Abstract：
An investigation on the secondary metabolites from a rice culture broth of the endophytic fungus Neurospora terricola HDF-Br-2 derived from the vulnerable conifer Pseudotsuga gaussenii led to the isolation and characterization of 34 structurally diverse polyketides (1-34). Seven of them are previously undescribed, including five unprecedented dihydropyran-containing (terricoxanthones A-E, 1-5, resp.) and one rare tetrahydrofuran-containing (terricoxanthone F, 6) dimeric xanthones. The structures were elucidated by spectroscopic methods and single-crystal X-ray diffraction analyses. Terricoxanthones each were obtained as a racemic mixture. Their plausible biosynthetic relationships were briefly proposed. Compounds 6, aspergillusone A (8), and alatinone (27) displayed considerable inhibition against Candida albicans with MIC values of 8-16 μg/mL. 4-Hydroxyvertixanthone (12) and 27 exhibited significant inhibitory activities against Staphylococcus aureus, with MIC values of 4-8 μg/mL. Furthermore, compounds 8 and 27 could disrupt biofilm of S. aureus and C. albicans at 128 μg/mL. The findings not only extend the skeletons of xanthone dimers and contribute to the diversity of metabolites of endophytes associated with the endangered Chinese conifer P. gaussenii, but could further reveal the important role of protecting plant species diversity in support of chemical diversity and potential sources of new therapeutics.
摘要：
对来自脆弱的针叶树Pseudotsugagaussenii的内生真菌NeurosporaterricolaHDF-2的水稻培养液中的次生代谢产物的研究导致了34种结构多样的聚酮化合物（1-34）的分离和表征。其中七个以前没有描述过，包括五种前所未有的含有二氢吡喃的（石头菌群A-E，1-5，分别。)和一种罕见的含四氢呋喃(terricoxanthoneF，6)二聚黄吨酮。通过光谱法和单晶X射线衍射分析阐明了结构。各自作为外消旋混合物获得地黄酮。简要提出了它们合理的生物合成关系。化合物6,曲霉酮A(8),和阿拉金酮（27）对白色念珠菌表现出相当大的抑制作用，MIC值为8-16μg/mL4-羟基维酮（12）和27对金黄色葡萄球菌表现出显着的抑制活性，MIC值为4-8μg/mL。此外，化合物8和27在128μg/mL时可以破坏金黄色葡萄球菌和白色念珠菌的生物膜。这些发现不仅扩展了xanthone二聚体的骨架，而且还有助于与濒临灭绝的中国针叶树相关的内生菌代谢产物的多样性。但可以进一步揭示保护植物物种多样性在支持化学多样性和新疗法的潜在来源方面的重要作用。
