海洋真菌Aspergillus ruber CTD-5000-2中的吲哚二酮哌嗪生物碱研究

目的对海洋来源真菌Aspergillus ruber CTD-5000-2中的吲哚二酮哌嗪生物碱的结构多样性及抗氧化活性进行研究。方法利用硅胶、十八烷基硅烷键合硅胶(ODS)、半制备高效液相色谱(semi-HPLC)等色谱学方法对菌株发酵物中的吲哚二酮哌嗪生物碱进行分离;利用紫外(UV)、核磁共振波谱(NMR)、质谱(MS)等波谱学方法,结合与文献的数据对比确定化合物的结构。利用1,1-二苯基-2-三硝基苯肼(DPPH法)测试了化合物的抗氧化活性。结果从菌株发酵的乙酸乙酯提取物中分离鉴定了10个吲哚二酮哌嗪生物碱,分别为rubrumlines P(1)、neoechinulin B(2)、isoechinulin B(3)、neoechinulin C(4)、cryptoechinulin G(5)、tetrahydroechinulin(6)、neoechinulin A(7)、isoechinulin A(8)、variecolorin G(9)和dehydroechinulin(10)。Neoechinulin A(7)在0.1 mg·mL^?1浓度下对DPPH自由基的清除率为71.83%。结论从海洋真菌Aspergillus ruber中发现了10个二酮哌嗪类生物碱,报道了1个新颖的二酮哌嗪生物碱rubrumlines P(1)。同时发现这10个化合物具有一定的抗氧化活性。

Study on indole-diketopiperazine alkaloids from marine-derived fungus Aspergillus ruber CTD-5000-2

Objective To investigate the chemical diversity and antioxidant activities of indole-diketopiperazine alkaloids from marine-derived fungus Aspergillus ruber CTD-5000-2. Methods Indole-diketopiperazine alkaloids were isolated from the crude extracts of the culture medium by column chromatography on silica gel, ODS and semi-HPLC. Their structures were elucidated by UV, NMR, MS analysis and comparison with the data of literatures. The antioxidant activities of the compounds were screened through DPPH radical scavenging method. Results Ten indole-diketopiperazine alkaloids were isolated from the EtOAc extracts and their structures were elucidated as rubrumlines P(1), neoechinulin B(2), isoechinulin B(3), neoechinulin C(4), cryptoechinulin G(5), tetrahydroechinulin(6), neoechinulin A(7), isoechinulin A(8), variecolorin G(9) and dehydroechinulin(10), among which rubrumlines P(1) was reported for the first time. Neoechinulin A (7) exhibited antioxidant activitiy with DPPH radical scavenging ratio of 71.85% at the concentration of 0.1 mg/mL. Conclusion Ten indole-diketopiperazine alkaloids were isolated from marine-derived fungus Aspergillus ruber CTD-5000-2, and a novel diketopiperazine alkaloid -rubrumlines P was reported. Neoechinulin A (7)was found to have antioxidant activity.