tailieunhanh - Antioxidant properties of folic acid: A DFT study
This result shows that FA has higher ability to donate electrons into free radicals, while the ability to receive electrons is quite weak. Finally, the HAT reaction between FA and reactive radical like HOO was also calculated at the same level of theory. This provides more insight into its mechanism on free radicals scavenging. | Vietnam Journal of Science and Technology 56 (4A) (2018) 39-45 ANTIOXIDANT PROPERTIES OF FOLIC ACID: A DFT STUDY Nguyen Thi Thuy Nga1, Vu Thuy An2, Dao Duy Quang3, * 1 2 Department of Pharmacy, Duy Tan University, 03 Quang Trung, Da Nang city Department of Environment and Chemical Engineering, Duy Tan University, 03 Quang Trung, Da Nang city 3 Institute of Research and Development, Duy Tan University, 03 Quang Trung, Da Nang city * Email: daoduyquang@ Received: 25 July 2018; Accepted for publication: 13 October 2018 ABSTRACT Antioxidant activity of folic acid (FA) was investigated via two main antioxidant mechanisms: hydrogen atom transfer (HAT) and single electron transfer (SET) by Density Functional Theory (DFT) at the DFT/B3LYP/6-311G(d,p) level of theory. The characterizing thermochemical properties such as bond dissociation enthalpies (BDEs), ionization energy (IE) and electron affinity (EA) were calculated in the gas phase. Analyses of HOMOs distribution show that the positions which easily donate electrons to free radicals are essentially found at C ring, while the positions which easily accept electrons (LUMOs) from radicals are mainly situated at B ring. The lowest BDE values equal to and kcal/mol are obtained at C19 H and C9–H position, respectively. It is showed that FA represents a potential antioxidant via HAT mechanism. In addition, the IE and EA values calculated in the gas phase are equal to eV and eV, respectively. This result shows that FA has higher ability to donate electrons into free radicals, while the ability to receive electrons is quite weak. Finally, the HAT reaction between FA and reactive radical like HOO• was also calculated at the same level of theory. This provides more insight into its mechanism on free radicals scavenging. Keywords: folic acid, antioxidant, density functional theory, HAT, SET. 1. INTRODUCTION Folic acid (FA) (Fig. 1) is one of eight vitamins B that are essential for many .
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