Daphnane diterpenes with a 5/7/6-tricyclic ring system exhibit potent anti-HIV activity but are found in low abundance as plant natural products. In this study, an effective approach based on mass spectrometric fragmentation pathways was conducted to specifically recognize and isolate anti-HIV compounds of this type from Daphne genkwa. Briefly, the fragmentation pathways of reference analogues were elucidated based on characteristic ion fragments of m/z 323 → 295 → 267 or m/z 253 → 238 → 197 by ultra-high-performance liquid chromatography-ion trap tandem mass spectrometry (UPLC-IT-MSn) and then applied to the differentiations of substances with or without an oxygenated group at C-12. Twenty-seven daphnane diterpenes were successfully recognized from a petroleum ether extract of D. genkwa, including some potential new compounds and isomers that could not be identified accurately only from the ion fragments. Further separation of these target compounds using high-speed countercurrent chromatography (HSCCC) and preparative HPLC led to the isolation of three new (11, 25, and 27) and 14 known compounds, whose structures were identified and confirmed based on MS, NMR, and electronic circular dichroism (ECD) spectroscopy. The isolates exhibited anti-HIV activities at nanomolar concentrations. The results demonstrated that this strategy is feasible and reliable to rapidly recognize and isolate daphnane diterpenes from D. genkwa.

中文翻译：

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在UPLC-MSn的指导下，快速识别和有针对性地分离出Daphne genkwa的抗HIV达芙烷二萜。

具有5/7 / 6-三环系统的瑞香烷二萜显示出有效的抗HIV活性，但作为植物天然产物的含量低。在这项研究中，基于质谱碎裂途径的有效方法被用来从达芙妮根克（Daphne genkwa）特异性识别并分离出这种抗HIV化合物。简而言之，通过超高效液相色谱-离子阱串联质谱法（UPLC-R）根据m / z 323→295→267或m / z 253→238→197的特征离子片段，阐明了参考类似物的裂解途径。然后将其应用于C-12处带有或不带有氧化基团的物质的区分。从D. genkwa的石油醚提取物中成功鉴定出27种达芬烷二萜，包括一些潜在的新化合物和异构体，这些化合物和异构体仅能从离子片段中准确识别出来。使用高速逆流色谱（HSCCC）和制备型HPLC进一步分离这些目标化合物，导致分离出三种新化合物（11、25和27）和14种已知化合物，并根据MS，NMR对其结构进行了鉴定和确认，和电子圆二色性（ECD）光谱。分离物在纳摩尔浓度下表现出抗HIV活性。结果表明，该策略是可行的和可靠的，以快速识别和分离D. genkwa的萘烷二萜。使用高速逆流色谱（HSCCC）和制备型HPLC进一步分离这些目标化合物，导致分离出三种新化合物（11、25和27）和14种已知化合物，并根据MS，NMR对其结构进行了鉴定和确认，和电子圆二色性（ECD）光谱。分离物在纳摩尔浓度下表现出抗HIV活性。结果表明，该策略是可行的和可靠的，以快速识别和分离D. genkwa的萘烷二萜。使用高速逆流色谱（HSCCC）和制备型HPLC进一步分离这些目标化合物，导致分离出三种新化合物（11、25和27）和14种已知化合物，并根据MS，NMR对其结构进行了鉴定和确认，和电子圆二色性（ECD）光谱。分离物在纳摩尔浓度下表现出抗HIV活性。结果表明，该策略是可行的和可靠的，以快速识别和分离D. genkwa的萘烷二萜。