Elisa Zironi

Potent Inhibition of Human Phosphodiesterase-5 by Icariin Derivatives

Plant extracts traditionally used for male impotence (Tribulus terrestris, Ferula hermonis, Epimedium brevicornum, Cinnamomum cassia), and the individual compounds cinnamaldehyde, ferutinin, and icariin, were screened against phosphodiesterase-5A1 (PDE5A1) activity. Human recombinant PDE5A1 was used as the enzyme source. Only E. brevicornum extract (80% inhibition at 50 microg/mL) and its active principle icariin (1) (IC50 5.9 microM) were active. To improve its inhibitory activity, 1 was subjected to various structural modifications. Thus, 3,7-bis(2-hydroxyethyl)icaritin (5), where both sugars in 1 were replaced with hydroxyethyl residues, potently inhibited PDE5A1 with an IC50 very close to that of sildenafil (IC50 75 vs 74 nM). Thus, 5 was 80 times more potent than 1, and its selectivity versus phosphodiesterase-6 (PDE6) and cyclic adenosine monophosphate-phosphodiesterase (cAMP-PDE) was much higher in comparison with sildenafil. The improved pharmacodynamic profile and lack of cytotoxicity on human fibroblasts make compound 5 a promising candidate for further development.

Organophosphorus pesticides residues in Italian raw milk

Organophosphorus pesticides (OPPs), widely used in agriculture, can cause toxic effects to humans and animals. The main purpose of the present work was to determine the contamination in raw milk by the main organophosphorus pesticides used in Italy and to evaluate the opportunity to start specific procedures of risk management along the milk production chain. The samples, collected in 4 Italian dairy plants directly from the tank trucks during the delivering, were representative of 920 tonnes of raw milk. The isolation of the OPPs (acephate, chlorpyriphos, chlorpyriphos-methyl, diazinon, methamidophos, methidathion, phorate, pirimiphos-methyl) was performed by liquid partition followed by clean-up with solid phase extraction. The analyses were carried out by dual column gas chromatography using two nitrogen-phosphorus detectors. Among the 135 samples analysed, 37 were positive in traces and 10 showed an OPP contamination ranging from 5 to 18 microg/kg. The higher results were recorded in the samples collected during the autumn-winter period. The main pollutants detected were acephate and chlorpyriphos. In every positive sample found, the OPP contamination was lower than the maximum residue level (MRL) fixed by the European Commission.

Brain distribution of ribavirin after intranasal administration

Ribavirin has proved to be effective in vitro against several RNA viruses responsible for encephalitis in humans and animals. However, the in vivo efficacy towards the cerebral viral load seems to be limited by the blood-brain barrier. Since the nose-to-brain pathway has been indicated for delivering drugs to the brain, we investigated here the distribution of ribavirin in the central nervous system (CNS) after intranasal administration. We first tested in vitro ribavirin diffusion from an aqueous solution across a biological membrane, using Franz cells and rabbit nasal mucosa. About 35% of ribavirin permeated in 4 h across the mucosa, after reaching steady-state flux in less than 30 min. In the first in vivo experiment, ribavirin aqueous solution was administered intranasally to Sprague Dawley rats (10 mg/kg). Animals were sacrificed at 10, 20 or 30 min after administration to collect brain areas (cerebellum, olfactory bulb, cerebral cortex, basal ganglia and hippocampus) and biological fluids (cerebrospinal fluid and plasma). Ribavirin, quantified by LC-MS/MS spectrometry, was detected at each time point in all compartments with the highest concentration in olfactory bulb and decreasing in rostro-caudal direction. Two subsequent in vivo experiments compared the nasal route (ribavirin solution) with the intravenous one and the nasal administration of ribavirin solution with ribavirin powder (10 mg/kg). It was found that 20 min after administration, ribavirin concentration in olfactory bulb was similar after intravenous or nasal administration of the ribavirin solution, whereas the powder led to significantly higher levels. Ribavirin was also present in deeper compartments, such as basal ganglia and hippocampus. Even if the mechanisms involved in ribavirin nose-to-brain transport are not clear, these results suggest a rapid extracellular diffusive flux from the nasal epithelium to the olfactory bulb and different CNS areas.

Development of a rapid LC–MS/MS method for ribavirin determination in rat brain

A rapid and specific liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the determination of ribavirin (RBV) in rat brain was developed. Sample preparation required only two centrifuge steps before LC-MS/MS analysis and the chromatographic separation was achieved in isocratic conditions using an Atlantis T3 column with a nearly totally aqueous (95%) mobile phase. The method showed a good linearity over a concentration range of 5-1000ppb and satisfactory results in terms of accuracy.

Development and validation of a liquid chromatography/tandem mass spectrometry method for quantitative determination of amoxicillin in bovine muscle

A simple, quick and economical liquid chromatographic/tandem mass spectrometry (LC-MS/MS) method for the quantitative determination of amoxicillin in bovine muscle was developed and validated. The sample preparation procedure involved a liquid extraction with water, followed by a protein precipitation step with acetonitrile. The extract was purified by a liquid-liquid partition with dichloromethane and the upper aqueous layer was directly injected into the LC-MS/MS system. Chromatographic separation was achieved on a reversed phase column, using a mixture of acetonitrile, water and 0.005% formic acid in water as mobile phase. Gradient elution was performed at a flow rate of 0.2 mL min⁻¹. Amoxicillin was detected using positive electrospray ionization in selected reaction monitoring (SRM) mode and was quantified using terbutaline as internal standard. The responses for standards prepared in solvent and in matrix were equivalent and additionally the absence of signal suppression was confirmed by the post column infusion technique. Amoxicillin stability in standard solution and in matrix was investigated at different times and storage conditions. Amoxicillin standards prepared in water were stable on storage up to 20 days at -20°C. Amoxicillin stability in matrix (spiked bovine muscle samples) was assessed up to 15 days at -20°C. The method was validated according to the parameters requested by European Commission Decision 2002/657/EC in terms of specificity, linearity, trueness, precision, decision limit (CCα) and detection capability (CCβ). All the trueness values fell within a range between 14.5% and 6.3%. Precision values for all levels of concentration tested were lower than the relative limit calculated by the Horwitz equation. The amoxicillin MRL is set at 50 μg kg⁻¹ and the CCα and CCβ of the method were 61.2 μg kg⁻¹ and 72.4 μg kg⁻¹, respectively.

Technical note: development and validation of a method using ultra performance liquid chromatography coupled with tandem mass spectrometry for determination of vitamin B12 concentrations in milk and dairy products.

A method using ultra performance liquid chromatography coupled with tandem mass spectrometry was developed to measure cobalamins in naturally enriched raw milk and to evaluate their fate during thermal treatments and along the process of cheese making. After addition of methotrexate as internal standard, samples were submitted to heat treatment in the presence of cyanide, which converts all the less-stable cobalamins into cyanocobalamin; then, purification was performed by a solid-phase extraction step. Reverse-phase ultra performance liquid chromatography separation coupled with tandem mass spectrometry provided a fast and reliable determination. Mass spectrometric analysis was carried out in multiple reaction monitoring mode. The monitored transitions were m/z 678.36 → 147.10 and 678.36 → 359.30 for vitamin B12 and m/z 455.22 → 175.13 and 455.22 → 308.22 for methotrexate (internal standard). The limit of quantification was 2 ng/g. The method showed good linearity from 2 to 20 ng/g (R(2) ≥ 0.98) and intra- and interday precisions were always less than 19%.

Short communication: Monitoring the presence of perfluoroalkyl substances in Italian cow milk

Perfluoroalkyl substances (PFAS) are fully fluorinated compounds widely used during the last 60 yr in the production of multiple industrial and consumer applications, such as food packaging, nonstick cookware, cleaning agents, and many more. These emerging contaminants have recently become of concern for human health because of their potential negative effects. The risk of exposure to PFAS for humans is mainly related to diet, and the increasing interest in food safety has led the European Commission to call Member States to monitor these contaminants in food matrices. The purpose of the present work was to perform the first monitoring on the presence of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), the 2 main and most widely investigated molecules of this family, in cow milk commercially available in Italy. We used an analytical protocol consisting of liquid-liquid extraction followed by 2 purification steps through solid-phase extraction cartridges and injection on an ultra-performance liquid chromatography-tandem mass spectroscopy system. The analysis of 67 samples of different types of cow milk from Italy demonstrated that contamination by PFOS was often present, although at relatively low concentrations (up to 97 ng/L), whereas PFOA was rarely found. On the basis of these results and data reported in the literature on this matrix, milk does not seem to be a major source of PFAS compared with other food categories such as fish and seafood. However, variability among different types of milk must be taken into account, and surveys of milk-derived products would be helpful to better define the risk for consumers.

Proposal of an analytical method for determination of residues of organophosphorus pesticides in milk by GLC-NPD.

G. Pagliuca*, T. Gazzotti, E. Zironi, N. Pavoncelli and R. Rosmini Department of Veterinary Public Health and Animal Pathology – Alma Mater Studiorum – University of Bologna *Correspondence: Dipartimento di Sanita Pubblica Veterinaria e Patologia Animale – Sezione di Igiene e T ecnologia Alimentare – Alma Mater Studiorum – Universita di Bologna, via T olara di Sopra, 50 – 40064 Ozzano dell’Emilia, Bologna, Italy E-mail: pagliuca@vet.unibo.it

Bisphenol A in edible part of seafood

Bisphenol A (BPA) is a man-made compound, mainly used as a monomer to produce polycarbonate (PC), epoxy resins, non-polymer additives to other plastics, which have many food related applications, such as food storage containers, tableware and internal coating of cans, as well as non-food applications such as electronic equipment, construction materials and medical devices. BPA exposure can occur when the residual monomer migrates into packaged food and beverages. Moreover, due to the ubiquitous presence of this compound, the general population can be exposed to environmental sources such as water, air and soil. Many studies have investigated the potential health hazards associated with BPA, which can elicit toxic and cancerogenic effects on humans. According to the European Food Safety Authority opinion, diet is considered to be the main source of exposure, especially canned food; moreover, among non-canned food, meat and fish products have the highest levels of BPA contamination. This review focuses on BPA contamination in seafood, analysing worldwide literature (from January 2010 to October 2015) on BPA contamination of edible parts. The authors try to identify differences between canned and non-canned seafood in literature, and gaps in the state of art. The data evaluated underline that all concentrations for both canned and non-canned seafood were below the specific migration limit set by the European Community Directive for BPA in food. Moreover, the canned seafood is more contaminated than the non-canned one.

A Quick LC–MS-MS Method for the Determination of Flunixin in Bovine Muscle

A simple, fast and cost-effective liquid chromatographic/tandem mass spectrometry (LC-MS-MS) method for the quantitative determination of flunixin (FLU) in bovine muscle was developed and validated. The sample preparation procedure involved an extraction with acetonitrile, followed by evaporation and reconstitution. Chromatographic separation was achieved on a reverse-phase column under programmed conditions. FLU detection was performed with positive electrospray ionization in selected reaction monitoringmode, monitoring one precursor and two products ions. For quantification purposes, FLU-d3 was used as an internal standard. The matrix effect on the analysis of FLU in bovine muscle was evaluated by comparison between calibration curves prepared with standard solution and in blank matrix extracts. The equivalent responses obtained confirmed the absence of signal suppression or/and enhancement. The method was extensively validated according to the parameters requested by European Commission Decision 2002/657/EC in terms of specificity, limit of detection, linearity, trueness, precision, decision limit (CCα) and detection capability (CCβ). FLU stability was also investigated in matrix and in sample extracts at different times and storage conditions.