María Jimena Correa

Synthesis, characterization, antitumoral and osteogenic activities of quercetin vanadyl(IV) complexes

The development of new vanadium derivatives with organic ligands, which improve the beneficial actions (insulin-mimetic, antitumoral) and decrease the toxic effects, is of great interest. A good candidate for the generation of a new vanadium compound is the flavonoid quercetin because of its own anticarcinogenic effect. The complex [VO(Quer)2EtOH]n (QuerVO) has been synthesized and characterized by means of different spectroscopic techniques (UV–vis, Fourier transform IR, electron paramagnetic resonance) and its magnetic and stability properties. The inhibitory effect on bovine alkaline phosphatase (ALP) activity has been tested for the free ligand, the complex as well as for the vanadyl(IV) (comparative purposes). The biological activity of the complex on the proliferation of two osteoblast-like cells in culture, a normal one (MC3T3E1) and a tumoral one (UMR106), has been compared with that of the vanadyl(IV) cation and quercetin. The differentiation osteoblast markers ALP specific activity and collagen synthesis have been also tested. In addition, the effect of QuerVO on the activation of the extracellular regulated kinase (ERK) pathway is reported. The bone antitumoral effect of quercetin alone was established with the cell proliferation assays (it inhibits the proliferation of the tumoral cells and does not exert any effect on the normal osteoblasts). Moreover, the complex exerts osteogenic effects since it stimulates the type I collagen production and is a weak inhibitory agent upon ALP activity. Finally, QuerVO stimulated the ERK phosphorylation in a dose–response manner and this activation seems to be involved as one of the possible mechanisms for the biological effects of the complex.

Characterization of two new zinc(II) complexes with saccharinate and imidazole or benzimidazole as ligands

The crystal structure of the complexes [Zn(sac)2(im)2] (1) and [Zn(sac)2(bzim)2]2⋅2Et-OH⋅H2O (2) (sac = saccharinate anion; im = imidazole; bzim = benzimidazole; EtOH = ethanol) was determined by single crystal X-ray diffractometry. Complex 1 crystallizes in the monoclinic P21/n space group with a = 9.1585(5), b = 16.4409(6), c = 15.0249(5) Å, β = 94.079(1)°, and Z = 4, whereas complex 2 belongs to the triclinic space group P1 with a = 10.8500(2), b = 12.4860(2), c = 13.5640(3) Å, α = 115,696(1), β = 100.086(1), γ = 102.169(1)°, and Z = 1. In both complexes, the Zn(II) cations are in a slightly distorted tetrahedral ZnN4 environment, coordinated to two saccharinate anions and to two imidazole (1) and to two benzimidazole (2) molecules. The complexes were also characterized by means of infrared spectroscopy and their thermal behavior investigated by means of thermogravimetric and differential thermal analytical techniques.

Alp Inhibitors: Vanadyl(IV) Complexes Of Ferulic And Cinnamic Acid

Two new vanadyl(IV) carboxylate complexes have been obtained: Na2[VO(Fer)2(CH3OH)2] and Na2[VO(Cin)2(CH3O)2] and characterized by elemental analysis and UV-vis, diffuse reflectance and IR and Raman spectroscopies (FerH2 = ferulic acid, CinH= cinnamic acid). The thermal behavior was also investigated. The inhibitory effect on alkaline phosphatase activity was tested for the compounds and ferulic and cinnamic acids as well as for the vanadyl(IV) complex of quinic acid for comparison. The ferulic complex together with the free ligands exhibited the lowest inhibitory effect, while the VO/quinic and VO/cinnamic complexes showed an intermediate inhibition potential

Rheological and Microstructural Characterization of Wheat Dough Formulated with High Levels of Resistant Starch

Fiber-enriched breads can contribute to increasing the daily fiber intake. Resistant starches (RS) are a useful resource to increase the amount of non-digestible carbohydrates while preserving as far as possible the technological quality of white bread. The effects of high concentrations of Hi-Maize (HM), a type 2 RS, in dough formulations were analyzed by farinograph, dynamic rheometric assays, texture profile analysis, and 1H-NMR relaxation measurements and related to particle size and microstructural characteristics studied by different microscopy techniques (SEM, ESEM, CLSM). Up to 30% replacement with HM was performed. Water absorption increased and development time and stability decreased when the amount of HM increased. Water mobility increased suggesting a change in water binding. The mechanical spectra indicated a prevalence of the solid-like character in all samples, but the G′ (storage modulus) vs. G″ (loss modulus) plot suggested a pronounced change in the microstructure of dough at the highest level of replacement. Dough was harder, more adhesive, and less resilient when the HM content was increased. The use of HM in the premix formulations not only diluted the gluten content but also changed the size particle distribution of starch granules by increasing the fraction with smaller sizes. Thus, more compact matrices were obtained with a noticeable disruption of the gluten network at the highest level of replacement. However, an intermediate level of RS addition (20%) still rendered a dough with satisfactory rheological properties for breadmaking.

High-Amylose Resistant Starch as a Functional Ingredient in Breads: a Technological and Microstructural Approach

Resistant starches (RS) are important functional fibers with high potential for the development of healthy foods. The technological, nutritional, and commercial possibilities of introducing type 2 RS in white breads were studied. Four levels of maize RS (HM) as wheat flour replacement were evaluated: 0%, 10%, 20%, and 30% (control, HM10, HM20, and HM30, respectively). Thermal transitions experiments were assessed on doughs prior to breadmaking. The bread quality was studied by specific volume, color of crust and crumb, porosity, and texture of the crumb. The microstructure of the crumb was analyzed by environmental scanning electron microscopy (ESEM). Proximate composition and in vitro starch digestibility were performed to characterize the nutritional profile of breads and estimate the glycemic index (GI). Consumer acceptability of breads was also evaluated. Breads with HM showed great performance up to 20% replacement in the specific volume, the crumb porosity, and the texture. Replacement up to 30% caused major damage to those parameters. Differential scanning calorimetry runs demonstrated that HM starch did not gelatinize under the baking conditions, as confirmed by ESEM. The presence of increasing levels of native starch is thought to have the greatest influence on reducing the crust browning, increasing the crumblier texture and decreasing starch digestibility. With respect to the control, a high and progressive reduction in the estimated GI and an outstanding increase of fiber with increasing levels of HM were found. The sensory evaluation of HM20 bread showed that this level of substitution has great consumer acceptance, giving it the chance to become a healthy substitute of white bread.