Inspired by the recently discovered phenomenon of "horizontal natural product transfer" we investigated the putative uptake of phenolic specialized metabolites. Umbelliferone was chosen for this case study, since this coumarin as well as its derivatives can easily be determined by HPLC analyses. Barley (Hordeum vulgare L.), radish (Raphanus sativus L.), pea (Pisum sativum L.), flax (Linum usitatissimum L.), and garden cress (Lepidium sativum L.) were cultivated in hydroponic media, to which the coumarin was applied. Uptake of umbelliferone was verified by corresponding HPLC analyses of extracts obtained from the aerial parts of the seedlings. In all cases, a tremendous uptake of umbelliferone was observed. In plants that genuinely contain coumarins, the umbelliferone taken up was modified: in garden cress, it was hydroxylated and glucosylated to yield esculin, while in barley seedlings, the imported umbelliferone was modified by methoxylation to yield scopoletin. Corresponding reactions are known from modifications of xenobiotics to be catalyzed by cytochrome P450 enzymes. Accordingly, in an additional approach, umbelliferone was applied together with naproxen, which is reported to reduce enzyme activity of P450 enzymes. As predicted, the conversion of umbelliferone to scopoletin in barley as well as the modification to esculin in garden cress was strongly reduced by the addition of naproxen. These data for the first time demonstrate that - in addition to alkaloids - also phenolic compounds are taken up by various acceptor plants. Apart from the leaching of rotting plants, coumarins are known to be exuded by many plants. Accordingly, these compounds are frequently present in soils and will be taken up. These coherences imply that the horizontal natural product transfer might represent a more general phenomenon in plant ecology. Moreover, this study outlines that - in analogy to the modification of xenobiotics - also natural products taken up are modified in the acceptor plants.

中文翻译：

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不同幼苗对伞形花酮的吸收和修饰

受最近发现的“水平天然产物转移”现象的启发，我们研究了酚类特殊代谢物的假定吸收。本案例研究选择伞形酮，因为这种香豆素及其衍生物可以通过 HPLC 分析轻松确定。大麦 (Hordeum vulgare L.)、萝卜 (Raphanus sativus L.)、豌豆 (Pisum sativum L.)、亚麻 (Linum usitatissimum L.) 和水芹 (Lepidium sativum L.) 在水培培养基中栽培，其中使用香豆素。通过对从幼苗地上部分获得的提取物进行相应的 HPLC 分析来验证伞形酮的吸收。在所有情况下，观察到伞形酮的大量摄取。在真正含有香豆素的植物中，所吸收的伞形酮被改变：在水芹中，它被羟基化和糖基化产生七叶苷，而在大麦幼苗中，进口的伞形酮通过甲氧基化修饰产生东莨菪碱。从由细胞色素 P450 酶催化的异生素修饰已知相应的反应。因此，在另一种方法中，伞形酮与萘普生一起使用，据报道这会降低 P450 酶的酶活性。正如预测的那样，添加萘普生大大降低了大麦中伞形酮向东莨菪碱的转化以及水芹中对七叶苷的修饰。这些数据首次证明——除了生物碱——酚类化合物也被各种受体植物吸收。除了腐烂植物的浸出，众所周知，香豆素会被许多植物渗出。因此，这些化合物经常存在于土壤中并将被吸收。这些连贯性意味着水平天然产物转移可能代表植物生态学中更普遍的现象。此外，这项研究概述了 - 类似于异生素的修饰 - 吸收的天然产物也在受体植物中被修饰。