Behavior of the potential antitumor VIVO complexes formed by flavonoid ligands. 2. Characterization of sulfonate derivatives of quercetin and morin, interaction with the bioligands of the plasma and preliminary biotransformation studies

Preparation and evaluation of the pentavalent antimony-quercetin complex (SbV-QUE)

“…Through UV-Vis technique, presented in figure 1b, a bathochromic shift from 371 (free quercetin) to 379 nm in the SbV-QUE SOL complex was noticed, as described by Tong et al (2016), in which quercetin bands were shifted from 255.67 to 259.13 nm for band II and 375 to 391nm, for band I. That happens because of the extension of conjugated system, when complexation occurs (SANNA et al 2015). This result and the fluorimetry analysis proved the SbV-QUE complex formation.…”

Vanadium–Flavonoid Complexes: A Promising Class of Molecules for Therapeutic Applications

“…If the coordination of flavonoids with vanadium-based ions at physiological pH occurs through the donor groups CO and O − , it yields pentacoordinated species with "acetylacetone-like" coordination and forms a sixmembered chelate ring structure. 71 The same donor sets (C O, O − ) have been reported to form five-membered chelate rings by cis-octahedral complexes with "maltol" coordinations. 71 Additionally, in the physiological pH, the donor sets from flavonoids (O − , O − ) form square pyramidal structure with catechol-like coordination with vanadium-based ions.…”

“…61,63 In the case of vanadium complexes, the coordination of flavonoids with vanadium is mainly attributed to the presence of hydroxyl groups in different positions that leads to the formation of maltolate-like, acetylacetonate-like, or catecholate-like configurations (Figure 4). 71 The coordination site in the flavonoid ring involved in the complexation reaction with vanadium determines the structure of the resultant complex. Different types of coordination models, such as maltol or acetylacetone donor set coordination, ring size-dependent catechol-like coordination (five-or six-membered), pentacoordinated, cis-octahedral, and transoctahedral coordination, are possible in vanadium−flavonoid complexes.…”

Spectroscopic determination of intracellular quercetin uptake using erythrocyte model and its implications in human aging

“…Quercetin has been reported to interact with phosphatidylcholine and phosphatidylethanolamine head groups in the cell membrane bilayer through hydrogen bonds at low concentrations and hydrophobic tail region at high concentrations (Kim et al 2015). These interactions may induce changes in membrane fluidity of RBCs which are associated with transport system (Kumar et al 2016b;Sanna et al 2015).…”