Isolation and Structure Identification of Novel Brominated Diketopiperazines from Nocardia ignorata—A Lichen-Associated Actinobacterium
Alba Noël,
Solenn Ferron,
Isabelle Rouaud,
Nicolas Gouault,
Jean-Pierre Hurvois,
Sophie Tomasi
Affiliations
Alba Noël
CORINT, UMR CNRS ISCR 6226, UFR Sciences Pharmaceutiques et Biologiques, Université Bretagne Loire, 2 Av. du Professeur Léon Bernard, 35043 Rennes, France
Solenn Ferron
CORINT, UMR CNRS ISCR 6226, UFR Sciences Pharmaceutiques et Biologiques, Université Bretagne Loire, 2 Av. du Professeur Léon Bernard, 35043 Rennes, France
Isabelle Rouaud
CORINT, UMR CNRS ISCR 6226, UFR Sciences Pharmaceutiques et Biologiques, Université Bretagne Loire, 2 Av. du Professeur Léon Bernard, 35043 Rennes, France
Nicolas Gouault
CORINT, UMR CNRS ISCR 6226, UFR Sciences Pharmaceutiques et Biologiques, Université Bretagne Loire, 2 Av. du Professeur Léon Bernard, 35043 Rennes, France
Jean-Pierre Hurvois
CORINT, UMR CNRS ISCR 6226, UFR Sciences Pharmaceutiques et Biologiques, Université Bretagne Loire, 2 Av. du Professeur Léon Bernard, 35043 Rennes, France
Sophie Tomasi
CORINT, UMR CNRS ISCR 6226, UFR Sciences Pharmaceutiques et Biologiques, Université Bretagne Loire, 2 Av. du Professeur Léon Bernard, 35043 Rennes, France
Actinobacteria are well known for their potential in biotechnology and their production of metabolites of interest. Lichens are a promising source of new bacterial strains, especially Actinobacteria, which afford a broad chemical diversity. In this context, the culture medium of the actinobacterium Nocardia ignorata, isolated from the terrestrial lichen Collema auriforme, was studied. The strain was cultivated in a BioFlo 115 bioreactor, and the culture medium was extracted using an XAD7HP resin. Five known diketopiperazines: cyclo (l-Pro-l-OMet) (1), cyclo (l-Pro-l-Tyr) (2), cyclo (d-Pro-l-Tyr) (3), cyclo (l-Pro-l-Val) (4), cyclo (l-Pro-l-Leu) (5), and one auxin derivative: indole-carboxaldehyde (8) were isolated, along with two new brominated diketopiperazines: cyclo (d-Pro-l-Br-Tyr) (6) and cyclo (l-Pro-l-Br-Tyr) (7). Structure elucidation was performed using HRMS and 1D and 2D NMR analysis, and the synthesis of compounds 6 and 7 was carried out in order to confirm their structure.