Structure Elucidation And Bioactivities Evaluation Of The Secondary Metabolites From Two Polar Fungi

Due to the unique and special living environment in polar regions,polar microorganisms endow with the specific genetic and metabolic properties which have been regarded as an important source for bioactive secondary metabolites with novel structures.In recent years,polar microorganisms research have become an active frontier for natural products and drug lead compounds all over the world[1-2].In this paper,anti-bacterial and cytotoxicity activities of the secondary metabolites of two fungi supplied by Polar Research Institute of China were evaluated.The results showed the ethyl acetate extract of the polar fungi Articulospora sp.Z1-1 and Penicillium sp.S-1-10 not only exhibited antibacterical activities against Escherichia coli,Bacillus subtilis as well as Staphylococcus aureus,but also exhibited cytotoxic activities against the A549,H460,SGC7901,SW1990 and other cell lines.Therefore,the secondary metabolites of Articulospora sp.Z1-1 and Penicillium sp.S-1-10 were studied.According to the properties of Articulospora sp.Z1-1 and Penicillium sp.S-1-10,a preliminary study of the suitable fermentation conditions was evaluated.Under the same culture conditions,different media(PDB or GPY+1% NaCl)and different fermentation period were tested.Comparing with the mass of the broth extract,polar distribution of the products(TLC and HPLC-UV)and the activity of the extracts,the optimal fermentation conditions were determined: Articulospora sp.Z1-1 was cultivated in PDB medium,inoculation dose 2%,incubated at 25°C and 80 r/min on a rotary shaker for one day then static cultured for 27 days;Penicillium sp.S-1-10 was cultivated in(GPY+1% NaCl)medium,inoculation dose 2%,incubated at 24°C and 80 r/min on a rotary shaker for 14 days.The whole broth was extracted with ethyl acetate,which were subjected to a sequential fractionation on column chromatography,thin preparation layer chromatograph-y and HPLC under bioassay-guided fractionation.11 compounds were elucidated on the basis of ESI-MS and NMR spectroscopic data as 3,7-dihydroxy-9-methoxy-1-methy-l-benzo-6-one(1),1,4-dihydroxytoluene(2),3-hydroxy-methyl phenol(3),2-hydroxyphenethyl alcohol(4),dibutyl phthalate(5),1,7-dihydroxy-3-hydroxyl-8methoxy-dibenzo [b,e]oxepine-13,14-dione(6),bis(2-ethylhexyl)phthalate(7),4-tridecyl-benzaldehyde(8)and(Z)-7-tetradecenoic acid(9),kojic acid(10)and emestrin(11).Comp ounds 1-6 were firstly isolated from Articulospora,compound 8 was a new natural product,compound 11 was firstly obtained from Penicillium.The bioactivities of these compounds were evaluated.Compound 2 and 11 showed potent antibacterical activities against Escherichia coli,Bacillus subtilis and Staphyloccocus aureus.Compound 1,4,10 and 11 showed significant antifungal activities against conidia of Pyricularia oryzae,of which compound 11 displayed the lowest MIC value at 2.0 ?g/mL.Compound 11 could effectively inhibit the growth of A375 and M14 human melanoma cell line tumor cells with IC50 of 0.25 and 0.26 ?M,displaying strong cytotoxic activities aganist various cancer cells.Flow cytometry verified it could induce A375 cells apoptosis.Compound 3 and 10 elicited strong antioxidant activities and total antioxidant capacities were 2.4 times and 3.1 times higher than Trolox(positive control).Compound 10 showed an inhibitory effect on tyrosinase in vitro and in vivo.Finally,compound 11 exhibited antiinlammatory activity by inhibiting the proliferationof LPS-stimulated RAW 264.7 cells.