Supporting Material for: "NMR-based metabolomics for frauds detection and quality control of oregano samples"

Abstract

Table S1. Summary of NMR experiments performed in order to elucidate the structure of salvianolic acid B. Sample was solubilized in CD3OD. Fig. S1 1H NMR spectrum obtained for apigenin (in fraction 114) solubilized in CD3OD. Fig. S2. 1H NMR spectrum obtained for rosmarinic acid (found in EtOAc fraction from Oregano vulgare) solubilized in CD3OD. Fig. S3 1H NMR spectrum obtained for thymol, and p-cymene (found in CHCl3 fraction from Oregano onites) solubilized in CD3OD. Fig. S4 1H NMR spectrum of salvianolic acid B solubilized in CD3OD. Fig. S5 NMR COSY spectrum of salvianolic acid B solubilized in CD3OD. Fig. S6 NMR HSQC spectrum of salvianolic acid B solubilized in CD3OD. Fig. S7 NMR HMBC spectrum of salvianolic acid B solubilized in CD3OD. Fig. S8 NMR J-res spectrum of salvianolic acid B solubilized in CD3OD. Fig. S9 A) S-plot from OPLS-DA model showing the most important spectral bins for the discrimination between the two commercial species of oregano. B) Result of the permutation test of the OPLS-DA model. C) Loading column plot from OPLS-DA model. Fig. S10 Main biomarkers found in this work. Fig. S11. PCA score scatter plot where unknown species (green dots) are distinguished from marketable oregano and placed as outliers by the model. Fig. S12 Extended regions of observed vs predicted plots from OPLS models (y = % of total impurity) of A) Origanum vulgare B) Origanum onites. Fig. S13 Graphic obtained by permutation test of the OPLS model built using as y variable the % of cistus contamination. Fig. S14 J-res spectra of Oregano contaminated with cistus (A) and pure oregano (B). The contaminated sample presents a singlet at δ 3.57.