Clara Naccari

Antioxidant properties of 4-methylcoumarins in in vitro cell-free systems

4-methylcoumarins that possess two hydroxyl groups ortho to each other in the benzenoid ring have shown to have excellent antioxidant and radical-scavenging properties in different experimental models. Furthermore, they cannot be metabolized by the liver P450 monoxygenases and thus cannot form 3,4-coumarin epoxides, which are believed to be mutagenic. Herein, we present a study on the structure activity relationship of eight synthetic 4-methylcoumarins, carried out by employing a series of different chemical cell-free tests. These compounds were tested by means of three assays involving one redox reaction with the oxidant (DPPH assay, ABTS.+ assay and FRAP). Other assays were employed to evaluate the antioxidant properties of the coumarins under investigation against NO, O2.- and HClO, which are some of the major reactive oxygen and nitrogen species causing damage in the human body. Finally, we have measured the protective capacity of these coumarins against the oxidative damage in a simple biomimetic model of phospholipid membranes. Our results confirm the good antioxidant activity of the 7,8-hydroxy-4-methylcoumarins. In general, their activity is not significantly affected by the introduction of an ethoxycarbonylmethyl or an ethoxycarbonylethyl moiety at the C3 position. A discrete antioxidant activity is retained also by the 7,8-diacetoxy-4-methylcoumarins, although they are less efficient than the corresponding 7,8-dihydroxy compounds. Furthermore, as demonstrated in the brine shrimp toxicity test, none of the tested coumarins significantly affect the larvae viability. Two of the 4-methylcoumarins (7,8-dihydroxy-4-methylcoumarin and 7,8-dihydroxy-3-ethoxycarbonylethyl-4-methylcoumarin), very interestingly, showed strong scavenging activities against the superoxide anion and were also very effective in protecting the lipid bilayer against peroxidation. On the basis of these findings, these 4-methylcoumarins may be considered as potential therapeutic candidates for pathological conditions characterized by free radical overproduction.

Influence of levetiracetam on the anticonvulsant efficacy of conventional antiepileptic drugs against audiogenic seizures in DBA/2 mice

Levetiracetam (LEV, [S]-alpha-ethyl-2-oxo-1-pyrrolidine acetamide) is a new antiepileptic that has been used as adjunctive therapy to treat patients with intractable epilepsy. Systemic administration of levetiracetam (2.5-30 mg/kg, intraperitoneally (i.p.)) was able to produce a dose-dependent decrease in DBA/2 audiogenic seizure severity score. In combination with conventional antiepileptic drugs, levetiracetam, 5mg/kg, i.p., which per se did not significantly affect the occurrence of audiogenic seizures in DBA/2 mice, potentiated the anticonvulsant activity of some antiepileptic drugs studied against sound-induced seizures in DBA/2 mice. The degree of potentiation induced by levetiracetam was greater, approximately twice, for carbamazepine, diazepam, felbamate, topiramate, gabapentin, and valproate, less for lamotrigine, phenobarbital and phenytoin. This increase was associated with a comparable impairment in motor activity; however, the therapeutic index of combined treatment of antiepileptic drugs with levetiracetam was more favourable than the combination with saline with the exception of lamotrigine, phenytoin and phenobarbital. Since levetiracetam did not significantly influence the total and free plasma and the brain levels of antiepileptics studied. In addition, levetiracetam did not significantly affect the hypothermic effects of the anticonvulsants tested. In conclusion, levetiracetam showed an additive anticonvulsant effect when administered in combination with some classical anticonvulsants, most notably carbamazepine, diazepam, felbamate, gabapentin, topiramate and valproate, implicating a possible therapeutic relevance of such drug combinations.

Evaluation of mercury levels in pangasius and cod fillets traded in Sicily (Italy).

Predator fishes at the top of the aquatic food chain can accumulate large concentrations of metals and their consumption, consequently, makes a significant contribution, in particular, to mercury intake. The aim of this study was to determine mercury levels in fillets of two predatory species: pangasius (Pangasius hypophthalmus) from the Vietnam region of Megong and Chao Pharayai and cod (Gadus morhua) from the Baltic and North Sea, both being commercially important in the Italian market. A comparative analysis of these two imported fish species was carried out as a risk assessment for consumer safety. The results showed the presence of higher mercury levels in pangasius (0.41 ± 0.08 mg kg−1) than in cod (0.11 ± 0.004 mg kg−1) fillets. These data underline the importance of monitoring on imported fish before marketing, to evaluate better the risk of mercury exposure through fish and seafood consumption, and of selecting safer fishes for consumption by those groups more sensitive to the toxic effects of this metal.

Levels of benzo[a]pyrene and benzo[a]anthracene in smoked “Provola” cheese from Calabria (Italy)

Levels of benzo[a]pyrene (BaP) and benzo[a]anthracene (BaA) in “Provola” cheese samples from Calabria, smoked naturally and using commercial smoke-flavouring, have been determined. A comparative study of BaP and BaA concentrations was carried out on rind, exterior zone, core and slice of these samples. Quantitative determination of BaP and BaA was ascertained by HPLC using fluorescence detection. Levels of BaP and BaA were found in all smoked “Provola” cheese samples, but higher in cheese smoked with natural methods (0.46–1.13 µg kg−1 for BaP and 1.38–9.29 µg kg−1 for BaA) compared to samples smoked using commercial flavouring (0.085–0.32 µg kg−1 for BaP and 1.20–2.98 µg kg−1 for BaA). The smoking process contributes to polycyclic aromatic hydrocarbons contamination; however, for improved food safety, the use of commercial buffered smoke is preferable to traditional smoking procedures.

Cytotoxic effects induced in vitro by organic extracts from urban air particulate matter in human leukocytes.

Abstract Urban areas represent major pollution sources as a result of anthropogenic activities located in these districts. Among the legislated air pollutants, polycyclic aromatic hydrocarbons (PAHs), which are mostly adsorbed on the surface of dust particles, are known for their adverse health effects. The present study has been carried out to examine the cytotoxic effects induced in vitro on human peripheral monocytes (PBMCs) by extractable organic matter (EOM) from PM10 (characterized for its PAH content) collected at four sites in the urban center of Messina, Italy. Chromatographic analyses showed the presence of PAHs in all EOM. Only EOM from one site induced a marked cell death probably resulting from the highest PAH content in this sample. Conversely, apoptosis activation was evident after PBMC exposure to all the EOM tested. These apoptotic effects do not appear related only to the total PAH content, but are probably influenced by chemical composition. In conclusion, our findings confirm that the cytotoxic potential of organic matter associated to ambient respirable air particles depends predominantly on the quantity and quality of the chemicals contained in it. In particular, the present data strongly evidence that the only evaluation of air concentration of particulate matter and benzo[a]pyrene, as well as the generally used risk models based on additivity, are not sufficient to evaluate air quality and PAH effect on human health because they do not take into account the possible inhibitory or synergic or antagonistic effect of combined exposure and the interference of other organic compounds present in respirable matter.

Monitoring of neonicotinoid pesticides in beekeeping

Abstract The decline of pollinating species is correlated to the extensive use of neonicotinoids against pest insects for crop protection. In this study, the concentrations of neonicotinoid insecticides were determined in honeybees, honeycomb and honey samples, collected in Spring 2015 (blooming period) from different areas in Sicily (IT), to carry out an evaluation of bees products’ safety and an overview of neonicotinoid contamination in beekeeping. The results obtained showed only the presence of clothianidin in bee samples and these concentrations don’t represent a risk for bees’ vitality and safety. The absence of residue in all honey samples, instead, showed the quality of bee products.

Mineral composition of some varieties of beans from Mediterranean and Tropical areas

Abstract In this study has been evaluated the mineral composition (Cd, Pb, As, Hg, Ba, Cr, Co, Ni, Se, Sb, V, Cu, Fe, Zn, Mo, Na, K, Ca, Mg) of some varieties of bean (Phaseolus vulgaris, Vigna unguiculata and V. angularis) from Mediterranean and Tropical areas of the world (Italy, Mexico, India, Japan, Ghana and Ivory Coast); the correlation between beans mineral composition in micro and macroelements and botanical and/or geographical origin; trace elements dietary intake by beans consumption. The results showed a correlation between beans mineral composition and their geographical origin, with higher values in Ivory Coast samples. Moreover, minerals content found confirmed the importance of these legumes in the diet for the significant content of essential micro and macroelements and a safe consumption of beans for the low residual levels of toxic metals.

Does the Clam Ensis siliqua Provide Useful Information About Contamination by Polychlorinated Biphenyls and Organochlorine Pesticides Beyond that of Mussel Mytilus galloprovincialis

Several polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) investigated in soft tissues of the frequently monitored Mytilus galloprovincialis were compared to those of Ensis siliqua, a highly dispersed and economically important bivalve species, though rarely investigated. Overall PCBs had higher concentrations than OCPs in both species with a prevalence of tri- tetra-and penta-chlorinated biphenyls in E. siliqua and a prevalence of hexa- hepta and octa-chlorinated biphenyls in M. galloprovincialis. E. siliqua emerges as a suitable complement to mussels for monitoring PCBs and OCPs pollution.

Are Biometric Parameters Helpful to Assess the Health Risk of Consuming Organochlorine Compounds Contaminated Silver European Eel (Anguilla anguilla)

Several organochlorine compounds (OCs) were measured in European eels from the Tevere river (Italy). It followed that some of them are still important chemical contaminants. Concentrations of dichlorodiphenyltrichloroethanes (DDTs) are hazardous for the consumer health; those of the 6 indicator polychlorinated biphenyls (PCBs) are often close to the current European maximum residue limit and always higher than the former limit. The relationship between OC concentrations, biometric parameters and the lipid content was then investigated. A strong positive correlation with eel size emerged for the indicator PCBs and DDTs concentrations expressed on wet weight basis. This is explained by the corresponding higher lipid percentage that characterizes bigger eels and the absence of a dilution effect for compounds of main concerns. On the basis of the PCB-TDI threshold for a 70 kg person, we suggest that 1 should consume no more than 2 eels per week each weighing about 100 g. Thus, we conclude that eel consumption should be limited and restricted to eels relatively shorter and lighter.