Syntheses, characterization and anti-hyperglycaemic activity of coordination compounds of amino acids and their schiff base derivatives.
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Date
2016
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Abstract
This study investigated the synthesis and characterization of transition metals with phenylalanine, tyrosine and its schiff base which are non-toxic and compatible with human metabolism. This was done with a view to determining the comparative effectiveness of the metal salts, ligands and metal complexes in lowering blood glucose.
Metal ions of vanadium, cobalt, chromium and molybdenum coordinated with phenylalanine and tyrosine in ratio 1:2 of metal to ligand and a Schiff base in ratio 1:1 were synthesised and characterised by determination of their percentage metal analysis, applications of infrared and electronic spectra, magnetic moments and melting points determination. The anti-hyperglycaemic activities of the metal complexes, as well as the component metal salts and ligands, were studied in glucose-loaded rats, using glibenclamide (5 mg/kg) as the standard drug. The data collected were appropriately analysed using statistical model of Analysis of variance, and Student-Newman-Keulposthoc test.
Percentage metal analysis for Co(II) and Cr(III) complexes confirmed that the complexes were in ratio 1:2 of metal to ligand, while infrared spectra confirmed that the coordination was via oxygen and nitrogen atoms of the carboxylate and amino groups, respectively. Magnetic moments and electronic spectra data indicated square pyramidal, square planar and octahedral geometries for oxovanadium, cobalt and chromium complexes, respectively. The in vivo anti-hyperglycaemic activity of all metal complexes were found to be more active in lowering blood glucose compared to metal salts and free ligands alone. Comparison of the hyperglycaemia-lowering effects of the free ligands, metal ions and metal-ligand complexes showed the ligands were devoid of hyperlgycaemia-lowering activity, while those of the coordinated compounds demonstrated higher activities than those of the metals salts.
The study concluded that oxovandium-tyrosine was the most active coordinated compound synthesised with a probable extra-pancreatic and insulinotropic actions.
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137p
Keywords
transition, metals, metabolism, phenylalanine, pancreatic