Spirostaphylotrichin W, a spirocyclic 纬-lactam isolated from liquid culture of Pyrenophora semeniperda, a potential mycoherbicide for cheatgrass (Bromus tectorum) biocontrol

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• 作者：Marco Masi ; Susan Meyer ; Suzette Clement ; Anna Andolfi ; Alessio Cimmino ; Antonio Evidente
• 关键词：Bromus tectorum ; Biocontrol ; Pyrenophora semeniperda ; Spirocyclic 纬-lactam ; Spirostaphylotrichin W
• 刊名：Tetrahedron
• 出版年：18 February, 2014
• 年：2014
• 卷：70
• 期：7
• 页码：1497-1501
• 全文大小：414 K

文摘

A novel spirocyclic 纬-lactam, named spirostaphylotrichin W (1), was isolated together with the well known and closely related spirostaphylotrichins A, C, D, R and V, as well as triticone E, from the liquid cultures of Pyrenophora semeniperda (anamorph: Drechslera), a seed pathogen proposed for cheatgrass (Bromus tectorum) biocontrol. Spirostaphylotrichin W was characterized as (3S*,4S*,5S*,6S*,9Z,10Z)-4,6-dihydroxy-2,3-dimethoxy-3-methyl-10-propyliden-2-azaspiro [4.5]dec-8-ene-1,7-dione, by spectroscopic and chemical methods. The relative stereochemistry of spirostaphylotrichin W was assigned using NOESY experiments and in comparison to those of spirostaphylotrichin V (2) and triticone E (6). In fact, the relative stereochemistry at C-3 was the same of that of 2, while that at C-4 and C-6 was inverted in respect to that reported, respectively, for 2 and 6. In a B. tectorum coleoptile bioassay at concentration of 10^鈭?, spirostaphylotrichin A proved to be the most active compound, followed by spirostaphylotrichins C and D. Spirostaphylotrichin W and V showed mild toxicity while spirostaphylotrichin R and triticone E were not active. When tested on host and non-host plants by leaf puncture bioassay, spirostaphylotrichins A, C and D caused the appearance of necrotic spots while the other compounds were inactive.