The relationship between structure, kinetic, thermochemical and electronic properties of the morin flavonoid was researched in order to establish the molecular characteristics related to its maximum radical scavenging activity. The reaction of morin with the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH 1) was carried out in ethanol, through the hydrogen-atom transfer (HAT) mechanism. Morin showed the highest radical scavenging activity under conditions of excess of free radical. It was found, by means of experimental and computational methods, that 3-OH, 2′-OH and 4′-OH are the main reactive sites, as well as that the 3-O-2′-O quinone is the first product of the reaction, tending to prevail in the enol form through a tautomerism effect, whose observed structural arrangement corresponds to the 3-O semiquinone.
Bibliographical noteFunding Information:
The authors of this paper are very grateful with the Consejo Nacional de Ciencia y Tecnología (CONACYT) which financed the investigation under Grant No. 91541 . Also with Centro de Investigación en Alimentación y Desarrollo, A.C. (CIAD, A.C.), especially with the Ph.D. Rogerio R. Sotelo-Mundo, and Universidad de Sonora, for the support to carry out this work.
- Antioxidant activity
- Density functional theory
- Infrared spectroscopy
- Radical scavenging