Xylaropyrones B and C, new γ-pyrones from the endophytic fungus Xylaria sp. SC1440

Abstract

Two new γ-pyrones, xylaropyrones B (1) and C (2), together with three known compounds, xylaropyrone (3), annularin A (4) and annularin C (5), were isolated from solid cultures of the endophytic fungus Xylaria sp. SC1440. The structures of these compounds were determined mainly by analysis of their NMR spectroscopic data. The relative configurations of 1 and 2 were assigned on the basis of J-based configurational analysis, and the absolute configurations were established by experimental and TDDFT calculated ECD spectra. The isolated compounds were evaluated for cytotoxic and tyrosinase inhibitory activity.

Keywords:

• γ-pyrones
• endophytic fungus
• Xylaria sp.
• secondary metabolites

Acknowledgements

We thank Ai-Jun Sun and Yun Zhang, South China Sea Institute of Oceanology, Chinese Academy of Sciences, for the measurement of HRESIMS. We gratefully acknowledge support from the Guangzhou Branch of the Supercomputing Center of Chinese Academy of Sciences.