Phytotoxins from Tithonia diversifolia
Phytotoxins from Tithonia diversifolia
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DOI：
10.1021/acs.jnatprod.5b00040
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发表时间：
2015-05-01
影响因子：
5.1
通讯作者：
Macias, Francisco A.
中科院分区：
文献类型：
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作者：
Miranda, Maria A. F. M.;Varela, Rosa M.;Macias, Francisco A.
Tithonia diversifolia（墨西哥向日葵）是菊科的优势植物，这表明它产生干扰周围植物发育的化感物质。进行本文所述的研究以鉴定在T.胡芦巴提取物叶、茎和根的乙酸乙酯提取物对小麦胚芽鞘的生长有明显的抑制作用，叶提取物的抑制效果与市售除草剂相当。共分离得到14个化合物，其中12个为倍半萜内酯类化合物。首次报道了两种倍半萜内酯，并分离为8 β-O-（2-甲基丁酰基）tirotundin（4）和8 β-O-（异戊酰基）tirotundin（5）的不可分离的混合物。它们的结构通过光谱分析，包括NMR技术和质谱确定。倍半萜内酯1 β-甲氧基diversifolin（6），tagitinin A（7）和tagitinin C（8）是鉴定的主要产物。这些化合物对小麦胚芽鞘黄化、种子萌发、STS和杂草的生长均有抑制作用。这些倍半萜内酯显示的植物毒性活性表明它们是导致初始提取物显示的活性的化合物。
Tithonia diversifolia (Mexican sunflower) is a dominant plant of the Asteraceae family, which suggests it produces allelochemicals that interfere with the development of surrounding plants. The study described herein was conducted to identify the compounds that have phytotoxic activity in T. diversifolia extracts. Ethyl acetate extracts of the leaves, stems, and roots showed significant inhibition of wheat coleoptile growth, and the leaf extract had similar inhibitory effects to a commercial herbicide. Fourteen compounds, 12 of which were sesquiterpene lactones, have been isolated. Two sesquiterpene lactones are reported for the first time and were isolated as an inseparable mixture of 8 beta-O-(2-methylbutyroyl)tirotundin (4) and 8 beta-O-(isovaleroyl)tirotundin (5). Their structures were determined by spectroscopic analysis, including NMR techniques and mass spectrometry. The sesquiterpene lactones 1 beta-methoxydiversifolin (6), tagitinin A (7), and tagitinin C (8) were the major products identified. These compounds were active on etiolated wheat coleoptiles, seed germination, and the growth of STS and weeds. The phytotoxic activity shown by these sesquiterpene lactones indicates that they are the compounds responsible for the activity exhibited by the initial extracts.