(-)- and (+)-Asperginulin A, a Pair of Indole Diketopiperazine Alkaloid Dimers with a 6/5/4/5/6 Pentacyclic Skeleton from the Mangrove Endophytic Fungus Aspergillus sp. SK-28

Org Lett. 2019 Dec 6;21(23):9633-9636. doi: 10.1021/acs.orglett.9b03796. Epub 2019 Nov 25.

Abstract

A pair of enantiomeric indole diketopiperazine alkaloid dimers [(-)- and (+)-asperginulin A (1a and 1b)] with an unprecedented 6/5/4/5/6 pentacyclic skeleton were isolated from the mangrove endophytic fungus Aspergillus sp. SK-28. The enantiomeric dimers were separated by chiral-phase HPLC. Their structures including absolute configurations were elucidated by spectroscopic analysis, X-ray diffraction, and quantum chemical calculation. (+)-Asperginulin A (1b) exhibited antifouling activity against the barnacle Balanus reticulatus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkaloids* / chemistry
  • Alkaloids* / isolation & purification
  • Alkaloids* / pharmacology
  • Animals
  • Aspergillus / chemistry*
  • Biofouling
  • Diketopiperazines* / chemistry
  • Diketopiperazines* / isolation & purification
  • Diketopiperazines* / pharmacology
  • Dimerization
  • Endophytes / chemistry*
  • Indoles* / chemistry
  • Indoles* / isolation & purification
  • Indoles* / pharmacology
  • Molecular Structure
  • Rhizophoraceae / microbiology*
  • Stereoisomerism
  • Thoracica / drug effects

Substances

  • Alkaloids
  • Diketopiperazines
  • Indoles