Studies On The Secondary Metabolites Of Aspergillus Oryzae

This thesis is composed of three chapters. The first chapter, the capital part of this thesis, is regarding the study on metabolites of Aspergillus oryzae. The second chapter studies on quality standard of Lythnum salicaria L.. The third chapter reviews on researches in chemicals produced by Aspergillus oryzae and their bioactivies.Aspergillus oryzae is of much importance in manufacturing fermentation food and other industries. The ability to secret various enzymes facilitating its increasing application modern industry. Therefore, this study concerns about chemicals produced by A. oryzae to provide more sufficient information for its safer use and searching for bioactive metabolites.Ccompounds 1-12 have been isolated from the mycelia and the fermented broth of Aspergillus oryzae and they are elucidated as following: 12,13-dihydroxy fumitremorgin C (1), verruculogen (2), fumitremorgin A (3), aszonalenin (4), acyl aszonalenin (5), N-2'-hydroxy-(E)-3-oct-adecenoyl-1-O-β-D-galactopyranosyl-(4E) -9-me-thyl-4-8-sph-inga dienine (6), ergosterol (7), peroxidized ergosterol (8), henolic acid (9), 12(S)-hydroxy,13(R)-methoxy-fumitremorgin C (10), 3,7,9-trihydroxy- 5,22-diene-ol (11) and hexadecanoic acid (12). The stereochemistry of compound 10 has never been reported before. Thus, it's initially identified as a new compound.MTT assay has been conducted to test protective effects of compounds 4, 5, 6, 11 against CoCl2 or H2O2-induced injury to SH-SY5Y cells, as well as effects to proliferation of this cell. Compound 6 protects SH-SY5Y cells from H2O2-induced injury at low concentration between 20nM-20μM, but has no influences on CoCl2-induced injury or natural proliferation. Antibacteria activities of compounds 4, 5, 8 as well as the mycelia extracts and the broth extracts have been tested against S. aureus, E. coli and k. peneumoniae by microtitre broth dilution method. The mycelia extracts significantly inhibits the growth of S. aureus between 1.25-10mg/ml, yet the three compounds show no activites.A RP-HPLC analysis, both in qualitative and quantitative aspects, has been carried out to investigate influence of culture conditions on extra- and intracellular metabolites produced by A. oryzae. Five kinds of culture medium were applied and compounds 2, 3, 4, 5 were used for quantitative comparison. The result reveals that culture conditions greatly influence metabolites produced by A. oryzae , especially for those extracellular. The quantitative analysis indicates that compound 1 is a predominant intracellular metabolites while compound 5 is predominant in extracellular metabolites.