Bioactive metabolites from the endophytic fungus Ampelomyces sp. isolated from the medicinal plant Urospermum picroides Amal H. Aly a,1 , RuAngelie Edrada-Ebel b , Victor Wray c , Werner E.G. Mu ¨ ller d , Svitlana Kozytska e , Ute Hentschel e , Peter Proksch a, * , Rainer Ebel f, * a Institut fu ¨ r Pharmazeutische Biologie und Biotechnologie, Heinrich-Heine-Universita ¨ t, Universita ¨ tsstrasse 1, Geb. 26.23, D-40225 Du ¨ sseldorf, Germany b Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, The John Arbuthnott Building, 27 Taylor Street, Glasgow G4 0NR, Scotland, UK c Helmholtz Centre for Infection Research, Inhoffenstrasse 7, D-38124 Braunschweig, Germany d Institut fu ¨ r Physiologische Chemie und Pathobiochemie, Johannes-Gutenberg-Universita ¨ t, Duesbergweg 6, D-55128 Mainz, Germany e Zentrum fu ¨ r Infektionsforschung, Julius-Maximilians-Universita ¨t, Ro ¨ ntgenring 11, D-97070 Wu ¨ rzburg, Germany f Department of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland, UK Received 1 November 2007; received in revised form 15 February 2008 Available online 8 April 2008 Abstract Extracts of cultures grown in liquid or on solid rice media of the fungal endophyte Ampelomyces sp. isolated from the medicinal plant Urospermum picroides exhibited considerable cytotoxic activity when tested in vitro against L5178Y cells. Chromatographic separation yielded 14 natural products that were unequivocally identified based on their 1 H and 13 C NMR as well as mass spectra and comparison with previously published data. Six compounds (2, 4, 5, 7, 9 and 11) were natural products. Both fungal extracts differed considerably in their secondary metabolites. The extract obtained from liquid cultures afforded a pyrone (2) and sulfated anthraquinones (7 and 9) along with the known compounds 1, 3, 6 and 8. When grown on solid rice medium the fungus yielded three compounds 4, 5 and 11 in addition to several known metabolites including 6, 8, 10, 12, 13 and 14. Compounds 4, 8 and 10 showed the strongest cytotoxic activity against L5178Y cells with EC 50 values ranging from 0.2–7.3 lg/ml. Furthermore, 8 and 10 displayed antimicrobial activity against the Gram- positive pathogens, Staphylococcus aureus, S. epidermidis and Enterococcus faecalis at minimal inhibitory concentrations (MIC) of 12.5 lg/ml and 12.5–25 lg/ml, respectively. Interestingly, 6 and 8 were also identified as constituents of an extract derived from a healthy plant sample of the host plant U. picroides thereby indicating that the production of bioactive natural products by the endophyte pro- ceeds also under in situ conditions within the host plant. Ó 2008 Elsevier Ltd. All rights reserved. Keywords: Ampelomyces; Endophytic fungi; Anthraquinones; Pyrones; Chromones; Cytotoxic activity; Antibacterial activity 1. Introduction Fungal endophytes are microorganisms that colonize living, internal tissues of plants without causing any imme- diate, overt negative effects (Bacon and White, 2000). They have proven to be promising sources of new and biologi- cally active natural products which are of interest for spe- cific medicinal or agrochemical applications (Strobel, 2002). In this study we investigated the fungal endophyte Ampelomyces sp. isolated from flowers of Urospermum picroides growing in the wild in Egypt. U. picroides is a typ- ical constituent of the traditional Mediterranean diet and its extract shows anti-inflammatory activities (Ebel, 2006; Strzelecka et al., 2005). 0031-9422/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.phytochem.2008.02.013 * Corresponding authors. Tel.: +49 211 8114163; fax: +49 211 8111923 (P. Proksch), tel.: +44 1224 272930; fax: +44 1224 272921 (R. Ebel). E-mail addresses: proksch@uni-duesseldorf.de (P. Proksch), r.ebel@ abdn.ac.uk (R. Ebel). 1 Permanent address: Department of Pharmacognosy, Faculty of Pharmacy, Khartoum Sq. Azarita, Alexandria, Egypt. www.elsevier.com/locate/phytochem Available online at www.sciencedirect.com Phytochemistry 69 (2008) 1716–1725 PHYTOCHEMISTRY