| Marine fungus has become an important source of bioactive natural product, recently. Today there are about 300 new compounds derived from marine fungi. Because of its unique living environment, marine fungus has produced special metabolites with unusual chemical structure to adapt the living condition such as salinity, high pressure and low temperature. For these reasons, the metabolites from marine fungus may possess new bioactivities or novel chemical structures.Secondary metabolites from two marine fungi strains were observed in this study. The entire region ITS1-5.8s-ITS2 of CB -2 was amplified by PCR. Associated with morphological character, CB-2 was identified as Articulospora sp.. Employing different isolation and purification methods, six compounds were isolated from the fermentation broth of CB-2, two of them were methyl 4,6–Dihydroxy- 2,3-dimethybenzoate (CB-4) and 3-(4-hydroxy-benzyl)-piperazine-2,5-dione (CB-6). Four compound were isolated from HLY-2, they were 7–Hydroxy-4, 6–dimethyl-3H– isobenzofuran-1-one (H-2), 7-Methoxy-4,6-dimethyl-3H-isobenzofunan-1-one (H–3), nectriapyron (H-4), ergosterol (H-6).Four of above compounds were studied for their bioactivities, including antimicrobial, anti-tumor, and antioxidant activities. H-2 and H-3 showed anti-tumor activity against Raji cell line with the IC50 value as 15μg/mL and 7.8μg/mL respectively. H-2, CB-4, and CB-6 showed anti-oxidant activity as scavenging of DPPH radicals with the IC50 value as 61.2μg/mL, 15.8μg/mL and 200μg/mL respectively. CB-4 and CB-6 showed moderate activity against S. aurens with the IC50 100μg/mL respectively. H-2 and CB-6 showed moderate activity against Penicillium avellaneum with the IC50 value as 200μg/mL respectively.Production of anti-tumor agent mycoepoxydiene was optimized by orthogonal design. Two types of fermentation were tested, which are agar surface and submerged fermentation. The result shows that the optimal condition for mycoepoxydiene production included potato 250g/L, sea water 300ml/L, glucose 30g/L, lactose 50g/L, KH2PO4 0.65mmol/L, (NH4)2SO4 1g/L in the agar surface condition. The production of mycoepoxydiene reached 521mg/L, and it equaled to 16 times of the production in customary half-seawater PD medium. The differences of production, biomass, and consuming rate of sugar, amino acid, and phosphate between agar surface and submerged fermentation were studied.Strain HLY-2 was fermented by optimal medium in agar surface manner for 10L, and 1.5g mycoepoxydiene were gained. The in vivo test showed that the compound has the toxicity to mouse with LD50 125.98mg/kg, and the anti-tumor activity inhibited mice sarcoma s-180 cell line with ED50 11.87mg/kg. The therapy index was 10.61. MycoE also suppressed human gastric cancer BGC-823 xenograft on nude mice,the inhibition rate was 42.62% at the dose of 10mg/kg which equals to 1/12 of LD50, and the mice body weight of that group had the biggest increase.Primary anti-tumor mechanism of mycoepoxydiene was also studied. The results of morphological observation, FCM, comet assay, and DNA ladder electrophoresis showed that the compound did not induce apoptosis of tumor cell. The exact mechanism of its anti-tumor activity, maybe necrosis or something else, is still puzzled. It is needed to have further study.Our study indicated that metabolites from strain CB-2 and HLY-2 were worth to be researched in-depth. Compound mycoepoxydiene had the potentiality to be a new anti-tumor drug in clinic.
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