Ivânia Schuquel | Universidade Estadual de Maringa (original) (raw)

Papers by Ivânia Schuquel

Journal of Agricultural and Food Chemistry, 2015

Certain members of the genus Eugenia are used as foods. One of these species is Eugenia umbellifl... more Certain members of the genus Eugenia are used as foods. One of these species is Eugenia umbelliflora, which is used for its fruits. The aim of the study was to isolate the constituents of the CH2Cl2 fraction obtained from E. umbelliflora O. Berg (Myrtaceae) and also to evaluate its antimicrobial properties. Two new meroterpenoids, eugenial C (3) and eugenial D (4) were isolated from the unripe fruits of E. umbelliflora and their structures established mainly by extensive NMR spectroscopy. In previous studies, the CH2Cl2 extract showed significant antibacterial activity, which can be attributed to meroterpenoids isolated in this study. The compounds eugenials C and D exhibited potent activity against Bacillus subtilis and Staphylococcus aureus and different strains of MRSA and activity similar to those of the antibiotics used in antimicrobial therapies.

quimicanova.sbq.org.br

CHEMICAL CONSTITUENTS OF THE LEAVES AND ANTI-INFLAMMATORY ACTIVITY EVALUATION OF EXTRACTS OF ROOT... more CHEMICAL CONSTITUENTS OF THE LEAVES AND ANTI-INFLAMMATORY ACTIVITY EVALUATION OF EXTRACTS OF ROOTS AND LEAVES OF Guettarda pohliana Müll. Arg.(RUBIACEAE). The phytochemical investigation of Guettarda pohliana leaves led to ...

The infrared spectra of 3-X-2-methylpropenes (X = Cl, Br, I, NMe(2), NEt(2), OH, OMe, OEt, SH, SM... more The infrared spectra of 3-X-2-methylpropenes (X = Cl, Br, I, NMe(2), NEt(2), OH, OMe, OEt, SH, SMe and SEt) have been recorded at room temperature in CCl(4) solution. The C=C stretching mode was analyzed and compared to theoretically calculated data to give insight about the conformational isomerism of these compounds. A combination band systematically appears in all spectra (except for amines); the remaining ν(C=C) band and the corresponding intensities were used to obtain the conformer populations. For second-period atoms bonded to C-3, two or more conformers are observed in CCl(4) solution, but when substitution by heavier atoms takes place, only one conformer is observed under the tested conditions, i.e., the gauche form with respect to the C=C-C-X dihedral angle. Therefore, steric hindrance between X and =CH(2) in the s-cis form is strongly dependent on the heteroatom size, while the effect of the alkyl chain bonded to the heteroatom seems to be of secondary importance.

Journal of Molecular Structure, 2014

ABSTRACT Twelve methallylic derivatives were studied using C-13 NMR spectroscopy and theoretical ... more ABSTRACT Twelve methallylic derivatives were studied using C-13 NMR spectroscopy and theoretical calculations. Theoretical coupling constants were obtained with SOPPA (CCSD). All atoms were described by the EPR-III basis set, except for halogens, which were represented by the cc-pVTZ basis set. Geometries were optimized at the MP2/aug-cc-pVTZ level of theory, confirming previous results that the gauche and s-cis conformers predominate. Experimental (n)J(CH) coupling constants were determined from coupled C-13 NMR spectra, while the (1)J(CC) couplings were measured through the INADEQUATE technique. The experimental and theoretical values were in good agreement. Correlations with the usual substituent physicochemical parameters indicated that the (1)J(C3Hc) values (where Hc is attached to the C3 carbon bearing the substituent) exhibit good correlations with Taft's sigma (sigma(1) inductive parameter) and the Swain-Lupton Field Effect (F) (R similar to 0.957), while other correlations were not similarly significant (R values <0.9).

Carbohydrate Polymers, 2015

New pectin derivative (Pec-MA) was obtained in specific reaction conditions. The presence of male... more New pectin derivative (Pec-MA) was obtained in specific reaction conditions. The presence of maleoyl groups in Pec-MA structure was confirmed by 1 H NMR and FTIR spectroscopy. The substitution degree of Pec-MA (DS = 24%) was determined by 1 H NMR. The properties of Pec-MA were investigated through WAXS, TGA/DTG, SEM and zeta potential techniques. The Pec-MA presented amorphous characteristics and higher-thermal stability compared to raw pectin (Pec). In addition, considerable morphological differences between Pec-MA and Pec were observed by SEM. The cytotoxic effect on the Caco-2 cells showed that the Pec-MA significantly inhibited the growth of colon cancer cells whereas the Pec-MA does not show any cytotoxic effect on the VERO healthy cells. This result opens new perspectives for the manufacture of biomaterials based on Pec with anti-tumor properties.

Journal of the Brazilian Chemical Society, 2001

As proporções dos confôrmeros axial-equatorial do N,N-dimetilcarbamato de cicloexila foram determ... more As proporções dos confôrmeros axial-equatorial do N,N-dimetilcarbamato de cicloexila foram determinadas, pela primeira vez, pelo método de Eliel, pela ressonância magnética nuclear dinâmica(RMND) de 1 H e de 13 C e foram comparados com resultados obtidos através de cálculos teóricos. Pelo método de Eliel foram utilizados pelo menos cinco parâmetros experimentais independentes, em CCl 4 , CDCl 3 e CD 3 CN. Os experimentos de 1 H e de 13 C a baixas temperaturas foram realizados em CF 2 Br 2 /CD 2 Cl 2 . Os métodos semiempíricos MNDO, AM1 e PM3 e cálculos ab initio de orbital molecular nos níveis HF/STO-3G e HF/6-31G(d,p) também foram utilizados. Tanto os métodos que utilizaram a RMN como os cálculos teóricos corretamente indicaram a preferência do confôrmero equatorial em relação ao axial e os valores obtidos pelos diferentes métodos demonstraram boa concordância.

Phytochemistry, 1998

From the aerial parts of Bouchea fluminensis, a new iridoid glucoside, named boucheoside, along w... more From the aerial parts of Bouchea fluminensis, a new iridoid glucoside, named boucheoside, along with four known iridoid glucosides, lamiide, lamiidoside, durantoside II, and duranterectoside C, were isolated. The structure of the new compound was elucidated based on the spectroscopic evidence.

Spinal Cord, 2009

Study design: A case-control evaluating seminal citrate in patients with spinal cord injury (SCI)... more Study design: A case-control evaluating seminal citrate in patients with spinal cord injury (SCI). Objective: Several studies have shown neurological prostatic dysfunction in patients with SCI, as confirmed by low levels of seminal prostate-specific antigen (PSA), which is used as a parameter of gland activity. However, seminal citrate, produced almost exclusively by the prostate, could also be used as a marker of prostate function. Thus, the objective of this study was to determine whether SCI causes any changes in seminal citrate concentration and to compare the results obtained for patients and healthy men (controls). Setting: The study was carried out in Brazil. Methods: We studied 30 men with SCI aged on average 37.77±10.04 years and 30 controls aged on average 38.03 ± 10.06 years. Blood and semen samples were collected after 3 days of abstinence from ejaculation. Fifteen minutes after collection, semen was stored in liquid nitrogen and the samples were submitted to 1 H nuclear magnetic resonance ( 1 H NMR). Serum was stored at a controlled temperature of À70 to À79 1C and later used for the determination of testosterone, prolactin and total PSA using an AxSYM instrument and Abbott reagents. Results: The median concentration of seminal citrate was significantly lower in patients than in controls (521.65 versus 858.30 mg per 100 ml, Po0.001). Conclusions: Patients with SCI have a significant reduction of seminal citrate as a consequence of neurological dysfunction of the prostate.

Planta Medica, 2010

Because of the need for new anti-cancer drugs, many compounds have been evaluated for treatment o... more Because of the need for new anti-cancer drugs, many compounds have been evaluated for treatment of the disease [1]. We assessed the crude extract (CE), ethyl acetate fraction (EAF), and onopordopicrin compound isolated from leaves of Arctium lappa L. CE was obtained by 50% hydro-alcohol extraction (Ultra-Turrax), and was partitioned with ethyl acetate to obtain the EAF. EAF was subjected to sequential column chromatography with Merck ® silica gel (0.063-0.200mm), and Merck ® silica gel (0.040-0.063mm), thus obtaining onopordopicrin, which was identified by spectroscopic methods (NMR, MS) and by comparison with the literature. The in vitro antiproliferative test was performed on human tumor cell line Caco-2. The activities of the fractions and compound against Caco-2 cells were determined by sulforhodamine assay, as described by Skehan et al. [2]. The cells were seeded in 96-well tissue plates at a density of 8×10 5 cells/mL for 24h in the CO2 incubator. The compounds were dissolved in dimethyl sulfoxide and added to the medium at various concentrations. After incubation for 48h, the cell monolayers were fixed with trichloroacetic acid and stained for 30min with 0.4% sulforhodamine B. The protein-bound dye was extracted with 10 mM unbuffered Tris base for determination of optical density in a computer-interfaced, microtiter plate reader (Power Wave XS, BIO-TEK®). The results of CC50 in Caco-2 cells were 347.6±26.9 (RSD%=7.7) 24.7±3.0 (RSD%=12.2), and 19.8±3.7 (RSD%=18.5)µg/mL for EC, EAF, and onopordopicrin, respectively. These results showed that onopordopicrin may be a promising anti-cancer drug.

Phytochemistry Letters, 2010

1 H-1 H COSY and the HMQC spectra pointed to a proton spin system ranging from H-5 [d 8.33 (d, J ... more 1 H-1 H COSY and the HMQC spectra pointed to a proton spin system ranging from H-5 [d 8.33 (d, J = 6.6 Hz), d C 132.5] to H-6 [d 8.41 (d, J = 6.6 Hz), d C 116.0], and a second one ranging to H-9 [d 8.28 (d, J = 8.1 Hz), d C 122.8], over H-10 [d 7.48 (t, J = 8.1 Hz), d C 122.4] and H-11 to H-12 [d 7.76-7.91 (m), d C 132.3 and 113.2]. In addition to these

Dental Materials, 2014

d e n t a l m a t e r i a l s 3 0 ( 2 0 1 4 ) 155-163 Restorative dentistry Polymerization shrink... more d e n t a l m a t e r i a l s 3 0 ( 2 0 1 4 ) 155-163 Restorative dentistry Polymerization shrinkage Sorption Solubility Flexural strength Urethane Multifunctional monomers a b s t r a c t Objectives. To synthesize and characterize different molar weight urethane multimethacrylates with a single stage (one-pot) procedure. To prepare and characterize the properties of related composites.

Chemical Physics, 2008

The photoelectron (PE) spectra of some 3-monosubstituted 2-methylpropenes H 2 C@C(CH 3 )CH 2 X [X... more The photoelectron (PE) spectra of some 3-monosubstituted 2-methylpropenes H 2 C@C(CH 3 )CH 2 X [X = Cl, Br, I, OH, OMe, OEt, SH, SMe, SEt, N(Me) 2 and N(Et) 2 ] have been recorded. A preliminary analysis is presented indicating some trends in the ionization potentials associated with application of OVGF method and NBO analysis from MP2/6-31G(d,p) and cc-pVDZ level of theory indicating that the more effective hyperconjugation effect leads to the most stable conformers. The sensitivity of the outermost ionization energies of selected molecules with respect to the level of theory was analyzed. Application of the CASPT2 method with ANO basis set and geometries from MP2 calculations provided results in excellent agreement with the experimental data.

Carbohydrate Research, 2008

A new tetrahydro b-carboline alkaloid that has an oligosaccharide unit was isolated from the root... more A new tetrahydro b-carboline alkaloid that has an oligosaccharide unit was isolated from the root extracts of the Palicourea coriacea. The structure was elucidated using spectral methods, including 2D NMR: COSY, HMQC, HMBC and NOESY.