Antioxidant properties of ergothioneine (ESH) have been investigated via hydrogen atom transfer (HAT), single electron transfer-proton transfer (SET-PT) and sequential proton loss electron transfer (SPLET) mechanisms. Three new DFT methods including M06, WB97XD and TPSSTPSS at the 6-311++G(2df,2p) basis set were used to compute the thermochemical parameters of ESH in the gas phase. | Journal of Science and Technology 54 (2C) (2016) 299-305 THERMOCHEMICAL PARAMETERS OF ERGOTHIONEINE: A DFT STUDY USING M06, WB97XD AND TPSSTPSS METHODS Ngo Thi Chinh1, *, Dinh Tuan2, Nguyen Thi Hoa3, Ho Thi Huong3, Phung Quy Ngoc3, Pham Cam Nam3, 4, * 1 Institute of Research and Development, Duy Tan University, K7/25 Quang Trung, Da Nang 2 3 Department of Chemistry, Hue University’s College of Sciences, 77 Nguyen Hue, Hue University of Science and Technology - The University of Da Nang, 54 Nguyen Luong Bang, Da Nang 4 VNUK Institute for Research and Executive Education, The University of Da Nang, 41 Le Duan, Da Nang * Email: ; pcnam@ Received: 15 June 201631 May 2016; Accepted for publication: 22 October 2016 ABSTRACT Antioxidant properties of ergothioneine (ESH) have been investigated via hydrogen atom transfer (HAT), single electron transfer-proton transfer (SET-PT) and sequential proton loss electron transfer (SPLET) mechanisms. Three new DFT methods including M06, WB97XD and TPSSTPSS at the 6-311++G(2df,2p) basis set were used to compute the thermochemical parameters of ESH in the gas phase. Based on these methods, bond dissociation enthalpy (BDE), ionization energy (IE), proton dissociation enthalpy (PDE), proton affinity (PA) and electron transfer enthalpy (ETE) were calculated. The results were also compared with the values obtained by B3LYP method. The calculated results show that ergothioneine plays a role as a potential antioxidant via HAT mechanism. Keywords: ergothioneine, antioxidant, HAT, SET-PT, SPLET, BDE, IE, PA, ETE. 1. INTRODUCTION Antioxidants have played an important role in protection against oxidative stress present in food as well as human (health) biology. Particularly, natural and safer antioxidants have received great interest for food, pharmacological and medicinal applications [1]. Ergothioneine (ESH) (2mercaptohistidine trimethylbetaine) based on histidine, one of classes of intracellular .
