Xanthone-chromanone homo- or heterodimers are regarded as a novel class of topoisomerase (Topo) inhibitors; however, limited information about these compounds is currently available. Here, 14 new (1–14) and 6 known tetrahydroxanthone chromanone homo- and heterodimers (15–20) are reported as isolated from Penicillium chrysogenum C-7-2-1. Their structures and absolute configurations were unambiguously demonstrated by a combination of spectroscopic data, single-crystal X-ray diffraction, modified Mosher’s method, and electronic circular dichroism analyses. Plausible biosynthetic pathways are proposed. For the first time, it was discovered that tetrahydroxanthones can convert to chromanones in water, whereas chromone dimerization does not show this property. Among them, compounds 5, 7, 8, and 16 exhibited significant cytotoxicity against H23 cell line with IC₅₀ values of 6.9, 6.4, 3.9, and 2.6 μM, respectively.

中文翻译：

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结构引导下发现来自产黄青霉 C-7-2-1 的多种细胞毒性二聚氧杂蒽酮/色满酮及其相互转化特性

氧杂蒽酮-色满酮同二聚体或异二聚体被认为是一类新型拓扑异构酶 (Topo) 抑制剂；然而，目前有关这些化合物的信息有限。据报道，从Penicillium chrysogenum C-7-2-1中分离出14 种新的 ( 1 – 14 ) 和 6 种已知的四氢氧杂蒽酮色满酮同二聚体和异二聚体 ( 15 – 20 ) 。通过结合光谱数据、单晶 X 射线衍射、改进的 Mosher 方法和电子圆二色性分析，明确地证明了它们的结构和绝对构型。提出了合理的生物合成途径。首次发现四氢氧杂蒽酮可以在水中转化为苯并二氢吡喃酮，而苯并二氢吡喃二聚体则不表现出这种性质。其中，化合物5、7、8和16对H23细胞系表现出显着的细胞毒性，IC 50值分别_为6.9、6.4、3.9和2.6 μM。