We investigated the organ-specific phytochemistry of the inflorescences, leaves at different stages of senescence, and roots of Xiphidium caeruleum (Haemodoraceae) and elucidated the structure of six undescribed compounds. Among these, a phenylcarbamoylnaphthoquinone (PCNQ), representing the first member of a class of undescribed phenylphenalenone-derived nitrogenous compounds, was identified and its spontaneous formation elaborated. Starting from phenylbenzoisochromenone glucosides, the reaction cascade proceeds through oxidative decarboxylation and several oxidation steps to an anhydride, which is further converted to a carboxy-phenylnaphthoquinone. In the presence of amino acids, this carboxy-phenylnaphthoquinone readily reacts to PCNQs. Hence, the carboxy-phenylnaphthoquinone was hypothesized to be involved in plant defense because of its reactivity towards amino acids. It was also hypothesized that reduced levels of the corresponding glucosidic phenylbenzoisochromenone precursors in older leaves may foster pathogen-driven senescence.

中文翻译：

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器官特异性分布和非酶促转化表明剑鞘中苯酚的代谢网络

我们研究了花序、不同衰老阶段的叶子和剑鞘 (Haemodoraceae) 根的器官特异性植物化学，并阐明了六种未描述的化合物的结构。其中，苯基氨基甲酰基萘醌 (PCNQ) 是一类未描述的苯基苯萘酮衍生的含氮化合物的第一个成员，已被鉴定并详细说明了其自发形成。从苯基苯并异色酮糖苷开始，反应级联通过氧化脱羧和几个氧化步骤进行，生成酸酐，酸酐进一步转化为羧基苯基萘醌。在存在氨基酸的情况下，这种羧基苯基萘醌很容易与 PCNQ 反应。因此，羧基苯基萘醌被假设参与植物防御，因为它对氨基酸具有反应性。还假设老叶中相应的糖苷苯基苯并异色酮前体水平降低可能会促进病原体驱动的衰老。