaluated with methyl acid catalysts due to high levels of free fatty acids oil contained in the mesocarp. The variables studied were: the mass ratio of methanol: oil, temperature, type of acid catalyst (HCl and H2SO4) and reaction time. The maximum yield was close to 98.0%, obtained with 1% H2SO4 catalyst at a temperature of around 74.0 °C and mass ratio methanol: oil equal to 7,6:1.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais

Biodiesel is the fuel obtained from vegetable oils or animal fats that can partially or totally replace diesel oil. Besides being obtained from renewable sources, biodiesel is less polluting than diesel and biodegradable. One disadvantage of biodiesel is the byproduct of transesterification reaction of raw material, glycerol, which can cause damages to combustion engines and therefore is limited to 0.25 % (m/m) as total glycerol and 0.02 % (m/m) as free glycerol according to technical regulations as ANP 7, ASTM D 6751 and EN 14214. This paper proposes an amperometric method for the determination of free glycerol in biodiesel at gold electrode in basic medium, coupled with flow injection analysis system (FIA). Voltammetric characterization was made from -0.8 to 0.5 V, verifying an electrochemical profile consistent with literature. To glycerol determination in the FIA system, multiple pulse amperometry was used with application of three sequential potentials: -0.2, 0.25 and 0.7 V, each one applied for 100 ms. Free glycerol was extracted to the analyzed aqueous phase by vortex stirring (5 min) followed by centrifugation (5 min). FIA system was evaluated in order to obtain the highest current signal to glycerol detection. Best conditions were sampling loop of 150 μL and flow of 4.0 mL min-1. To validate some parameters as repeatability, linearity, recovery, detection and quantification limits were determined. The repeatability had low standard deviation (4.8% with 14 injections), high analytical frequency (100 injections h-1), recovery values from 96% to 117 %, linear range from 49.10 to 2288 μmol L-1, detection limit of 14.73 μmol L-1 e quantification limit of 49.10 μmol L-1. Therefore, the determination of free glycerol in biodiesel based on aqueous extraction and gold electrode detection in basic medium under flow can be used to determine concentrations less than 15.0 μmol L-1 glycerol, while the regulated upper limit is 200 ppm, which corresponds to 2.17 mmol L-1.

The species Vernonia brasiliana Less., a.k.a. assa-peixe, assa-peixe preto, assa-peixe roxo, pau de múquem, pau de muqueca and manjericão de cavalo, is a very used plant in folk medicine. The root syrup fights against cough and flu; the bud tea is used in eye diseases and respiratory failure; the leaves are used to inhibit inflammatory rheumatism, hepatic colic and some cases of hemorrhage. The objectives of the present work were to produce ethanolic extracts and essential oil of the plant parts (leaves, flower and root) of Vernonia brasiliana. Also, we evaluated the level of phenolic compounds, proanthocyanidins, antioxidant and antimicrobial activity, oxidation potentials level, and identified the compounds of the essential oils. The oils were tested against Staphylococcus aureus and Escherichia coli in vitro bacteria and against Trypanosoma cruzi and Leishmania, in vitro protozoa. The ethanolic extracts presented a total phenol by Folin-Ciocalteau method of 133, 127 and 87 mg of GAE (gallic acid equivalents) per gram of sample, respectively for leaves, flowers and root. The condensed tannins presented values of 122, 147 and 109 mg of catechin equivalents (CE) per gram of sample, respectively for flower, leaves and root. The antioxidant activity by DPPH method presented CE50 values 25, 27 and 37 for leaves, root and flowers, respectively. The diferential pulse voltammetry presented values of 0.205, 0.232 and 0.199 volts for oxidation potential and 158.2, 160.3 and 113.2 microcouloumbs of charge for leaves, flowers and root, respectively. The compounds with higher percentage identified in the essential oil were: modheph-2- ene, alpha-isocomene, ciperene, beta-isocomene and beta-caryophyllene in the root; palmitic acid, hexan-1-ol and septacosane in the flower; and trans-caryophyllene, germacrene D, bicyclogermacrene, spathulenol and palmitic acid in the leaves. There was no evidence of antimicrobial effect for extracts and essential oil against Staphylococcus aureus and Escherichia coli. The extracts of Vernonia brasiliana were not significant because they are considered toxic at concentrations that were active aganst antitrypanossoma and antileishmaina. However the three oils showed a valid activity against Trypanosoma cruzi and Leishmania amazonensis, since it shows no toxicity at concentrations that have shown activity.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior