Search

Non-motor alterations such as anxiety and memory deficit may represent early indications of Parkinson’s disease (PD), and therapeutic strategies that reduce non-motor alterations are promising alternatives for the treatment. Therefore, the search for natural compounds that act on motor and non-motor complications is highly relevant. In this sense, we demonstrated the role of hesperidin (Hsd) as a citrus flavonoid and its pharmacological properties as an antioxidant and neuroprotective agent. Our objective was to evaluate Hsd in developing motor and non-motor alterations in a Drosophila melanogastermodel of Parkinson-like disease induced by iron (Fe) exposure. The flies were divided into six groups: control, Hsd (10 µM), L-dopa (positive control, 1 mM), Fe (1 mM), Fe + Hsd, and Fe + L-dopa. Motor coordination tests, memory assessment through aversive phototaxy, and anxiety-like behaviors characterized in flies, such as grooming and aggressiveness, were performed. The Hsd attenuated motor and non-motor alterations, such as motor coordination, memory deficits and anxiety-like behaviors, attenuated monoaminergic deficits, and lowered Fe levels in the head of flies. In addition, Hsd prolonged the life of the flies, thereby standing out from the L-dopa-treated group. Thus, Hsd can protect the dopaminergic system from insults caused by Fe, preventing non-motor alterations in PD; Hsd also reduced Fe levels in the flies’ heads, suggesting that iron chelation may represent an important mechanism of action, in addition to its antioxidant action.

The pyrohydrolysis method was applied for digestion of high purity flexible graphite (FG) used in nuclear applications and subsequent determination of Cl and S was performed by inductively coupled plasma optical emission spectrometry (ICP OES) and ion chromatography (IC). Instrumental parameters for pyrohydrolysis were studied such as reaction time, air and water flow-rates pumped through the reactor, the type and concentration of absorbing solution (water, 10 to 200 mmol L−1NH4OH or 100 to 1000 mmol L−1H2O2) and the use of V2O5as an accelerator. Sample masses up to 250 mg were decomposed using pyrohydrolysis at 1100 °C for 30 min. Quantitative recoveries of Cl and S were obtained using air and water flow-rates pumped through the reactor at 0.1 L min−1and 0.5 mL min−1, respectively, without the use of V2O5. Absorbing solution of 50 mmol L−1NH4OH and 250 mmol L−1H2O2was suitable for quantitative absorption of Cl and S. The limit of detection (LOD) was 1 μg g−1for Cl determination by IC that was 20-fold better than that obtained by ICP OES. In this sense, IC determination is recommended for Cl determination in FG in order to meet the General Electric (GE) recommendations for nuclear materials. On the other hand, LODs obtained for S using IC and ICP OES were similar (1 μg g−1). For S determination by IC, the absorbing solution should be H2O2in order to convert all S species to SO42−. For comparison, Cl and S were also determined in digests obtained using microwave-induced combustion (MIC). In spite of high chemical inertness that allowed combustion of only 25 mg of FG, the statistical difference between pyrohydrolysis and MIC results was not observed. Evaluation of accuracy was carried out using certified reference materials (NIST 1632c – bituminous coal and SARM 19 coal) and significant differences were not observed between certified reference values and pyrohydrolysis results. After optimizing conditions, pyrohydrolysis was suitable for quality control of Cl and S impurities in FG used for nuclear applications.

A digestion method based on microwave-induced combustion (MIC) was developed for bromine and iodine determination in shrimp and its parts (shells and head, and tissue) by inductively coupled plasma mass spectrometry (ICP-MS). Ammonium nitrate solution was used as an igniter for combustion and vessels were pressurized with O2at 20 bar. Solutions of (NH4)2CO3(50 or 100 mmol L−1) and NH4OH (25, 50, 75 or 100 mmol L−1) were evaluated as absorbing media for Br and I. Better results were obtained for Br and I determination using 50 mmol L−1NH4OH as absorbing medium. Using this solution, blanks were always negligible and memory effects were virtually absent. The accuracy of the proposed MIC method was evaluated using a reference material (NIST 8414) with agreement better than 99% for both analytes. The limits of detection by MIC and further ICP-MS determination (Br: 0.12 μg g−1; I: 0.001 μg g−1) were better than those obtained when the extraction procedure was used. Additionally, a microwave-assisted alkaline extraction method was also evaluated using 0.11 mol L−1TMAH as extractant solution. However, alkaline extraction was only feasible for shrimp tissue and not for whole shrimp or shells. Decomposition using MIC allowed the determination of Br and I by ICP-MS in shrimp and the respective distribution of these elements in shells and head, and in tissue avoiding the use of concentrated digestion or extraction solutions.