Secondary Metabolites From Two Fungus And Their Biological Activities

Fungi are one of the most prevalent sources for the discovery of structurally novel and biologically meaningful secondary metabolites,which played an important role in discovering lead compounds or drug candidates.The statin,lipid-lowering in clinical drugs,and antibiotics such as penicillin and cephalosporin are all derived from fungi.In order to search for novel compounds and highly bioactive secondary metabolites,a comprehensive investigation on an endophytic fungus Diaporthe lithocarpus A740 and a marine fungus Phomopsis lithocarpus FS508 was carried out,and isolated compouds were tested for their cytotoxic,antibacterial,and antioxidant activities.All compounds were isolated from the fermentation extracts of the two fungal strains by using various chromatographic methods including silica gel column chromatography,RP-18 chromatography,Sephadex-LH20 column chromatography and HPLC preparation.The structures of these compounds were elucidated by means of extensive analysis of spectroscopic techniques such as ESI-MS,HR-ESI-MS,¹H-NMR,¹³C-NMR,¹H-¹H COSY,HMQC,HMBC,and NOESY.All of the isolates were tested for their cytototxic activity against HepG-2 MCF-7,SF-268,and A549 cell lines by SRB method.Some compounds were evaluated for their antibacterial activity against Staphylococcus aureus,Escherichia coli and Bacillus subtilis by filter paper method.In addition,some isolates were tested for their antioxidant activity by DPPH method.35 compounds,including 14 new compounds and 21 known compounds,were isolated and identified from the two fungal strains of Diaporthe lithocarpus A740 and Phomopsis lithocarpus FS508.Among them,5 compounds?2,13,15,27,and 28?exhibited cytotoxic activity against SF-268,MCF-7,A549 and HepG-2 cell lines with the IC₅₀ values in the range of 11.3 to 53.3?M.The results of this study not only enriched the chemical constituents of the gernera Diaporthe and Phomopsis,but also provided a scientific basis for the development and utilization of natural products from endophytic and marine-derived fungi.