The geometry of myricetin and dihydromyricetin was optimized by DMol3 program based on DFT. The optimized structures have been proved to be stable by real frequencies obtained.The parameters of geometry optimization,v...The geometry of myricetin and dihydromyricetin was optimized by DMol3 program based on DFT. The optimized structures have been proved to be stable by real frequencies obtained.The parameters of geometry optimization,vibration frequencies,atomic charges,thermodynamics,Fukui functions,and frontier molecular orbital had been obtained. The thermodynamic properties of 2 molecules were fitted and the relationship between the thermodynamic function and temperature was obtained. The correlation coefficient of the obtained equations is larger than 0.99,indicating that the function is approximately linear in the whole temperature range. The calculated results showed the O–H molecular structures were the main group affecting the antioxidant activity and the oxygen in the benzene ring is the electrophilic reaction site. Ortho-OH on the benzene formed intramolecular hydrogen bonds,which contributed to the stability of the benzene ring. It may be the active site for the occurrence of the reaction.展开更多
This study aimed to analyze the antioxidant mechanism of four different anthocyanins in purple sweet potato. The DPPH test and the lipid peroxidation inhibition ability test were used to analyze the in vitro antioxida...This study aimed to analyze the antioxidant mechanism of four different anthocyanins in purple sweet potato. The DPPH test and the lipid peroxidation inhibition ability test were used to analyze the in vitro antioxidant activity of four anthocyanins, and then the optimal structure, bond dissociation energy(BDE) and ionization potential(IP) of the anthocyanins and their simplified molecular models were analyzed by density functional theoretical study, and the antioxidant mechanisms were explored. The results showed that OH-4′ phenolic hydroxyl group of the four anthocyanins has the highest activity, and its bond dissociation energy is less than that of resveratrol. The theoretical calculation results of antioxidant activity are consistent with the results of in vitro antioxidant tests. The results showed that anthocyanins of purple sweet potato have good antioxidant activity, and the DFT method provides a powerful theoretical basis for the development of anthocyanin antioxidant activity.展开更多
基金supported by the Science and Technology Project of Guangdong Province(2016B010122032)Natural Science Foundation of Guangdong Province(05300953)
文摘The geometry of myricetin and dihydromyricetin was optimized by DMol3 program based on DFT. The optimized structures have been proved to be stable by real frequencies obtained.The parameters of geometry optimization,vibration frequencies,atomic charges,thermodynamics,Fukui functions,and frontier molecular orbital had been obtained. The thermodynamic properties of 2 molecules were fitted and the relationship between the thermodynamic function and temperature was obtained. The correlation coefficient of the obtained equations is larger than 0.99,indicating that the function is approximately linear in the whole temperature range. The calculated results showed the O–H molecular structures were the main group affecting the antioxidant activity and the oxygen in the benzene ring is the electrophilic reaction site. Ortho-OH on the benzene formed intramolecular hydrogen bonds,which contributed to the stability of the benzene ring. It may be the active site for the occurrence of the reaction.
基金Supported by National Natural Science Foundation of China(81772290)Sichuan Provincial Key Laboratory of Brewing Biotechnology and Application(NJ2017-04)Open Fund of Sichuan Provincial Key Laboratory of Solid State Fermentation Resources Use(2016GTJ004)
文摘This study aimed to analyze the antioxidant mechanism of four different anthocyanins in purple sweet potato. The DPPH test and the lipid peroxidation inhibition ability test were used to analyze the in vitro antioxidant activity of four anthocyanins, and then the optimal structure, bond dissociation energy(BDE) and ionization potential(IP) of the anthocyanins and their simplified molecular models were analyzed by density functional theoretical study, and the antioxidant mechanisms were explored. The results showed that OH-4′ phenolic hydroxyl group of the four anthocyanins has the highest activity, and its bond dissociation energy is less than that of resveratrol. The theoretical calculation results of antioxidant activity are consistent with the results of in vitro antioxidant tests. The results showed that anthocyanins of purple sweet potato have good antioxidant activity, and the DFT method provides a powerful theoretical basis for the development of anthocyanin antioxidant activity.
