Fig 1.
The concept of a logical series of seven ligands.
Fig 2.
(a) The FRAP values (concentration of tested compounds 20 mmol/dm3); (b) the EC50 values [μM] obtained in the DPPH assay for the series of ligands.
Table 1.
Theoretically and experimentally determined logP values.
Table 2.
The toxicity of the described series of compounds (IC50 [μM]).
Table 3.
The NBO atomic charges calculated for studied compounds (conformers with the lowest energy).
Fig 3.
The energy and distribution of LUMO and HOMO orbitals for the studied compounds in the gas phase calculated at B3LYP/6-311++G** level.
Table 4.
Calculated electronic parameters for the studied ligands at the B3LYP/6-311++G** level.
Table 5.
The O-H bond dissociation enthalpies (BDE), ionization potentials (IP), proton dissociation enthalpies (PDE), proton affinities (PA), electron transfer enthalpies (ETE) in kJ/mol obtained at B3LYP/6-311++G** level of theory.
Fig 4.
Atom numbering in flavone molecule.
Table 6.
The chemical shifts δ [ppm] from the experimental and theoretical 1H and 13C NMR spectra of studied ligands.
Table 7.
Wavenumbers and intensity of selected bands from the experimental IR and Raman spectra of studied compounds.
Fig 5.
Scree plot and percentage of total variance accounted for by each factor for principal component analysis.
Fig 6.
Principle component analysis of biological properties (i.e. FRAP values, IC50 for the cytotoxic activity towards Caco-2 cell line) and calculated physicochemical parameters.
Table 8.
The correlation matrix between different obtained descriptors.
Fig 7.
The mechanism of pro-oxidative activity [36].
Table 9.
Different mechanisms of antioxidant action and the parameters describing the activity [37].
Fig 8.
The toxicity on lipophilicity (ACD/LogP Classic) dependence of the described series of compounds.
The two exceptions are chromone (1) and flavone (2).
Fig 9.
Dendrogram of the series of 7 ligands based on their biological properties (i.e. FRAP values, IC50 for the cytotoxic activity towards Caco-2 cell line) and calculated physicochemical parameters.