Antioxidant synergism and antagonism between selected monoterpenes using the 2,2‐diphenyl‐1‐picrylhydrazyl method

Abstract

Abstract This research aims to investigate synergistic and antagonistic antioxidant interactions for binary mixtures of common monoterpenes. The activity was determined spectrophotometrically with the use of the DPPH • assay. Significant antioxidant synergism, between two different monoterpenes, was observed for a mixture of inactive p ‐cymene and one of the compounds, characterized by moderate antioxidant activity, e.g. (±)‐citronellal, α ‐phellandrene or α ‐terpinene. It has been proven that the activity of (±)‐citronellal is increased in the presence of hydrocarbons possessing the aromatic nucleophilic ring, which may react with electrophiles. A possible reaction mechanism was proposed for the synergistic antioxidant effect of p ‐cymene and (±)‐citronellal. This research opens new perspectives for studying interactions between isoprene derivatives, found in essential oils. Copyright © 2016 John Wiley & Sons, Ltd.