Antitrypanosomal metabolites from an endophytic Penicillium sp. isolated from Limonium tubiflorum
Trypanosomiasis (also known as sleeping sickness), an important parasitic disease caused by Trypanosoma brucei, is considered as a neglected disease that reemerged over the last few decades. This fact necessitates the search and development of new drugs to target this disease. In our continuous search for new and biologically active natural products for medicinal applications or as leads for the development of new therapies, fungal endophytes have proven to be a promising vast resource of unique metabolites with great pharmacological potential. In this study we investigated an endophytic Penicillium sp. which was isolated from stem tissues of Limonium tubiflorum (Rutaceae) growing in Egypt. Chemical investigation of the fungal extract yielded four new metabolites, including a new bianthrone (1), two new curvularin derivatives (2 and 3), as well as a new sulfinylchromone (4), in addition to 13 known metabolites (5-17). All structures were assigned by comprehensive spectral analysis (1D and 2D NMR) and mass spectrometry. Some of the isolated constituents proved active against T. brucei with MIC values ranging from 4.9 to 9.7 µM.