Abstract
One new xanthone, chryxanthone C (1), together with four known analogues (2−5), were isolated from the cultures of Paecilamyces sp. TE-540, an endophytic fungus obtained from the leaves of Nicotiana tabacum L. The structure of 1 was elucidated by comprehensive spectral analysis including HRESIMS and 1D/2D NMR, which were confirmed by Cu Kα X-ray crystallography. Compound 1 featured an unusual dihydropyran ring fused to an aromatic ring, rather than the commonly occurring prenyl moiety. The cytotoxicity of compounds 1−5 were evaluated against five human tumour cell lines and 4 exhibited moderate to strong cytotoxicities with IC50 values ranging from 5.6 to 14.2 µM.
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Supplementary material
Supplementary material relating to this article is available online, including HRESIMS, 1D and 2D NMR spectra, and single-crystal X-ray structure of compound 1.
Disclosure statement
The authors declare no conflict of interest.