Abstract：
By co-culturing two endophytic fungi (Chaetomium virescens and Xylaria grammica) collected from the medicinal and edible plant Smilax glabra Roxb. and analyzing them with MolNetEnhancer module on GNPS platform, seven undescribed chromone-derived polyketides (chaetoxylariones A-G), including three pairs of enantiomer ones (2a/2b, 4a/4b and 6a/6b) and four optical pure ones (1, 3, 5 and 7), as well as five known structural analogues (8-12), were obtained. The structures of these new compounds were characterized by NMR spectroscopy, single-crystal X-ray diffraction, 13C NMR calculation and DP4+ probability analyses, as well as the comparison of the experimental electronic circular dichroism (ECD) data. Structurally, compound 1 featured an unprecedented chromone-derived sulfonamide tailored by two isoleucine-derived δ-hydroxy-3-methylpentenoic acids via the acylamide and NO bonds, respectively; compound 2 represented the first example of enantiomeric chromone derivative bearing a unique spiro-[3.3]alkane ring system; compound 3 featured a decane alkyl side chain that formed an undescribed five-membered lactone ring between C-7\' and C-10\'; compound 4 contained an unexpected highly oxidized five-membered carbocyclic system featuring rare adjacent keto groups; compound 7 featured a rare methylsulfonyl moiety. In addition, compound 10 showed a significant inhibition towards SW620/AD300 cells with an IC50 value of PTX significantly decreased from 4.09 μM to 120 nM, and a further study uncovered that compound 10 could obviously reverse the MDR of SW620/AD300 cells.
摘要：
通过共培养从药用和食用植物SmilaxglabraRoxb中收集的两种内生真菌（Chaetomiumvirescens和Xylariagrammica）。并在GNPS平台上使用MolNetEnhancer模块进行分析，七种未描述的色酮衍生的聚酮（甲氧吡喃酮A-G），包括三对对映异构体(2a/2b，4a/4b和6a/6b）和四个光学纯的（1、3、5和7），以及五种已知的结构类似物（8-12），已获得。这些新化合物的结构通过NMR光谱进行了表征，单晶X射线衍射,13C核磁共振计算和DP4+概率分析，以及实验电子圆二色性（ECD）数据的比较。在结构上,化合物1具有前所未有的色酮衍生的磺酰胺，由两个异亮氨酸衍生的δ-羟基-3-甲基戊烯酸通过丙烯酰胺和NO键定制，分别；化合物2代表对映体色酮衍生物的第一个实例，带有独特的螺环-[3.3]烷烃环系统；化合物3具有癸烷烷基侧链，在C-7'和C-10'之间形成未描述的五元内酯环；化合物4包含意外的高度氧化的五元碳环系统，其特征是罕见的相邻酮基；化合物7具有罕见的甲基磺酰基部分。此外,化合物10对SW620/AD300细胞显示出显著的抑制作用,PTX的IC50值从4.09μM显著降低至120nM,进一步研究发现，化合物10可以明显逆转SW620/AD300细胞的MDR。
