Density Functional Theory Study on the Reactivity of Anti-oxidants toward DPPH

초록

DPPH is an abbreviation for the organic compound 2,2-diphenyl-1-picrylhydrazyl. It is a dark-coloured crystalline powder composed of stable free-radical molecules. DPPH is widely used in a laboratory experiment to monitor chemical reactions involving radicals, most notably in a common antioxidant assay. Many food ingredients contain polyphenol compounds, such as vitamin C, vitamin E, gallic acid, salicylic acid, quercetin, and kaempferol. In this work, the relative reactivity of these compounds toward DPPH was examined by the density functional theory (DFT) using the B3LYP/6-31G(d,p) level of theory. All the structures were optimized using Gaussian 16 package and were verified as minima with positive frequencies or as a transition state with one imaginary frequency. As there are many possible sites for proton abstraction in each compound, all the possible pathways were examined. One of the products of the reaction is another reactive radical, which will further complicate the interpretation of reactivity data.