Interpretation of the IR and Raman spectra of morin by density functional theory and comparative analysis

Density functional theory calculations, with M05-2X functional and 6-311++G(d,p) basis set implemented in the Gaussian 09 package, are performed with the aim to support molecular structure and spectroscopic characteristics of morin, a bioflavonoid molecule known for its antiproliferative, antitumor, and anti-inflammatory effects. Detailed vibrational spectral analysis and the assignments of the bands, done on the best-fit basis comparison of the experimentally obtained and theoretically calculated IR and Raman spectra, match quite well indicating DFT calculations as very accurate source of normal mode assignments. The assignment of the most prominent normal modes of morin is qualitatively verified through comparative spectral analysis with quercetin, a structurally isomeric molecule of morin which differs only by the substitution pattern of the B ring. Performed comparative analysis reflects quite accurately all the structural differences between the investigated molecules additionally proving the applied theoretical method

Antiradical activity of delphinidin, pelargonidin and malvin towards hydroxyl and nitric oxide radicals: The energy requirements calculations as a prediction of the possible antiradical mechanisms

Naturally occurring flavonoids, delphinidin, pelargonidin and malvin, were investigated experimentally and theoretically for their ability to scavenge hydroxyl and nitric oxide radicals. Electron spin resonance (ESR) spectroscopy was used to determine antiradical activity of the selected compounds and M05-2X/6-311+G(d,p) level of theory for the calculation of reaction enthalpies related to three possible mechanisms of free radical scavenging activity, namely HAT, SET-PT and SPLET. The results obtained show that the molecules investigated reacted with hydroxyl radical via both HAT and SPLET in the solvents investigated. These results point to HAT as implausible for the reaction with nitric oxide radical in all the solvents investigated. SET-PT also proved to be thermodynamically unfavourable for all three molecules in the solvents considered