Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, P. R. China.
State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, P. R. China.
Phytochem Anal. 2022 Apr;33(3):344-354. doi: 10.1002/pca.3092. Epub 2021 Nov 9.
In addition to the mycotoxin swainsonine, the locoweed endophytic fungus Alternaria oxytropis (Pleosporaceae) also produces a series of rarely reported, highly oxygenated bicyclic guaiane sesquiterpenoids. Few investigations on the electrospray tandem mass fragmentation pattern of this sesquiterpenoid have been reported.
We aimed to analyze and detect new guaiane sesquiterpenoid analogues from crude extracts of the locoweed endophytic fungus A. oxytropis by UPLC-Q-TOF-MS/MS experiments.
Oxytropiols A-J (1-10) and the extract of the locoweed endophytic fungus A. oxytropis were analyzed by UPLC-Q-TOF-MS/MS in positive mode.
Typical neutral losses, McLafferty rearrangement, 1,2-rearrangement, and 1,3-rearrangement were considered to be the main fragmentation patterns for the [M + H] /[M + Na] ions of 1-10 by UPLC-Q-TOF-MS/MS experiments, and possible fragmentation pathways of 1-10 were suggested. A unique and undescribed analogue named oxytropiol K (11) was found in the extract based on UPLC-Q-TOF-MS/MS analysis. Compound 11 was isolated and elucidated by NMR spectrometry, and its UPLC-Q-TOF-MS/MS analysis was consistent with the fragmentation pathways of 1-10.
The results further support that UPLC-Q-TOF-MS/MS is a powerful and sensitive tool for the characterization of known compounds (dereplication) and the detection of new analogues from crude extracts and imply that the locoweed endophytic fungus A. oxytropis, with few chemical investigations, is an important resource for undescribed metabolites.
除了霉菌毒素 swainsonine 外，疯草内生真菌交链格孢（交链孢霉科）还产生一系列报道很少的高度氧化的双环瓜环倍半萜。对该倍半萜的电喷雾串联质谱碎裂模式的研究很少。
我们旨在通过 UPLC-Q-TOF-MS/MS 实验分析和检测疯草内生真菌 A. oxytropis 粗提物中的新型瓜环倍半萜类似物。
采用 UPLC-Q-TOF-MS/MS 分析 Oxytropiols A-J（1-10）和疯草内生真菌 A. oxytropis 的提取物。
典型的中性丢失、麦拉弗蒂重排、1,2-重排和 1,3-重排被认为是通过 UPLC-Q-TOF-MS/MS 实验对[M+H]+/[M+Na]+离子进行的主要碎裂模式，并且提出了 1-10 的可能碎裂途径。基于 UPLC-Q-TOF-MS/MS 分析，在提取物中发现了一种独特的未描述的类似物，命名为 oxytropiol K（11）。通过 NMR 光谱分离和阐明了化合物 11，其 UPLC-Q-TOF-MS/MS 分析与 1-10 的碎裂途径一致。
结果进一步支持 UPLC-Q-TOF-MS/MS 是一种用于鉴定已知化合物（去重复）和检测粗提物中新类似物的有力且敏感的工具，并暗示尚未进行化学研究的疯草内生真菌 A. oxytropis 是未描述代谢物的重要资源。
