Figure 9: One-dimensional 13C NMR spectra of thymol. A. Standard sample (with natural 13C abundance of 1.1%) of thymol solved in CDCl3. Signals were assigned to the corresponding carbon atoms of thymol. B. Sample of T. transcaucasicus flowers harvested and extracted with chloroform 12 days after the labelling with 13CO2 (4 hours). The solvent was CDCl3.