蚁巢膝束霉次级代谢产物及生物活性

菌株L342分离自中国四川省的废弃白蚁巢，rDNA序列分析表明L342为蚁巢膝束霉Geniculisynnema termiticola。抗氧化活性评价结果显示其PDB发酵产物的乙酸乙酯提取物具有很强的还原能力和中等强度的DPPH清除能力。采用硅胶柱色谱、ODS柱色谱、Sephadex LH-20柱色谱、HPLC等分离方法，从G. termiticola的PDB发酵粗提物中分离鉴定了6个化合物：3,4-Dihydro-6,8-dihydroxy-3-methylisocoumarin (1), regiolone (2), (3S, 4S)-3,4,6,8-tetradydroxy-3,4-Dihydronaphthalen-1(2H)-one (3), ergosta-4,6,8(14),22-tetraen-3-one (4), cerebroside A (5), and cerebroside C (6)。其中化合物4-6具有中等强度的铁离子还原能力，化合物4还具有一定的HeLa细胞毒活性（IC50=98.3μmol/L）。G. termiticola发酵产物具有产生有生物活性次级代谢产物的潜力，有望开发成为一种新型的功能性食品。

Secondary metabolites from mycelium of Geniculisynnema termiticola associated with termite nests and their bioactive effects

The Geniculisynnema strain L342 was isolated from the nest of Odontotermes formosanus in Sichuan Province, P. R. China, and sequence analysis of rDNA revealed strain L342 is G. termiticola. Ethyl acetate extract of G. termiticola in patato/dextrose broth (PDB) culture showed strong reducing ability and moderate 1,1-diphenyl-2- picrylhydrazuyl (DPPH) scavenging ability in antioxidant bioassay. Six secondary metabolites were isolated from the ethyl acetate extract of G. termiticola, and their structures were elucidated on the basis of HR-ESI-MS and NMR spectroscopic data as 3,4-dihydro-6,8-dihydroxy-3-methylisocoumarin (1), regiolone (2), (3S, 4S)-3,4,6,8-tetradydroxy-3,4-dihydronaphthalen- 1(2H)-one (3), ergosta-4,6,8(14),22-tetraen-3-one (4), cerebroside A (5), and cerebroside C (6). Their antioxidant effect and cytotoxic activity of 6 compounds isolated were assayed, and compounds 4, 5 and 6 showed moderate reducing ability, compound 4 showed weak cytotoxic activity against HeLa cells with IC50 value of 98.3μmol/L. It could be concluded that the fermentative products of G. termiticola greatly possess their potential of producing bioactive secondary metabolites, and might be hopeful of developing a new functional food.