Physicochemical, antioxidant, DNA cleaving properties and antimicrobial activity of fisetin-copper chelates.

Fisetin (3,3',4',7-tetrahydroxyflavone) metal chelates are of interest as this plant polyphenol has revealed broad prospects for its use as natural medicine in the treatment of various diseases. Metal interactions may change or enhance fisetin biological properties so understanding fisetin metal chelation is important for its application not only in medicine but also as a food additive in nutritional supplements. This work was aimed to determine and characterize copper complexes formed in different pH range at applying various metal/ligand ratios.

Chelating ability and biological activity of hesperetin Schiff base.

Hydrazone hesperetin Schiff base (HHSB) - N-[(±)-[5,7-dihydroxy-2-(3-hydroxy-4-methoxy-phenyl)chroman-4-ylidene]amino]benzamide has been synthesized and its crystal structure was determined. This compound was used for the formation of Cu(II) complexes in solid state and in solution which were characterized using different spectroscopic methods. The analyses of potentiometric titration curves revealed that monomeric and dimeric complexes of Cu(II) are formed above pH7.

Synthesis and characterization of V(IV)O complexes of picolinate and pyrazine derivatives. Behavior in the solid state and aqueous solution and biotransformation in the presence of blood plasma proteins.

Oxidovanadium(IV) complexes with 5-cyanopyridine-2-carboxylic acid (HpicCN), 3,5-difluoropyridine-2-carboxylic acid (HpicFF), 3-hydroxypyridine-2-carboxylic acid (H2hypic), and pyrazine-2-carboxylic acid (Hprz) have been synthesized and characterized in the solid state and aqueous solution through elemental analysis, IR and EPR spectroscopy, potentiometric titrations, and DFT simulations. The crystal structures of the complexes (OC-6-23)-[VO(picCN)2(H2O)]·2H2O (1·2H2O), (OC-6-24)-[VO(picCN)2(H2O)]·4H2O (2·4H2O), (OC-6-24)-Na[VO(Hhypic)3]·H2O (4), and two enantiomers of (OC-6-24)-[VO(prz)2(H2O)] (Λ-5 and Δ-5) have been determined also by X-ray crystallography. 1 presents the first crystallographic evidence for the formation of a OC-6-23 isomer for bis(picolinato) V(IV)O complexes, whereas 2, 4, and 5 possess the more common OC-6-24 arrangement.

Evaluation of polyphenols and anthocyanins contents in black chockeberry--Photinia melanocarpa (Michx.) fruits extract.

An evaluation of total polyphenols and anthocyanins contents in dietary supplements is important analysis in medical aspect of human and animal diets. The content of the mentioned compounds should be higher in 100 g of solid extracts than in 100 g of fruits. Thus, the presented work concerns the evaluation of total polyphenols and anthocyanins contents in black chockeberry--Photinia melanocarpa (Michx.