Mollecarbamates, Molleureas, and Molledihydroisoquinolone, o-Carboxyphenethylamide Metabolites of the Ascidian Didemnum molle Collected in Madagascar

J Nat Prod. 2017 Jun 23;80(6):1844-1852. doi: 10.1021/acs.jnatprod.7b00123. Epub 2017 Jun 2.

Abstract

The extract of a sample of the tunicate Didemnum molle (MAY13-117) collected in Mayotte afforded eight new metabolites, mollecarbamates A-D (1-4) and molleureas B-E (5-8), along with the two known natural products, N,N'-diphenylethyl urea (10) and molleurea A (11). Another sample of D. molle (MAD11-BA065) collected in Baie des Assassins, Madagascar, afforded molledihydroisoquinolone (9). Mollecarbamates 1-4 are a family of compounds that possess repeating o-carboxyphenethylamide units and a carbamate moiety, while the molleureas 5-8 contain tetra- and penta-repeating carboxyphenethylamide units and a urea bridge in different positions. Molledihydroisoquinolone (9) is a cyclic form of o-carboxyphenethylamide. We propose that these unique natural products are most probably produced by an unprecedented biosynthetic pathway that contains a yet unknown chorismate mutase variant. The structures of the compounds were elucidated by interpretation of the data from 1D and 2D NMR, HRESIMS, and MS/MS analyses of the positive ESIMS experiments. Compounds 1-8 were tested against pathogenic bacteria and in a cytoprotective HIV cell based assay but did not show any significant effects in these assays.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carbamates / chemistry
  • Carbamates / isolation & purification*
  • Carbamates / pharmacology
  • HIV / drug effects
  • Humans
  • Isoquinolines / chemistry
  • Isoquinolines / isolation & purification*
  • Isoquinolines / pharmacology
  • Madagascar
  • Microbial Sensitivity Tests
  • Molecular Structure
  • Nuclear Magnetic Resonance, Biomolecular
  • Urea / analogs & derivatives*
  • Urea / chemistry
  • Urea / isolation & purification*
  • Urea / pharmacology
  • Urochordata / chemistry*

Substances

  • Carbamates
  • Isoquinolines
  • Urea