Secondary metabolites of halotolerant fungus Penicillium chrysogenum HK14-01 from the Yellow River Delta area

Abstract:

Abstract:［Objective］To search for structurally novel and biologically active compounds from the secondary metabolites of halotolerant fungi from the Yellow River Delta area．［Methods］We screened halotolerant fungi with rich chemical diversity and antitumor or antimicrobial activity by means of integrated chemical and biological method． We cultured halotolerant fungi under different conditions at first． Then we investigated the chemical diversity and the bioactivity of the EtOAc extracts of the fermentation broth by HPLC and TLC，and cytotoxic assay or antimicrobial assay． We selected Penicillium chrysogenum HK14-01 to further study for the large yield，producing alkaloids and cytotoxicity on P388 cells in YMDP culture medium containing 10% NaCl． We fermented P． chrysogenum HK14-01 on a large scale; we isolated and purified the compounds by column chromatography over silica gel，Sephadex LH-20，and semipreparative HPLC; and we identified the structures by spectroscopic analysis，X-ray diffraction (Mo-Kα)，CD spectra and the time-dependent density functional theory electronic circular dichroism (TDDFT ECD) calculation． ［Results］We isolated and identified a halotolerant fungal strain，P． chrysogenum HK14-01，from the sediments collected in the Yellow River Delta area． From the fermentation broth of P. chrysogenum HK14-01，we isolated and identified eight compounds，i.e. (2S，3R)-oxaline (1，a major product)，(3R，4R)-3，4，8-trihydroxy-3，4-dihydronaphthalen-1(2H)-one (2)，(Z)-N-(4-hydroxy styryl) formamide (3)，(E)-N-(4- hydroxystyryl) formamide (4)，emodin (5)，4-(2- hydroxyethyl) benzene-1，2-diol (6)，methyl 2-( 4- hydroxyphenyl ) acetate (7)，and 2-(4-hydroxyphenyl ) acetonitrile (8).［Conclusion］ Bioactive compounds can be obtained from the secondary metabolites of halotolerant microorganisms from the Yellow River Delta area．

Key words:Keywords: Yellow River Delta，halotolerant fungus，Penicillium chrysogenum，secondary metabolites，antimicrobial activity