Synthesis,spectroscopic characterization (IR, 1H, 13C and 119Sn NMR,electrospray mass spectrometry) and toxicity of new organotin(IV) complexes with N,N′,O‐ and N,N′,S‐scorpionate ligands

New organotin(IV) derivatives containing the anionic ligands bis(3,5‐dimethylpyrazol‐1‐yl)dithioacetate [LCS₂]⁻ and bis(3,5‐dimethylpyrazol‐1‐yl)acetate [LCO₂]⁻ have been synthesized from reaction between (CH₃)₂SnCl₂ and lithium salts of the ligands. Mononuclear complexes of the type {[LCX₂](CH₃)₂SnCl} (X = S or O) have been obtained and fully characterized by elemental analyses and FT‐IR in the solid state and by NMR (¹H, ¹³C and ¹¹⁹Sn) spectroscopy, conductivity measurements and electrospray ionization mass spectrometry in solution. The acute toxicity of new organotin(IV) derivatives on rat was studied, comparing their effect with those of dimethyltin chloride (CH₃)₂SnCl₂. The comparison of LD₅₀ of organotin(IV) complexes and (CH₃)₂SnCl₂ administered intraperitoneally, as a single dose, evaluated in vivo on rats, showed that toxicity decreases as follows: (CH₃)₂SnCl₂ > LCO₂ > LCS₂. The effect of these organotin(IV) complexes on DNA was evaluated in vitro and in vivo on rats treated with different doses of these compounds (1/20 LD₅₀ and 1/100 LD₅₀). The lymphocyte DNA status was assessed by the comet assay, a rapid and sensitive single‐cell electrophoresis technique, used to detect primary DNA damage in individual cells. After 36 h from the start of treatment the two new organotin(IV) derivatives induced a significant rise in comet assay parameters, indicating an increasing presence of damaged DNA. Copyright © 2005 John Wiley & Sons, Ltd.     

Effect of organotin compounds on trout AMP‐deaminases

The comparative toxicity of the organotin compounds tributyltin chloride (TBTC), dibutylin dichloride (DBTC) and monobutyltin trichloride (MBTC) was investigated on 5′ adenylic acid deaminase (AMP‐deaminase) purified from trout skeletal muscle and heart. Treatment with TBTC of both enzymatic forms of AMP‐deaminase rapidly decreases the enzyme activity, and the organotin derivatives DBTC and MBTC have a significant minor inhibitory effect. Differences were observed in TBTC inhibition rate between trout muscle and heart purified enzymes that could be related to the different cellular localization of the two AMP‐deaminases. Copyright © 2001 John Wiley & Sons, Ltd.     

Chemical Constituents and Biological Activities of the Leaves of Knema saxatilis

Chemistry of Natural Compounds -     

Plasma Membrane Perturbation Induced by Organotins on Erythrocytes from Salmo irideus Trout

Tributyltin chloride and its degradation products monobutyltin and dibutyltin act as water pollutants, owing to the use of tributyltin chloride as a biocide in marine paint formulations. These compounds are lipid-soluble and undergo bioaccumulation and bioconcentration. Salmo irideus trout erythrocytes were studied to evaluate the possible effects of these compounds on freshwater fish, which could be exposed to long-term effects due to bioaccumulation of organotins. Data showed that tributyltin increases the haemolysis rate, starting at 10 μM, while dibutyltin has a scant protective effect at each concentration tested. Similar studies were performed in the presence of carbon monoxide (CO), which is protective against membrane oxidative stress due to haemoglobin (Hb) auto-oxidation. In these conditions all the organotins tested induced an increase in the haemolysis rate. These results suggest that the consequence of auto-oxidation of Hb could condition the effects of some organotin compounds. Steady-state fluorescence of probes embedded in the lipidic part of the membrane was used to evaluate the modifications induced by organotins to the physico-chemical state of phospholipids.     

Radiochemical characterisation,heavy metal determination and morphologic evolution of coastal sediments in the Ravenna area (Italy)

The basic aim of this work was to achieve a preliminary but integrated characterisation of an area of the Ravenna littoral coastline. The use of suitable computerised procedures has allowed the reconstruction of the morphological evolution of this area by means of historical and recent cartography. Coastal sediments were characterised by sampling 3 cores at about 2 km offshore. The following aspects were studied: 1) Mineralogical characterisation of both the total and the fine fraction of sediments by X-ray Diffraction. 2) Characteristion of sedimentary horizons by radiodating. 3)Magnetic susceptibility profiling. 4) Determination of some heavy metals (Cu, Pb, Zn, Cd) by anodic stripping voltammetry.