Objective: To explore composition of metabolites of Ophiocordyceps sinensis and Isaria cicadae by gas chromatography-mass spectrometry(GC-MS) metabonomics

in order to provide scientific basis for quality control of O. sinensis. Method: Samples were extracted by 50% methanol and then were subjected to GC-MS analysis.Metabolites were identified by NIST and GMD databases.Principal component analysis(PCA) and partial least squares-discriminant analysis(PLS-DA) were applied to explore sample classification and screen metabolites which contributed to discrimination

respectively. Result: A total of 64 metabolites were identified from all samples

mainly including amino acids and their derivatives

sugars alcohols

organic acids

fatty acids and others.PCA results showed clear separation of O. sinensis and I. cicadae

indicating that the metabolic characterization between those two samples was significantly different.Furthermore

21 metabolites responsible for discrimination were screened out.The contents of D-mannitol

trehalose

proline and pyroglutamic acid were significant higher in O. sinensis.Whereas

other compounds

including myo-inositol

γ-aminobutyric acid

ornithine and threonine showed higher values in I. cicadae. Conclusion: The chemical composition of O. sinensis and I. cicadae differs greatly

which suggesting that I. cicadae can not be used as alternative of O. sinensis.