A pair of novel scalemic meroterpenoid dimers, (+)- and (−)-pabmaragramin (1), featuring an unprecedented 6/6/5/6/6/6/5 seven-membered ring system, were obtained from Marasmius graminum via precursor-assisted biosynthesis (PAB). Their structures and absolute configurations were determined on the basis of extensive spectroscopic analysis, single-crystal X-ray diffraction, and electronic circular dichroism (ECD) calculations. A plausible biosynthetic pathway for 1 was proposed. Additionally, (+)-1 and (−)-1 exhibited inhibitory activity against α-glucosidase with IC₅₀ values of 3.4 μM and 12.0 μM, respectively.

中文翻译：

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（±）-Pabmaragramin，由Marasmius graminum通过前体辅助生物合成产生的一种鳞状类金属萜

从Marasmius graminum获得了一对具有前所未有的6/6/5/6/6/6/5七元环系统的新颖的鳞片肾上腺皮质二聚体，（+）-和（-）-pabmaragramin（1）。前体辅助生物合成（PAB）。根据广泛的光谱分析，单晶X射线衍射和电子圆二色性（ECD）计算，确定了它们的结构和绝对构型。一种可能的生物合成途径1中提出的。另外，（+）- 1和（-）- 1表现出对α-葡萄糖苷酶的抑制活性，IC ₅₀值分别为3.4μM和12.0μM。