Title
Absolute Configurations of 14,15-Hydroxylated Prenylxanthones from a Marine-Derived Aspergillus sp. Fungus by Chiroptical Methods
Author
Ao Zhu, Meng-Yue Yang, Ya-Hui Zhang, Chang-Lun Shao, Chang-Yun Wang, Lian-Dong Hu, Fei Cao, Hua-Jie Zhu
Year
2018
Journal
Scientific Reports
Abstract
Determination of the absolute configrations for natural products is one of the most important and challenging tasks, especially when the molecules display high conformational flexibility. In this paper, eight new prenylxanthones, aspergixanthones A-H (1–8), and one known analogue (9), were isolated from the marine-derived fungus Aspergillussp. ZA-01. The absolute configurations of C-14 and C-15 in 1–8 were difficult to be assigned due to the high conformational flexibility of the chains. To solve this problem, the experimental ECD, ORD, and VCD spectra of 1 were combined for analysis with the corresponding theoretical predictions for its different diastereomers. This study suggested that a concerted application of more than one chiroptical methods could be used as a preferable approach for the stereochemical characterizations of flexible molecules. Compounds 1–9 were evaluated for their cytotoxic and antibacterial activities. Among them, 6 showed cytotoxicity against the A-549 cell line with the IC50 value of 1.1 μM, and 7 exhibited antibacterial activity against Micrococcus lysodeikticus with the MIC value of 0.78 μg/mL.
Full Article
Instrument
J-715
Keywords
Circular dichroism, Induced circular dichroism, Absolute configurations, Cotton effect, Natural products