Chlorophyll breakdown in tobacco: on the structure of two nonfluorescent chlorophyll catabolites

Chem Biodivers. 2004 Apr;1(4):657-68. doi: 10.1002/cbdv.200490057.

Abstract

In extracts of senescent leaves of the tobacco plant Nicotiana rustica, two colorless compounds with UV/VIS characteristics of nonfluorescent chlorophyll catabolites (NCCs) were detected and tentatively identified as Nr-NCCs. These two polar NCCs were found in similar amounts in the fresh extracts, and their constitutions could be determined by spectroscopic analysis. The data showed both of the two Nr-NCCs to have the same tetrapyrrolic core structure, as reported previously for all other NCCs from senescent higher plants. In the less polar catabolite, named Nr-NCC-2, this core structure was conjugated with a glucopyranose unit, as similarly discovered earlier in Bn-NCC-2, an NCC from oilseed rape (Brassica napus). The more polar NCC from tobacco leaves, Nr-NCC-1, carried an additional malonyl substituent at the 6'-OH group of the glucopyranosyl moiety. Partial (enzyme-catalyzed) hydrolysis of Nr-NCC-1 gave Nr-NCC-2, while enzyme-catalyzed malonylation of Nr-NCC-2 gave Nr-NCC-1, establishing the identity of their basic tetrapyrrole structure. In earlier work (on the polar NCCs from oilseed rape), only separate glucopyranosyl and malonyl functionalities were detected. Nr-NCC-1, thus, represents a further variant of the structures of NCCs from senescent higher plants and exhibits an unprecedented peripheral refunctionalization in chlorophyll catabolites.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chlorophyll / chemistry
  • Chlorophyll / isolation & purification*
  • Cyclic AMP Receptor Protein / chemistry
  • Cyclic AMP Receptor Protein / isolation & purification*
  • Nicotiana*
  • Nuclear Magnetic Resonance, Biomolecular / methods
  • Plant Extracts / chemistry
  • Plant Extracts / isolation & purification
  • Plant Leaves

Substances

  • Cyclic AMP Receptor Protein
  • Plant Extracts
  • Chlorophyll