Evaluation of Antioxidative Constituents from Thyme

The non-polar fraction of thyme was examined for the occurrence of phenolic components and their antioxidative activity. In addition to carvacrol (II) and thymol (III), p-cymene-2,3-diol (I; 2,3-dihydroxy-4-isopropyl-1-methylbenzene) was isolated for the first time from thyme. The structure of Iwas elucidated using 1H nuclear magnetic resonance (NMR), 13C NMR, and mass spectrometry. Antioxidative activity was investigated with the Rancimat method (100°C) and the Schaal test (60°C). Compound Iexhibited the strongest antioxidative activity which was greater than that of α-tocopherol and butylated hydroxyanisole. Five thyme species were analysed by means of HPLC with electrochemical detection for the concentration of compounds I–III. The highest amounts of I–IIIwere found in Thymus vulgarisL.