Isolation of lolicine A, lolicine B, lolitriol, and lolitrem N from Lolium perenne infected with Neotyphodium lolii and evidence for the natural occurrence of 31-epilolitrem N and 31-epilolitrem F
Isolation of lolicine A, lolicine B, lolitriol, and lolitrem N from Lolium perenne infected with Neotyphodium lolii and evidence for the natural occurrence of 31-epilolitrem N and 31-epilolitrem F
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DOI：
10.1021/jf9706787
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发表时间：
1998-02-01
影响因子：
6.1
通讯作者：
Miles, CO
中科院分区：
文献类型：
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作者：
Munday-Finch, SC;Wilkins, AL;Miles, CO
从感染内生真菌Neotyphodium lolii的多年生黑麦草种子提取物中鉴定出Lolicines A（1a）和B（2a），这两种化合物是晚洗脱的Lolitrem样化合物。分离得到11-O-丙酸酯（1b和2b），并通过质谱和一维和二维NMR光谱确定其结构。lolicines A和B的结构与雀稗碱（5a）和雀稗碱B（5 B）的结构相似，这些化合物已知是几组更复杂的吲哚-二萜类化合物的生物合成前体，这表明lolicines可能是吲哚-二萜类神经毒素lolitrem组的生物合成前体。在1b和2b的纯化过程中，分离出第三种化合物lolitrem N（4c），作为其丙酸酯（4d），并鉴定为35-epilolitriol。另一种较晚洗脱的化合物作为其乙酸盐从与lolicines相同的级分中分离出来。发现该化合物与从lolitrem B（3a）制备的lolitriol 10-O-乙酸酯（4 B）相同。这一发现证实了lolitriol（4a）是内生菌感染的多年生黑麦草的天然成分，并且与lolitriol是lolitrems A（9）、B（3a）和E（10）的生物合成前体的提议一致。对4 b的H-1 NMR光谱的详细检查揭示了作为天然存在的污染物的31-epilolitrem N 10-O-乙酸酯（4f）的存在，表明31-epilolitrem N（4 e）是内生菌感染的黑麦草的代谢物。对3a的NMR谱进行分析，重新分配了Lolitrems的C-19-C-21共振，并确定31-epilolitrem F（3c）为L.多年生植物
Lolicines A (1a) and B (2a), late-eluting lolitrem-like compounds, were identified in extracts of perennial ryegrass (Lolium perenne) seed that was infected with the endophytic fungus Neotyphodium lolii. The lolicines were isolated as their 11-O-propionates (1b and 2b) and their structures determined by mass spectrometry and one-and two-dimensional NMR spectroscopy. The structures of lolicines A and B were similar to those of paspaline (5a) and paspaline B (5b), compounds known to be biosynthetic precursors of several groups of more complex indole-diterpenoids, suggesting that the lolicines might be biosynthetic precursors of the lolitrem group of indole-diterpenoid neurotoxins. During purification of 1b and 2b, a third compound, lolitrem N (4c), was isolated as its propionate (4d) and identified as 35-epilolitriol. A further late-eluting compound was isolated as its acetate from the same fraction as the lolicines. This compound was found to be identical with lolitriol 10-O-acetate (4b) prepared from lolitrem B (3a). This finding confirms lolitriol (4a) as a natural constituent of endophyte-infected perennial ryegrass, and is consistent with the proposal that lolitriol is a biosynthetic precursor of lolitrems A (9), B (3a), and E (10). Detailed examination of the H-1 NMR spectra of 4b revealed the presence of 31-epilolitrem N 10-O-acetate (4f) as a naturally occurring contaminant, indicating that 31-epilolitrem N (4e) is a metabolite of endophyte-infected ryegrass. Analysis of the NMR spectra of 3a led to a reassignment of the C-19-C-21 resonances of the lolitrems, and identified 31-epilolitrem F (3c) as a natural constituent of L. perenne.