Studies On The Secondary Metabolites Of Arctic-derived Fungi Nectria Sp. B-13

Polar regions where characterized by low temperature, low water availability,frequent freeze–thaw cycles, strong winds and high ultraviolet radiation are remote and challenging areas on the earth. Due to their unique living environment, polar microorganisms have been considered as an important source of bioactive leading compounds. In recent years, numerous unique and novel compounds were isolated from polar-derived microorganisms, and the studies of secondary metabolites from polar-derived microbes became popular in the world.In this paper, we studied the extraction, isolation and identification of secondary metabolites from two strains of marine fungus, which will promote the research of secondary metabolites from marine fungus.The paper selects a strains fungi B-13 which from the Arctic as starting strain for further study. After the strain was identified as the Nectria fungi, belonging to the Ascomycota, Hypocreales, Nectriaceae. The Nectria fungi widely exist in worldwide tropical and subtropical regions. Though the polar expedition, Chinese scholars also found fungi of the genus Nectria in the high latitude Arctic region, and found the Nectria fungi accounted for Cultured Fungi in second place, second only to the Penicillium fungi. The subject group had screened a strain Nectria sp. B-13 from the soil samples from Arctic Ny-?lesund area and found that the its fermentation products had the inhibitory activity against Aspergillus fumigatus, and the value of MIC is 25 μg/mL. According to the founding, we carried out the system of the active compounds’ identification.According to the nature of the strain Nectria sp. B-13, the optimum fermentation culture medium was the GPY medium containing 1% NaCl; the fermentation temperature was 20 ?C; and the incubation period conditions was on the shaker at the speed of 180r/min, by 2% inoculation amount, for 9 days.The separation and purification of polar fungus Nectria sp. B-13 secondarymetabolites extraction was adopted by means of normal phase gel colum chromatography,reversed phase silica gel column chromatography, Sephadex LH-20 gel column chromatography, reversed-phase high performance liquid phase chromatography. The results were that 27 compounds were isolated from Nectria sp.B-13 fermentation liquid extraction with ethyl acetate part. And by using modern spectrum techniques(LCMS, 1H NMR, 13 C NMR, HMBC, HMQC COSY, NOESY) to identity isolated compounds, 17compounds(1-17) were identified as 6-methylbenzene- 1,2,4-triol(compound 1),Colletochlorin B(compound 2),ilicicolin A(compound 3), LL-Z 1272 β(compound 4),ilicicolin C(compound 5), ilicicolin D(compound 6), ilicicolin F(compound 7),8’-hydroxyascochlorin(compound 8), ilicicolin E(compound 9), LL-Z-1272 ε acid(compound 10), Deacetylchloronectrin(compound 11), Dechlorodeacetyloronctrin(compound 12), Nectriatone A(compound 13), Nectriatone B(compound 14), dibutyl phthalate(compound 15), diisobutyl phthalate(compound 16), ergosterol peroxide(compound 17). What’s more two new comopunds named Nectriatone A(compound 13),Nectriatone B(compound 14), and two new natural compounds named LL-Z-1272 ε acid(compound 10), Dechlorodeacetyloronctrin(compound 12) were isolated.Secondary metabolites of gungal have a wide range of biological activities. In this paper,The bioactivities including antibacterial, antifungal, and antitumor activities of those compounds were evaluated. The results showed that compound 9(ilicicolin E)significantly inhibited Escherichia coli, Bacillus coli and Staphylococcus aureus growth activities. The value of MIC is 3.125 μg/mL. Compounds 5, 6, 9, and 10 can completely inhibit the germination of Pyricularia oryzae with MIC values were 7.8μg/mL, 31.2 μg/mL,3.125 μg/mL and 15.6 μg/mL. Compounds 2, 3, 5, 6, and 9 all showed strong antitumor activity against tumor cell lines 22RV1; Compound 2, 3, 5, 6, 8, 9, and 11 showed strong antitumor activity against tumor cell lines HTC-116, MCF-7 and K562.