Abstract Context: Mitrephora sirikitiae Weeras., Chalermglin & R.M.K. Saunders (Annonaceae) is a plant endemic to Thailand. Its constituents and their biological activities are unknown. Objective: Isolation and identification of the compounds in the leaves and stems of M. sirikitiae and determination of their cytotoxicity. Materials and methods: Methanol extracts of the leaves and stems of M. sirikitiae were separated by chromatography, and spectroscopic methods were used to determine the structures of the components. The cytotoxicity of the extracts and pure compounds was evaluated using the sulforhodamine B assay with several cell lines. The cells were treated with the compounds at concentrations of 0.16–20 µg/mL for 48 or 72 h. Results: The investigation of the extracts of M. sirikitiae leaves and stems resulted in the isolation of a new lignan, mitrephoran, and 15 known compounds. Among these compounds, 2-(3,4-dimethoxyphenyl)-6-(3,5-dimethoxyphenyl)-3,7-dioxabicyclo[3.3.0]octane, ciliaric acid, 6-methoxymarcanine A, and stepharanine were isolated from this genus for the first time. The alkaloids liriodenine and oxoputerine exhibited strong cytotoxicity against all tested cells (IC50 values of 6.59–11.02 µM). In contrast, magnone A, 3′,4-O-dimethylcedrusin, and 6-methoxymarcanine A inhibited the growth of some of the tested cells (IC50 values of 2.03–19.73 µM). Magnone A and 6-methoxymarcanine A showed low toxicity for Hek 293 cells (IC50 >20 µM). Discussion and conclusions: M. sirikitiae is a source of cytotoxic lignans and alkaloids. Among the cytotoxic compounds, magnone A and 6-methoxymarcanine A are potentially useful lead compounds for the further development of anticancer agents because of their selective inhibitory effects on cancer cell lines.

中文翻译：

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来自泰国特有植物 Mitrephora sirikitiae 叶和茎的细胞毒性化合物

摘要背景： Mitrephora sirikitiae Weeras., Chalermglin & RMK Saunders (番荔枝科) 是泰国特有的植物。其成分及其生物活性未知。目的：分离、鉴定西兰花叶和茎中的化合物并测定其细胞毒性。材料与方法：用层析法分离山竹叶和茎的甲醇提取物，并用光谱法确定成分的结构。提取物和纯化合物的细胞毒性使用磺基罗丹明 B 测定法对几种细胞系进行评估。用浓度为 0.16–20 µg/mL 的化合物处理细胞 48 或 72 小时。结果：对M.提取物的调查。Sirikitiae 叶和茎分离出一种新的木酚素、mitrephoran 和 15 种已知化合物。在这些化合物中，从中分离出 2-(3,4-二甲氧基苯基)-6-(3,5-二甲氧基苯基)-3,7-二氧杂双环[3.3.0]辛烷、纤毛酸、6-甲氧基马卡宁 A 和千金藤碱属第一次。生物碱 liriodenine 和 oxoputerine 对所有测试细胞表现出强烈的细胞毒性（IC50 值为 6.59–11.02 µM）。相比之下，magnone A、3',4-O-二甲基雪松素和 6-甲氧基马卡宁 A 抑制了一些测试细胞的生长（IC50 值为 2.03–19.73 µM）。Magnone A 和 6-甲氧基马卡宁 A 对 Hek 293 细胞显示出低毒性 (IC50 >20 µM)。讨论和结论： M. sirikitiae 是细胞毒性木酚素和生物碱的来源。在细胞毒性化合物中，