A preliminary elemental and isotopic investigation to develop authentication tools for Chinese Ganoderma lucidum

Abstract

Isotope ratio mass spectrometry (IRMS) combined with multivariate analysis was employed to develop a new quality control tool for Chinese Ganoderma lucidum. The effect of growth stage, substrate, cultivar type and geographical origin on the elemental and isotopic compositions was investigated. Stable isotopes (δ13C, δ15N, and δ18O) and elemental contents (%C, %N) showed significant variations at different growth stages. Growth substrate did not impart significant variations on δ13C or δ18O values; however, δ15N values of G. lucidum were strongly associated with the substrate. In addition, large isotopic variations were observed among different G. lucidum cultivars. A strong positive correlation was observed between major active compounds and elemental contents. Finally, classification models based on LDA and PLS-DA were constructed to discriminate the geographical origin of G. lucidum. Both models achieved very high classification rates in both the training and test set (up to 100% accuracy). In conclusion, elemental and isotopic fingerprints along with multivariate statistical analysis showed strong potential in characterizing G. lucidum according to variety, production region and cultivation method. These preliminary results will provide valuable insights in controlling the fraudulent labeling of Ganoderma lucidum and provide authentication tools for regulatory authorities to authenticate origin claims.