Copper(II) complexes of methimazole,an anti Grave’s disease drug. Synthesis,characterization and its potential biological behavior as alkaline phosphatase inhibitor

Methimazole (MeimzH) is an anti-thyroid drug and the first choice for patients with Grave’s disease. Two new copper(II) complexes of this drug: [Cu(MeimzH)₂(NO₃)₂].0.5H₂O and [Cu(MeimzH)₂(H₂O)₂](NO₃)₂·H₂O were synthesized and characterized by elemental analysis, dissolution behavior, thermogravimetric analysis and UV-vis, diffuse reflectance, FTIR and EPR spectroscopies. As it is known that copper(II) cation can act as an inhibitor of alkaline phosphatase (ALP), the inhibitory effect of methimazole and its copper(II) complexes on ALP activity has also been investigated.     

Directionality,convergence, and rate of change during early succession in the Inland Pampa,Argentina

Abstract. We tested the following hypotheses forthe first five years of a grassland succession: (a) community changes are mainly directional and related to time after disturbance ratherthanto environmental fluctuations; (b) rates of succession decrease over time, and (c) plant communities in different plots converge on a similar composition within five years of succession. We tested those hypotheses using a Principal Components Analysis applied to data from four successional plots established in successive y ears in a large cropland in the Inland Pampa, Argentina. Community changes were correlated to the age of the plots, and unrelated to rainfall variability, a major environmental variable in grasslands. Successional rates were constant over the five years, probably because of the continued dominance of different annuals; we conclude that successional rates depend on the life history of the dominant species rather than on any emergent community property. We found no evidence of convergence ordivergence; we concluded that the results of successional studies may depend on the temporal and spatial scale of observation.     

Antioxidant,DNA cleavage,and cellular effects of silibinin and a new oxovanadium(IV)/silibinin complex

A new complex of the oxovanadium(IV) cation with the flavolignan silibinin has been synthesized and characterized. Vanadium compounds show interesting biological and pharmacological properties and some of them display antitumoral actions. Flavonoids are part of a larger group of antioxidant compounds called polyphenols which may inhibit the proliferation and growth of cancer cells. The antioxidant and antitumoral effects of silibinin and its oxovanadium(IV) complex were investigated. Silibinin acted as a very strong antioxidant and its complexation with oxovanadium(IV) improved this behavior. Besides, the generation of reactive oxygen species (ROS) by this compound was favored in tumoral (UMR106) cells and correlated with the deleterious behavior in the proliferation of this cell line. Conversely, silibinin did not exert any effect on the proliferation of normal osteoblasts (MC3T3E1). The cytotoxic action and ROS generation of the oxovanadium(IV) complex was more effective in tumoral cells. This behavior was not consistent with cleaving DNA of plasmid DNA pA1 because no significant cleaving activity was observed in both cases. These results suggest that the main deleterious mechanisms may take place through cytotoxic effects more than genotoxic actions. A comparison with our own findings on the behavior of other flavonoids and their vanadyl(IV) complex has also been performed.