951 resultados para phenolic compound


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Purpose: This study investigated the energy system contributions of judo athletes to the Special Judo Fitness Test (SJFT). Methods: Fourteen male judo athletes performed the SJFT, which comprised three periods of judo activity (A = 15 s, B and C = 30 s) interspersed with 10 s rest intervals. During this test, one athlete threw two others positioned 6 m from each other using the ippon-seoi-nage technique. The fractions of the aerobic, anaerobic alactic and anaerobic lactic systems were calculated based on oxygen uptake, the fast component of excess postexercise oxygen uptake, and changes in net blood lactate, respectively. The contribution of the three energy systems was compared using a repeated measures analysis of variance and Bonferroni's multiple comparisons test. Compound symmetry, or sphericity, was determined by Mauchly's test. A level of significance of 5% (P < .05) was adopted in all analyses. Results: The alactic energy system presented a higher (F = 20.9; P < .001; power observed = 1.0) contribution (86.8 +/- 23.6 kJ; 42.3 +/- 5.9%) during the test when compared with both aerobic (57.1 +/- 11.3 kJ; 28.2 +/- 2.9%) and lactic (58.9 +/- 12.1 kJ; 29.5 +/- 6.2%) energy systems (P < .001 for both comparisons). Conclusions: The higher alactic contribution seems to be a consequence of the high-intensity efforts performed during the test, and its intermittent nature. Thus, when using the SJFT, coaches are evaluating mainly their athletes' anaerobic alactic system, which can be considered to be the most predominant system contributing to the actions (techniques) performed in the match.

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Temperature-dependent electrical resistance in quasi-one-dimensional Li(0.9)Mo(6)O(17) is described by two Luttinger liquid anomalous exponents alpha, each associated with a distinct one dimensional band. The band with alpha < 1 is argued to crossover to a higher dimension below the temperature T(M'), leading to superconductivity. Disorder and magnetic fields are shown to induce the Bose metal behavior in this bulk compound.

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Transport properties and magnetization measurements of the K(x)MoO(2-delta) (0 <= x <= 0.25) compound are reported. The compound crystallizes in the oxygen deficient MoO(2) monoclinic structure with potassium atoms occupying interstitial positions. An unconventional metallic behavior with power-law temperature dependence is related to a magnetic ordering. Superconducting transition with small volume fraction is also observed near 7 K for a sample with low potassium composition.

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The effects of chromium or nickel oxide additions on the composition of Portland clinker were investigated by X-ray powder diffraction associated with pattern analysis by the Rietveld method. The co-processing of industrial waste in Portland cement plants is an alternative solution to the problem of final disposal of hazardous waste. Industrial waste containing chromium or nickel is hazardous and is difficult to dispose of. It was observed that in concentrations up to 1% in mass, the chromium or nickel oxide additions do not cause significant alterations in Portland clinker composition. (C) 2008 International Centre for Diffraction Data.

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Background: Brazilian propolis type 6 (Atlantic forest, Bahia) is distinct from the other types of propolis especially due to absence of flavonoids and presence of other non-polar, long chain compounds, but presenting good in vitro and in vivo antimicrobial activity. Several authors have suggested that fatty acids found in this propolis might be responsible for its antimicrobial activity; however, so far no evidence concerning this finding has been reported in the literature. The goals of this study were to evaluate the antibacterial activity of the main pure fatty acids in the ethanolic extract and fractions and elucidate the chemical nature of the bioactive compounds isolated from Brazilian propolis type 6. Methods: Brazilian propolis type 6 ethanolic extract (EEP), hexane fraction (H-Fr), major fatty acids, and isolated sub-fractions were analyzed using high performance liquid chromatography (HPLC), high resolution gas chromatography with flame ionization detection (HRGC-FID), and gas chromatography-mass spectrometry (GC-MS). Three sub-fractions of H-Fr were obtained through preparative HPLC. Antimicrobial activity of EEP, H-Fr, sub-fractions, and fatty acids were tested against Staphyloccus aureus ATCC 25923 and Streptococcus mutans Ingbritt 1600 using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Results: EEP and H-Fr inhibited the growth of the microorganisms tested; nevertheless, no antimicrobial activity was found for the major fatty acids. The three sub-fractions (1, 2, and 3) were isolated from H-Fr by preparative HPLC and only sub-fraction 1 showed antimicrobial activity. Conclusion: a) The major fatty acids tested were not responsible for the antimicrobial activity of propolis type 6; b) Sub-fraction 1, belonging to the benzophenone class, was responsible for the antimicrobial activity observed in the present study. The identification of the bioactive compound will improve the development of more efficient uses of this natural product.

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Strawberries represent the main source of ellagic acid derivatives in the Brazilian diet, corresponding to more than 50% of all phenolic compounds found in the fruit. There is a particular interest in the determination of the ellagic acid content in fruits because of possible chemopreventive benefits. In the present study, the potential health benefits of purified ellagitannins from strawberries were evaluated in relation to the antiproliferative activity and in vitro inhibition of alpha-amylase, alpha-glucosidase, and angiotensin I-converting enzyme (ACE) relevant for potential management of hyperglycemia and hypertension. Therefore, a comparison among ellagic acid, purified ellagitannins, and a strawberry extract was done to evaluate the possible synergistic effects of phenolics. In relation to the antiproliferative activity, it was observed that ellagic acid had the highest percentage inhibition of cell proliferation. The strawberry extract had lower efficacy in inhibiting the cell proliferation, indicating that in the case of this fruit there is no synergism. Purified ellagitannins had high alpha-amylase and ACE inhibitory activities. However, these compounds had low alpha-glucosidase inhibitory activity. These results suggested that the ellagitannins and ellagic acid have good potential for the management of hyperglycemia and hypertension linked to type 2 diabetes. However, further studies with animal and human models are needed to advance the in vitro assay-based biochemical rationale from this study.

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Commonly consumed carbohydrate sweeteners derived from sugar cane, palm, and corn (syrups) were investigated to determine their potential to inhibit key enzymes relevant to Type 2 diabetes and hypertension based on the total phenolic content and antioxidant activity using in vitro models. Among sugar cane derivatives, brown sugars showed higher antidiabetes potential than white sugars; nevertheless, no angiotensin I-converting enzyme (ACE) inhibition was detected in both sugar classes. Brown sugar from Peru and Mauritius (dark muscovado) had the highest total phenolic content and 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, which correlated with a moderate inhibition of yeast alpha-glucosidase without showing a significant effect on porcine pancreatic alpha-amylase activity. In addition, chlorogenic acid quantified by high-performance liquid chromatography was detected in these sugars (128 +/- 6 and 144 +/- 2 mu g/g of sample weight, respectively). Date sugar exhibited high alpha-glucosidase, alpha-amylase, and ACE inhibitory activities that correlated with high total phenolic content and antioxidant activity. Neither phenolic compounds or antioxidant activity was detected in corn syrups, indicating that nonphenolic factors may be involved in their significant ability to inhibit alpha-glucosidase, alpha-amylase, and ACE. This study provides a strong biochemical rationale for further in vivo studies and useful information to make better dietary sweetener choices for Type 2 diabetes and hypertension management.

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We report the synthesis and total NMR characterization of 5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid-3-[[[(4''-nitrophenoxy)carbonyl]oxy]-methyl]-8-oxo-7[(2-thienyloxoacetyl)amino]-diphenylmethyl ester-5-dioxide (5), a new cephalosporin derivative. This compound can be used as the carrier of a wide range of drugs containing an amino group. The preparation of the intermediate product, 5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid-3-[methyl-4-(6-methoxyquinolin-8-ylamino) pentylcarbamate]-8-oxo-7-[(2-thienyloxoacetyl)amino]-diphenylmethyl ester-5-dioxide (6), as well as the synthesis of the antimalarial primaquine prodrug 5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid-3-[methyl-4-(6-methoxyquinolin-8-ylamino) pentylcarbamate]-8-oxo-7-[(2-thienyloxoacetyl)amino]-5-dioxide (7) are also described, together with their total H-1- and C-13-NMR assignments.

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The Te(IV) atom in the title compound, [Te(C(4)H(9))(C(8)H(10)Br)Cl(2)] or C(12)H(19)BrCl(2)Te, is in a distorted psi-trigonal-bipyramidal geometry, with the lone pair of electrons projected to occupy a position in the equatorial plane, and with the Cl atoms being mutually trans [172.48 (4)degrees]. Close intramolecular [Te center dot center dot center dot Br = 3.3444 (18) angstrom] and intermolecular [Te center dot center dot center dot Cl = 3.675 (3) angstrom] interactions are observed. The latter lead to centrosymmetric dimers which assemble into layers in the bc plane. The primary connections between layers are of the type C-H center dot center dot center dot Cl.

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The pyrrolidine-2,5-dione ring in the title compound, C(15)H(15)NO(6), is in a twisted conformation with the acetyl C atoms projecting to opposite sides of the ring. The acetyl groups lie to opposite sides of the five-membered ring. The benzene ring is roughly perpendicular to the heterocyclic ring, forming a dihedral angle of 76.57 (14)degrees with it. In the crystal, molecules are connected through a network of C-H center dot center dot center dot O and C-H center dot center dot center dot pi interactions.

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Two independent pseudo-enantiomeric molecules comprise the asymmetric unit in the title compound, C(15)H(14)O(2). While the central O-C-C-C residue approaches planarity [torsion angles = -15.8 (3) (molecule a) and 15.4 (3)degrees (molecule b)], the benzene rings are approximately orthogonal [the dihedral angles formed between the benzene rings are 62.89 (12) (molecule a) and 80.15 (12)degrees (molecule b)]. Two-dimensional arrays in the ab plane sustained by O-H center dot center dot center dot O hydrogen bonding are found in the crystal structure.

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The 1,3-dioxin-4-one ring in the title compound, C(16)H(16)O(3), is in a half-boat conformation with the quaternary O-C(CH(3))(2)-O atom lying 0.546 (1) angstrom out of the plane defined by the remaining five atoms. The crystal structure is consolidated by C-H center dot center dot center dot O contacts that lead to supramolecular layers.

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The tetrahydropyrimidinone ring in the title compound, C(20)H(20)N(2)O(2), is in a half-boat conformation with the N-C-N C atom 0.580 (2) angstrom out of the plane defined by the remaining five atoms. In the crystal structure, molecules are connected into centrosymmetric dimers via N-H center dot center dot center dot O interactions. The dimeric aggregates are linked into supramolecular chains along the a axis via C-H center dot center dot center dot pi interactions.

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The title compound, K(+)center dot C(8)H(13)BF(3)O(2)(-)center dot H(2)O, which was obtained from the reaction of a modified form of Z-vinylic telluride via a transmetalation reaction with n-BuLi, crystallizes as K(+) and C(8)H(13)BF(3)O(2)-ions along with a water molecule. The K(+) cation is surrounded by four anions, making close contacts with six F atoms at 2.659 (3)-2.906 (3) angstrom and with two O atoms at 2.806 (3) and 2.921 (3) angstrom in a distorted bicapped trigonal-prismatic geometry.

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Esenbeckia leiocarpa Engl. (Rutaceae), popularly known as guaranta, goiabeira, is a native tree from Brazil. Bioactivity-guided fractionation of the ethanol stems extract afforded the isolation of six alkaloids: leiokinine A, leptomerine, kokusaginine, skimmianine, maculine and flindersiamine. All isolated compounds were tested for acetyl cholinesterase inhibition, in vitro and displayed anticholinesterasic activity. The alkaloid leptomerine showed the highest activity (IC(50) = 2.5 mu M), similar to that of the reference compound galanthamine (IC(50) = 1.7 mu M). The results showed for the first time the presence of alkaloids leptomerine and skimmianine in E. leiocarpa (Engl.) with potent anticholinesterasic activity.