Isolation and identification of antitumor substance from endophytic fungus Aspergillus oryzae YX-5 isolated from Ginkgo biloba

Abstract:

[Background] Plant endophytic fungi are an important source of natural bioactive substances. [Objective] The active substance of an antitumor endophytic fungus Aspergillus oryzae YX-5 isolated from Ginkgo biloba was investigated. [Methods] First, strain YX-5 was fermented. Then, the culture broth was extracted with ethyl acetate. By using vacuum liquid chromatography, Sephadex gel chromatography and high performance liquid chromatography, the active compound was isolated from the crude extract and the antitumor activity was measured by MTT assay. [Results] Four pure compounds were isolated from the crude extract of strain YX-5. Based on the analysis of NMR and HR-ESI-MS, these compounds were identified as hydroxyaspergillic acid (1), cyclo(4-Hydroxypro-Phe) (2), Cyclo(Leu-Phe) (3) and Cyclo(Ala-Phe) (4). Hydroxyaspergillic acid exhibited significant cytotoxic activity against HeLa cell with IC50 of 1.07 μg/mL. [Conclusion] Hydroxyaspergillic acid exhibited antitumor activity, indicating that Aspergillus oryzae and hydroxyaspergillic acid might have application potential in antitumor natural products development.