Phomanolides A and B from the Fungus Phoma sp.: Meroterpenoids Derived from a Putative Tropolonic Sesquiterpene via Hetero-Diels-Alder Reactions

  • J Nat Prod. 2015 Dec 24;78(12):3058-66. doi: 10.1021/acs.jnatprod.5b00969.
Jinyu Zhang  1  2 ,  Ling Liu  1 ,  Bo Wang  3 ,  Yang Zhang  3 ,  Lili Wang  3 ,  Xingzhong Liu  1 ,  Yongsheng Che  3
Affiliations
  • 1. State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences , Beijing 100101, People's Republic of China.
  • 2. University of Chinese Academy of Sciences , Beijing 100049, People's Republic of China.
  • 3. State Key Laboratory of Toxicology & Medical Countermeasures, Beijing Institute of Pharmacology & Toxicology , Beijing 100850, People's Republic of China.
PMID: 26651221 DOI: 10.1021/acs.jnatprod.5b00969
Abstract

Phomanolides A (1) and B (2), unique meroterpenoids with new pentacyclic and tetracyclic skeletons, respectively, and phomanoxide (3), the double-epoxidation product of a putative biosynthetic precursor of 1 and 2, were isolated from the solid substrate fermentation cultures of the fungus Phoma sp., along with the known compound eupenifeldin (4). The structures of 1-3 were elucidated based on NMR spectroscopic data and electronic circular dichroism calculations and further secured by X-ray crystallography. Biogenetically, compounds 1 and 2 could be derived from a hypothetical monotropolonic sesquiterpene intermediate via hetero-Diels-Alder reactions. Compound 4 showed potent antiproliferative effects against three human glioma cell lines, with IC50 values of 0.08-0.13 μM.