Secondary Metabolites And Antibacterial Activity Of Marine-derived Endophytic Fungi Penicillium Janthinellum, P. Crustosum And Aspergillus Sydowii

Indole diterpenes are a class of secondary metabolites which play an important role in natural product research.Their chemical structures are diverse and have good antibacterial,antiviral and antitumor activities.They have a long history and attract more and more attentions currently.In this paper,Indole diterpenes found from 1970 s to now were systematically reviewed.More than 130 secondary metabolites were described and classified according to their source and structure types,and details of activities of various secondary metabolites were revealed.The study found that about 31% of the total amount of indole diterpenes were marine-derived,showing that ocean is an important source of natural products and has great potential.In this paper,the crude extracts of Penicillium janthinellum AS-79 were separated by silica gel column chromatography,gel column chromatography,preparative thin layer chromatography(pTLC)and preparative high performance liquid chromatography(pHPLC).14 secondary metabolites were obtained(PJ1-14),of which 12 were indole diterpenes(PJ1-12).3 new secondary metabolites(PJ1-3)were determined by NMR,calculated ECD and X-Ray crystallographic analysis.Compounds PJ5,PJ7,and PJ11 showed activity against the aquatic pathogen Pseudomonas aeruginosa.Compounds PJ5,PJ7,PJ8 and PJ11 exhibited activity against the human pathogen Escherichia coli.Compounds PJ2,PJ5,PJ7,PJ9 and PJ11 exhibited activity against the aquatic pathogen Vibrio parahaemolyticus.In this paper,19 fungal strains isolated from Rhodomela species were screened and co-cultured.The fermentation product were detected by means of HPLC,TLC and NMR to determine the scale fermentation strain.The isolation and identification of the secondary metabolites of co-culture and pure culture of Penicillium crustosum EN-311 and Aspergillus sydowii EN-434 were accomplished.The new natural product PA3 was isolated from co-culture.Pure culture of EN-434 gained two compounds PA1 and PA2,and the absolute configuration was determined by ECD calculation.In summary,the chemical diversity of secondary metabolites was further enriched by systematic review and identification of three fungal fermentation products.It revealed the importance of endophytic fungi in the study of secondary metabolites.The antimicrobial activity of the isolated compounds was tested,and some antibacterial indole diterpenes were found.