南极海洋假单胞菌Pseudomonas sp.NJ-013的化学成分

Secondary metabolites of Pseudomonas sp. NJ-013 from the Antarctic

本研究进行了一株南极假单胞菌Pseudomonas sp.NJ-013代谢产物多样性分析、化学成分的分离和结构鉴定,以探讨其产物结构类型。菌株NJ-013甲醇提取物经LC-TOF MS测试分析其代谢产物多样性;还经柱层析和半制备高效液相色谱制备得到4个化学成分;化合物结构经TOF MS、1H-和13C-NMR等波谱学方法和文献数据对照鉴定。假单胞菌Pseudomonas sp.NJ-013的代谢产物主要类型为含氮的生物碱或寡肽类,分离得到的化合物1-4分别鉴定为环(4'-羟基苯丙氨酸-脯氨酸)(1)、环(4-羟基脯氨酸-亮氨酸)(2)、环(4-羟基脯氨酸-苯丙氨酸)(3)、环(异亮氨酸-脯氨酸)(4)。结构较为复杂的微量成分尚待进一步富集、研究。

Diversity analysis on secondary metabolites of an Antarctic microbe strain, Pseudomonas sp. NJ- 013, together with the structural elucidation of some purified compounds, was carried out for exploration of its＇ chemical constituents. Pseudomonas sp. NJ-013 was isolated from sea water samples collected from the fishing area of Antarctic krill. After being cultured in GAUZE＇s Medium NO. 1 for 7 d at 28 ℃, Pseudomonas sp. NJ-013 was extracted with acetone/methanol to give a total extract, or absorbed by HP-20 macroporos resin to afford three extract sections NJ-013-A, NJ-O13-B and NJ-O13-C. The methanol solution of the total extract was subjected to HPLC-TOF MS test for diversity analysis on its＇ secondary metabolites. The possible formula of 54 sample peaks were obtained among 68 observed peaks by high-resolution HPLC-TOF MS spectra. The possible formula indicated 41 -43 N-containing compounds, and the other 11 -13 compounds without nitrogen in their structures. There were also 3 metabolites which were both S- and N-containing compounds, but no halogen-containing sample peaks were found by typical MS spectra. Most sample peaks showed very low relative contents with their Vol% much less than 1.0%. The Vol% of only 13 sample peaks were higher than 2.0% , including 7 - 8 N-containing compounds and other 4 peaks without possible formula. So chemical constituents of Pseudomonas sp. NJ-013 were mainly N-containing compounds, including alkaloids and oligopeptides. Four compounds were also obtained from high polarity sections NJ-O13-A and NJ- 013-B of the extract, by different column chromatography and repeated preparative HPLC, and their structures were elucidated by direct comparison of HPLC-TOF MS, tH- and 13C-NMR data with those reported. The structures of four purified compounds were identified as 3-（ 4-hydroxybenzyl ） hexahydropyrrolo [ 1,2-a ] pyrazine-1,4-dione （ 1 ）, 7-hydroxy-3-isobutylhexahydropyrrolo [ 1,2-a ] pyrazine-1,4-dione （2）, 3-benzyl-7- hydroxyl-hexahydropyrrolo [ 1,2-a] pyrazine-1,4- dione （ 3 ） and 3-（ 1-methylpropyl ） -hexahydropyrrolo [ 1,2- a] pyrazine-1,4-dione （4） , NJ-O13 should be provided which were all cyclic dipeptides. More microbial materials of Pseudomonas sp for exploration of minor constituents with complicated structures