Juliana Maria de Mello Andrade

Polyphenol Antioxidants from Natural Sources and Contribution to Health Promotion

Polyphenols are the most abundant antioxidants in the diet. The main dietary sources of these compounds are fruits and plant-derived beverages such as fruit juices, tea, coffee, and red wine. These compounds present different mechanisms to exert their antioxidant property, such as scavenging free radicals, improving the endogenous enzymatic defenses, reducing lipoperoxidation, among others. It is well-established that oxidative processes are related to diverse pathologies, such as neurodegeneration, cancer, diabetes, cardiovascular and anti-inflammatory diseases. Thus, in an attempt to find new bioactive sources, researchers are concerned with the study of polyphenols with antioxidant potential, which may be capable of preventing and/or treating the above-mentioned diseases. However, pharmacokinetic studies of interesting polyphenols may be done in order to ensure safety and effectiveness in the administration.

Quantitative evaluation of besifloxacin ophthalmic suspension by HPLC, application to bioassay method and cytotoxicity studies.

Besifloxacin (BSF) is a synthetic chiral fluoroquinolone developed for the topical treatment of ophthalmic infections. The present study reports the development and validation of a microbiological assay, applying the cylinder-plate method, for determination of BSF in ophthalmic suspension. To assess this methodology, the development and validation of the method was performed for the quantification of BSF by high performance liquid chromatography (HPLC). The HPLC method showed specificity, linearity in the range of 20-80 µg mL(-1) (r=0.9998), precision, accuracy and robustness. The microbiological method is based on the inhibitory effect of BSF upon the strain of Staphylococcus epidermidis ATCC 12228 used as a test microorganism. The bioassay validation method yielded excellent results and included linearity, precision, accuracy, robustness and selectivity. The assay results were treated statistically by analysis of variance (ANOVA) and were found to be linear (r=0.9974) in the range of 0.5-2.0 µg mL(-1), precise (inter-assay: RSD=0.84), accurate (101.4%), specific and robust. The bioassay and the previously validated high performance liquid chromatographic (HPLC) method were compared using Students t test, which indicated that there was no statistically significant difference between these two methods. These results confirm that the proposed microbiological method can be used as routine analysis for the quantitative determination of BSF in an ophthalmic suspension. A preliminary stability study during the HPLC validation was performed and demonstrated that BSF is unstable under UV conditions. The photodegradation kinetics of BSF in water showed a first-order reaction for the drug product (ophthalmic suspension) and a second-order reaction for the reference standard (RS) under UVA light. UVA degraded samples of BSF were also studied in order to determine the preliminary in vitro cytotoxicity against mononuclear cells. The results indicated that BSF does not alter the cell membrane and has been considered non-toxic to human mononuclear cells in the experimental conditions tested.

Comparison of the Fatty Acid Profiles of Edible Native Fruit Seeds from Southern Brazil

Three different Myrtaceae species and one species of Annonaceae were analyzed for the fatty acid composition of their seed oil. All species were characterized by high concentrations of unsaturated fatty acids that ranged from 54.61 to 91.65 g/100 g of the total fatty acid content. The main fatty acid presented by Feijoa sellowiana was linoleic acid (84.44 g/100 g). Oleic acid was the main fatty acid found in the seed oil from Myrcianthes pungens and Rollinia sylvatica, whose contents were 57.03 and 54.41 g/100 g, respectively. For Eugenia uniflora oil seed, the main fatty acid detected was palmitic acid (40.07 g/100 g).

Main Degradation Products of Dabigatran Etexilate Evaluated by LC-UV and LC-ESI-MS, Degradation Kinetics and in vitro Cytotoxicity Studies

The present study reports the stability profile of an antithrombotic drug: dabigatran etexilate (DAB). The drug was subjected to thermal degradation at 60 oC and products formed were investigated by liquid chromatography-UV (LC-UV) and liquid chromatography-mass spectrometry (LC-ESI-MS). Chromatographic separation of the degradation products was performed on a GL Sciences Inc. Inertsil ODS-2 column (250 mm × 4.6 mm i.d., with a particle size of 5 µm and pore size of 110 A) with mobile phase consisting of acetonitrile and ammonium acetate buffer (pH 5.5; 10 mmol L−1) (65:35, v/v) pumped at 1.0 mL min−1 flow rate. Column temperature was set at 30 oC and detection at 225 nm using a UV detector. LC-UV method previously validated was extended to LC-ESI-MS for the characterization of the degradation products (DP-01 and DP-02) formed, without complicated isolation or purification processes, based on retention times and confirmation of molecular weight. Degradation kinetics of DAB was also evaluated and could be described as a first-order process (R2= 0.9900). Furthermore, no evidence of cytotoxicity in human mononuclear cells was observed for DAB degraded samples.

In vitro Antioxidant and Enzymatic Approaches to Evaluate Neuroprotector Potential of Blechnum Extracts without Cytotoxicity to Human Stem Cells.

Background: Investigation of selected plant extracts on multi-targets related to neurodegeneration, such as monoamine oxidases (MAO), cholinesterase enzymes, and antioxidant activities (AOA) is a useful tool for identification of new scaffolds. Objective: This work investigated biological effects of three Blechnum methanol extracts from Brazil and chemical profile of the most active sample. Materials and Methods: AOA included scavenging of hydroxyl and nitric oxide radicals, also lipid peroxidation inhibition. Enzymatic modulation of Blechnum binervatum, Blechnum brasiliense, and Blechnum occidentale extracts on MAO and cholinesterases was conducted. Moreover, total phenol content was performed with all samples, and high-performance liquid chromatography-diode array detection mass spectrometry HPLC-DAD-MS analysis was carried out with B. brasiliense. Possible toxic effects were evaluated on Wistar rats polymorphonuclear cells (PMN) and human stem cells. Results: B. brasiliense extract presented the highest phenolic amount (9.25 g gallic acid equivalent/100 g extract) and lowest IC50values (112.3 ± 2.61 and 176.1 ± 1.19 μg/mL) against hydroxyl radicals and on lipid peroxidation, respectively, showing strong AO effects. On nitric oxide assay and cholinesterase inhibition, all extracts were considered inactive. MAO-A selective action was evidenced, being B. brasiliense powerful against this enzyme (IC50: 72.7 μg/mL), followed by B. occidentale and B. binervatum (IC50: 130.85 and 165.2 μg/mL). No cytotoxic effects were observed on PMN and human stem cells treated with Blechnum extracts. HPLC-DAD-MS analysis of B. brasiliense allowed the identification of chlorogenic and rosmarinic acids. Conclusion: Our results especially highlight B. brasiliense, with pronounced phenols content and strong effects on selected targets related to neurodegeneration, being characterized as a natural safe source of bioactive hydroxycinnamic acids. SUMMARY Blechnum crude extracts showed high phenolic amounts and valuable IC50 values on targets related with neurodegenerative disorders Blechnum brasiliense was the most active sample, with strong radical scavenging and lipid peroxidation inhibition, also with monoamine oxidases: A selective modulation No cytotoxic effects were observed on polymorphonuclear cells rat cells and human stem cells treated with Blechnum extracts High-performance liquid chromatography-diode array detection-mass spectrometry analysis of Blechnum brasiliense allowed the identification of hydroxycinnamic derivatives: Chlorogenic and rosmarinic acids. Abbreviations used: IC50: half maximal inhibitory concentration; MAO: monoamine oxidase; MAO-A: monoamine oxidase isoform A; MAO-B: monoamine oxidase isoform B; HO•: hydroxyl radical.

Delapril and Manidipine Main Degradation Products: LC-UV and LC-ESI-MS Evaluations, Decay Kinetic, and in vitro Cytotoxicity Studies

A simple, stability-indicating, and compatible method by liquid chromatography with ultraviolet (LC-UV) and mass spectrometry (LC-MS) detections was developed for the evaluation of delapril (DEL) and manidipine (MAN) degradation products formed under alkaline and photolytic forced conditions, respectively. The chromatographic separation of all compounds was obtained within 7 min and carried out on a C18 column with mobile-phase composed by ammonium acetate and acetonitrile for both techniques. Thereby, the main degradation products detected were studied by LC coupled to electrospray ionization mass spectrometry (LC-ESI-MS). Based on retention times and molecular weight confirmation, a comprehensive degradation pathway for both drugs and the identity of its major products formed could be suggested, without complicated isolation or purification processes. The degradation kinetics of the drugs was also evaluated and could be best described as first-order process for DEL (R2 = 0.9991) and zero-order process for MAN (R2 = 0.9867). Furthermore, no evidence of cytotoxicity in human mononuclear cells was observed for DEL and MAN degraded samples. The proposed LC-UV method was successfully validated according ICH guidelines and thus helping to improve the quality control of pharmaceuticals.

Byproducts of orange extraction: influence of different treatments in fiber composition and physical and chemical parameters

In this work we evaluated the variability in fiber content and physical and chemical parameters of byproducts from orange juice extraction. Five different treatments and two drying methods were evaluated. The results indicate that drying by lyophilization was better than that drying in an oven. The pH ranged from approximately 3.47 to 3.96. The variation in moisture values was 9.22% ± 0.02 to 18.48 ± 0.52%. The total dietary fiber content in the resulting flours ranged from 42.44% to 62.74%. The soluble and insoluble dietary fiber contents differed among the samples, ranging from 5.04% to 19.95% for the first fiber type, and 23.96% to 57.70% for the second. In conclusion, three treatments, associated with freeze-drying, showed promising results in the development of fiber-rich product. However, some modifications are needed, as well as further analysis, to guarantee the benefits of these products for human health. This study contributes to the possible application of industrial byproducts.

The influence of bath temperature on the properties of pultruded glass fiber reinforced rods

Pultrusion is one of the several manufacturing processes for polymer composites. It involves resin-impregnated fibers that passed through a heated die, while the resin cures to produce a solid profile in the desired shape. Many processing variables such as die temperature, pull speed, fiber impregnation, resin viscosity, among others, affect the composite quality and the process efficiency. In fact, a good understanding and careful control of all these variables are needed to avoid defective profiles as well as to achieve better processing conditions. In this paper, the relationship between the resin bath temperature and the mechanical properties of pultruded rods such as tensile strength, elastic modulus, and hardness was established. The effect of resin viscosity on the fibers wet-out, cure position inside the die and the void formation was also investigated. The results showed that the rods made at higher bath temperatures presented higher tensile strength, elongation at break and hardness, but lower modulus of elasticity. This behaviour was correlated with the void content yielded during the profile formation.

Identification of compounds from non‐polar fractions of Blechnum spp and a multitarget approach involving enzymatic modulation and oxidative stress

The hexane (HEX) and dichloromethane (DCM) fractions from Blechnum binervatum, Blechnum brasiliense and Blechnum occidentale were studied about phytochemicals and biological properties using multitarget approach.

Photodegradation kinetics of lodenafil carbonate, structure elucidation of two major degradation products using UPLC-MS/MS and in vitro cytotoxicity

The photostability of lodenafil carbonate was studied and some degradation products were observed. A stability-indicating liquid chromatography method for the determination of lodenafil carbonate was used to determine the kinetics of photodegradation. The identification of two major photodegradation products was performed by an isocratic ultra performance liquid chromatography-tandem mass spectrometry method (UPLC-MS/MS). UPLC-MS/MS was carried out on a Waters® Acquity Ultra Performance LC system coupled to a Micromass® Quadrupole Time of Flight tandem mass spectrometer equipped with an electrospray ionization interface in positive ion mode. The column applied was Acquity UPLC® BEH C18; the mobile phase consisted of a mixture of methanol–formic acid 0.1% pH 4.0 (55 : 45, v/v) at a flow-rate of 0.4 mL min−1 and UV detection at 290 nm. The photodegradation of lodenafil carbonate followed first-order reaction kinetics and the kinetic parameters of degradation rate constant and t90% were calculated. Under photodegradation conditions, ion products were detected at m/z 393 (DP-1) and at m/z 377 (DP-2). The product DP-1 is 4-ethoxy-3-(1-methyl-7-oxo-3-propyl-6,7-dihydro-1H-pyrazolo [4,3-d]pyrimidin-5-yl)-benzenesulfonic acid and DP-2 probably is 4-ethoxy-3-(1-methyl-7-oxo-3-propyl-6,7-dihydro-1H-pyrazolo [4,3-d]pyrimidin-5-yl) benzenesulfinic acid. The degraded samples of lodenafil carbonate were also evaluated in order to determine the in vitro cytotoxicity against mononuclear cells.