Original Article

Heptemerones A~G, Seven Novel Diterpenoids from Coprinus heptemerus: Producing Organism, Fermentation, Isolation and Biological Activities

Melanie Kettering, Carola Valdivia, Olov Sterner, Heidrun Anke, Eckhard Thines

Received: March 18, 2005 / Accepted: June 6, 2005
© Japan Antibiotics Research Association

Abstract Seven novel diterpenoids, named heptemerones A~G, were isolated from the broth of submerged cultures of Coprinus heptemerus, a basidiomycete which previously had not been known to produce secondary metabolites. The compounds were purified by solid phase extraction and silica gel chromatography followed by preparative HPLC. Among the biological activities the inhibition of fungal germination was the most potent, and depended highly on the composition of the assay medium. In water, inhibition occurred at 5~10 fold lower concentrations as compared to complex media. Heptemerone G was the most active compound with MICs starting at 1 μg/ml. Four of the antifungal compounds exhibited plant protective activity in a leaf segment assay using Magnaporthe grisea as the pathogen. Growth of yeasts and bacteria was hardly affected. Cytotoxic activities were moderate and only heptemerone D was phytotoxic.

Keywords Coprinus heptemerus, heptemerones, diterpenes, inhibition of conidial germination, Magnaporthe grisea

H. Anke (Corresponding author), M. Kettering: Institute for Biotechnology and Drug Research (IBWF), Erwin-Schrödinger-Strasse 56, D-67663 Kaiserslautern, Germany, E-mail: anke@ibwf.de
E. Thines (Corresponding author): University of Kaiserslautern, Department of Biotechnology, D-67663 Kaiserslautern, Germany, E-mail: thines@ibwf.de
O. Sterner, C. Valdivia: Division of Organic and Bioorganic Chemistry, University of Lund P.O.Box 124, S-22100 Lund, Sweden.