Position Impact of Hydroxy Groups on Spectral, Acid–Base Profiles and DNA Interactions of Several Monohydroxy Flavanones

Abstract

Structure-related biological activities of flavanones are still considered largely unexplored. Since they exhibit various medicinal activities, it is intriguing to enter deeper into their chemical structures, electronic transitions or interactions with some biomolecules in order to find properties that allow us to better understand their effects. Little information is available on biological activity of flavanone and its monohydroxy derivatives in relation to their physicochemical properties as spectral profiles, existence of protonated/deprotonated species under pH changes or interaction with Calf Thymus DNA. We devoted this work to research demonstrating differences in the physicochemical properties of the four flavanones: flavanone, 2′-hydroxyflavanone, 6-hydroxyflavanone and 7-hydroxyflavanone and linking them to their biological activity. Potentiometric titration, UV–Vis spectroscopy were used to investigate influence of pH on acid–base and spectral profiles and to propose the mode of interaction with DNA. Cyclic voltammetry was applied to evaluate antioxidant potentiality and additionally, theoretical DFT(B3LYP) method to disclose electronic structure and properties of the compounds. Molecular geometries, proton affinities and pKa values have been determined. According to computational and cyclic voltammetry results we could predict higher antioxidant activity of 6-hydroxyflavanone with respect to other compounds. The values of Kb intrinsic binding constants of the flavanones indicated weak interactions with DNA. Structure–activity relationships observed for antioxidant activity and DNA interactions suggest that 6-hydroxyflavanone can protect DNA against oxidative damage most effectively than flavanone, 2′-hydroxyflavanone or 7-hydroxyflavanone.

Structural and Spectral Investigation of a Series of Flavanone Derivatives

“…In an alkaline medium, the intensity of the bands was only changed in the case of FIN ( Figure 6 b). Chalcone probably was formed [ 29 ].…”

“…Due to the lack of hydroxyl groups in the flavanone ring, the basis of our modified compounds, there are no significant changes in bathochromic or hypsochromic shifts as is observed in monohydroxy flavanones [ 29 ]. In FHSB and FTSC with increasing pH, only the hypochromic effect is noticeable.…”

“…Geometry optimization of the compounds under study was performed with the use of DFT applying the hybrid B3LYP functional [ 38 , 39 , 40 ] and the 6-31+G(d,p) basis set. Our previous study has shown that this level of theory provides a quite reasonable description of structurally similar compounds [ 29 ]. Solvent effects (DMSO) were included in the calculations within the framework of the Polarizable Solvation Model (PCM).…”

Nafion® Coated Electropolymerised Flavanone‐based pH Sensor

“…9.5 kJ mol −1 ) than the R ‐form, at least in the gas phase and has the aromatic B‐ring twisted from planarity (dihedral angle of ca . 24°) [21], so that intra‐molecular hydrogen bonding between the donor oxygen in the 1‐position and the hydrogen of the 2’‐hydroxyl moiety is not possible, at least in the solid state. In solution, however, this six‐ring intra‐molecular hydrogen bond is thought to exist [22, 23], and this is compounded by the experimental pK a of the 2’‐hydroxyl functional group being 10.9 (in 40/60 vol.…”

DNA Binding Characteristics and Protective Effects of Yellow Pigment from Freshly Cut Yam (Dioscorea opposita)

“…DNA is a remarkable genetic material found in living organisms [1]. The bases and sugar moieties in DNA are easily attacked by excessive reactive oxygen species [2], and enzymatic repair may not always be sufficient to protect against permanent DNA damage [3].…”