An epigenetic modifier induces production of 3-(4-oxopyrano)-chromen-2-ones in Aspergillus sp. AST0006, an endophytic fungus of Astragalus lentiginosus

Marcelo R de Amorim; E M Kithsiri Wijeratne; Shengliang Zhou; A Elizabeth Arnold; Andrea N L Batista; João M Batista Jr; Lourdes C Dos Santos; A A Leslie Gunatilaka

doi:10.1016/j.tet.2020.131525

An epigenetic modifier induces production of 3-(4-oxopyrano)-chromen-2-ones in Aspergillus sp. AST0006, an endophytic fungus of Astragalus lentiginosus

Tetrahedron. 2020 Oct 23;76(43):131525. doi: 10.1016/j.tet.2020.131525. Epub 2020 Aug 22.

Authors

Marcelo R de Amorim^{1

2}, E M Kithsiri Wijeratne¹, Shengliang Zhou^{1

3}, A Elizabeth Arnold⁴, Andrea N L Batista⁵, João M Batista Jr⁶, Lourdes C Dos Santos², A A Leslie Gunatilaka¹

Affiliations

¹ Southwest Center for Natural Products Research, School of Natural Resources and the Environment, College of Agriculture and Life Sciences, University of Arizona, 250 E. Valencia Road, Tucson, Arizona 85706, United States.
² Institute of Chemistry, São Paulo State University, Araraquara, São Paulo 14800-900, Brazil.
³ The Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province, Jiangsu Normal University, 101 Shanghai Rd, Xuzhou 221116, P. R. China.
⁴ School of Plant Sciences, College of Agriculture and Life Sciences, University of Arizona, Tucson, Arizona 85721, United States.
⁵ Department of Organic Chemistry, Chemistry Institute, Fluminense Federal University, Niterói, RJ 24020-141, Brazil.
⁶ Institute of Science and Technology, Federal University of São Paulo, São José dos Campos, São Paulo 12231-280, Brazil.

Abstract

Incorporation of the epigenetic modifier suberoylanilide hydroxamic acid (SAHA) into a potato dextrose broth culture of the endophytic fungus Aspergillus sp. AST0006 affected its polyketide biosynthetic pathway providing two new 3-(4-oxopyrano)-chromen-2-ones, aspyranochromenones A (1) and B (2), and the isocoumarin, (-)-6,7-dihydroxymellein (3). Eight additional metabolites (4-11) and two biotransformation products of SAHA (12-13) were also encountered. The planar structures and relative configurations of the new metabolites 1-2 were elucidated with the help of high-resolution mass, 1D and 2D NMR spectroscopic data and the absolute configurations of 1-3 were determined by comparison of experimental and calculated ECD data. Possible biosynthetic pathways to 1 and 2 are presented.

Keywords: Aspergillus sp. AST0006; Aspyranochromenones A and B; Endophytic fungus; Epigenetic modifier; Natural products.

Abstract

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