A plant used in an Indonesian traditional herbal medicine as a diabetes treatment and known locally as “Jampu Salo” was collected on Sulawesi Island, Indonesia. It was identified as Syzygium oblanceolatum (C. B. Rob.) Merr. (Myrtaceae) and found for the first time in Sulawesi; it was previously reported only in the eastern Philippines and Borneo. A phytochemical study of S. oblanceolatum led to the isolation of three unprecedented meroterpenoids, syzygioblanes A–C (1–3, respectively). These compounds might be biosynthesized through [4+2] cycloaddition of various germacrane-based cyclic sesquiterpenoids with the flavone desmethoxymatteucinol to form a spiro skeleton. The unique and complex structures were elucidated by microcrystal electron diffraction analysis in addition to general analytical techniques such as high-resolution mass spectrometry, various nuclear magnetic resonance methods, and infrared spectroscopy. Synchrotron X-ray diffraction and calculations of electronic circular dichroism spectra helped to determine the absolute configurations. The newly isolated compounds exhibited collateral sensitivity to more strongly inhibit the growth of a multidrug resistant tumor cell line compared to a chemosensitive tumor cell line.

中文翻译：

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环状倍半萜-黄烷酮 [4+2] 杂种，Syzygioblanes A-C，发现于印度尼西亚传统药物“Jampu Salo”（Syzygium oblanceolatum）


印度尼西亚苏拉威西岛采集了一种用于治疗糖尿病的印度尼西亚传统草药植物，当地称为“Jampu Salo”。它被鉴定为 Syzygium oblanceolatum (C. B. Rob.) Merr。 （桃金娘科），首次发现于苏拉威西岛；此前仅在菲律宾东部和婆罗洲有过报道。对 S. oblanceolatum 的植物化学研究分离出三种前所未有的类萜，syzygioblanes A–C（分别为 1–3）。这些化合物可能是通过各种基于香叶兰的环状倍半萜类化合物与黄酮去甲氧基马藤辛醇进行[4+2]环加成形成螺骨架来生物合成的。除了高分辨率质谱、各种核磁共振方法和红外光谱等通用分析技术之外，还通过微晶电子衍射分析阐明了独特而复杂的结构。同步加速器X射线衍射和电子圆二色光谱的计算有助于确定绝对构型。与化学敏感的肿瘤细胞系相比，新分离的化合物表现出更强烈地抑制多重耐药肿瘤细胞系生长的附带敏感性。