中文摘要：

研究红树林真菌Alternaria sp.R6固相培养代谢产物,用硅胶和Sephadex LH-20柱层析手段从甲醇提取物分离单体,波谱技术鉴定结构,二倍稀释法测试抗菌活性。分离到（4R,5R）-4,5-二羟基-3-甲氧基-5-甲基-环己-2-烯-1-酮（1）,（4R,5S,6R）-4,5,6-三羟基-3-甲氧基-5-甲基-环己-2-烯-1-酮（2）,xylariacyclone B（3）,（4S,5S,6S）-5,6-环氧-4-羟基-3-甲氧基-5-甲基-环己-2-烯-1-酮（4）,LL-C10037α（5）,1-羟基-8-（羟甲基）-6-甲氧基-3-甲基-9H-呫吨-9-酮（6）,6-甲基-1-甲氧羰基-8-羟基呫吨-9-酮（7）,6-羧基-1-甲氧羰基-2,8-二羟基呫吨-9-酮（8）,麦角甾醇和过氧化麦角甾醇共10个化合物。化合物1,2,3,4,5,6和8为首次从Alternaria属分离到。化合物6和8对小麦赤霉、香蕉炭疽,化合物2对香蕉炭疽显示良好抗菌活性。

英文摘要：

To study the metabolites of the mangrove fungus Alternaria sp. R6,the compounds were isolated by silica gel and Sephadex LH-20 column chromatography. Their structures were characterized by spectroscopy. The antifungal activities were investigated using the broth tube dilution method. Ten compounds,including（ 4R,5R）-4,5-dihydroxy-3-methoxy-5-methyl-cyclohex-2-en-1-one（ 1）,（ 4R,5S,6R）-4,5,6-trihydroxy-3-methoxy-5-methyl-cyclohex-2-en-1-one（ 2）,xylariacyclone B（ 3）,（ 4S,5S,6S）-5,6-epoxy-4-hydroxy-3-methoxy-5-methyl-cyclohex-2-en-1-one（ 4）,LL-C10037α（ 5）,1-hydroxy-8-（ hydroxymethyl）-6-methoxy-3-methyl-9H-xanthen-9-one（ 6）,8-hydroxy-6-methyl-1-meth-oxy-carbonyl-xanthen-9-one（ 7）,8-dimethoxy-1,6-dimethoxycarbonyl-xanthen-9-one（ 8）,ergosterol and ergosterolperoxide,were isolated from the methanol extracts. Among them,the compounds1,2,3,4,5,6 and 8 were obtained from Alternaria sp. for the first time. The compounds 6 and 8showed good inhibitory activity against Fusarium graminearum Schw. and Colletotrichum musae（ Berk. M. A. Curtis） Arx. While the compound 2 only showed good inhibitory activity against the latter.