Accumulation of biologically active metabolites is a specific feature of plant biochemistry, directing the use of plants in numerous applications in the pharmaceutical and food industries. Among these substances, the plethora of phenolic compounds has attracted particular interest among researchers. Here, we report on new findings in phlorotannin research, a large group of multifunctional phenolic substances, produced in brown algae. Comprehensive LC-MS profiling of three algal species allowed us to depict the complex pattern of this structurally diverse compound group across different tissues and subcellular compartments. We compiled more than 30 different phlorotannin series in one sample and used accurate mass spectrometry to assign tentative structures to the observed ions based on the confirmed sum formulas. From that, we found that acetylation, hydroxylation, and oxidation are likely to be the most common in vivo modifications to phlorotannins. Using an alternative data mining strategy to cope with extensive coelution and structural isomers, we quantitatively compared the intensity of different phlorotannin series in species, tissues, and subcellular compartments to learn more about their physiological functions. The structure and intra-thallus profiles of cell wall-bound phlorotannins were studied here for the first time. We suggest that one of the major dibenzodioxin-type phlorotannin series may exclusively target integration into the cell wall of fucoid algae.

中文翻译：

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岩藻类藻类细胞内和细胞壁结合的叶皮单宁组分的组成表明这些代谢物的特定功能取决于化学结构。

生物活性代谢物的积累是植物生物化学的一个具体特征，指导植物在制药和食品工业的众多应用中的使用。在这些物质中，大量的酚类化合物引起了研究人员的特别兴趣。在此，我们报告了根皮单宁研究的新发现，根皮单宁是褐藻中产生的一大类多功能酚类物质。对三种藻类的全面 LC-MS 分析使我们能够描绘这种结构多样的化合物组在不同组织和亚细胞区室中的复杂模式。我们在一个样品中编制了 30 多种不同的草单宁系列，并使用精确的质谱分析法，根据已确认的总和公式为观察到的离子分配了暂定结构。由此，我们发现乙酰化、羟基化和氧化可能是原单宁最常见的体内修饰。使用替代数据挖掘策略来应对广泛的共洗脱和结构异构体，我们定量比较了物种、组织和亚细胞区室中不同叶皮单宁系列的强度，以更多地了解它们的生理功能。首次研究了细胞壁结合的根皮单宁的结构和叶状体内的分布。我们认为主要的二苯并二恶英型叶皮单宁系列之一可能专门针对岩藻类藻类细胞壁的整合。