Carpodesmia tamariscifolia is a brown alga rich in (poly)phenols with important cytotoxic and antioxidant effects. However, the relationship between its chemical composition and its effects is unknown. The aim of this study is to identify the potential compounds and mechanisms responsible for its main effects. The alga was extracted consecutively with hexane, dichloromethane and methanol and further fractionated using Sephadex LH‐20 and silica gel columns when appropriate. The fractions were subjected to thin‐layer chromatography and liquid chromatography‐mass spectrometry analysis and evaluated for their total phenolic content (Folin‐Ciocalteu assay), radical scavenging activity (DPPH assay), cytotoxic activity (MTT assay on the SH‐SY5Y cell line), and ability to generate H2O2 (Amplex Red assay). Chromatographic and phenolic analyses of the fractions indicate that abundant redox‐active phenols are present in all the fractions and that a high amount of prenylated hydroquinone derivatives is present in the apolar ones. In the hexane and dichloromethane fractions, the cytotoxic and antioxidant activities are closely related to their phenolic content, whereas in the methanol fractions, the cytotoxicity is negatively related to the phenolic content and the antioxidant activity is positively related to it. In the same tests, hydroquinone behaves as both strong cytotoxic and antioxidant agent. H2O2 assay shows that C. tamariscifolia fractions and hydroquinone can autoxidize and generate H2O2. Our results suggest that redox‐active phenols produce the pharmacological effects described for C. tamariscifolia and that the hydroquinone moiety of prenylated hydroquinone derivatives is responsible for both cytotoxic (through a pro‐oxidant mechanism secondary to its autoxidation) and antioxidant effects of the apolar fractions.

中文翻译：

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氧化还原活性酚类化合物介导 Carpodesmia tamariscifolia (=Cystoseira tamariscifolia) 的细胞毒性和抗氧化作用

Carpodesmia tamariscifolia 是一种富含（多）酚的褐藻，具有重要的细胞毒性和抗氧化作用。然而，其化学成分与其作用之间的关系尚不清楚。本研究的目的是确定导致其主要影响的潜在化合物和机制。用己烷、二氯甲烷和甲醇连续提取藻类，并在适当时使用 Sephadex LH-20 和硅胶柱进一步分馏。对馏分进行薄层色谱和液相色谱-质谱分析，并评估它们的总酚含量（Folin-Ciocalteu 测定）、自由基清除活性（DPPH 测定）、细胞毒活性（SH-SY5Y 细胞系的 MTT 测定） )，以及产生 H2O2 的能力（Amplex Red 检测）。馏分的色谱和酚类分析表明，所有馏分中都存在丰富的氧化还原活性酚，而非极性馏分中存在大量异戊二烯化氢醌衍生物。在己烷和二氯甲烷馏分中，细胞毒性和抗氧化活性与其酚含量密切相关，而在甲醇馏分中，细胞毒性与酚含量呈负相关，抗氧化活性与酚含量呈正相关。在相同的测试中，对苯二酚表现为强细胞毒剂和抗氧化剂。H2O2 测定表明，柽柳馏分和对苯二酚可以自动氧化并生成 H2O2。我们的结果表明，氧化还原活性酚产生了对 C.