Tricinonoic acid and tricindiol, two new irregular sesquiterpenes from an endophytic strain of Fusarium tricinctum

Abstract

Two new rare irregular sesquiterpenes, tricinonoic acid (1) and tricindiol (2), and the known furanopyrrolidones, NG-391 (3) and NG-393 (4), have been isolated from an EtOAc extract of Fusarium tricinctum, a fungus endophytic in the root tissue of the Sonoran desert plant, Rumex hymenosepalus. The structures of 1 and 2 were elucidated on the basis of their high-resolution mass, 1D and 2D NMR spectroscopic data. A possible biosynthetic route to 1 and 2 from farnesyl diphosphate is proposed.

Keywords:

• Fusarium tricinctum
• endophytic fungus
• Rumex hymenosepalus
• irregular sesquiterpenes
• tricinonoic acid
• tricindiol

Acknowledgements

This work is supported by a grant from US National Institutes of Health/National Cancer Institute (Grant No. R01 CA90265) and this support is gratefully acknowledged. We thank Dr Stanley H. Faeth (Arizona State University) for providing the fungal strain and C.J. Seliga, S. Wittlinger, C. Hamilton, L. Morse, C. Hayes and A. Das for their expert technical assistance.