Study on fisetin-aluminium(III) interaction in aqueous buffered solutions by spectroscopy and molecular modeling

Spectroscopic (UV/visible and IR) and theoretical studies were used to assess relevant interaction of fisetin, a tetrahydroxylated flavone molecule, and trivalent aluminium in a wide range of buffered aqueous solutions. The chelation sites, stoichiometry, stability and the dependence of the complexes structures on pH and aluminium/fisetin mole ratios were defined. Obtained results implicated successive formation of two complexes with aluminium(III)-fisetin stoichiometries of 1:1 and 2:1. Considering the fisetin molecular structure, results of vibrational analysis and theoretical calculations, it is possible to implicate 3-hydroxyl-4-carbonyl and 3′4′-dihydroxyl groups as those with the possible chelating power. The equilibrium geometries were optimized in vacuum at the B3LYP/6-31G(d) level of theory, which predict structural modifications between the ligand molecule in free state and in the complex structure. The theoretical model has been validated by both vibrational and electronic spectroscopies

The influence of supplement feed preparation on the fatty acid composition of carp and Chironomidae larvae in a semi-intensive production system

In order to examine how extruded and pelleted feed affects the fatty acid composition of carp meat and Chironomidae larvae, two-month-old carp specimens were set in two fishponds (L1 and L2). The fatty acid composition of extruded and pelleted feed is characterized by a significantly higher content of ω-3 fatty acids and higher ω-3 to ω-6 fatty acids ratio (ω-3/ω-6) in extruded (11.34±0.12% and 0.315±0.005, respectively) compared to pelleted feed (7.72±0.08%, 0.180±0.001, respectively). The fatty acid composition of carp meat is characterized by higher ω-3 fatty acid content and ω-3/ω-6 in carp fed with extruded feed (L1, 6.98±0.53% and 0.295±0.022, respectively) compared to carp fed with extruded feed (L2, 5.46±0.07% and 0.232±0.009, respectively). Chironomidae larvae from the fishpond L2 had significantly higher ω-3 fatty acid content (8.22±0.89%), and therefore higher ω-3/ω-6 (0.81±0.09) in comparison to Chironomidae from the L1 fishpond where these parameters were 4.48±0.06% and 0.21±0.01, respectively. [Projekat Ministarstva nauke Republike Srbije, br. TR 31075 i br. 173040