RESUMO
The molecular and electronic structure of parent flavone and 49 (poly)methoxylated flavones (P)MFs were studied theoretically. Selected group of flavonoids consists of compounds naturally occurring in citrus plants or synthetic derivatives of flavone. These compounds exhibit several bioactivities in vitro and in vivo and can protect plants from solar ultraviolet (UV) radiation. Substitution induced structural changes in (P)MFs were correlated with published experimental values of P-glycoprotein inhibition effect. We have demonstrated that the C5-C10 bond length of 1-benzopyran-4-one moiety represents a suitable structural descriptor for this bioactivity. Obtained linear equations for the compounds with substituted and non-substituted C3 position enable the prediction of the potential anti-cancer chemo-preventive effect of the rest of studied (P)MFs. Consequently, potentially more effective substances were suggested. Optical properties of (P)MFs and their relationship with the molecular structure was examined in detail for methanol environment, as well. The multiple linear regression model was applied to assess the correlation between experimental absorption and fluorescence wavelengths with the theoretically predicted ones. The UV photo-protective potential of studied derivatives was estimated from the calculated optical properties.