Electrochemical investigation on interaction between DNA with quercetin and Eu–Qu 3 complex

DFT and1H NMR molecular spectroscopic studies on biologically anti-oxidant active paramagnetic lanthanide(III)-chrysin complexes

“…In recent years great attention has been devoted to the design and synthesis of lanthanide coordination complexes with polyphenolic ligands such as flavonoids [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Flavonoids are polyphenolic organic compounds and are most frequently found in vegetable and other vascular plants that have potential applications in various fields of medical science [15][16][17][18].…”

“…Because of the presence of the hydroxyl and ketonic groups, they have strong chelating ability and bind to the metal ion in neutral solution. Several reports are available in the literature on flavonoids and their metal complexes with transition and non-transition metal ions [2][3][4][5][6][7][8][9][10][11][12][13]. It is known that polyphenolic ligands (flavonoids) play a very important role as anti-oxidants and demonstrate free radical scavenging ability [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19].…”

“…They found that the suppression ratios of O 2 radicals for the metal complexes were mostly higher than with the ligand *Corresponding author. E-mail: aneesaansari@gmail.com alone [2][3][4][5][10][11][12]. This indicated that the inhibitory ratio of the free radicals in the polyphenolic complexes increased after complexation.…”

1H NMR and spectroscopic studies of biologically active yttrium (III)-flavonoid complexes

“…There are only two absorption bands observed in the spectrum of L1 and L2 in methanol and DMF solutions ( Figures 2 and 3) [16,[27][28][29]. Two peaks at 412 (I) and 238 nm(II) in methanol, 375(I) and 262 nm (II) in DMF; at 403(I) and 236(II) in methanol, at 411(I) and 244 nm(II) in DMF are observed in the spectrum of free L1 and L2, respectively [19][20][21][22]. The observed absorption band at higher wavelength (lower frequency) is assigned to the p-p and n-p transitions, and a second band observed at lower wavelength (higher frequency) is due to Main Group Chemistry 135 the p-p and n-s transitions, that correspond to ring A (quinolic system) and ring B (catechol system), respectively [28,29].…”

“…Some flavonoids possess strong antioxidant activity through their ability to scavenge free radicals and chelate metal ions [15][16][17][18][19][20]. The chelating capacities of flavonoids with metal ions such as transition and non-transition metals have been reported earlier and demonstrated that their coordination complexes were better inhibitors of free radicals than the ligands alone [17][18][19][20]21]. As a result of their potential utility in biomedical science flavonoid coordination chemistry has been extensively studied [15][16][17][18][19][20][21][22][23][24][25].…”