Metabolomic differences among different parts of Isaria cicadae cultured on Antheraea pernyi

Abstract:

[Background] Isaria cicadae is a Chinese traditional medicine. A preliminary study showed that wild I. cicadae contains similar metabolites with cultured I. cicadae on Antheraea pernyi. Therefore, the cultured I. cicadae has the potential to be used as an alternative. [Objective] Reveal the metabolites difference between different parts of the cultured I. cicadae. The results will provide a theoretical basis for the rational use of the cultured I. cicadae. [Methods] HPLC-DAD-TOF/MS-based metabolomics was used to compare the metabolic difference between the insect body part, mycelia on the insect surface and coremia of I. cicadae. [Results] Different parts of cultured I. cicadae showed significantly different metabolomics. Despite that, the insect part is full of mycelia (sclerotia) which contains less small molecular metabolites than the other parts, and has only a relatively higher level of dihydroceramide and phytosphingosine. This result implied that it contained mainly insoluble macromolecular substances. The high level of phytosphingosine was possibly related to immune injury from the host insect. Lots of small molecular metabolites were detected from mycelia on the surface of the insect body implying that nutrients from the insects were preferentially absorbed by the mycelia. The coremia contain relatively few secondary metabolites. [Conclusion] Different parts of cultured I. cicadae on A. pernyi contain significantly different metabolites, and mycelia on the surface of the insect contain relatively higher level of secondary metabolites suggesting more potential of metabolites utilization.