Planta Med 2010; 76 - P429
DOI: 10.1055/s-0030-1264727

New bioactive altersolanol derivatives from the endophytic fungus Stemphylium globuliferum isolated from Mentha pulegium

M El Amrani 1, A Pretsch 2, R Edrada-Ebel 3, V Wray 4, W Müller 5, P Proksch 1, A Debbab 1
  • 1Institute for Pharmaceutical Biology and Biotechnology, Heinrich-Heine University, Universitätsstr. 1, Gebäude 26.23., 40225 Düsseldorf, Germany
  • 2SeaLife Pharma GmbH, Technopark 1, 3430 Tulln, Austria
  • 3Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, The John Arbuthnott Building, 27 Taylor Street, G4 0NR Glasgow, United Kingdom
  • 4Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
  • 5Institute for Physiological Chemistry and Pathobiochemistry, Johannes Gutenberg University, Duesbergweg 6, 55128 Mainz, Germany

Extracts of the fungus Stemphylium globuliferum, an endophyte of the Moroccan medicinal plant Mentha pulegium, exhibited considerable cytotoxic and antimicrobial activities when tested in vitro. Chemical investigation of the extracts yielded four new secondary metabolites, including altersolanol K (1), altersolanol L (2), altersolanol M (3), and altersolanol N (4), together with the known compounds 6-O-methylalaternin (5), macrosporin (6), altersolanol A (7), tetrahydroaltersolanol B (8), altersolanol C (9), altersolanol J (10), stemphypyrone (11) and indole-3-carboxaldehyde (12). The structures of all compounds were determined on the basis of one- and two-dimensional NMR spectroscopy and mass spectrometry. Among the altersolanol derivatives tested, compound (3) was the most active congener against L5178Y cell line with an EC50 value of 1.14 µM. Moreover, all anthraquinones exhibited antibiotic activity against several pathogenic microbes. Interestingly, the new altersolanol N together with altersolanol C showed considerable antiviral activity against HRV39, whereas tetrahydroaltersolanol B was very active against HRV2, HRV8 and HRV16.