A DENSITY FUNCTIONAL THEORY STUDY OF ANTIOXIDANT ACTIVITY OF ISOTHIOCYANATES IN BROCCOLI SPROUTS (BRASSICA OLERACEA L.)

Abstract

Antioxidant activity of 9 isothiocyanate derivatives (−N=C=S) extracted from Broccolisprouts (Brassica oleracea L.) has been investigated using density functional theory (DFT) –based computational methods. Through the hydrogen atom transfer (HAT) and single electrontransfer (SET) mechanisms, three thermodynamic parameters including bond dissociationenthalpy (BDE), vertical ionization energy (IE), and vertical electron affinity (EA) werecalculated in the gas phase using B3LYP/6-311++G(3df,3p)//B3LYP/6-311G(d,p) modelchemistry. As a result, the isothiocyanate (ITC) shows potential antioxidant activity via HATmechanism. The most potential antioxidant is 3-isothiocyanato pro-1-en (3ITCP) withBDE(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 intialneutral compounds with lower IE, higher EA and ω.