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As a result, the isothiocyanate (ITC) shows potential antioxidant activity via HAT mechanism. The most potential antioxidant is 3-isothiocyanato pro-1-en (3ITCP) with BDE(C−H) of 72.9 kcal/mol. The SET mechanism is not dominant in case of the studied ITCs. Moreover, the radicals formed H• removal had more reactive and less stable than the intial neutral compounds with lower IE, higher EA and ω. | Journal of Science and Technology 54 (2C) (2016) 306-312 A DENSITY FUNCTIONAL THEORY STUDY OF ANTIOXIDANT ACTIVITY OF ISOTHIOCYANATES IN BROCCOLI SPROUTS (BRASSICA OLERACEA L.) Nguyen Phan Truc Xuyen1, Dao Duy Quang2, *, Ngo Thị Chinh2 1 Faculty of Environment and Chemical Engineering, Duy Tan University, 03 Quang Trung, Da Nang 2 Institute of Research and Development, Duy Tan University, 03 Quang Trung, Da Nang * Email: daoduyquang@gmail.com Received15 June 2016; Accepted for publication: 22 October 2016 ABSTRACT Antioxidant activity of 9 isothiocyanate derivatives (−N=C=S) extracted from Broccoli sprouts (Brassica oleracea L.) has been investigated using density functional theory (DFT) – based computational methods. Through the hydrogen atom transfer (HAT) and single electron transfer (SET) mechanisms, three thermodynamic parameters including bond dissociation enthalpy (BDE), vertical ionization energy (IE), and vertical electron affinity (EA) were calculated in the gas phase using B3LYP/6-311++G(3df,3p)//B3LYP/6-311G(d,p) model chemistry. As a result, the isothiocyanate (ITC) shows potential antioxidant activity via HAT mechanism. The most potential antioxidant is 3-isothiocyanato pro-1-en (3ITCP) with BDE(C−H) of 72.9 kcal/mol. The SET mechanism is not dominant in case of the studied ITCs. Moreover, the radicals formed H• removal had more reactive and less stable than the intial neutral compounds with lower IE, higher EA and ω. Keywords: Brassica oleracea L., isothiocyanate, antioxidant, HAT, SET, DFT. 1. INTRODUCTION Broccoli sprouts (Brassica oleracea L.) is one of nutrient vegetables which is widely consumed in Vietnam. Several studies have demonstrated that Broccoli sprouts contains several chemical compound families that represent chemopreventive properties such as alkylhydrocarbon, -carbonyls, -alcohols, esters, aromatic compounds, nitriles, sulfides, etc. [1, 2, 3]. Among them, isothiocyanates (ITCs) represent as one of the most massive .
